STI Exhaust

snowjob · Post by **snowjob** » Sun Jun 13, 2004 7:41 pm

I have a line on a relatively new 04 STI turbo back exhaust. Has anyone done this? Any problems or fitment issues. What were the benifits?
Thanks for any info

Frazer

THAWA · Post by **THAWA** » Sun Jun 13, 2004 7:53 pm

you're going to have to increase the overall length of it. I'm not sure where but the impreza has a shorter exhaust system since the wheelbas is shorter.

snowjob · Post by **snowjob** » Sun Jun 13, 2004 8:12 pm

That's not too big a deal, I assume their would be some benifits, right now anything would be better than a hold in the midpipe...

BAC5.2 · Post by **BAC5.2** » Sun Jun 13, 2004 8:16 pm

It's identical to the stock WRX system (minus a mounting point difference because of the wider tranny tunnel). The stock WRX system is almost identical to the stock Turbo Legacy system.

Not worth it unless it's free, IMO.

LegacyT · Post by **LegacyT** » Sun Jun 13, 2004 8:19 pm

I agree, the only benefit from an STi exhaust is the muffler with STi stamped into it. The system may sound a little better, but who knows on a Legacy. I'd rather spend a bit more money and get a nice 3" turbo-back.

Mark,

Brat4by4 · Post by **Brat4by4** » Sun Jun 13, 2004 8:36 pm

The STi muffler flows better than the WRX system. But if you look at it.... it's still gots plenty of backpressure. I could have got one for cheap until I saw the little piping do two 90 degree bends before entering the muffler. It just doesn't look right after staring at 3 inch exhaust going straight back all the way from the downpipe.

stillkckn · Post by **stillkckn** » Mon Jun 14, 2004 1:27 am

We've had the CES Racing (WRX) exhaust on our STI, and it went on just fine. There is an issue, but it is not with the fit. There are reports of boost creep with free-flowing 3" systems on the STI, and there is some evidence of boost spiking. We think we know how to fix the spike (simple "tweak"), but the creep (if it can be documented) may require a more serious mod (like porting the wastegate).

If you're interested (here), I'll post the results of what we find, though there is no telling how long it may be before I can do much with my STI (it is sitting, on it's rotors, having been dropped off by the insurance company, as a total rightoff)

snowjob · Post by **snowjob** » Mon Jun 14, 2004 8:45 pm

Sorry to hear about your sti, what will you do with it??part it out

Just kidding, Thanks for the info Guys, this has been very helpful, maybe i'll invest my money elsewhere...
Thanks
Frazer

Mackenzie · Post by **Mackenzie** » Sun Feb 27, 2005 2:26 am

so a turbo back exhaust for a wrx will fit on a SS awd turbo?

J-MoNeY · Post by **J-MoNeY** » Sun Feb 27, 2005 4:50 am

Mackenzie wrote:so a turbo back exhaust for a wrx will fit on a SS awd turbo?

Sorta. I think the midpipe is going to need to be extended.

azn2nr · Post by **azn2nr** » Sun Feb 27, 2005 7:21 am

the mid pipe or the axle back ( your call ) needs to be extended 6 inches and one hanger on the muffler needs to be lenghtenes and the midpipe hanger needs to be moved if you want. i didnt move it on my tbe because the hangers for the dp and the axle back were suficcent in holding it up

Mackenzie · Post by **Mackenzie** » Sun Feb 27, 2005 7:10 pm

i see. so the extension of the midpipe is the only issue? thats not to bad then.

Mackenzie · Post by **Mackenzie** » Fri Mar 04, 2005 3:15 am

where could you get the extending done, muffler shop? i could prolly do it myself but where would i get a 3inch ss pipe that is six inches?

bignose · Post by **bignose** » Fri Mar 04, 2005 1:46 pm

muffler shop.

legacy92ej22t · Post by **legacy92ej22t** » Fri Mar 04, 2005 2:20 pm

Mackenzie wrote: but where would i get a 3inch ss pipe that is six inches?

Are you trying to do it in SS? Call around to piping companies. Also try places that work on diesel trucks, or places that make Pharmacutical equipement. I got mine from the later.

If you're in a larger city then there should be exhaust shops that work with SS.

yazmo · Post by **yazmo** » Mon Jun 16, 2008 5:18 pm

hey guy i just brough the hallman boost controller now i read that i should have " One is a free flow exhaust. Backpressure causes heat in the turbo and as small as the stock IHI turbo is already, you do not need anymore. At the least, you should have a 2.5" or 3" cat-back system with a very free-flow muffler. It would be ideal to have the downpipe since that is probably the biggest restriction in the system"

dunno which should a get my achivement would be around 200-300hp.

i try looking on internet about downpipe i dint find anything usefull

anyone have suggestion

SubaruNation · Post by **SubaruNation** » Mon Jun 16, 2008 7:01 pm

it will fit, i have it on my car (06 sti)

you might need an extention

homegrwn97 · Post by **homegrwn97** » Thu Sep 10, 2009 2:37 am

Okay sorry im a newb....

but from reading many threads....a stock oem exhaust system from a wrx or sti (no matter what year) will fit our 91 SS with some extending of the axle back....correct?

SubaruNation · Post by **SubaruNation** » Thu Sep 10, 2009 2:39 am

yep.

i have one for sale if anyone is interested

93Leg-c · Post by **93Leg-c** » Thu Sep 10, 2009 2:54 am

Are the exhaust pipe diameters in the wrx system vs the sti system the same? Or does the sti piping have a larger diameter?

SubaruNation · Post by **SubaruNation** » Fri Sep 11, 2009 2:31 am

no idea. my sti one is like 2.5 or something

kleinkid · Post by **kleinkid** » Fri Sep 11, 2009 6:49 pm

I also want to know if the sti or wrx inside diameter of the exhaust header is larger than the ej22t headers.

ScottyS · Post by **ScottyS** » Wed Sep 16, 2009 1:13 am

The WRX header is identical, except for the O2 sensor hole. AFAIK, the STi is also the same, diameter and all.

The WRX turbo-back exhaust diameter is 2.25", where the STi is 2.5" AFAIK.

My STi exhaust is extended at the midpipe, and the hanger points on the muffler are moved.

homegrwn97 · Post by **homegrwn97** » Wed Sep 16, 2009 3:52 am

ScottyS wrote:The WRX header is identical, except for the O2 sensor hole. AFAIK, the STi is also the same, diameter and all.

The WRX turbo-back exhaust diameter is 2.25", where the STi is 2.5" AFAIK.

My STi exhaust is extended at the midpipe, and the hanger points on the muffler are moved.

Good info! thank you!

SLODRIVE · Post by **SLODRIVE** » Wed Sep 16, 2009 5:38 am

I can say for sure that the STi header is identical to the Legacy unit besides the O2 hole (for which there's an undrilled boss on the Legacy one). I had both in my garage at the same time, and I only used the STi header because the other one was caked in old mud.

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