so im looking into building an exhaust system for my 2002 wrx wagon but im i need of some advice. Im just not sure which pipe sizes will give me what sound, and how much i can do while still keeping it smog legal. The idea i have so far is just a 3" catback but im not sure about the resinator? Will a resinator delete take away the rumble sound? Also whats the best way to get more of the turbo spool sound in the exhaust? sorry if its kinda a noob question but this is my first subaru and i dont know enough about it yet to make a decision on the exhaust without answering a few questions first.

 

if you do resonator delete your car will be louder and possibly a little more spool "whistle" but the best way to get your "whistle" from your turbo is to do a full Turbo Back and Tune.

 

I would just get a good downpipe. My preference is Invida (beefy flanges, good selection, great sizing, cheap). and then I'd go 3 all the way back w/ a muffler on it.

I'm full turboback, catless and Ti catback w/ no resonators so I'm a bit raspy sometimes but for the fact its Ti I love the way my exhaust sounds.


Whatever you decide to do, if you do put on a muffler. Make sure it's a high quality one, because it'll blow out and sound like shiett.

 

If you have a stock uppipe, get an sti uppipe or other catless one, better flow and spool noise, and there are many different possible exhaust setups...go to some meets and listen to peoples cars


Good luck

 

yeah i figured that i was probably gonna have to do a turbo back but after doing a little reserch i read that there are 3 seperate cats in the stock wrx. do i need all 3 or could i get away with just one and still pass a smog test?

 

The best bet for smog is to keep your stock downpipe (2 cats) and swap it out every time you need to pass smog. The high flow catted downpipes do not pass smog reliably.. (my cobb failed even when red hot)

 

You'll pass with a catless uppipe but not a catless dp...the first isn't needed as long as you warm your car up fully before smogging...and if its an sti uppipe - it'll look factory and won't fail visual...some people have passed with only one cat in their dp but its a rare occasion

 

Yes, there are 3 cats, one in the up pipe, one in the down pipe, and I believe one in the midpipe. Get rid of the up pipe cat, as it will eventually break and destroy your turbo. It mainly helps with cold starts, so you can pass smog easily if your car is warm. You really only need 1 cat to the smog sniffer test. I have only a high-flow on my downpipe and have passed easily multiple times.

If you have a good tune, your car should run pretty clean with just one cat.

 

Incorrect...1 cat in the uppipe (discard immediately after purchase) and 2 in the downpipe (keep these for passing smog)

 

Oops, I guess I considered our dp a1 piece design. But I was going by this diagram... Oh well, now that I look yeah, it's in the 2nd pipe of the dp.

 

If you are looking for the turbo spool sound, you'll get more of that from an air intake.
http://www.cobbtuning.com/products/?id=2310

Just do that and a replacement muffler (Magnaflow or Borla Pro-XS) and you'll get 99% of what you are looking for without dropping $1000 or dealing with smog

 

I got the Perrin SRI a little while back and that defenitly got the turbo spool and the BOV louder. im just looking to get more of the whistle from the other end

 

catless uppipe!

there was an sti uppipe for sale in the classifieds for like $60 i think...i just installed mine and turbo noise is definitely louder

 

not trying to jack your thread but this is pretty relevant, if i run a straight 3 inch exhaust with no cats from the turbo back, do i need a muffler for back pressure? i was told that with turbo cars, you dont really need back pressure? or should i just run the straight 3 inch into a axleback?

 

The Turbo impeller suppliers more than enough back pressure.
You need a muffler of some sort so I don't murder you if you drive past my house at night