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Vorshlag 2011 Mustang GT + S197 Development Thread

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  • #46
    Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

    continued from above

    March 17 - TX2K11 (Mustang)

    Amy and I left north Dallas at around 8 pm Wednesday night and made it to downtown Houston before midnight. Some serious traffic there on I-45 considering the hour, and we had no less than 6 vehicles pass us at 100+ mph near downtown, with two different trucks at different times drifting across 3 lanes and nearly taking the front of my truck off. Somehow we survived that parade of death race entrants and got to the middle of nowhere, 30 miles south of Houston, at 12:30. We arrived at nearby Grandsport Speedway Thursday morning at 7:30 AM and prepared to run the TX2K11 Time Attack event. This event was part of a 4 day festival of speed that started 10+ years ago mostly as a big Supra meet, and has grown to include a number of other imports, Vipers, Corvettes, Lotus Elises and other cars. People come from all over the country, even other countries, to enter TX2K events. Thursday was their track event (HPDE + Time Attack), Friday was the dyno day, and Sat-Sunday were the drag race portions of the event. We only entered the Time Attack, as we had the SCCA National Tour event to enter on Sat-Sunday, and a test-n-tune to run on Friday.



    This TX2K event was on our calendar months in advance and I had planned to run the E30 and Amy the Mustang, with Costas running his GT-1 Camaro as well. Since the E30 was down, I switched entries to the Mustang and Amy and I both ran it in alternating sessions, and all 3 of us instructed as well. It was a very busy day! The track was 1.3 miles of twists and turns on super smooth asphalt, with gentle curbing and good places to pass on the front and back straights.

    The new DTC-60 brake pads up front REALLY helped - I could brake later/deeper than almost anything in my session (only one GT-R and the GT2 Porsche could stop with the Mustang). I fared well early on, and I took the 3rd fastest times in the morning A1 session, but ending up with only a slightly quicker 1:06.3 best lap time after my three 30 minute on-track sessions, which was 9th fastest at the end of the day (using a rented Westhold transponder). Amy also ran 3 sessions in the same car and knocked down a 1:07.3 lap time, 10th fastest overall (we had the same transponder so she isn't listed separately, but we tracked her laps after her session). Not too bad considering the 100% stock power and somewhat narrow street tires - against a gaggle of 500-900hp GT-Rs and Supras, Vipers, Corvettes, an Aerial Atom, and a 911 GT2. Costas drove in only 2 sessions and nabbed FTD and the win with a 58.9 second lap. The GT-1 car was brutally fast and was a handful to drive on the smallish road course - he only used 2nd and 3rd gears, and only part throttle.



    With a serious array of high-powered and exotic hardware on hand for this event, the 40 or so entrant's skill levels were all over the place. There were some very good drivers there, even some SCCA + NASA racers, but plenty of lots of noobs that needed in-car guidance, and even some of the proverbial "That's how I drive - flat out!" folks. My student was totally new - a complete first timer on track - but went from spinning twice on his first lap to confident and quicker by day's end, as did Amy's two students and Costas' as well. They needed more instructors than they had on hand, really. Being new is fine, but being a squirrel driving over your head is frustrating and dangerous. I saw some on-track issues that would have had many drivers booted from most HPDE events. Anyway, nobody was killed, so I guess that's good. I'll get off my soap box and just keep this all in mind in mind before entering again.



    We eventually ended the day a session early due to "some exuberant driving by one individual" (it had to do with one of those "driving Flat Out" people), so they called the event to an end early at 3:30 PM and had a trophy presentation for Costas at our trailers - with 2 photographers, a videographer, and an on-camera interview. That was pretty cool. We then broke down Costas' massive covered paddock structure, loaded up both cars & trailers, and headed out by 5:30 pm... only to sit in Houston traffic for 3+ hours, just trying to make it 60 miles north to my friend's shop to retrieve the Toyos. After stopping for a quick bite hoping traffic would subside, we got there at 9:30 pm, but only 2 tires were delivered. Frantic calls to Matt here at Vorshlag and some investigations on his end showed that 4 tires had indeed delivered, but the genius FedEx driver dropped off 2 at some random address clear across Houston, and they were now closed. This is one more reason why Vorshlag NEVER SHIPS FEDEX.

    So we ate a second dinner with our friend then blasted back across Houston with the trailer all the way to Baytown, arriving there around midnight, exhausted from a long day racing, standing in the sun, and Houston traffic.

    March 18 - SCCA Test-N-Tune (Mustang)

    Friday was the registration / set-up / test day for the National Tour weekend, which included a test session where you could buy laps for about $4 each. We had planned on doing DL-1 data logged runs on the Yokohama AD08s then running out and swapping the wheels to the Toyos, but the second 2 tires were still MIA by mid-day, as was our co-driver and his data logger. So we just made 5 runs each runs on the Yokohamas, testing tire pressures and shock settings, and getting a feel for the new brakes. It felt OK, and the brakes seemed to be a LOT better at this lower speed event. The practice lap times were close to the STX cars I could see, but who knows if they were making good runs on the times I saw? We had set up our vendor table, unpacked the car, and finished our laps by 3:30 pm, when we finally had word that FedEx had picked up and redelivered our missing two Toyo tires, so we dropped everything and raced 70 miles across town again to our friend's shop. We got there by 4:30, then drove to a Discount tire and paid an enormous amount of money to have 4 tires mounted and balanced (grumble... crooks!... grumble). Trying to stay ahead of Friday 5 pm traffic we somehow managed to get back all the way to Baytown by 6:30, and grabbed 5 gallons of 93 octane on the way. The car was on jack stands so we mounted the wheels with the fresh Toyos on them, put in the gasoline, and had the car ready to race by 6:45 pm. The past several hours of frantic driving at 85 mph in Houston traffic behind us.

    The welcome party that Vorshlag had sponsored was going until 7 pm, and people were walking the course for tomorrow's event... we showed up in time but they had run out of food literally 5 minutes before we found the caterer. While we were looking all over the paddock for the food, the Saturday autocross course was also quickly taken down. Wait, what??? Well we found out that it was because there was a drag race event that night here at the HRP facility, like every Friday night, and they needed the parking lot for the racers starting to show up. Oh well, at least the concession stands were open and had hot burgers for sale. For cash only - and I had a whopping $2 on me. Amy had pocket change. WTF?! I had like $200 the day before, but somehow burned it all on transponder rentals and track food at Grandsport, and bags of ice and snacks along the way. Our luck was failing miserably today.

    So we walked to the SCCA trailer and checked in for the National Tour event, drove the Mustang into town to scrub the new R1R tires in, and got some cash - and dinner. Went back out to HRP, found some friends and saw that several autocrossers were entering the Friday night drag racing...

    Friday evening - Houston Raceway Park drag racing (Mustang)

    For only another $20 cash we could run down the fastest dragstrip in the USA from now until midnight. Hell yes! I've run down this dragstrip hundreds of times in the past, and always seem to get my best times here (good surface + sea level track = fast). We still needed to scrub in these new 265/35/18 Toyo R1R tires anyway - with burnouts and launches! So I made two quick passes right off the highway drive in from town and cracked off two 12.96 second runs at 109+ mph, and on that 2nd pass I accidentally stayed on the rev limiter in 3rd gear for at least 2-3 tenths of a second. Oh damn, if I could clean up my shifts that would mean that a mid 12 second ET was in store?? I was also checking the on-board data logger I had just picked up - a new G-Tech Pro RR - against the track's clocks. It was spot-on at 60', 1/4 mile ETs and trap speeds. It has g meters and a GPS sensor, graphic LCD display, SD memory, windshield mount, with a built in lap timer, segment timer, and predictive lap timer. Neat little $300 gizmo I'll talk about more in future posts.



    Amy wanted to make some passes so she got in and made some 13.5 second runs while me and a dozen of the SCCA entrants for the weekend taunted our fellow autocrossers trying to make 1/4 mile passes. Amy handed the keys back to me and I made 2 more runs, and I left the hood up between them as the staging lane started to get backed up - the locals don't really show up until after 9-10 pm. I cracked off a 13.1 second run and on my last run I was paired up with a 4th gen LS1 Firebird with some work done. I had pushed it to the line hood up for 15 minutes, letting the engine cool all the while. This helped and I got to the line with a nice cool motor. We lined up and the Firebird tree'd me, and in my haste to catch up I spun a little in 1st gear (2.1 sixty), but managed to nail my shifts and ran him down and passed him, and the clocks showed a 110.2 mph trap speed - the best ever in the car. Pretty good for 100% bone stock drivetrain! Gotta take the little victories where I can.

    March 19-20 - SCCA Houston National Tour (Mustang)

    Saturday and Sunday was the National Tour event, and Amy ran in STXL while Costas and I ran in STX. We started the day with overcast skies and cooler temps, which the Toyos supposedly favor. STX had 7 entrants and I started "off the pace", and in my 3 runs never really strung a good one together. Times were erratic and I ev3en DNF'd; I was driving very poorly. The event was all erratically paced slaloms (and "wall-oms") with one big turn around at the end of the lot, none of which were the strong suit for this car. The brakes at least worked better, but we struggled in the slaloms and the car pushed heavily in the turn-around, costing us time. Acceleration was just an exercise in wheelspin. Strangely we all got a 4th run, which was timed but not scored (a "fun run"), and it was then that I pulled my head out and put a good run together (proper slalom timing), running a solid 1.2 seconds faster and finally closer to the faster cars in STX class. Costas had similar trouble on his first 3, and also a fast 4th. Amy ran later in the day, after the sun was out, and ran times a tick quicker than both of to us, and also much faster in her 4th (unscored) run. The tires felt grippier than the AD08s, but with no data collected on the AD08s Friday we couldn't tell by how much.



    Sunday was more of the same (almost identical course, with 2 small changes), but at least we drove better. All 3 of my runs were within a tenth of a second and they all felt a lot smoother - I didn't get so behind on the many slaloms. Costas had prior event he had to help run and couldn't race on Day 2. Amy was about 1 second off my times this day. She was running lower tire pressures than I recommended and it didn't help at all - I was working on course and couldn't help her when she ran, either.



    We learned several things at this event: Don't ship FedEx. Houston traffic sucks no matter the time of day. The Mustang isn't putting power down well. Or turning all that well. Slaloms are a mess. I put the seat to far back for my co-drivers. This car needs much more development. Oh well, this event offered up 28 more autocross runs between us - more testing never hurts with a new car, even if its losing badly at an SCCA National Tour.


    So we bombed 300 miles back to Dallas and somehow logged 1000 miles for the weekend - meaning we drove just inside the Houston city limits for a solid 400 miles. Did I mention I hate Houston traffic? Monday we unloaded and prepared for yet another short week and a 3 day weekend of racing, this time at the SCCA ProSolo in Mineral Wells, TX. Before this event we slapped on the rear DTC-60 brake pads that arrived and bled the system with Motul 600 fluid. We had been testing an all new, non-inverted single adjustable rear shocks were found over at AST-USA that we wanted to run, and they had been working great the past week. With some custom machined bushings out back they fit the S197 very well - adding more bump travel. AST now wanted us to try some new super-digressive pistons in the rear shocks that sounded like what we needed to control the excessive brake dive/rear axle rise. We also re-mounted the seat forward 2 inches and it fit Amy and Costas much better - no pillows needed! Since Mineral Wells just chews up race tires and street tires like a meat grinder, I had the still new Toyo R1Rs removed from the 18x9" wheels and mounted the Yokohama AD08s again. Cleaned up everything, reorganized the trailer completely, and loaded up for a Friday morning tow out to the event site 2 hours across Dallas and Ft. Worth (somehow this is still a local event for us).



    continued below
    Last edited by Fair!; 07-31-2015, 12:55 PM.
    Terry Fair - www.vorshlag.com
    2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
    EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

    Comment


    • #47
      Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

      continued from above

      March 25-27 - Mineral Wells SCCA ProSolo (Mustang)

      Amy and I got to MW around 10:30 Friday morning after picking up McCall, who was coming out to the site to help out the local SCCA region set-up for this National ProSolo event. We were soon joined by Costas and the 4 of us pitched in to work the gate, set-up the region trailer stuff, the Vorshlag vendor table, and try to lend a hand wherever needed. Amy and I had entered in the EVO school, which was just some classroom coaching on the event format (its been years since we ran a ProSolo), and then several test starts on the .500 drag race tree.



      A ProSolo is a unique event combining a pair of mirror imaged autocross courses and a drag race start, with your best times from each side added together for a total time in class, and we had 6 runs on each side over 2 days to get it right. Reaction times count and you can red light or cut a slow reaction time, which can hurt your run times or DSQ the run (red light). Drag race starts with a nice straight at the beginning of each run. Lots of power... runs 12s stock. Should be a good fit for the Mustang, right?


      Well, when the straights are a good 1000+ feet long, sure, it helps... But on this course set-up this time the starting straights barely took up 1st gear in the Mustang before the first turn, and we lost out badly to the AWD cars (2.2 sec 60 foot times in the Mustang vs 1.8 sec in the AWD VW in our class) and barely matched the RX8s and BMWs in class. So any hope for advantage was just not there.

      We quickly noted a new problem with the brakes on Saturday - ABS Ice Mode. When the brakes were pressed quickly the ABS system freaked out and you lost 50% or more of the braking power, and we all blew many turns on course because of this. We don't know what it was, but the only change since the previous weekend when the brakes worked SO well was a swap to DTC-60 race pads out back and the change back to AD08s, but we had run these tires before. The surface was different as well, but I have run at Mineral Wells dozens of times over the past decade, never seeing anything like this. WTF??



      We ended up switching from "drive into the corner on the brakes to load up the front tires, just so it will turn" method of driving this plowing pig, to more of a "momentum/Miata" driving style, trying to reduce the time under braking and maximize lateral grip and slalom speed. Driving into a corner on the brakes is a work-around for a pushy car, and Costas and I have used this on many Pony cars in the past, but it just wasn't possible when the brakes were not there. The momentum method sort of worked, and kept the car out of ABS and Ice Mode, but sure was frustrating as all hell. We were dead slow in the big sweeping corners and we knew it.

      After our 4 dismal runs per side Saturday were over, I put the car on jack stands and yanked off the rear wheels and brakes. The pads looked... weird. Discoloration and weird build-up of material in the grove in the pad, especially strange for a brand new set of pads. The rear pad swap was the one main variable that changed, so I wanted to change back to a more normal street pad out back, hoping it would get the ABS computer out of the Ice Mode tendencies under heavy braking. So I took the pads to a local O'Reily's parts store in town hoping to match up with a set of pads they had in stock. The 2011 was too new for their catalog but they had 2009 Mustang GT listings, and we found a match for pad shape. ThermoQuiet house brand Ceramic/metallic pads, which AJ has used on a dozen cars with no ill-effects, so I gave them a try. I wanted less braking power out back, not more.



      I got back to the event site and realized I needed a caliper piston retractor tool and a caliper compression clamp, so back to town I went. By the time I had all of the right tools and the rear pads swapped it was getting dark, so I drove out to a nearby highway and tried to bed the pads in, after many stops. The stopping power was still very diminished, and easily getting into the "ABS freak out mode". WTF? I came back to the site and pulled the pads back off for a look - they weren't bedding in well. Then I took the G-Tech data logger and went out and did some 60-0 mph braking tests, with what looked like poor results (157 feet??). Then I took Paul M's STU-classed and Brembo equipped 2011 GT (stock pads/rotors on 275mm Dunlops), and it was stopping just as poorly. I did some 0-60 mph test in both cars as well, pulling a 4.5 sec time and .65g in 1st gear in my car and 5.3 second run and .58 g in his car. So they were closely matched, even with his car's 3.73 vs my car's 3.31 gearing. By then it was pitch black out, I ate some of the food at the party we sponsored and drank some beer, then we hit the hotel for some shut-eye. Tried to stay awake and watch F1, but my eyes wouldn't have it.



      Since I was Impound Chief for the event, on Saturday I managed to get the Mustang on the scales... haven't weighed it in a while. Showed 3479 lbs with 1/8th tank of fuel in the car. Much better than before but still a solid 55% on the front tires.

      Sunday's driving was more of the same frustration, even with the new rear pads - no heavy braking possible or it went into Ice Mode. On this day the ambient temps went from sunny and high-70s/low-80s from Friday and Saturday to overcast, mid 40s, with a BRUTAL wind all day. Most racers brought clothes and shorts for Spring weather but were under-dressed for this late winter cold front. A few racers still picked up some time in the last 2 runs per side, but Costas and I only got a tick faster each. Amy was slow in her class as well. At least she and Costas BOTH cut one perfect .500 reaction time each (I was cutting consistent crap lights). Costas and I were 2.6 and 2.9 seconds off the class winners for both sides, ending up in 5-6th out of 11 according to the results on site, but the posted results show a driver ahead of us that DQ'd himself for driving the course during set-up. No matter - the results still stunk, and we were slow.

      We couldn't ever get a complete, good run in without hitting Ice Mode or fighting lots of mid-corner understeer. Tire pressures and shock changes were not enough to counter this massive push, and the wheelspin on corner exit was again ridiculous. Did we simply have too much power and weight for a 265mm street tire? Is all hope lost? Help me Obi-Wan Kenobi!



      I think not. We keep seeing bad tendencies in the data and the close-up pictures of the tires. I think we've been in the completely wrong ballpark on tire pressures, the rear spring rates need to drop, and the brakes need more attention. We've probably run into some pad compound cross-contamination issues with the rotors, so we've ordered a whole new set of rotors and another set of autocross pads (Hawk HP+). We'll cut the existing rotors and re-bed them with the DTC-60 track pads and swap between the matched sets of pads and rotors from autocross to track events - these pads have VERY different cold bite characteristics, as well as different coef of friction, dusting & noise parameters.

      We're also awaiting our initial stocking order from Energy Suspension bushings, with some much needed polyurethane bushings for the Mustang being made to order. The OEM front LCA bushings are the softest I've ever felt on an OEM suspension, and as big around as your fist. Soft - like a Nerf football soft. That bushing is deflecting under load and losing lots of camber in corner, and the rear control arms and panhard bar are just as soft, causing who-knows-what out back. We've also noted a side-offset of the entire axle, also due to the panhard bar's fixed length and lowering of the back. We need to start developing a Watts Link for the car. We also still have the stock, non-adjustable swaybars, so we're getting a set of Eibach adjustable/tubular front swaybar set coming ASAP (the 2011 has been "in development" for far too long and I'm tired of waiting). AST is also working with us on this new rear shock and the front strut is getting a revalve as well - we'll get this thing to carve cones, by damn!



      We've tested several more wheels in the past week, including an 18x10.5" Enkei with a 285/30/18 Hoosier mounted, which is more appropriate for NASA TT use. But the 285/30 is too short, so we're looking at the 275/35/18 and a Pirelli 305 race tire as well. Another set of 18x9" wheels is on order to help test the many 265mm tires needed for STX autocross use back-to-back; so many choices available, and we need to test most of them. And power never hurts on track, so the headers + custom exhaust bends are going to be ordered soon, and the Steeda cold air + SCT Tuner is already en route.

      The E30 isn't forgotten, either. We've ordered a 2nd aluminum seat and two I/O port seat back braces for this thing, as well as another 6-point harness. We need to adjust the rear control arm mounts for adjustable toe and camber and get that sorted. The wiring issues are also being addressed now. And of course we need to find a transmission that can last more than 2 events (we've broken 2 transmissions in 3 events). We have some home-brew aero tricks up our sleeves as well, mostly for on-track improvement. And the ride heights and fender openings will again be lowered/trimmed further, until they are right. We also need to design and build a low-buck adjustable rear swaybar - from scrap metal and used parts (ugh).

      Somewhere in this crazy month of March our lead tech AJ managed to replace the tie rods on the E36 M3, align it, pull the transmission, install the shifter/spring kits, a new clutch/pressure plate/TOB, reinstall the trans, fix the shifter, and tidy up a number of things in the process. The car drives like a DREAM now, and is ready for sale finally. More on that in its own thread soon.

      Meanwhile I'm going to take a weekend off in April - this weekend - well, one day at least. Already burned out and the season has just begun. There's a Lemons race at ECR I'm driving in (hopefully not crashing in! I've been at the gym for 2 months trying to get ready) and a NASA track event plus 2 or 3 autocrosses, and a test day at the track scheduled. We're trying to set-up a mid-week autocross test day with the AST-USA folks as well. Lots to do.

      More soon,
      Last edited by Fair!; 07-31-2015, 12:56 PM.
      Terry Fair - www.vorshlag.com
      2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
      EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

      Comment


      • #48
        Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

        What pressures were you running on the Mustang for the Houston Tour and the Pro? I tried looking back to see if they were listed but didn't spot them.

        Comment


        • #49
          Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

          Originally posted by Mrazny View Post
          What pressures were you running on the Mustang for the Houston Tour and the Pro? I tried looking back to see if they were listed but didn't spot them.
          Toyos: 32F, 30R. Not enough - rolled over halfway down the sidewall!
          AD08s: 34F, 32R.


          Project update for March 30, 2011: The Quest For Wheels!

          As you may have noticed in several of my thread updates, we've been fairly well stymied on our search for lightweight wheels on this car. Here's the parameters we've had:

          1. They have to clear the stock front 14" Brembo brakes. This means some 18" wheels will fit, but definitely not all.

          2. 17" wheels are out, as are 19" wheels. Seventeens won't clear the brakes, nineteen are too heavy and race tire selection/weight/cost sucks.

          3. We need two distinctly different sets:
          A) A set of 18x9" wheels for STX autocross use
          • Something with an ET45 fits easily
          • Even an ET38 will fit
          • Lightness is important! We've already lost ELEVEN POUNDS PER CORNER but could lose even more

          B) A set of 18x10 (or 18x10.5") for track use (when we move up to NASA TTA)
          • We've found that there's really not one backspacing that fits properly front and rear (the GRAND AM teams use 18x10's with slightly different offsets front and rear)
          • The 18x10.5" ET38 fits on the front with camber, but not the rear
          • The 18x10 ET38 Enkei RPF-1 fit the rear "fairly well" but needed 7mm of spacer to clear the brakes

          4. As much as I'd love to run 18x9.5" wheels - they are MANY more choices in this size - these aren't legal for STX and are too narrow for my needs on track.

          5. Cost matters, too... Something under $400 a wheel would be ideal. Weight matters more than cost

          6. Looks matter a very small mount. I don't want hot pink wheels or blingy chrome, but I'm pretty open on the rest. Form follows function.



          Right now we've got these 18x9" Enkei FP-01 wheels (see above) in ET45 and they are 19.3 lbs each. They clear the front brakes and front fenders and front struts by a mile - they have fairly curved spokes - and the are tucked inside the fenders a good bit (that's how we were able to fit the 10.5" wheels on the front) With similarly shaped spokes they could go outboard another 10mm and still fit inside the rear fenders.

          We need another set of 18x9" wheels to better test the various 265mm "ST" legal tires. I was going to order another set of these and had a set on order, but I'm holding off for now. I want to try something new, and hopefully lighter. Please post more suggestions for 18x9 wheels in 114.3 bolt parttern that are under 19 lbs and under $400 each! Thanks.

          As for the wider track wheels... well we've got one each of these:



          I love the weight on the 18x10" RPF-1, but it only fits the rear (front needs big spacer to clear the brakes). Love the width of the FP-01 in 10.5" but it only fits the front (sticks out on the rear, and its a bit on the hefty side). Hell, I might just use the 10.5" on front and the RPF-1 10" on the back, and get one more of each. Not pretty, mis-matched, and the rears are less than ideal (they really need an 8" backspacing) but it works... well, poorly. This option kind of sucks, but you can see the fit of this mis-matched set with 285/30/18s below.


          18x10.5" ET38 on front... 18x10" ET38 on back

          We are eventually going to try to make an 18x10" wheel that fits this car correctly, and clears these brakes, and is even lighter - soon. But I need wheels to race on later this month (NASA @ TWS) and I'm tired of waiting.

          The alternative is CCW Classics. $2380 for a set of race 18x10" versions, take at least 4 weeks to make, not exceptionally light (figure they'd be 22-23 lbs) but they look good and are at least serviceable. Again, anyone who thinks a 3-piece 18" wheel are light has never accurately weighed one. Lots of bad data out there. LOTS. Accurate scales don't lie. There are many 1-piece cast wheels that are significantly lighter than the same sized 3-piece. The modularity and customization of a 3-piece wheel is the benefit, not the weight. Yea, your brother had a set of 3-piece wheels that were super light. SHOW THEM ON A DIGITAL SCALE. I only believe wheel weights I can take myself, period.



          Hanchey's 17x9.5" CCWs from the E36 (above left) were a staggering 20.4 lbs each and the 18x11" CCWs on the E30 (above right) are much heavier.

          Sure, with custom built 3-piece wheels I could then get two different offsets (front and rear), but these Classic centers aren't known for clearing big calipers without adding spacers. So they still might need maybe... 7.5" to 8" backspacing + a big spacer on the front to clear the calipers. That backspacing would fit under the rear fenders better and then with a ~1/2" spacer up front to clear the calipers. Might be the easiest solution for now, but neither affordable, quick to build, nor lightweight. Pretty bad option, really. Already have long wheel studs up front for this very purpose, though.

          Alternatives? A 1-piece 18x10" wheel with an ET50 or so and under 19 lbs would be ideal!
          Last edited by Fair!; 07-31-2015, 01:00 PM.
          Terry Fair - www.vorshlag.com
          2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
          EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

          Comment


          • #50
            Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

            You know CCW does a lot of monoblock wheels for Corvettes, Vipers, 911s, etc., right? Maybe they've got something that would work for the Mustang. They list their C10 as 24.3 lbs for an 18x13 on their website.
            Iain

            '01 Honda S2000 - extra crispy
            '05 Honda CR-V EX AWD - alphabet soup family truckster
            Always looking for a co-drive...

            "We don't stop playing because we grow old, we grow old because we stop playing." - George Bernard Shaw

            Comment


            • #51
              Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

              Project Update for April 1, 2011: No April Fools silliness in here, just some thread questions, my answers & the logic behind them.

              First off, I don't mean to be argumentative or sound like a know-it-all, because I surely do not. Let me try to explain why I keep saying a wheel that "fits" or "doesn't fit". I strongly believe using as much tire width as you can possibly fit, and sometimes even more (flares), when the class allows it. And to use the proper wheel width for a given tire, if not more. So I go to great lengths to maximize wheel and tire width on my cars.

              I have been test fitting, measuring and weighing race wheels for 20+ years, and have amassed a lot of data, so I just cannot believe almost anything I read on the interwebs about wheel and tire data. As we all here know, most of the "facts" posted on most forums are just regurgitated crap someone else read somewhere. You see it enough times and it becomes fact, even when its bunk. Even data published on websites (especially wheel weights) or from wheel retailers is often incorrect. Its shocking to me how few of the population knows how to weigh a freagin wheel accurately. I've sent more than a couple of sets of wheels back for a refund when their published/promised weights were off by 3 or more pounds (I warned them up front and they agreed to that stipulation each time). I'm not prejudicial about my skepticism - I simply don't believe anybody. I have to see it with my own eyes. I might as well be from Missouri... since you have to show me.

              So if someone says "this wheel fits" or "this wheel weighs about X", I need to see a picture. Or a dozen. And then measure the wheel for myself to verify width, backspace and weight. Huge skeptic. Then I'll still want to see the car raced (load the suspension up and see if the tire touches) and look at the wheelwells for tire residue or watch for smoke. I've posted about certain tires not fitting a given car and than seen the inevitable "I race on that giant tire and it fits!" posts. Then later see them at an autocross or the track and watch as plumes of tire smoke pour out of their car. Or watch as they crawl around at half speed, so they never load up the suspension or tires. So my definition of "what fits" is probably different from someone else's.

              And different racing conditions have different tire clearance requirements. A typical autocross car sees only spikes of G-loading (slaloms and small turns) but on a road course everything happens SOOO SLOOOOWLY... with loooong turns... so you tend to load the suspension up laterally for much longer periods of time, and see higher g loading. If you touch the curbs at all that can load the suspension even further. If a tire rubs a bit on an autocross car, what's the worst that can happen? You're never on course for more than 60 seconds, and you can check for the the tire rubbing and residue after each run when in doubt. On track you are out there for 20+ minutes, and a lot can happen in that time if you have a tire touching a fender...



              When we stuffed 18x10" wheels and 265/35/18s on my E46 330 (above) it worked fine on the street and even autocross, but when I ran it at the track in TTD the rears would rub the outboard upper section of the fenders BADLY. It took hours of massaging the rear fenders - and proper tire testing with the shock on the bumpstops without a spring installed - to clearance it fully for track use.

              So, let's see some pics...

              Originally posted by blackbolt9
              How much better do you want them to fit? JBS Motorsports Boss 302R with the BBS wheel, no spacers on the rear. Photo stolen from Rehagen website, I assume taken by Wes Duenkel
              Hmm... OK, from that angle that wheel looks like it fits... its a little close in the rear, but it would probably work. So are you telling me the GA cars use the cast BBS wheel? I've heard (there I go using second hand info!) that there's another 18x10" mesh wheel that BBS makes (at double the cost) for the GA teams that has a different offset for the rear. Of course if you're going to GRAND AM races and working at Rehagen then you'd know this to be true or false better than me, so I will defer to you. What's the skinny - is there indeed a street version of this 18x10" BBS wheel, and a different GA wheel?

              And as for the 7.0" backspacing claim I made, I trusted the interwebs and look - its burned me again. The early data I found on Rehagen's website about the cast 18x10" BBS showed that it had a 7" backspacing and weighed 20-21 lbs. I literally cut and pasted that data from the website right into the caption on this picture, last year. And of course there's the $637 cost.

              Since then I've tested an 18x10 with 7" backspace on the rear and it stuck out on my car a bit more than I liked. But if its now showing to be a 7.2" B.S. wheel, that would indeed fit better out back (barely), and that is also the most backspacing you can get away with on the front before losing clearance to the strut. So if its now showing as a 7.2" backspacing then that's probably pretty darn good. But did someone say you still have to use a spacer up front to clear the caliper?? That seems like an odd requirement for a $637 wheel...

              But If I was going to spend over $600 on a 18x10" wheel it damn sure wouldn't be a heavy-ish cast wheel. CCW monoblocks are only $700 each (ha! only), and can be custom made to your specs. Very strong, might even be light (depending on who you believe - I believe calibrated, digital scales, but have yet to see these wheels pictured atop one). And if I was going to to make a custom set of wheels for this car for track use, I'd make them 10.5" front and rear, and maybe even 11" on the back. If I wasn't running NASA TTA with its imbalanced points penalties for tire width, I'd put as much tire under this fat-assed Mustang as we could fit. Probably 295 fronts and 315 rears. But tire width is heavily penalized in NASA Time Trial... anything more than a 285mm and I'm looking at a class bump up to TTS, so that's not going to work. Since I can only afford the class points for a 285 (grumble) then a 10" wheel is sufficient, therefore its easier to make a single wheel fit front and rear. And therefore not really beneficial to make a custom set of wheels. And hence why I'm spinning around in circles trying to find an 18x10" or 10.5" 1-piece wheel that's off-the-shelf and under $400 each.

              And I think my comments were misconstrued (and poorly written) about lightweight wheels - the autocross set I need (18x9) can afford to be very light, as running over cones in a parking lot doesn't take the same strength of wheel as track abuse. But even on track this car isn't raced W2W (only TT + HPDE), so it doesn't see the "fighting for the lead" type of abuse the Continental GA cars would normally, so it can probably afford to be a bit lighter than what the GRAND AM teams use.


              Originally posted by Thinkkker
              Its the way to go really.....

              18X10.5 in the front: *sorry, best I could find*


              18X10.5 in the rear: *there is over 1" or so clearance on the inside*


              The fronts fits about perfect, and without fender mods, I don't think you will get more. These are 30mm Offset....
              Kent - sorry, but those 18x10.5" ET30 Enkei NT01+M's don't fit on either end with anything close to perfection, at least to my standards. The poor lighting and odd angle on those pictures you posted (especially from the back) don't really show the situation clearly. Costas and I looked at your car and those very wheels & tires in person at the National Tour event 2 weeks ago and both the front and rear tires stick out past the fenders. A lot out back. Sure, "it works" for autocrossing and is common for the category, I'll grant you, but its not what I'm looking for. Madderash's F-Body wheels stick out as well.


              Left: 18x10.5" ET38 (7.2" backspacing) fits up front - BARELY. Right: Same wheel on back sticks out a ton

              As you can see above, we've fit an 18x10.5" ET38 (another 8mm inboard than Kent's) on our car with little 285s and they just barely cleared in front but stuck way out in the rear. These have a measured 7.2" of backspacing and have about 3mm of room inboard to the AST strut. Not any room to be gained up front, so nothing wider would "fit" in my book, without flared fenders.



              The rear on this 18x10.5" ET38 wasn't even close to fitting - it stuck out more than 1/2" - and this is why I'm still somewhat curious how an 18x10 with the same 7.2" backspacing would fit really well. The rears need to go inboard another inch, if not 1.5". As you can see in the picture above, right, there's a good "three fingers" of clearance inboard to the unibody with these 10.5" (7.2" B.S.) wheels on back. Using something like an ET60 would be a good place to start (8.1" of backspacing). But then you'd need a good sized spacer up front (nearly an inch thick) to have a set of wheels that rotate easily (and yes, ideally I'd want that - as would most track guys). That's a lot of spacer, so realistically a rotatable set of 18x10.5" wheels isn't possible... but an 18x10" set is.

              For a properly fitting 18x10" set, in my eyes, I'd want to have the front end up at 7.2" backspacing, but I'd be happier with 7.5" B.S. on the rear, or a 10.5" with 8.0". So I might (if I have to go custom) build an 18x10" to 7.5" B.S. and use a ~1/4" spacer up front. That's if I have to resort to a custom set (CCW). Don't know yet... still looking at some Porsche rear wheels...

              Good news on the 18x9" wheel search, thanks to BRODA's suggestion about the WedSport. Found one of our dealers that had a set in stock and they made us a significant;y better deal than $620 each, so a set is incoming. This will be for autocross use (only) for the 265/35/18 Toyo R1Rs. They claim to be 16.9 lbs but I'll snap a shot on the scale and post it up when they arrive, next week. For reference here's a Speedline C5 Z06 17x9.5" wheel that Costas brought by and we weighed today. Not bad for an OEM wheel, but Speedline is very weight conscious.



              Also as you can see above, we have the Mustang torn apart awaiting more parts. New rotors and Hawk HP+ pads are going on and the front struts are being revalved at AST-USA today. Trying some new spring rates and I'll report back how they work in a little over a week (two autocrosses that weekend). Also, we weighed the stock front and rear rotors, which can be seen below.



              Wow. The front rotor weighs more than the wheel. That's... just, wow. And no, we're not paying $800 for the 2-piece Girodisc rotors that are on the market, but we will be doing something about that. I bet there's 10 pounds in the front rotors alone that could be lose. The hat section of the stock front rotor is THICK steel.

              More next time...
              Last edited by Fair!; 04-01-2011, 02:39 PM.
              Terry Fair - www.vorshlag.com
              2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
              EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

              Comment


              • #52
                Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

                Originally posted by altiain View Post
                You know CCW does a lot of monoblock wheels for Corvettes, Vipers, 911s, etc., right? Maybe they've got something that would work for the Mustang. They list their C10 as 24.3 lbs for an 18x13 on their website.
                Yea, the CCWs are definitely on my short list for the 18x10" wheel set that we need for track use.



                I've had many sets of the 3-piece CCW Classics ($575) but the 1-piece monoblock CCWs look intriguing as well ($700 each). If I keep striking out on a 1-piece wheel that fits correctly (and hopefully at a lower cost), then I'll call CCW back once again.

                Thanks,
                Terry Fair - www.vorshlag.com
                2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

                Comment


                • #53
                  Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

                  Originally posted by altiain View Post
                  You know CCW does a lot of monoblock wheels for Corvettes, Vipers, 911s, etc., right? Maybe they've got something that would work for the Mustang. They list their C10 as 24.3 lbs for an 18x13 on their website.
                  Yea, those are definitely worth a look. I'm just doubtful about the weights. CCW has... claimed lower weights in the past than what we've measured. I'm a huge skeptic.
                  Terry Fair - www.vorshlag.com
                  2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                  EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

                  Comment


                  • #54
                    Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

                    Project Update for April 11, 2011: We had a lot going on the past 2 weeks (prep on 4 of our cars and very busy Vorshlag business) but we still managed to make several changes to the Mustang and then autocross it this past Sunday. Let's take a look at the latest round of mods in this post and talk about the autocross in a post to follow.

                    First up was the Steeda Cold Air kit that finally arrived, along with the SCT Tuner. This combo-package from Steeda was chock Full Of WIN.



                    The stock 2011 GT's air inlet box is pretty typical - lots of restrictive accordion style tubing, a closed-element air box, a flat paper element air filter, and weird sound muffling chambers in the inlet tube. There was also the separate "sound tube" silliness that piped sound from the inlet track into the passenger compartment. The stock car is so quiet (81 dB wide open, as tested at an SCCA event!) that this helps you hear the choked up engine sound. The Steeda cold air kit consisted of an all new aluminum MAF housing, a new air inlet tube/elbow all the way to the throttle body, a heat shield that tied into the lower air inlet scoop, a larger lower air scoop piece, and the conical/open element high flow air filter. The kit came with instructions and everything we needed to install it.



                    I was impressed with the craftsmanship. I've made most of the "cold air" kits on my own personal race cars in the past 20 years, but this car looked a little more complicated with the integral MAF housing in the OEM plastic tube. And with a new higher flowing MAF comes the need for a tune - this has been the standard for Mustangs since the earliest MAF equipped Mustangs 5.0L Mustangs I raced in back in college (MY1986-up). This Steeda kit was not an inexpensive kit, and I am leery of high priced parts that are heavy on the bling and lacking in performance, but this was money well spent. The inlet bell for the MAF housing was a beautifully machined and welded part, and much nicer than I had expected to see (or than I would have made!), with a smoothly tapered inlet bell that has to help air flow. The aluminum heat shield was also very well made and fit perfectly to the new MAF housing, lower inlet scoop, and to the chassis.



                    AJ had the stock parts out and the new bits back together fairly quickly, but Matt and I snapped some pics of the parts and the install while it was going together. He cleaned up the stock inner fender section under the OEM airbox while it was out (I like my engine bays uber-clean), and it all fit together perfectly. Since its STX-class legal and holds in a little engine heat we removed the plastic OEM "5.0" engine cover piece as well - then cleaned up the hoses and looms underneath. Looks good under there and has less clutter. We did not re-install the OEM inlet air "sound tube"; I consider that part of the OEM cold air system, so its STX-class legal to modify/remove it, in my eyes. That stupid tube weighed less than 1 pound and is more of a marketing gimmick than performance anything. Plugged the hole in the Steeda inlet tube with a a big rubber plug and hose clamp. Again - less clutter under the hood.

                    Will it be too quiet now without the sound tube artificially pumping engine sound into the cabin? Not hardly! This car SOUNDS GOOD now, and external sound testing shows about a 9dB increase in sound at the SCCA Pro Solo (between my Mustang with OEM airbox and Paul M's identical Mustang with this Steeda cold air) 2 weeks back. See the in-car autocross video below for sounds. We'll plug the 30mm hole in the firewall with some grommet plugs, that Paul found and ordered online, when they arrive.



                    The SCT Tuner was loaded with a custom Tune Steeda developed for Paul's car as well, which has a more linear throttle response for the drive-by-wire throttle body. Paul was the guinea pig on this mod - he bought this same package and had Steeda tweak the tune a couple of times and we just had them load the same tune for our SCT programmer, as I had driven his car with the same cold air and SCT tune and REALLY liked the improvement. Uploading the tune via the OBD-II port was easy, if not a bit time consuming the first time around (its not nearly as quick as say... a COBB AccessPORT upload, but it has a few more customer-tweakable settings, too). The adjustable speedometer feature (for gearing and/or tire height changes) is a nice feature on this programmer, as is the adjustable rev limit. The OEM limiter is around 6800 rpm and I raised it to 7400 for autocross use (quick bursts up to that limit to avoid a 2-3 shift on some courses), which is plenty safe (the new Boss302 has a 7500 limit). Lots of '11 "Coyote 5.0" Mustang racers are revving stock motors higher than that, but I won't push it further. This ain't no M54.



                    We then put on a heavier part up front - an Eibach 2005-2010 Mustang GT adjustable, hollow swaybar. They supposedly have had a 2011 GT swaybar kit (with 1mm larger front and an adjustable rear bar) coming out since SEMA 2010, but all we have heard after 6 months of trying to buy one is delays and excuses, and I was tired of waiting, so we ordered the adjustable front '05-'10 bar (but not the matching rear, as it wasn't adjustable; we might make our own rear bar at some point to work with some other mods we have planned). Now this front bar is still 35mm OD, which is the exactly the same as the stock 2011 GT front bar, but as you can see the Eibach tubular unit is 3.4 pounds heavier than the stock non-adjustable front unit, so it has to have thicker wall tubing, which means it should be stiffer at the stiffest settings. And it feels as stiff or stiffer than stock in the "middle" setting we started at - but we need to test this properly and post the numbers up. We'll test the settings on the bar on course at a test-n-tune event later this month. I made sure our tech got the bar installed with no bind in the chassis mounts, which I checked to have "pinky finger effort" to rotate with the end links off. Perfect.... well, almost.

                    We also switched the 2.5" ID x 200 #/in Hyperco rear springs to a longer 2.25" ID x 175#/in rate Hyperco, and I machined the AST rear ride height adjusters (made for 60mm and adaptable up to 2.5") down to fit the 2.25" ID springs. Problem was there's not a lot of lengths or rates available in 60mm ID or 2.5" ID, but TONS of choices in 2.25". We do this on all sorts of cars when the choices move us to the smaller ID spring. The 2.25" spring is lighter, but costs more than 2.5" or 60mm, and we usually stock and sell 60mm Hyperco springs if possible (most AST struts are made to fit 60mm springs). We have played with no less than 5 different rear springs in the past few months and we finally got a winner in a softer rate with the 2.25" ID that works with the new rear shocks, rate and lower ride height. A lot of trial fitting went into this. Long story short - we now have 3 different rear spring length/rate packages that should please a wide range of the autocrossers and track guys, and we're trying more front rates as well.



                    The new lightweight WedsSport TC105N 18x9" ET50 wheels arrived from Vivid Racing this past week. I immediately weighed one wheel, and at 17.4 lbs on our scale it came in only 1/2 pound more than the claimed 16.9 lbs, which is better than normal for claimed weights, from our experience. With their high prices its easy to understand the confusion, but upon inspection I noted that the WedsSports were simply a one-piece "flow formed" wheel (like D-Force, SSR, some BBS and others) and not a "forged wheel" as some folks like to think. I mounted the 265/35/18 Toyo R1Rs to this set for the coming autocross weekend and weighed them together; the wheel and tire package came in at a scant 43.1 lb per corner.



                    Putting these pricey WedsSports on for the first time was a pucker moment - the spokes only cleared the Brembo front caliper by about .040". It was a close one but it works, and we've run with wheels this tight to this caliper in the past. It definitely fits inside the stock fenders with inches to spare - this is definitely NOT HellaFlush. For an autocross car I prefer a narrower track width, as this makes the car easier to navigate (and faster though) a tight slalom and allows the rear differential to work more efficiently. For road course use I'll let the track width push wide as you please, well, hopefully without disrupting aero (which will if the wheels push out past flush).



                    The wheels are fairly simple but very well made looking, and look damn good on the car, and so does the now lower rear ride heights. We tried these heights on 150#/in rear springs (and even 1/2" higher) and it bottomed the shocks (and nearly touched axle to frame) too often on the street, so we're scratching that one off the list of rates we recommend. The 175#/in rates worked well for daily driving and autocross both, and we're VERY happy with the performance improvements. You'll see this in the autocross pictures in my next post - its finally squatting well under acceleration (from the new ride height + new spring rate + new shock length + new piston and valving).

                    This WedsSport+Toyo package is now 13.8 pounds lighter per corner than the 56.7 lb OEM 19x9" wheels and tires, and remember: this is both rotational and unsprung mass. That's... just HUGE. We could possibly get the front rotors 10 lighter, too. We'll get the lead out of this Pony Car, by damn! The 18x9" Enkei FP-01s are still mounted with the 265/40/18 Yokohama AD08s (and weigh in at 48.2 lbs, or 5.1 pounds heavier than the Toyo/WedsSport combo) which we'll test back to back with the Toyos at an upcoming test day, and we'll share what we learn here.



                    We also had AST-USA put in some more compression in the base valving in the front struts, which was very noticeable and more matched the new rear shock valving added earlier. We weighed the AST + Vorshlag + Hyperco bits from the front suspension while it was off, and AJ cleaned up the rear of the chassis which had been covered in rear axle lube (new aluminum catch can and bracket parts are here and will be installed soon).

                    Costas asked what changes were in store for this coming autocross on Sunday, which he was scheduled to co-drive the Mustang in. I rattled off that we had new rear spring rate (450F/175R) and lower ride heights (14.5" F&R), new front strut valving, new adjustable and stiffer front swaybar. New cold air and SCT tune, with probably +35 whp if not more, a new rev limit 600 rpm higher, lighter 18x9" WedsSport wheels with a slightly narrower track width, and went from the taller Yokohamas at the last event to shorter and stickier Toyos. We also had planned on running 10 psi more tire pressure front and rear. "So... not so many changes?"

                    Race write-up is next...
                    Last edited by Fair!; 04-11-2011, 09:56 PM.
                    Terry Fair - www.vorshlag.com
                    2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                    EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

                    Comment


                    • #55
                      Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

                      Project Update for April 12, 2011: This is the autocross recap from Sunday April 10ths SCCA event at Lone Star Park. I forgot to mention in my previous "prep post" that we had new Hawk HP+ pads and rotors on the car, which were bedded in and seemed to work well on the street the past 2 weeks.

                      The LSP site with an asphalt parking lot surface and lots of weird hills and valleys, and the surface comes apart badly if you even look at it funny. Not my favorite place to race but that's where the competition was this week. The Texas Region event workers work diligently to clean the racing line before the runs begin but it doesn't matter much - it starts dirty and ends VERY dirty, with bad marbles evident offline after just a handful of runs.



                      Still we had lots of parts and set-up changes to test, and this event would have good STX class competition in the form of Chris Ledbetter and his co-driver Brian in the white E36 328is below (VTPP Tester, AST 4200s, car has placed at Nationals) as well as the debut of Brad Maxcy's black E36 328is (AST 5220s, also very fast driver), among others. Costas and I were to drive in STX and Amy in the PAX-factored "W" women's class. We had been placing pretty far behind both Brad and Chris (both driving in Chris' STX Bimmer) so far at the 3 autocross events we've done in the Mustang, and Amy had yet to place well in "W" in the car either. With all of the changes to the Mustang from the last 2 weeks we wanted to see where we now stood.



                      STX ran in the first heat so we lined up first in the 2 driver lane. Costas was one of the first cars on course, but with cold tires we knew that run wouldn't be his best. Even still, he was hopeful and our times were on par with the class. But he mentioned a loud BANGING that was evident in transitions. Hmm, that was worrisome. I made a run and noticed the same banging up front. Spooky loud. I pulled back around and we ran to the trailer for tools. Asked for a "mechanical" and we pulled the front wheels off. Costas noted a loose wheel bearing nut - very loose. The wheel would rock in-out by 1/4". WTH? That hub hasn't been off in many months (when we installed the long wheel studs).



                      We managed to get the 36mm wheel bearing nut sort of tighter (with all the wrong tools) and figured "that had to be the noise". Costas made his run #2, then so did I. Noise still there and VERY loud. We asked for a 2nd mechanical, pulled the front wheels back off, and checked more things hurriedly. Nothing evident. Costas took half of a 3rd run and aborted it from the sounds and a touch of ABS ice mode into one turn (only happened once all day and only in the worst of the gravel). I took a tentative 3rd and felt just as uneasy. We decided it was wise if skipped our 4th runs and avoided any potential damage. Drove the car back to the trailer and began a thorough tear down, hopefully getting the car repaired before the 3rd heat when Amy was to make her runs.



                      Impressions: My driving had lots of mistakes I can see on the videos, but I felt like the car was handling better than ever before. The brakes finally WORKED again, even on this gravel covered lot. The Toyo R1R tires seemed to like the new, higher tire pressures we were running (42F, 38R) and we ran the shock adjustments much higher per Brian at AST-USA's suggestion. That made the various transitions feel faster (but WOW the noise it was making) and front brake dive (and rear rise) was also down dramatically. The rear of the car was squatting well under acceleration (softer rear springs) and it was putting power down much better, but driving the car still involved varying degrees of wheel spin. Fun, and to be expected of ~400 whp on 265mm street tires. The new Steeda cold air made the engine sounds much nicer and finally audible to the driver, and the higher redline (7400) from the SCT Tuner was a welcome addition - all 3 drivers touched the higher rev limit just a tick on course, so we would have been shifting to 3rd with the original 6800 rpm limit.



                      Costas and I both noted some understeer at the two 180° turn-arounds, but Amy said it was a LOT better for her, so maybe the swaybar repairs we did fixed that. She said the car pivoted beautifully, which was not what we felt, as we were both resorting to "driving into corners on the brakes" to get it to understeer less at low speeds. At higher speeds the car was very neutral for us, though. All 3 drivers sprayed the tires with water after every run except the very first - we saw ambient temps of 88°F in the afternoon. That seemed to work fine, which was surprising given the weight of the car and the heat.



                      So before our run heat was even over Costas drove us in his B4C Camaro into glorious down town Grand Prairie (sarcasm) to find an AutoZone. We located a 36mm socket (needed to properly tighten the wheel bearing nut), and a few others we were missing. This allowed us to tighten every nut and bolt on the front suspension, and that's when Costas found the swaybar chassis mounts painfully loose. The brackets were shifting up and down under load, which explained the loud clunking in the slaloms. Wasn't really hurting anything but it wasn't allowing the swaybar to do its job properly, either. I had a talk with our tech here about the importance of tightening nuts and bolts properly on Monday morning, of course.

                      After we had everything tight and double checked half an hour later we went for a test drive to see that we did indeed fix the glitch. We had maybe 10 minutes of down time when we ate so by the 3rd run heat the car was prepped and ready for Amy. She worked course in heat 2 and we were assigned to course in heat 3, so as I passed her during a worker change and told her "Its fixed - drive hard, go fast, and let us know how it goes!"

                      She did just that, and put a solid second on the both of us in her last run. The car looked even better in the turn-arounds and she said it pivoted around them perfectly. Damn, wish we could have driven it like that. Oh well, she showed finally us that the Mustang has potential in STX. She won the "W" class and her raw time in her last run (where she ran over the base of a cone) would have placed her 2nd in STX, .3 sec back. She said she was pushing the car harder each run and was amazed at how well it handled transitions and the tight stuff, as well as the brakes finally being right again.


                      Click these two pics above for in-car video and Runs 1 & 2 result analysis

                      Since we were working course in heat 3 we didn't get a single picture of Amy driving, and she never turned on the video camera (doh!). Costas and I got a couple of our runs on video, and the quickest is linked above. We were within a few tenths of each other, but Costas only took 2 full runs, and all of our drives were before we fixed the clanging and banging swaybar. As you can see in the "results analysis" (linked here) we were still in the hunt after 2 runs, but the rest of STX class got quicker in runs 3 and 4, as we fumbled in the pits trying to find the source of the banging. Ledbetter had a 47.9 (+1) and his co-driver Brian had a 48.0. Brad Maxcy had a 48.5 and Amy had a 48.3 (+1) and a 49.0 (clean). She didn't have any noises or issues to deal with and all of her runs were quick, but she felt like there was more left.

                      So we feel like, even as bad as we did in STX class, with the bolts and nuts all tight the car has potential. Amy proved that for us on her runs. Costas and I will autocross the car at an event (and maybe two) this coming weekend and report back again. This time I'll make sure every bolt that has touched on the car is tight, and we'll use Costas' DL-1 to data log the runs.

                      More soon,
                      Last edited by Fair!; 04-13-2011, 12:17 PM.
                      Terry Fair - www.vorshlag.com
                      2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                      EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

                      Comment


                      • #56
                        Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

                        Project Update for April 20, 2011: So we don't end up with 8 events and a lot of modifications in one thread update, I'm trying to do them more quickly. Over the last week we only did one suspension update to the car, but it took a sizable amount of work over 2 days. Then I took the car to a local autocross last Saturday. That was a train wreck for me, with a course layout that was super tight/narrow, and the Mustang was a bear to fit through the gates. Pretty much wasted a day, but I did get some cold and warm weather data on the Toyos (none of it flattering). Then this week we've located some 18x10" track wheels, bought another set of STX tires to test with, and another new part for the Mustang arrived. Read below for more.



                        The front suspension on the S197 Mustang is pretty basic stuff: McPherson strut, spring mounted on the strut, with a beefy steel Lower Control Arm (LCA) that has two big rubber bushings. These bushings are very mismatched in size, with the rear unit being as big as a beer can and the front somewhat smaller, but they are at least lined up on the same axis. This means they are single axis of rotation bushings, which is a good place to use poly or nylon materials, especially if the bushings are large, rubber, and soft.

                        Our durometer hasn't arrived yet so I wasn't able to measure how soft the LCA bushings were, but the OEM rubber depressed easily by hand. Feels like a giant marshmallow, and I read somewhere that it was full of fluid as well. This is great for ride comfort and quiet, but will deflect badly under load, and we had noted some wheel deflection in some close-up pictures of the suspension under heavy loading. Toe change, camber loss - its never good for dynamic suspension geometry and overall handling to have super soft, large, compliant suspension bushings on a car. We began to look at solutions for the LCA bushings and more bits of this chassis months ago.


                        S197 poly Mustang bushings we now carry (click thumbnails for larger images)

                        Since there was almost no model coverage overlap between Powerflex (which we already stock/sell) and Energy Suspension, we went ahead did a buy-in with Energy a few months back. The initial stocking order had all of their S197 Mustang bushing kits in it, and they finally arrived a week ago. Energy had no idea if their "2005-2007" Mustang bits and pieces fit the later cars, so we bought everything to check for ourselves. We have been testing these bits on our 2011 and I can report this so far: Their front LCA kit works on the '11 GT, as does the track bar kit (panhard bar bushings), and it looks like the upper rear control arm kit might work (but we might go another route there). The shifter bushing kit most certainly does not fit the new Getrag 6-spd on the 2011, however.

                        Poly LCA Bushing Install - http://vorshlag.smugmug.com/Instruct...y-LCA-bushing/



                        So the lone modification we did to the Mustang last week was the bushing replacement on the front LCA. Let me tell you up front - this was not a quick, easy or fun job to perform. Our tech AJ fought with this install for part of 2 days, and we had the right tools, a lift, a press, had all done poly bushing installs many times - everything stacked in our favor. The OEM Mustang front LCA bushings (especially the fluid-filled, gigantic back ones) are some of the nastiest I've ever seen.



                        Just getting the LCAs out of the car took a good bit of work. The front bushing bolts are blocked by the giant electric power steering unit, which had to be unbolted and slid forward (he left the steering shaft installed). Even then the bolt barely came out. For the bushing swap, we followed the Energy's instructions. This says to "apply heat to the outer shell", to break the bond of the rubber to metal, but we resorted to cutting and burning the bushing out of the outer sleeve. Then cut the bushing remnants from the inner sleeve (both sleeves are re-used). Nasty, messy work. The damn fluid was under pressure, too. We used heat, then fire, then drills and a saws-all. Maybe spent 5+ hours getting the first LCA done. The second LCA went a lot smoother...



                        This time AJ and Matt teamed up and used more heat and brainpower than we did the first time. With the LCA held in the vice, one of them used the torch on the metal while the other pulled on the bushing housing (with a water bottle nearby to put out the small flash fires that flared up). This process took some time but eventually, with enough heat and pulling, the outer sleeve pulled clean off the bushing. No time wasted cutting the bushing up or cleaning up the outer sleeve. The inner sleeve worked almost the same way, with careful heat and pressure.



                        The inner sleeve has a knurled section that has to be sanded off, as the bushing slides over that when its installed. We also went the extra step and, after the bushing was pressed into the outer sleeve (only) we drilled a hole and tapped the outer sleeve for a grease zerk. Then installed the inner sleeve (which can stay pressed onto the LCA the whole time). Now we can go back and grease the bushings easily - to keep them from squeaking later (a common complaint on poly bushings when the original grease gives out). We don't show the front bushing in this install gallery but it was smaller and easier to swap.



                        After a quick check of the toe (nothing changed) AJ and I loaded the Mustang into the trailer by 8 pm Friday night, ready for the autocross the next day.

                        April 16th NTAXS Autocross

                        We had found a local autocross on Saturday I could attend (co-driver's Amy and Costas were both out of town) so I tried to enter on Thursday... but it was full at 65 entrants already. I said as much on FB and within 2 minutes (gotta love the internet) had a friend willing to sell me his entry (thanks Jason!), so I was in. NTAXS is what remains of an S2000 autocross club, and they cater to mostly S2000 and Miata drivers. This event was to be held at Texas Motor Speedway bus lot (slick sealed asphalt I've autocrossed on at 40+ events in the past, so I know the surface well), and normally Jarrett J sets up their courses - who does most of the local autocross courses for other clubs as well (and does an excellent job).



                        So I towed out there early and it was pretty cold in the morning, mid 40's and 10-20 mph winds. The surface was going to be slick, but it was predicted to get into the mid 70's that afternoon. With 4 runs in the morning and 4 more after lunch, I'd at least get some varied track temperature runs on the Toyos. Walked the course with Chris Ledbetter and we both groaned at the extreme tightness of some gates and oddly tight corner layouts... this course was made for a NARROW car. Sure enough, another course designer had set-up the course (his first), an S2000 driver, who ended up hitting cones on 4 of his 8 runs himself. Lots of DNFs, lots of cones felled, etc.

                        So long story short, the wider Mustang wasn't well suited for this course. At all. I was driving my ass off and just could not get the car to put any power down on this cold, slick surface. The uber-tight turn-arounds were also killing time, too. The tires didn't work worth a damn in the cold temperatures, yet after my first 4 runs (which are run in quick succession) the tires were badly overheated - front and rear. Tire pressures crept up by over 10 psi. Yikes. Another Toyo equipped STR Miata had similar troubles - no grip - and their tires made equally loud noises compared to the others (and they were uncharacteristically off the pace).



                        Watching cars in the 2nd heat of the morning, while I was then working course, they looked quicker as the track temperature began to rise. Sure enough, Ledbetter and Ken O were both running almost 3 seconds quicker than my heat 1 times. Not good, but not surprising.

                        After the lunch break the temps were in the 60's for heat 3, when I ran again. This time I moved my spray bottle, air gauge and gear over to the exit of the course, where I'd have about 60+ seconds between runs waiting in a short line, to pile out and spray tires/check pressures. Luckily I had some help this time (Ledbetter's co-driver Sherrie) and she bled tire pressures down while I sprayed and sprayed the quickly overheating Toyo R1Rs between runs. I held up the flow into the start line a bit, waving them around, but these tires were just boiling hot after each run - even with ambient temp still in the 60°F range. Rear wheel spin was still ridiculous but with lower pressures (dropped to 35 F/32 R for this lower grip lot) I could at least get some forward motion going on these runs. Still had some push in the tight turn-arounds but with this back-to-back run format there's no time to make real set-up changes (other than pressures and shock knobs, which I did). To me, running an event "the SCCA way" (with time between runs to make adjustments) makes for a more useful use of the time.



                        My 4 afternoon runs were 2 full seconds faster than my morning 4, which is an unusual gain for me at this site, even over that much ambient/track temperature change. I guess after 23 years you'd say I'm "a seasoned autocrosser" and don't tend to pick up huge amounts of time after my first 3-4 runs, so I chalk that 2 sec gain up to the set-up changes (lowering tire pressure), tire spraying (lots of water!), and warmer track temps. Still, I was well off the afternoon pace. Ledbetter's later 4 runs got .8 sec faster than earlier, and Ken O was almost 1 sec quicker as well. That left me still pretty far back from both...


                        When I checked times on the computer and print-outs throughout the day there were only 3 cars in class 3, which I led to the end. It appears some Honda looks to have been moved into the class. Who knows? I couldn't hear a thing from the announcer that was useful - just a bunch of clowning. Just look at the the times from Chris Ledbetter (STX BMW 328is) and Ken Orgeron (STU legal E46 BMW M3), the only other competitive STX and STU RWD cars. They were both on different tires (Chris on 255mm RS3s and Ken O on 285mm Dunlops) and ran in hotter times of the day (heats # 2 & 4) but both of them crushed my times... Ledbetter was 1.7 sec quicker and Ken was 1.1 quicker. I worked course when they both ran and they looked so much more stuck down - still skating somewhat on the slick TMS surface, but not the excessive wheel spin and loudly squalling tires like the Toyos were doing on the Mustang.

                        Lessons Learned: My times on that tight-assed course were a bust, but I learned that Toyo R1Rs are not all that in the cold, yet they can easily overheat - even in cooler temperatures. I won't make a run on these ever again without massive water spraying afterward. We'll get more accurate (pyrometer) data on this phenomenon at the big tire test we're going to do in 2 weeks. I left my video camera mount at the shop, so I couldn't take any in-car video - which would have been good for a laugh. We now have an extensive "trailer load list", with this and many other items listed and checked before each event. Also, bring a co-driver or find a helper at autocross events that have back-to-back runs like this, if you hope to check tire pressures and spray tires between runs, or if you'd like to make even the smallest of set-up changes. Lastly - know who the course designer is up front, or find a course map before you go to the trouble and expense of making an event. The NTAXS event folks always put on a great event, but this particular course really didn't work with this 71" wide car (several other "wide car" drivers said the same).

                        What's Next?

                        The latest things we're working on include finding some man-sized track wheels (18x10" or wider) and better track-worthy tires (not street tires). Not wasting any more time running NASA TTB class on skinny street meat with the rest of the class on wider Hoosiers. We've finally stumbled upon some 18x10" wheels that came off of a GRAND AM Mustang FRC500, shown below.



                        I've purchased seven of these 18x10" Forgelines but I need to get them from North Carolina to Dallas, TX - anyone that wants to make some $ delivering the wheels from I-95 in NC to I-20 in Dallas, please PM me. UPS is pretty spotty on delivering wheels to me that aren't boxed properly (these will likely have tires) so I'll either try to find space on an existing traveler's truck or call a freight company. Thanks!

                        We'll check, measure, and possibly rebuild these 3-piece wheels after they get here and hopefully they fit the 2011 with some wider tires. I'm going to try the 275mm Continental slicks or something similar (R6), which will allow us to stay in TTB and hopefully lower lap times a good bit.



                        We also got in a set of 265/35/18 Hankook RS-3 tires to test with in STX. I'm not too fond of the Toyos after that fiasco last weekend. Figured since we have 2 set of 18x9" STX wheels, a private auto-x test coming up, and the Toyos and Yokohamas, why not try the Hankooks at the same time? I've even managed to borrow a set of 18x9.5" wheels with 275/35/18 Dunlop Star Specs mounted... we'll test those and ponder those numbers as well. This will be as scientific of a test as we can manage: durometer, pyrometer, data logging, and timers with 3 competitive drivers over many runs. I will share this test as a tech article. Yes, GRM does a very nice series of autocross tire tests almost every year, including one on the "140-200" hot street tires, but they always seem to use light, small cars with narrower sizes than the 265mm we need. And from the rumors I've heard some of the ultra-small sizes have "unique compounds" that are softer than the wider tires we use have. Our autocross data seems to sometimes prove some long standing data inaccurate, which is mostly based on the narrower sizes. So....we'll see. May the best tire win!

                        Last but not least, the APR GTC-300 CF wing arrived yesterday.



                        I'm working up a set of stands that will fit the Mustang and another to fit the E30. This wing could be used at track events like the UTCC in July (E30?) or for NASA TT events (Mustang). On the Mustang, in TTB I'm already taking a +4 point hit for a "non-OEM wing configuration" (the OEM optioned rear cosmetic wing delete), so with this carbon 6 foot wingspan perched up above the roofline, I will bloody well get my 4 points worth.

                        Sorry if I seem a bit grumpy in this post, but well... I am a grumpy old bastard. The bushing install made a total mess of the shop and took longer than it should have. At least we know the shortcuts for this one, now. And I can't disguise my disappointment in the results from the autocross, and the course layout was far from my favorite. I'm sure the predominantly S2000 & Miata guys loved it, as it worked great for those cars. And being that the club caters to those cars, I can't fault them for that.

                        Until next time,
                        Last edited by Fair!; 02-13-2013, 03:56 PM.
                        Terry Fair - www.vorshlag.com
                        2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                        EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

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                        • #57
                          Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

                          Originally posted by Fair! View Post
                          Sorry if I seem a bit grumpy in this post, but well... I am a grumpy old bastard.

                          And I can't disguise my disappointment in the results from the autocross, and the course layout was far from my favorite.
                          Worry not Terry, if you're *only* 1.1 seconds off on a tight course and slick surface in a car that weighs 500 lbs more, I'd say you're doing pretty good!

                          Speaking of which, how much did you lose with the new seats?

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                          • #58
                            Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

                            Originally posted by murph View Post
                            Speaking of which, how much did you lose with the new seats?


                            The stock Mustang seat came in at 57.1 pounds and the Cobra Suzuka Pro was 32.5 with an E46 Seat bracket and slider. So we lost about 21.6# for swapping out the driver's seat. Passenger seat should be installed soon, and more weight savings to come too
                            Last edited by Fair!; 07-31-2015, 02:27 PM.

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                            • #59
                              Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

                              Project Update for May 9, 2011: So since my last post we've learned a lot, made significant changes in the set-up, found a ton of time on autocross courses. And we've decided to never track the Mustang again.

                              *** No more NASA TTB for the Vorshlag 2011 GT! ***

                              I know some of you will be disappointed to hear this, but please let me 'splain.

                              First, dual purpose autocross/time trial cars are always at the mercy of one set of rules, and that was very much the case here. Building around NASA TTB was severely limiting our choices in the STX autocross class. Over time I've come to realize that NASA has put this car into a poor base class (TTB) and with the high base weight (3770) its saddled with + the "points" system for modifications, it is crippled into uncompetitiveness in TTB or TTA, and cuts out fully half of the available suspension and power mods we could legally do in STX. No two ways about it - we cannot get enough tire under the car in TT for the weight it has, nor can we get anywhere near the power-to-weight limit and still stay within TTB, or for that matter, TTA.

                              I had thought about buying wider 18x10" wheels and going to Hoosiers for TTA, but the numbers just don't look very good. The typical TTA type cars will all be hundreds of pounds lighter, and this car simply cannot get there with the points left for that class. I'm not blaming anyone or going to stop racing in NASA TT, mind you, just coming to the realization that this chassis isn't classed or suited for TT.


                              We will run our 2011 GT in TTB (or TTA) no more...

                              The ruleset in the SCCA's Street Touring category, however, allowed us to do SO much more to the suspension and horsepower mods on this chassis than NASA TTB or even TTA allows, which is pretty funny considering STX is one of the slower ST category classes. STU and STR are both faster, and sometimes ST and STS are as well - STX itself could not only be the slowest ST class, but is often the slowest class at a given autocross event. But hey, its a different ball game in autocross, and a different set of rules. Its not like the 2011 GT is going to be an overdog in STX, not hardly, but it has a much better chance there than in TTB. Took me too long to finally come to this conclusion.

                              We came to this realization over time, after running the car at several track events this year and after looking at dozens of cars in TT classing. Just last week after a friend asked us to help him work up the TT classing for a 1998-2002 Camaro LS1 car. This car - which has a similar stock power to weight ratio as the 5.0L powered S197 - has a base class of TTD* (TTD +7 points) and a base weight of 3439 lbs, allowed to run fully 331 lbs lighter. After some more searching we quickly realized that every iteration of the S197 Mustang (its classed in 4 base classes, depending on year and engine) is fighting a losing battle in TT due to poor base classing compare to this otherwise very similar Camaro, among other cars - like the TTB BMWs that are currently winning that class handily. We helped him put together a TTC build sheet for the 4th gen LS1 F-Body that looked pretty unstoppable, and on paper (and from personal experience owning/racing in these) it would be faster than we could hope to get our 2011 GT in the "faster" TTB class. Just one example, but you get the idea.

                              Building for TT competitively means you need to be able to hit the power-to-weight max for the class, and still have enough points for a large enough R compound (Hoosier) tire for your (stipulated by NASA) given minimum chassis weight, and the '11 Mustang just doesn't work out that way no matter how you build it. Not trying to say these cars aren't fun and fast on track - they are - just that for NASA TT, they are too far out of the hunt to be not worth the expense, the risk, the effort, or the limitation to our STX prep any longer.

                              Second, Time Trial use with a new $35K car, that is still under the factory drivetrain warranty, is unwise. Tracking any car you cannot afford to write-off after an accident is pretty short sighted, and since I cannot control all of the variables that can cause an accident on track (other people's fluid spills, others' diving mistakes, etc), this car is going strictly to autocross/street duty. I've seen some nasty crash videos lately that made me re-think tracking heavily in this the cage/rollbar-less car. I tell friends and customers literally every day this same mantra - don't track your only street car, or any car you're making payments on, or any car you cannot afford to crash. And having a full cage in a street car is not safe without a helmet.

                              But look at it this way - pulling this car out of NASA TT will let us concentrate on making a competitive shot at STX class, which hasn't seriously been attempted in a V8 RWD car like this. This also unleashes many potential mods we couldn't do because of TT points, and this car looks more favorable in STX after we found some MAJOR performance gains in set-up changes in the recent autocross test-n-tune event (see below).

                              I am already looking to acquire another S197 chassis for a competitive W2W track car, in a class that is much more balanced with similar cars like the 4th gen F-Body. If you know of a 2010 Mustang V6 or GT that is a salvage title/flood car/affordable car, please drop me a line. That's a whole different story for another day, another thread.

                              Latest Mustang Mods

                              We've done two things in the past weeks to the Mustang. The night before the Test event (see below) we built a fixed seat bracket and the 2nd Cobra Suzuka kevlar race seat was finally installed. So there's another 30 lbs dropped. Its a fixed mount floor bracket that puts the passenger Cobra seat as low and far back as we can get it - the passenger sits almost 2" lower than the driver's side and even tall passengers can't reach the firewall with their feet. Perfect. Since we're not tracking it anymore, nobody can complain that we have fixed back seats in a track car without a roll bar - for parking lot events it matters not one iota. Car's don't flip over in parking lots.



                              We've also taken all of the NASA decals and class/extra number markings off the car, and although the de-cluttered look is certainly appealing, its only temporary. I spent an evening cleaning the car up after these were removed, using the clay bar to get the adhesive off and getting the car free of cone marks as well. Long overdue. We're still looking for the right "Vorshlag theme" to apply to this and our other 4 race cars, so graphic designers that want to show their stuff, please send me a note. Thanks.

                              This got pretty long so I'll cover the Test-N-Tune results below.
                              Last edited by Fair!; 05-11-2011, 10:40 AM.
                              Terry Fair - www.vorshlag.com
                              2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                              EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

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                              • #60
                                Re: Vorshlag 2011 Mustang GT 5.0 - auto-x/track build

                                Project update for May 10, 2011:

                                So, back to autocross performance of this 2011 GT. To say we have been struggling with the car in STX this season is an understatement: We've been getting beaten badly at both Regional and National SCCA events. The car started with off-the-shelf AST coilovers, our camber plates, 18x9" wheels, a 265mm street tire, and we just started autocrossing it. We've made a lot of updates since then but the results haven't been improving much. Sure, its faster, just not remarkably so. From day one we've been fighting to keep the rear tire spin under control - it was always a real motherf*cker to drive in a parking lot. As in - harder than anything I've autocrossed in the past decade. Rear traction under acceleration always severely limited every aspect of an autocross run. We also fought some other issues, but it always drove like it had 600 whp and 225mm mud and snow tires. It didn't matter how smooth you were on the throttle - it was always in a constant state of power oversteer, but we just came to accept that.

                                Costas, Amy and I got used to dancing that sideways dance, tip-toeing on the throttle at every corner exit, for months. On a road course (where you are in higher gears, and usually either WOT or almost completely off throttle most of the time) it was much easier to deal with, but in an autocross situation - where we are using part throttle so much more often than full throttle - we're slipping and sliding around like a greased pig. Also, on wet road courses it was also VERY difficult to control the back end of the car, and I had lots of oversteer issues in slow corners at both MSR-H and HHR in the wet.

                                April 29, 2011 - Riverside Annex Test-N-Tune

                                Come to find out, we needed another set of drivers that hadn't been driving it since day one to give us some much needed perspective. Another set of eyes/hands/feet to see the issues clearly. We got that and more at this private test day on April 29th. Todd F set up this event with AST-USA and we got the invite, as did 5 autocross cars. This was an intense day of testing, on concrete, with AST's shock valving trailer on site to make valving changes to test and verify on the spot. Couldn't have asked for a more ideal situation, and we're thankful Todd and AST let us join them. We brought lots of tools: DL1 data logger, Chase cam video aimed at the front tire, timers, durometer, pyrometer, and more. This degree of testing on this car was long overdue, and much information was gained - I'm still sorting through the data. I'll give a highlight of what we learned in this post and follow up with more data and video as time permits.



                                The Course

                                The site was the Riverside Annex, and the area was the 4-10 split, and the surface is concrete. The course laid out was typical for our Test-N-Tune events. It was 30 seconds in length, with a constant radius sweeper on one end, a decreasing radius on the other, with one long side of slaloms (60' spacing) and big offsets on the other side's length. The Mustang was only at WOT for maybe 2-3 seconds per run, so it was not a power course. To simplify testing it was run as a continuous circuit, with a start/finish line where we could mark consecutive laps, and each driver usually made 3-4 laps at a time with a running start. This minimized starting/launching variables, minimized driver learning curves, and made for quicker testing. So the driver would make a half lap before the start, then lap/lap/lap, then come in to look at times, adjust pressures, check data, and we'd shag any cones knocked down.

                                We used to hold 2-3 of these private Vorshlag autocross test-n-tune events for our own cars and VTPP testers every year, but haven't held one in 2 years, and it has showed. Our DSP run last year in the E46 was a train wreck, as was our untested E30 autocross set-up at the 2010 GRM challenge. Its hard to learn enough in a 4 run autocrosses to make speedy set-up progress or test things back to back, but when you can make 70 runs in a day (like we typically do at our test-n-tune events), you can learn and test a lot of variables much more rapidly. We had about 60 runs logged in the Mustang at this event, and we learned an enormous amount in only 6 hours.



                                So we got down to the site at around 9:30 am on that Friday, quickly unleaded the trailer, and helped set-up then mark the course - half of which was already up when we got there. We had 3 sets of wheels and 4 set of tires we had on hand to test (we ran out of time and didn't get the Hankook RS3s mounted or tested that day), plus we wanted to try some new shock settings and maybe even new base valving. As anyone running in Street Touring knows, there are a LOT of tires in the 140-200 treadwear range to test, and for this particular class & car there are at least 7 different potentially competitive tires we could choose from. We have very limited outside test data to rely upon for this somewhat unique STX car (heavier and more powerful than anything else run in ST so far) and max tire size (265mm), as we've been running in other classes (on Hoosier Rs) or on 245mm tires in STU for other cars in the past few years. Also, the ST tire tests done in GRM the past few years have been on smaller and lighter cars (Miatas and Civics), and the tires that are fast on those don't always "Scale up" to the bigger and more powerful cars like our 3600 pound mustang with 400 whp.



                                Baseline Set-up Testing

                                Before we could start putting the various tire brands to the test, we needed to play with a few things on the baseline set-up, and make the big shock adjustments. Before that, we had to get the driver familiar with the course, the site, and the existing set-up. A quick note about the existing setup: It has been a constant blur of changes, with never more than a few runs without some variables changed radically. That's pretty much a nightmare. We have never been to an autocross event where at least 3 or more major things had not been changed. Costas would jump in the car to make his run and if we were lucky, Amy and I might get a few miles around the block to test the latest round of changes. At the last event Costas drove the car at he had to quickly learn to drive with these changes: new Tires/Pads/Wheels/Front Swaybar/ECUmap/Coldair/etc. Whew! We were all very much looking forward to getting more acquainted with the car with a lot of runs today.

                                We came with 2 drivers, myself and Costas, but I had just run a LeMons endurance race the weekend before where I think I fractured a rib (3 weeks later it is still very painful). Long story short after one half of a lap on the 30 second autocross test course I was doubled over in pain and out of the car for the day. The race seat was digging into the injured rib on left turns, so this meant that one more variable would be removed from our testing - the driver. Costas took over as the main test driver for the day and I was on stop watch/tire pressure/durometer/camera duty. This would actually speed up our testing, as one driver could minimize the driver learning curve more quickly than two, and he's already shown to be super consistent, and we've typically been no more than .1 sec apart at most events.



                                So Costas ran half a dozen warm up laps to familiarize himself with the car and course, and his times quickly stabilized to within .1 sec between most runs. We then started "Baseline testing" the shock settings and tire pressures on the Yokohama AD08 tires, which are a very known quantity for us having run them on another ST car in 2009 and at most events this year on the Mustang. We also had Brian Hanchey and Stuart M of AST-USA on hand to closely watch the car as Costas got acclimated to the course and the Yokohamas, and Brian noticed something weird going on straight away. He made some shock adjustments and the car was a tick quicker, and we made some tire pressure adjustments (trying some radically new pressures) and found a few tenths more, but it was still the usual handful to drive.

                                Hanchey then hopped in and took a few laps, to see how it felt first hand (invaluable), fought it the whole way, then hopped out and said "How in the F*** are you DRIVING it like this?!!" We then asked Stuart to make some laps and he felt the same way, and has a 2006 GT that he daily drives and tracks as well. Later that day, former F Stock champion Casey Weiss took a few runs in it also; he's been running in S197 cars the past 3 years in F Stock. Same observation - the throttle is WAY too sensitive, car is too hard to drive. Hanchey has two decades of experience, as does Casey and Stuart, and they were all 2 seconds off the pace even after a few laps. That's not a knock on their driving - no, its showing that this mess of a set-up is that hard to get used to. I've co-driven with Weiss and Hanchey many times over the past 20+ years, and they can usually hop into any car and go fast as Hell within 1-2 laps. But when proven, fast drivers like these hop in the car, and it still takes a significant learning curve. Luckily we've already been "learning" this for months. Given another dozen laps they would have been right on pace. Even after 5+ autocross events in the car and dozens of laps, its still difficult. Costas was literally making throttle changes with his toes thru thin racing shoes - not the typical ankle movements - its that sensitive.


                                Left: Costas during one of our many tire changes for the day. Right: Hanchey working with some F Stock racers on ASTs in a 2007 Shelby

                                They all felt that because of the very abrupt power application the car was nearly undrivable, and certainly holding us back. Hanchey was convinced the car had serious throttle tip-in/mapping errors. We've been fighting it all year, just thought it was supposed to be this hard with 400 whp through 265mm street tires. From an outside perspective - it was obvious. This was a 30 second test course run entirely in 2nd gear, nowhere near redline but always in the meat of the powerband on every corner or transition exit. Hanchey said to "try a run in 3rd gear" to prove his point. I told him that was crazy, but we humored him. Costas made 3 laps in third gear. It was ~2000-2500 rpm lower than in 2nd gear at every spot on course. He came in and said "No way, that felt SLOW", but it was .3 sec faster - best run of the day so far. WTF?! Yes, there is a problem with power application and this proved it.

                                Now it wasn't faster on every lap. He took 3 laps like that to get used to it, and the first lap was slower, the second lap was even, and the last was a bit quicker then all previous laps. It was the change in power application, but also a *large* change in lines he took through the cones. Very different line could be utilized with the less sensitive throttle. More of a "momentum" line than a point and shoot line. But in the end, it was faster cutting back on the power by running the higher gear through the course.

                                Why is that? Let's explain - modern fly-by-wire throttle systems have the ability to have the throttle response (correlation between % pedal opening and % throttle body opening) tweaked, by both the OEMs and aftermarket tuners. The "trick" is to make the throttle mapping much more "falling rate" or digressive, which make the cars "feel faster". This means - the first small percentage of pedal opening makes for a LARGE percentage of throttle opening. So when you barely give the car a little gas pedal, its opening the throttle very aggressively, and it FEELS FAST. Which makes it very difficult to delicately adjust throttle, which is all you do in an autocross with a powerful car. That's been the case all along with this car, both with the stock tune and the aftermarket tune we added via the SCT Tuner. This is actually the 2nd throttle mapping we've tested and its still MUCH too aggressive.

                                Throttle Mapping Issue = Found!

                                What we actually need, to make the car easier to control at lower speed events like autocrosses, is a rising rate throttle map as described and charted on page 36 of Neil Robert's excellent "Think FAST" book. And I quote, "A rising rate throttle... provides fine control over the lower power end of the throttle range. That helps you blend cornering into forward acceleration smoothly and early". An example of this from the 1960s was the uber-powerful and light Can Am cars, another quote, "Jim Hall said that a rising rate throttle linkage was an absolute must on the big block Chevy (1000+ hp) Chevy-engined Chaparral Can Am cars to make them anywhere close to being drivable." We don't have a 1000 hp big block underhood but we are trying to take 400 whp V8 and power it through somewhat narrow street tires, and do so in a parking lot, in lower gears, with abrupt power transitions.



                                So the throttle mapping is a big thing that needs to be changed, and throughout the day I kept asking Costas to make a run or two in 3rd gear, every hour or so. And every single time, on every set of tires, and every permutation of shocks, the car was as fast or faster in 3rd, a higher than optimal gear, because it was so much more drivable. Matching those times in 2nd gear took extreme control and wasn't nearly as repeatable. The shop that is providing our custom SCT tunes for the Mustang was called and we described the issue in great detail; we were already on a supposedly less aggressive throttle map, but now a third custom tune was created, and Paul M and I just loaded it to the Mustang this evening. We'll be testing this in anger this coming weekend at a SW Texas Divisional series 2-day event.



                                The next big revelation was in shock revalving. We had already had AST-USA revalve the fronts but the rears were still pretty much "off the shelf". Hanchey had a suggestion, we asked them to try the valving change he thought would help, they revalved the shocks on the spot, and it made a huge difference in times right off. It has us thinking about some even more radical shock ideas to test in the near future- which, for business reasons, I'm going to test before we explain these plans.

                                After this significant jump in times was from the shocks verified on several more laps with the Yokohamas we moved on to the Toyo R1Rs, then the Dunlops, each time re-verifying the shock settings front and back as well as the tire pressures that worked best on the Yokes. So which tire won? Well, it was pretty close between two of them, and I don't want to spill everything just yet (need time to crunch numbers and edit video), but the Toyos are for sale...


                                Fresh set of 265/35/18 Toyo R1Rs ..... now FOR SALE!

                                These R1R tires are still full of tread and have less than 20 total autocross runs on them, all in the last 6 weeks. Still very fresh, great durometer numbers, so how about $600 + shipping? Probably make great track tires for somebody (and I will keep them for just that if I only get low-ball offers). They won't be going back on this Mustang for STX use, that's for sure. We do really like the Dunlops, even these 3 year old former street tires we tested with. I bet you will see a fresh set on our car soon, for testing head to head with the Hankooks and Yokohamas, and possibly in some unusual sizes. We learned some things that day that we want to verify with even more testing.

                                We didn't have time to run into town and have the Hankooks mounted - the 265/35/18 Hankook RS3. So we've already mounted those and they will be run this weekend at the SW Divisional here at TMS. But as the day was winding down we did re-mount the first set of ours - our control set, the Yokohamas. We noticed only a slight uptick against the original times, so the temperature creep didn't account for more than .1 sec of our overall gains, from beginning of day to end.



                                OK, so what did we learn? How much time did we gain, if any? From the beginning of the day, starting with shock and tire pressure settings we'd refined so far this season, to the end of the day, we found 1.1 seconds on a 30 second course. That's.... a lot. This was between testing some unusual tire pressures, the various tire testing, and most of all the shock changes (valving changes uncovered almost a second alone - you can't tell me "shocks don't matter much"). And this is still with 2nd gear power application almost impossible, and the car quicker in 3rd gear. Will this latest round of improvements + a new throttle map translate to a more competitive car on a full SCCA sized course? We hope so.



                                THere's a couple of stills from the "tire cam" videos (that I still need to edit/upload) showing sidewall deflection; the Toyo was compared to the Dunlop & Yokohama. Costas also managed to replicate that unusual "limp mode" error icon on the dash that I ran into event last month. It happened 3 times during the day, but he wasn't allowing any more wheelspin than normal, just the same massive amount we always see in 2nd gear. He'd notice an abrupt lack of power, abort the run and come in to show the icon; I snapped a picture of it. To clear the error you have to turn the key off and restart the car. Odd.

                                More soon,
                                Last edited by Fair!; 02-13-2013, 03:58 PM.
                                Terry Fair - www.vorshlag.com
                                2018 GT / S550 Dev + 2013 FR-S / 86 Dev + 2011 GT / S197 Dev + C4 Corvette Dev
                                EVO X Dev + 2007 Z06 / C6 Dev + BMW E46 Dev + C5 Corvette Dev

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