Vorshlag/AST EVO X - Project / Deveopment Thread

[Fair!]

Re: Vorshlag/AST begin Evo build!

Where did you get it, is that the normal published weight *ie is the published weight correct or off*, what is the CCA of this, have you compared any of the others *ETX16L, ETX20L........*?

Thank you!

I never trust published weights for... anything. But its actually pretty close to what they stated for the ETX18L. I believe the "18" in the part number refers to the approx weight, by the way.

[Fair!]

Re: Vorshlag/AST begin Evo build!

Project Update for January 11th, 2009: We finally got the spherical rear shock mounts in from AST for the EVO X and installed the 4200 rear shocks yesterday (the fronts went on a while back with our alloy steel Vorshlag spherical camber/caster plates). With these pieces in hand we can move forward with suspension testing.

NEW COILOVER SUSPENSION

Both Hanchey and I have driven the car around extensively now (test loop, street driving) with the 4200s on front and back, and its awesome. We'll tweak a few things then put these into production - and we already have a brand new shock design (upcoming 5100/5200 series ASTs) planned for testing on this car very soon.



We are scrambling to line up a track day to test 4200 shock settings, spring rates, alignment tweaks, etc. Brian wants to change the base rebound valving on the fronts before we hit the track, then we're ready.

Full gallery of AST / EVO X installation pics: http://vorshlag.smugmug.com/gallery/6894033_ZP2NB


These are the ride heights were are happiest with. No droop travel was lost at these heights.

Of course we rated the OEM rear springs (some goofy tapered/progressive Eibach spring). It was variable rate 160-215 #/in, and we used a 550 #/in rate for initial testing. The car rides better than stock with the compression valving turned down. The OEM shocks it came with are garbage - one of them is already leaking, at 6000 miles, and they have zero compression damping and too much rebound. Its not hard to improve handling over this stuff, even with nearly 3X the stock spring rate.


Better picture of the Vorshlag camber-caster plates (pre-production) add positive caster and negative camber adjustment


Our front spring package allows the lower spring perch to sit above the tire (lots more room inboard)


Setting rear ride height (left) then locking down the lower perch (right)


Left: Stock rear shock assembly = 12.6 lbs. Right: AST 4200 rear was 9.1 lbs


Rear rebound knobs are accessible with the forward plastic trunk bulkhead removed, but we'll add remote cable adjusters for easier access instead



Like up front, the rear shock's Compression adjuster knob is at the bottom. Its easy to reach if you lean down and reach behind the tire - enabling fast/pit stop valving adjustments. We'll post up with more data once we get this car on track with the DL-1 onboard.

Cheers,

[Fair!]

Re: Vorshlag/AST begin Evo build!

Project Update for January 13th, 2009: A quick update on my birthday, showing the new even lighter exhaust we made.

LIGHTWEIGHT RACE EXHAUST, Ver 2.0

After hearing how quiet our first "race" exhaust ended up at, and with the main muffler gobbling up a bit more weight than we liked, I went back and re-made the lightweight after cat exhaust on the EVO X. This is just a one-off exhaust we made for our shop car and not something we're going to mass produce or market, so its not exactly pretty but it is functional. The system is pieced together with thin wall 3" carbon steel exhaust tubing and mandrel bent bends from SPD Exhaust. We picked up a few V-band clamp assemblies from them for this version as well.



The first step was cutting off the rear section in front of the main (rearmost) muffler we added, with an eye for the added clearance room around the to the rear subframe (1/4" is enough). I tacked the clamp to the now "mid-pipe" section (shown above) and mocked up the exhaust with the muffler on the car and tacked that end in place.


The rear muffler section weighs 12.9 pounds and is now removable.

We then added a hanger to the back of the mid-pipe (bolting to one of the many chassis bracing points) and then made a new rear section to take the place of the muffler, and added an additional V-band stub and mount to that end. Everything fit great and it sounded a LOT better. The entire race exhaust (sans muffler) is now 16 pounds after the cat.


The "Race" version was mocked up. This rear section weighs just 4.5 pounds and is a bit louder.

Brian drove the car around for a day with the race setup, loved it, and now its removed for coating. Building another setup like this for a 2008 STI this week (Paul's STU car) and we'll get that one coated as well.



An extra 45° bend and a short length of 3" straight pipe + a V-band and a little bit of work, so wasn't much more money, and now we have a dual purpose, reconfigurable lightweight race/street exhaust. Thanks to Paul for helping with the version 2 work.

continued below

[Fair!]

Re: Vorshlag/AST begin Evo build!

continued from above

Here is the exhaust coated with a high temp black ceramic coating:





Should provide a little more long term protection on this carbon steel exhaust system.

Cheers,

[Fair!]

Re: Vorshlag/AST begin Evo build!

When are you going to test the bars? I am assuming you will use both front and rear. Will be interesting to see how you like them with the coilover set up. Have you thought of a rear bar upgrade only to start?

After looking at all of the many options available, Hanchey just contacted Cobb about anti sway bars and we'll likely go pick them up this week (along with their high flow catalyst). We're going to put them on the front for sure and probably both ends soon.


Left: Rear bar looks easy to change. Right: Front bar = notsomuch

The front bar doesn't look like fun to remove/replace on the EVO X but even with 450F/550R #/in spring rates it still needs help with roll control. We are going to up the front spring rate as well before doing one final test, then taking the entire suspension off and sending it to a magazine for one of their test cars. We have a new setup (5000 series Inverted ASTs) coming for our EVO to test with very soon. We're already testing 5100, 5200 and 5300 inverted shocks on a number of cars and the testing is going VERY well. We should have 5100s on the shelf for the EVO 8/9 and EVO X soon.

[Fair!]

Re: Vorshlag/AST begin Evo build!

Project Update for March 4, 2009: A little update on our custom race / street exhaust setup. We had this ceramic coated in black, mounted this to the EVO, and its working pretty well.



We have to make a new hanger for the "Street" rear section, as it wasn't as well made as the one I did for the "Race" rear section - the heavier Race section come loose at a bumpy race track. Don't ask.



The "Race" version is still very livable and that's what gets used almost all the time.

edit from 2018: This coating did not last well over the long term. About a year later it was falling off, and turns out our powder coater that we used was somewhat mis-representing the "ceramic coat" product he used.


Left: Bare 304SS headers from our E36 LS swap kit. Right: Ceramic coating added

We have since found another local supplier that uses a proper ceramic based coating, which lasts a LOT longer. That's the joy of doing things for a long time - we learn things, and share them with you!

Thanks,

[Redwood]

Re: Vorshlag/AST begin Evo build!

Excellent. It looks very professional!

[hancheyb]

Re: Vorshlag/AST begin Evo build!

Project Update for March 4, 2009: The Vorshlag Crew had a fun filled track test day on Tuesday of this week.

A magazine we work with was in the Austin area working on a Tech article, so we had asked them to drive the Vorshlag EVO X for a possible future article. They finished up their testing on time and had Tuesday morning free. Our good friend, Andy Hollis, is a member at the new Harris Hill Road country club track in San Marcos. We had a magazine writer, a track, and a car. Road trip!


Left: The magazine tester talks with Andy. Right: Heading out on course


Seeing as the EVO build is supposed to be a "do-it-all" project, we decided to make the 251 mile drive down there in the EVO versus trailering it down there. We've had the Dunlop Star Specs on it for a while - they are doing fine and wearing well, with several track days, many autocrosses, and 6000 street miles. They are a great tire if you want to "do it all".

We left Dallas at 5:30AM, arrived 5 minutes late in San Marcos at 10:05, unloaded the car and got started. The EVO's onboard GPS Navigation led us directly there (for once). We had added Cobb sway bars to the car last week and had not tested with them on yet. Also, we didn't have time to set the camber trackside for the initial drive by the magazine writer, as his schedule was pretty tight. It wasn't really crucial since this was just a brief test drive. We weren't trying to set fastest lap (yet) - more on that in a bit. After a brief photo shoot, airing up the tires and removing our wares from the car, we were off. The car was a little pushy for our liking, but there wasn't time to really dial the car in for him.


The Harris Hill Road course has excellent pavement, big elevation changes, and lots of room

Everything went well and the comments were positive concerning the ride quality and handling. Keep in mind it has to be daily driven, autocrossed, and track driven which is a challenge in the EVO. We were a little disappointed that the car didn't handle up to our track standards out of the box, although it wasn't a surprise. We had not had the chance to get on the track since getting the AST 4200 suspension installed plus the new Cobb bars. We had autocrossed it with the ASTs, but that is a complete different driving style and camber/shock setup. After the magazine writer had left we put in several additional sessions in the EVO, playing with camber & toe, shock settings, tire pressures and sway bar settings. We were able to get most of the push out and the car was extremely neutral when the tires were cool. In a few laps the weight of the EVO just overpowered the narrow 245mm tires. We know it would improve considerably with 275mm rubber. When the tires overheated it would push, and the DL-1 data showed it in lap times. It would slow down a second or more after the first few laps. We saw as high as 1.21g lateral and 1.12g under braking, however, even with the skinny tires.


These pictures were with the "street" camber of -2°. It got a lot faster at -4°

Thanks to Chris Fleming at Cobb Tuning of Plano, who helped source new Hawk DTC-70 brake pads for the track testing and helped with the swaybar install at their shop. With these new pads braking on track was MUCH improved. Even though you're not supposed to drive them on the street, we took the car down there with the track pads on it. We just made sure our stops were all hard and fast on the highway, hehe.


The horses in the background liked the EVO's exhaust note

You can see in the pictures the car still has some body roll. We plan to go up in spring rates to help combat this. It rides so well now that I'm confident we can revalve the shocks, go up in spring rate, and still maintain good ride quality. We asked the track management what a good time at Harris Hill was for their clockwise 1.8 mile course. They said in a street car a 1:35 is fast, anything 1:30 or less is really fast. By the end of the day we were running 1:30 laps according to our data logger. We were happy with the results and know there's more time in it, especially with properly sized track wheels/tires. We'll be running it at a NASA Time Trial event in two weeks and a BMW Club event after that, so we'll make some tweaks and go back for more. Stay tuned!


Fair in the Miata: "Its a bit different than driving our V8 powered BMW..."

As a nice bonus, H2R let Terry drive their club's track prepped Miata (NB). It was equipped one of our competitor's coilovers on it so it was nice to get an on-track comparison. He was "just going to do a lap or two" on the almost corded race tires, but had a blast and stayed out lap after lap. Of course he said it needed better shocks, ha. Driving the lightened Miata on 225mm R compounds is "too easy", yet still lots of fun.

The folks at Harris Hill were great and they have a fantastic Country Club road course and driver's facility. If anyone that lives near Austin or San Marcos hasn't been out there they need to look for a DE event there and go (and join - we were there on an open "member day" and had the place completely to ourselves!) We're thinking of renting the track in the future and coming down again to test with some AST customers - it was well worth the 3.5 hour drive from Dallas.

[hancheyb]

Re: Vorshlag/AST begin Evo build!

Project Update for March 6, 2009: Last night we were doing some "clean up" projects. I had a chance to throw the stock MR front strut on the shock dyno. Pretty interesting plot really. I did a run at 15 inches/second. This is a common "full sweep" people tend to want to see. It actually is completely unrealistic in the real world. There's no such thing as 15 ips in rebound so why measure it?

So I did a sweep at 5 ips as well. Notice how different the plot is on rebound (the negative side). Very little hysteresis and more progression AND zero or very little rebound at slow velocities. That's where you need rebound on turn-in. This curve has almost the opposite shape of all high end shocks out there where you have high rebound forces at very slow speeds and a digressive shape to the curve above 5 ips. 5 ips (or less) is more realistic as to what you see on the track or street and where you should look for performance. We've tested some of the low cost overseas coilovers where they made zero rebound force till 4 ips. That's the difference with high end shocks. Bistein makes good shocks and probably gets stuck with specs the manufacturer wants to meet liability and other requirements.

We recently purchased a potentiometer for testing (shock pot) to prove this in a real world situation by using our data logger and driving around on our test loop. We've got some really good pot holes, washboard bumps, and turns to show what your car is really doing on the street.

[hancheyb]

Re: Vorshlag/AST begin Evo build!

Project Update for March 13, 2009: I had a really interesting morning I thought I'd share. Late last night Fair and I decided to install a new spring rate package for this weekend's events. Saturday I'm taking the car to a NASA Time Trial, Sunday "the Fairs" will be running the car at an SCCA autocross in STU, a good mix for testing. After seeing all the body roll at Harris Hill we decided to go from 450/550 lb/in to 700/800 rates. Now the car had slight understeer with this first combination, but I attribute some of that to running a skinny, worn out street tire versus the balance AND the nose heavy platform that the Evo is doesn't help. So if we fix the front, it's possible that we fix the issue. We don't like to change the opposite end of the car if we don't have to, I.E. fix what's broken. Most of the time you'd think more spring rate would make that end push more, but sometimes that's not the case. As a side note, we'll be switching to Yokohama AD08s in late April, running AD07s in the meantime. We have always loved Yoks for their R Compound-like turn-in and have had a 1st and 2nd place at Nationals on them too which doesn't hurt.

I drove the car home last night and it definitely felt aggressive to say the least, but not unbearable. I still want a suspension that I can drink a Starbucks in. Call me a snob, but I gotta have my coffee. I had to meet AJ from Performance Speed Tech (shop at MSR) this morning to deliver a part for a customer. We met in downtown Fort Worth which is 65 miles one way for me. I figured it might be a good test for the new package. I revalved the front slightly and did nothing to the rear. The rear has been working well on soft settings so no need to go up. The front we were running at full stiff so with the increase in rate I upped the rebound valving. North Dallas to Fort Worth is a great test for a suspension. Concrete side streets, new concrete highways, old concrete highways, new asphalt and old, VERY old asphalt highways make up the trip. Not to mention downtown Fort Worth is a disaster of construction. You get a mix of every bump you could ever imagine.

The trip to Fort Worth was comfortable, still aggressive. Definitely not coffee cup worthy. The car was pitching more than I like, and it was pretty obvious the rear of the car was the likely problem since I had them full soft and 6 clicks on the front. After meeting AJ I turned the rears up 5 clicks and drove back to our shop down the same roads. It was a night and day difference! The car was super smooth, obviously stiffly sprung but you could definitely drink your favorite beverage now.

Why do I bring all this up? Aside from the fact that it proves that monotubes can do a great job of controlling high spring rates without beating you up, it comes back to all the chatter we hear about critical damping. Yes, the theory and practice of trying to find the "perfect" suspension via calculations works, it can never beat the actual practical testing on the street. With a simple turn of the knob, I was able to match the front and rear frequencies of the suspension without too much effort. I reached in the trunk, turned two knobs, and was done. I can probably tell you that 700/800 won't be the perfect combination in a spreadsheet (I didn't calculate it), but with some tuning and testing, it might end up being very fast. We'll see this weekend.

[hancheyb]

Re: Vorshlag/AST begin Evo build!

Project Update for March 19, 2009: Well, I was hoping to have all the race results in before I posted an update from the weekend. Last Saturday Terry and I took the Evo to MSR for the NASA event. The weather was pretty bad when we got there. It was in the low 40s, still raining and misty. The track was super slick. We were there late, but no point in going out since the weatherman said it would dry out slowly. Time Trial is a "best lap" effort so there's no point in beating the car up.



And it was sloooow to dry. The track wasn't fully dried till our 4:30 session later that day. Our first afternoon session was almost dry. The car turned a 1:27 in still slick conditions. That was good for 4th in the group behind two Vipers and a ZO6. The last session had some more "big guns" come out and the guys with R compounds started showing their grip. We managed a 1:25.1 in the Evo which was good enough to win TTA, and be within a few tenths of being a front runner in TTS. While a 1:25 isn't super fast when you consider the Evo is 3600 pounds and we still have the Dunlop 245mm street tires (Star Specs), a 1:25 doesn't sound so bad. A lighter, raced prepped E36 BMW usually runs 1:24s on Hoosiers for a comparison. So given the cold weather, the drying conditions and the prep of the car, we were happy with the results.

The car felt really awesome pretty much everywhere. It could use more power, but turn-in, mid corner, and corner exit were all great. For once, it had a touch of oversteer which was nice and much different than our first event at Eagle's Canyon on stock suspension. I was getting pulled on the straights by all the TTS and up cars, but usually closed the gap in the tighter turns (thank you autocross!). The Evo was definitely fast in the turns making 1.28g according to the DL-1. It made 1.15g in braking a time or two. And an interesting side note, when you start making 1.28g in an Evo you have to fill the tank every session. The Evo is thirsty on the track. Even with 5/8 of a tank, the car will suck air at some point. With stock suspension we could make 2 - 20 minute sessions, not anymore.



Sunday Terry and Amy took the Evo to Pennington Field for a SCCA autocross. Amy ran in "Women's" and Terry ran in the "X" class. Both classes are PAX based. Since he's probably running different cars this year, he wanted to be in a class that allowed that. Amy smoked even STU Open with a 37.2. That would have won STU by 0.4s! Terry was a few tenths behind with a 37.4. Amy wrapped up the 10th spot in PAX in a field of 148. That's an encouraging result, but still the car was 1.5s out of 1st place in PAX which means we'll need to do better to place well at Nationals. Considering the level of prep, this definitely was a promising finish in its 2nd autocross ever (with shocks). The transmission comes through again with some 2-1 downshifts and 2-3 upshifts you'd never dare do manually. Thumbs up to the SST!

Needless to say, the new spring rates really helped at the track and autocross course. Terry said the car turned in so fast you had to rethink your driving. This is definitely a change from the first autocross at TAMSCC where it was a little sluggish.



New things coming soon:

1. Race seats - get some of the "lead" out. The car is making enough grip now that even the awesome stock seats aren't cutting it.
2. Yokohama AD08s - this should be worth a few tenths at least over our beat up Star Specs, most likely much more.
3. Lighter and wider wheels - we'll probably get a 18x9 or 9.5 for the car, possibly 18x10s for the track wheels.
4. Lighter brakes - see if we can't get some weight off the front with some Racing Brake goodies. The stock brakes are still marginal at best on the track.

[hancheyb]

Re: Vorshlag/AST begin Evo build!

Project Update for March 30, 2009: Another fun weekend in the Evo! We joined the BMW CCA Saturday at MSR-C for their DE and Club Race. Kudos to Bruce Heersink and team for running a great event!



This was a great test after our NASA event two weeks ago where we ran very tired 245/40-18 Dunlop Z1 Star Specs. We switched to Yokohama AD07s (265/35/18s) and Enkei 18x10.5 wheels. The AD07s are on closeout since the AD08s are around the corner. This was a chance to try something new and bigger, for this "bigger" car. Robert Fuller of RobiSpec shipped out the wheels the day I called and we had them two days later. Thanks Robi! A mid week trip in the pouring rain to MSR where AJ at Performance Speed Tech had our Yoks and we were ready to go. The 265s were a perfect fit for the fronts. The rears required a little fender rolling, but we made sure to stick to the "letter of the law" for STU so they aren't aggressively rolled in the least. With the right offset rears, we believe we can run 285s no sweat. The front easily swallows it. We'll most likely settle on AD08s in 285mm width for NASA TT use.



Looking over the DL-1 data from the NASA event two weeks ago, we had max values of 1.25g lateral, with 98% values of 1.05g on the Dunlops. Using 98% values rules out the occasional variance in the data. The weather was almost identical for the two weekends, with most sessions were in the 40°s with high winds sustained at 25-35 mph, with gusts even higher - not your perfect day at the track. I had to close my helmet visor the wind would blow so hard into the car on the south side of the track that it would move your head!

The new, unshaved AD07 Yoks pulled a max of 1.40g and 98% values of 1.15g. So basically we picked up 0.1g going from a Dunop with 2/32" of tread to a full tread, wider Yokohama. Shaving the tires can be good for 1-2s a lap depending. Lap times were a second faster as well. The DL-1 recorded a 1:24.2 vs. a 1:25.1 from two weeks ago. Not that you can put much into theoretical laps, but the DL-1 says the "perfect" lap would have been a 1:23.4. I would believe it though since there wasn't a perfectly, traffic free, clean lap in any of the 4 DE sessions (unlike in NASA TT, there's only 4 places to pass at MSR in a DE). Unfortunately we could not take in reliable tire data during all this. We started with 36/34 psi and the outside tires climbed to 58/55. Yes, hard to believe. The car had an obvious tire pressure induced push towards the end of each session, no doubt related to the insane tire pressures. We didn't have enough sessions to play with pressures or tire temps. The tires weren't rolling over to the edges so the pressures we used were not ideal - 5-10mm of the tire tread wasn't even being used at these high pressures.



I lost the 2nd session entirely, betting 3/4 of a tank of fuel was enough, but on the first lap the car fuel starved and I had to go get filled up. The EVO does use some fuel in track use. Now that we've really got the car working, it can't even make a 20 minute session without fuel starving! MSR has a complex of left handers that ends up being one constant arc called "Buzzard's Neck". By the end of 20 minutes the poor EVO would fuel starve coming onto the straight after that sequence of left handers - Not ideal.

So another great weekend in the EVO. No issues, and no trans overheating. What's it like to drive? It is "simply amazing". It turns in when you want it to, it is so easy to correct in mid corner. Terry drove it on the new tires briefly and was shocked at how instantaneously it responds to steering inputs. It also never feels like you're in trouble even when the back end comes around, with a quick flick adjustment of the wheel putting the car back on line. Here is a car that has to run full of fuel, is daily driven, can carry 4 adults, and with driver and fuel probably weighs 3800 pounds (we're going to weigh it this week), on full tread street tires, and it turns 1:24s at MSR. That would have put it towards the front third of the qualifying grid for the BMW Club racers, most of whom are on Hoosiers and weigh around 1000 pounds less. We barely have any power mods either - the car is probably 80hp shy of most hard core track driven EVO Xs now. So we're happy with the track times its putting down.

So next up is the Houston SCCA National Tour this coming weekend, switching gears to STU class autocrossing. We're sort of in a jam on tires, unfortunately. Its 5 days before the event and we're not sure if we're getting the new tires or not. Long story, out of our control.

After that event we'll be installing race seats and a harness bar and heading to COBB for an updated "retune". They've played with the MIVEC and are getting more torque - sounds good to us. Our new inverted strut AST 5200s should be here this week, too. When we get the LS1 BMW back together (new LS2 based 550hp motor is done and going in soon!) we'll take both cars to MSR and try to do some comparable lap times of 4200s vs 5200s on the EVO.

[Fair!]

Re: Vorshlag/AST begin Evo build!

Project Update for March 30, 2009: I wanted to add a little more info on the new wheels and tires Brian mentioned above. This is the new track setup we're using for now, until the 285/30/18 Yokohama AD08 comes out. The 285 should fit the front great, but the back wheel might need more backspace.


L: Stock BBS 18x8.5" and 245mm Advan = 46.8 pounds. R: Enkei 18x10.5" and 265mm AD07 = 48.5 pounds

Front:

Fronts fit like a dream, no spacer. Lots of clearance inside and out. Wheel alone was 21.6 pounds

Rear:



Rear fender lips had to be rolled, but it didn't take much.



We also tried a 18x10 Enkei ET38 wheel and it fit the rear much better, but needed a spacer in front. If we go to a 285mm tire we may get two of these 18x10s for the rear and keep the 10.5" wheels we have now up front. This way they would all fit without spacers.

[Thinkkker]

Re: Vorshlag/AST begin Evo build!

Enkei NTS03+M's = new hawtness for racers.

Did you go with a 35mm offset or the 24 on the fronts? *that is the two sizes I can recall them offering*

What is the plans for STU wheels/tires? Stock ones?

[hancheyb]

Re: Vorshlag/AST begin Evo build!

Enkei NTS03+M's = new hawtness for racers.

Did you go with a 35mm offset or the 24 on the fronts? *that is the two sizes I can recall them offering*

What is the plans for STU wheels/tires? Stock ones?

35mm. Might go to a 18x9.5 for the STU setup.