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Hanchey / AST-USA 05 Subaru Legacy race car

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  • Hanchey / AST-USA 05 Subaru Legacy race car

    Just thought I'd get this thread started for Brian, since I snapped some pics of it up at COBB a few weeks ago and at our shop this week:







    I'll let Hanchey fill in what everything here is, what the car was originally built for, and what he's doing with the car now.
    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

  • #2
    Re: Hanchey / AST-USA 05 Subaru Legacy race car

    New exhaust: The Legacy received a COBB 3" downpipe recently and that made the old 2.5" exhaust no longer fit...



    The old system was a bit on the small side for the 2.5L turbo powerplant, so when the new downpipe went on Hanchey decided to go with a 3". Since all of the good exhaust shops were busy, we did the work instead.



    We picked up 6 feet of thin wall (.049") 304 stainless tubing and one 90° mandrel bend from Dallas Performance plus one 3" V-band we had on hand and got to it. The old ball-and-socket flange was cut off the downpipe (it necks down considerably there) and a internally smooth, higher flowing 3" V-band flange assembly was added, along with a small part of a mandrel 3" bend to get it lined up along the transmission tunnel. The rest is just straight 3" tubing and a turndown (made from the 90° bend) pointing down right before the diff, plus a small bracket to hold the system in place. Easy, light, and minimalist.



    The old exhaust was fairly light at 14.6 lbs... but the new system is less than half that at 6.6 lbs.



    The new system is all stainless and 100% TIG welded, and (currently) going without a muffler. Should flow plenty of exhaust gas volume with minimal back pressure, and it sounds mean.



    We did some before (with just the downpipe) & after (with the new 3" muffler-less pipe) sound tests which I'll post up soon.
    Last edited by Fair!; 08-16-2010, 06:24 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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    • #3
      Re: Hanchey / AST-USA 05 Subaru Legacy race car

      Looks good! Can't wait to get it tuned.
      Brian Hanchey
      AST Suspension - USA

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      • #4
        Re: Hanchey / AST-USA 05 Subaru Legacy race car

        Nice! So Hanchey, what are you going to do with this car?
        Thomas
        AST '04 S2000 (STR)
        '04 R32 with AST 4100s

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        • #5
          Re: Hanchey / AST-USA 05 Subaru Legacy race car

          Originally posted by Miatamoto View Post
          Nice! So Hanchey, what are you going to do with this car?
          Mainly to test GRAND-AM shocks. We might run a World Challenge race or two in it and a few NASA endurance races.

          I got my rookie license in it a few weeks ago and will wrap up the competition license in October. Any AST employees that go to GRAND-AM races will have to drive it before talking to any race teams.
          Last edited by hancheyb; 08-17-2010, 10:10 AM.
          Brian Hanchey
          AST Suspension - USA

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          • #6
            Re: Hanchey / AST-USA 05 Subaru Legacy race car

            Finally got the "after" sound test videos filmed and all 4 sets of clips edited, titled, and uploaded. Click the images below for the individual video tests.

            BEFORE (with open COBB downpipe only - no cat or muffler):


            Test 1: WOT 3rd gear 106 dB max



            Test 2: 40 mph Drive-By 99 dB max


            So the open downpipe (exits 3' from the turbo) was pretty loud at 106 dB - the loudest we've tested so far at WOT, even more remarkable with it being a turbo car. Cruising speed of 40 mph had a 99 dB max, also pretty loud. Then we made the 3" stainless system with a turn-down at the rear axle and knocked 4 dB off at WOT and 9 dB off at cruising speed.

            AFTER (with full 3" exhaust and turn-down - but still no cat or muffler):


            Test 3: WOT 3rd gear 102 dB max



            Test 4: 40 mph Drive-By 90 dB max


            I wouldn't call the new 3" system quiet, but its not any louder than my E46 330's exhaust - which is also a 3" thin wall stainless system, but has a muffler. And don't compare our peak test numbers (our sound meter is only 10 feet away from the car) to trackside tested or SAE tested numbers, which are usually at 50-75 feet from the road & car. The relative before/after change in the same mode (wide open or cruising speed) is what is worth noting. I figured the extra length of tubing would reduce the sound levels, but it was more of a reduction than I had expected. We even removed a "choke point" in the downpipe, where it necked down from 3" to 2.5" and a factory sized ball-and-socket flange, so I suspect the new, fully 3" exhaust with the V-band will flow as well as if not better than the original downpipe.

            Cheers,
            Last edited by Fair!; 08-18-2010, 05:50 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


            • #7
              Re: Hanchey / AST-USA 05 Subaru Legacy race car

              Nice! The turbo helps quiet it down. That's good to know it isn't any different than your E46.
              Brian Hanchey
              AST Suspension - USA

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