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Old 12-16-2005, 06:51 PM   #1
LeRoy
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Default open exhaust

Is there much advantage to running an open exhaust on a STi? I understand you can do anything you want from the 1st cat back and remain in A Stock. Would removing everything from the cat back and replacing with a short turn down or turn out give any significant hp gains? I've always hear any exhaust after a turbo robs power.
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Old 12-16-2005, 07:44 PM   #2
dwx
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That two cats are really what rob the power, and you can't touch them in AS. Sure you can just put a downturn on the car and it will save weight, but I wouldn't be looking for significant horsepower gains out of it.
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Old 12-16-2005, 07:51 PM   #3
cbarth3
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your mostly going to loose some weight. on my wrx i took the axle back off and made a straight pipe out the back to keep the exhaust heat and crap off of the diff. probably lost about 20 lbs
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Old 12-16-2005, 08:13 PM   #4
sciolist
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Quote:
Originally Posted by LeRoy
I understand you can do anything you want from the 1st cat back and remain in A Stock.
I think you mean the last cat.

A full TBE with only one high-flow cat definitely makes a difference in spool and a modest power increase, but that's outside the AS rules.

As mentioned, I think the main thing to be gained from AS exhaust mod's on the STi is a little weight reduction.
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Old 12-17-2005, 08:43 AM   #5
Fred
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Quote:
As mentioned, I think the main thing to be gained from AS exhaust mod's on the STi is a little weight reduction.
I think the main thing to be gained is the way it sounds.
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Old 12-17-2005, 02:02 PM   #6
AUTOwrXER
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I wouldn't say mine sounds good with the turn-down; only really damn loud.

I've never dyno'd the car with the full exhaust on versus the turndown. I did it for the weight savings, which is quite a lot. The factory muffler is heavy, plus you save some more weight by turning it down just behind the driver. You do need to secure the exhaust at the last hanger though as my turndown will slip off the hanger even with the Kartboy urethane pieces.
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Old 12-17-2005, 02:33 PM   #7
arco
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any pix of the setups?
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Old 12-17-2005, 04:54 PM   #8
LeRoy
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I could stand to lose some weight but I've done just the opposite by adding a trailer hitch. I guess if I'm going to get serious about autoX I need to think about removing that for events.
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Old 12-17-2005, 05:10 PM   #9
mccanixx
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Quote:
Originally Posted by LeRoy
I could stand to lose some weight but I've done just the opposite by adding a trailer hitch. I guess if I'm going to get serious about autoX I need to think about removing that for events.
I really wouldn't worry about the hitch. Mine didn't hurt me at all. It may add weight one place you'd want it. It's only about 25lbs. Most of us could probably make that up by skipping a few meals from now until race season.
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Old 12-18-2005, 09:54 AM   #10
AUTOwrXER
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Quote:
Originally Posted by LeRoy
I could stand to lose some weight but I've done just the opposite by adding a trailer hitch. I guess if I'm going to get serious about autoX I need to think about removing that for events.
Buy some good tire bags and cram them in the back seat.
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