Eventually, I want to get a new exhaust (uppipe, cat-back). I am thinking of losing 2 of the catalytic converters and keeping one. What is the best place to keep it. I was thinking the downpipe. If there is a better place to have it let me know?

 

BUMP the others and keep one in your DP
PS- did you get the PM/email about clearance prices on DPs?

 

i left the one in the uppipe because its the hardest to get out

 

that's a good point. i'm banking on being able to pass smog/emissions with the catless OE uppipe and the stock turboback.

obviously, i'd say keep a hi-flow downpipe cat & lose the other two since you're gonna have to replace the aftermarket DP for the stock one when it comes time to smog.

 

Get a catless uppipe and a turboback. You can find turbobacks that come with either a hi-flow catted downpipe or a hi-flow cat after the downpipe.

Dont keep the catted uppipe, thats the most useless one. Good Luck

 

Ideally, you should lose all three and get a high flow catted (metallic substrate) downpipe. If you keep just one of your stock crappy ceramic cats, you might not pass the sniffer test. The metal substrates in aftermarket HFCs are much better; for instance, the Helix HFC downpipe will pass the sniffer test with not other cats in the system. This will ensure that you have maximum exhaust flow and power while still passing emissions.

Thanks,

Geoff

 

Loose the UP cat (mine came loose), and the first DP cat. I only have the third cat. Usually cops look there first when inspecting a vehicle. I would agree with Geoff in getting a high flow cat, but are real explensive.

 

I'd get catless uppipe to help the turbo to spool up better (back pressure before turbo is bad, mkay...). I would get a catted downpipe with one cat (pretty standard) and an exhaust.

 

My reasoning as well. I'd get an STi uppipe or gut the stocker, The STi and Bosal uppipes look almost identical to the stock catted one. A "shorty" downpipe of your choice that will let you use the stock turbo heatshield, or gut the stock third cat.

 

I agree with VIBEELEVEN. Save money for relatively same power and get strut bars.
SLEEPER!

( I also have vf34 turbo for sale )

 

I got rid of the uppipe first (considering the STI doesn't even have it...it must be useless). I went with the Bosal since STI pulls were more expensive. Great mod! Spools up much quicker.

2nd, I was confused on whether to get rid of the downpipe or 3rd cat. Even contemplated getting a JDM factory downpipe. Found I could replicate the performance of the JDM downpipe and keep the USDM factory look by going with a 3rd cat delete (Prodrive center pipe) and retaining the factory heatshields.

I have other bolt-ons too that help the get up and go too (Vishnu IC hoses, Vishnu UD pulley, GP Moto intake elbow, STI axleback, etc). Flows much better over stock with only a slightly deeper rumble and very quiet. I figured that STI's with OEM exhausts and ECU tuning alone are capable of about 340hp at the crank which is probably more than I will ever get by tuning my WRX. With a COBB Protune from Gruppe-S it got me 200.4whp and 194.9ft-lbs, which is close to 280hp at the crank considering stock WRX'es are at 150-ish on Gruppe-S dyno.

I'm sure you could gain more by going with a better flowing downpipe and keeping the 3rd cat instead. I live in California and don't want to risk getting pulled over for being loud or polluting. Depends on what your goals for your car are.

Good luck!

 

+1 on getting rid of the cat in the uppipe, even subaru stopped putting them there.

Go for a catted dp and learn how to install it yourself . . . only about 8 nuts and bolts.

Keep your stocker exhaust because now you know it takes only an hour to swap it back into place on smog cert day.

enjoy the performance of fewer cats.

 

Looks like with 04+ you will need a tune to go with any uppipe or downpipe you may install because of the "fuel closed loop" Your car will run lean and possibly cause engine damage if raced.

 

I ran stock EM with a Bosal uppipe on my 2004. No problems at all.

 

NONE!!!...thats how i roll.....been catless for about 2 years now and no problems...besides decreased gas mileage (also due to full atmospheric BOV) and throwing huge blue/orange flames!!!!!..=o)