I haven't yet put my car on a dyno, but I just put in a VISHNU 321 up-pipe and noticed big gains. a lot more low end torque. even the guys at subaru said you get about 35 ft pounds of torque and 10-15 horsepower at the wheels. As well as the turbo spooling up faster. Where I really notice it is when I'm crusing at 60km/h in 2nd and step on it it throughs you back in the seat with almost no lag.

 

Nitro,

What other mods do you have, if any? I'm thinking of doing just the uppipe first, before anything else. I have an '04 sedan and it appears not much testing has been done on these yet with the mods for the prior years, so I'm waiting for more data. I'm brand new to this scene, so I'm still doing some reading/research. I see Cobb just got '04 ECU-burns sorted... cool deal.

So, did you get those gains w/just the up-pipe swap to an otherwise stock car?

I also am trying to keep the low-key, stealthy route. I don't want a coffee-can muffler hanging off the back of my car, and I don't want to rival open-pipe Harley cruisers for noise. If folks like that, that's cool, to each his own and I wouldn't judge anyone else's taste... it's just not for me.

So, if an uppipe and later, a better downpipe (with CAT though b/c Houston is getting tough on emissions testing ) and other small tweaks might be all I do... mid-pipe/CAT replacement (with high-flow CAT ) could be in the works. I am not out for mega-HP, I have motorcycles to get my real speed fixes on ... but to get up to maybe the 270hp range (SAE-net, or however the stock motor is measured??.. I don't know what that'd be at the wheels... certainly a lot less). If -that- is doable with just up-pipe + down-pipe and maybe a re-flash/air-filter swap... then that's what I want to find out about from folks like you who've actually done mods in stages and measured the gains.

I really like the stock two-outlet look of the muffler as well, and most of the aftermarket stuff is single outlet it seems. But, I like the Vishnu 2-outlet system, but it seems to remove the DP-cat, which worries me on emissions testing. I read somewhere that the stock DP is good to like 280hp anyway?... any truth to that?
I can't remember where I read it... there's a bazillion WRX sites I've found!

-James

 

mods I have in order:
-Dealer BBS 17" rims and tires
-3/16th mod($0.95 and gives you full boost in all of the gears and somethimes a 2 pound boost spike in second gear, not just 11pounds in first)
-front and rear sti strut tower braces
-Injen CAI
-Turbosmart BOV
-Vishnu up-pipe
-intercooler water sprayer(like the STI's, easy DYI that's good)

I have other mods for looks, but these are the one's that make a diff.

-Stock power at the crank 230hp 215fpt
-Stock ecu learns, gains 10hp 10fpt at wheels(dyno tested in sport compact mag)
-CAI 5-7 hp at wheels (tested in mag)
-BOV helps boost build up quicker between gears and sound cool
-Up pipe 35fpt 10-15hp (mag tested+ subie techs words)
-intercooler sprayer(might give a couple hp, but is more for keeping the intercooler from heat soaking while not moving, and on really hot days)

TOTAL: I figure about 260hp and 260fpt at crank

But check out VISHNU's tech site, they know what there doing

www.vishnutuning.com
and you can get any exhaust system that they offer with high flow cats (like on their up and down pipes). But keep in mind where I live there is no smog tests so leaving your cats in will make you loose power

Where you live do they check CARB numbers? If they do it is going to make it tricker for you to find parts. I don't have to worry about that so I never reasearched.

to get 270hp(crank)
- uppipe/down pipe with cats, CAI(or drop in K+N, your choice)
or
- re-flash(from Vishnu witch is dyno proven 40hp increase at wheels with better gas mileage)

both should get you about 270, but together

and exhausts, I know I guy that got a GREDDY exhaust that sounded nice and was only 2db louder that stock. he also had AEM CAI, BOV, underdrive pully's, clutch, up pipe, and that thing went pretty good.

Hope this helps,

nitro
Almost forgot, as far as I know the 04' sedan hasn't changed, expect for looks, so all most from 02' should fit.