i don't plan on upgrading from my 05 wagons stock turbo, and i heard that an up pipe with a diameter less than 2'' is the best for it.?.? And if so, what companies are less than 2''? Im also getting the catted helix DP, and am looking at a friends used tanabe ultra which is a 3.1 " exhaust off a STi. Or would i be better off going with a 3" or less on the stock wrx turbo? Im a daily driver that doesnt want to loose any low end torque, or have to get engine managment(maybe later for an upgrade). Also want to keep it on the quiet side. Need to know b4 i buy a set up. Thanx in advance.

 

you need an uppipe which is the same size as your turbo inlet....anything else is WRONG....

go with CRUCIAL Racing uppipe....its the best one on the market...

 

Kailua, You really should do the engine management first, biggest bang for the buck. That and an uppipe will give you better low end and a nice boost in power without being loud.

Don't do the downpipe until you have some engine management. If you had an 02 or 03 you could get away with it, but in 04, Subaru made some changes. They implemented a open loop/closed loop fuel delay for emissions reasons. You can actually damage your car by not running engine management with an aftermarket DP.

If you want quiet, do not get rid of your cats and add a 3" catback. It will be loud. If you want quiet, keep the stock catback. If you want it a little louder than stock, get a prodrive axleback. Also, the Helix DP will not mate up to the factory catback without a little work. The stock catback uses a donut gasket, where as the helix needs a flat flange.

A good sleeper solution would be catless uppipe, hiflo catted downpipe and factory cat/axleback. Look into the Turboxs stealthback with a hi/flow cat (or catless if you want to pollute). Add some engine management, and you will be practically stock quiet. You will also be making good power with the stock axleback robbing a few ponies at the expense of being stealth.

 

i've got an 04, and I am running up/down pipes w/ 3in catback + 3in dp...

before the 3in catback i was running a 2.75'' stromung... the change in diameter FELT like it made a difference, but i'm assuming the gain was negligable... i think the loudness ultimately boils down to the # resonators... because i've got about 2 resonators... and my exhaust isn't louder than a catted wrx running a free flowing exhaust

you can get away with running catless if you know someone that can take care of that OL/CL delay

 

ok, very much appreciated info guys. I took the first step and bought a catback( a used tanabe ultra) from what i heard it was a little bigger than 3'' but i actually measured the inside width of the pipe and it was only 2.75'' So i bought it! Now i just need to decide what up pipe to get. I really want one with a flex, and obviously not bigger than the stock opening. Also should have had my helix catted dp but they didnt even process my order and will probally have to re order. sound like a decent plan?

 

if you're going to get a 3" downpipe u might as well get a 3" catback as well.

As for the Helix catted downpipe, I have it on my wrx and the fitment isn't that great. There's a 1/2 inch gap between the downpipe and the turbo. It could cause turbo problems later on down the line (which I'll upgrade if it breaks on me). Just giving you a heads up.

 

dayum, any other catted dp's aroung 400$ ?? that fit better than helix? ive heard of this problem too, anybody ever have this problem?

 

You will be taking a risk running a TBE without engine management on an 04/05 WRX. Who cares about the CEL light. I'm saying your engine can go KABOOM. Your EGT's will be through the roof at WOT. Engine management is so much cheaper, safer and provides much more power than a TBE on a stock 04/05 WRX. The combination of the TBE and EM is what you want, but you need to do EM first if you can only afford one right now.

I suggest you do your own research on this subject if you don't want to take my advice. Afterall, it is your car, do what you want.

http://forums.nasioc.com/forums/show...ine+management

see what crucial racing has to say

http://forums.nasioc.com/forums/show...wnpipe+cl%2Fol

 

http://forums.nasioc.com/forums/show...wnpipe+cl%2Fol

http://forums.nasioc.com/forums/show...wnpipe+cl%2Fol