Stock Class Auto-X Exhaust question....

ploney · 03-10-2008, 04:37 PM

I am a bit "New car" poor now and can't afford a new cat-back.
I have heard that some folks in stock classes in auto-x just drop the muffler and run without it. That got me thinking. If I did that I could save about 40 lbs and be able to actually hear the darn rev limiter. With full stock exhaust I had issues hearing the rev. limiter at all.

Looking at the new layout of the exhaust, it's super simple to just drop the muffler and attach a shorty pipe to replace it.

Has anyone ever done this with stock class auto-xing an a STI before??

Hopefully the drop in back pressure will not mess with overboosting.
I have yet to try it on the street or track.
Sounded good at the muffler shop. Not bad at all at idle.

Here's a pic. of the pipe off the car.
Local muffler shop did a nice job for $66 bucks.

idrivesti · 03-11-2008, 11:09 AM

I did this on my RX-8 and it worked awesome. Let me know how this works out.
Thanks.

threader · 03-11-2008, 11:14 AM

This is what I was planning on doing with a custom exhaust and the original so that I could swap at will. When I go on a long lighway trip I'd put on the stock and when I'm just driving locally or having fun have the aftermarket exhaust in.

maron10 · 03-11-2008, 12:59 PM

I did this for stock AS on my 07, I swapped the Axle back for a straight 3 inch pipe. Not only does it sounds awesome at full rev, It saved me some weight at the rear. It is legal in AS.

waktasz · 03-11-2008, 06:56 PM

Nice. I am planning to do something similar as well.

The only thing you have to worry about is possible noise restrictions at your even sites. I'm going to have to test my straight pipe because we have a site with a 90dB limit.

ploney · 03-11-2008, 09:26 PM

Guys, got to do a private off-road test today. Worked beautifully. About as loud as a stage 2 setup. No mid-range changes, smooth power still. I need some better paint for it though

ploney · 03-11-2008, 09:44 PM

Oh, I should have some video soon too.

03-10-2008, 04:37 PM	#1
ploney Senior STI Driver Car: White 08 STI Fav Mod: Volk RE30's and 255-35 Dunlop Z1's Location: Redondo Beach Posts: 312 Join Date: Sep 2006 Trader Rating: (0)	Stock Class Auto-X Exhaust question.... I am a bit "New car" poor now and can't afford a new cat-back. I have heard that some folks in stock classes in auto-x just drop the muffler and run without it. That got me thinking. If I did that I could save about 40 lbs and be able to actually hear the darn rev limiter. With full stock exhaust I had issues hearing the rev. limiter at all. Looking at the new layout of the exhaust, it's super simple to just drop the muffler and attach a shorty pipe to replace it. Has anyone ever done this with stock class auto-xing an a STI before?? Hopefully the drop in back pressure will not mess with overboosting. I have yet to try it on the street or track. Sounded good at the muffler shop. Not bad at all at idle. Here's a pic. of the pipe off the car. Local muffler shop did a nice job for $66 bucks. This ad is not endorsed by this member. Please register or login to hide this ad. Last edited by ploney : 03-11-2008 at 09:30 PM.

03-11-2008, 11:09 AM	#2
idrivesti Amateur STI Driver Car: Black 08 WRX STI Fav Mod: Coming Soon Posts: 12 Join Date: Mar 2008 Trader Rating: (0)	Re: Stock Class Auto-X Exhaust question.... I did this on my RX-8 and it worked awesome. Let me know how this works out. Thanks.

03-11-2008, 11:14 AM	#3
threader Junior STI Driver Car: Dark Grey 08 WRX STi Fav Mod: COBB AP - Stage 1 - 93 Octane Posts: 79 Join Date: Jan 2008 Trader Rating: (0)	Re: Stock Class Auto-X Exhaust question.... This is what I was planning on doing with a custom exhaust and the original so that I could swap at will. When I go on a long lighway trip I'd put on the stock and when I'm just driving locally or having fun have the aftermarket exhaust in.

03-11-2008, 12:59 PM	#4
maron10 STI Driver Car: 08 STI Fav Mod: Driver Location: Durham, NC Posts: 201 Join Date: May 2007 Trader Rating: (0)	Re: Stock Class Auto-X Exhaust question.... I did this for stock AS on my 07, I swapped the Axle back for a straight 3 inch pipe. Not only does it sounds awesome at full rev, It saved me some weight at the rear. It is legal in AS.

03-11-2008, 06:56 PM	#5
waktasz Professional STI Racer Car: 02 Penis Extender Fav Mod: Autotrader.com Location: Philly Posts: 818 Join Date: Jan 2006 Trader Rating: (1)	Re: Stock Class Auto-X Exhaust question.... Nice. I am planning to do something similar as well. The only thing you have to worry about is possible noise restrictions at your even sites. I'm going to have to test my straight pipe because we have a site with a 90dB limit.

03-11-2008, 09:26 PM	#6
ploney Senior STI Driver Car: White 08 STI Fav Mod: Volk RE30's and 255-35 Dunlop Z1's Location: Redondo Beach Posts: 312 Join Date: Sep 2006 Trader Rating: (0)	Re: Stock Class Auto-X Exhaust question.... Guys, got to do a private off-road test today. Worked beautifully. About as loud as a stage 2 setup. No mid-range changes, smooth power still. I need some better paint for it though

03-11-2008, 09:44 PM	#7
ploney Senior STI Driver Car: White 08 STI Fav Mod: Volk RE30's and 255-35 Dunlop Z1's Location: Redondo Beach Posts: 312 Join Date: Sep 2006 Trader Rating: (0)	Re: Stock Class Auto-X Exhaust question.... Oh, I should have some video soon too. This ad is not endorsed by this member. Please register or login to hide this ad.