Just got an 03 Subaru WRX - Have some questions

[zipdoa]

So long time Audi fan, first time Subaru owner checking in. I'll get right to the questions.

#1:

Does my car have a viscous coupling center and rear diff?

#2:

Does anyone run Torsen differentials in Subaru's? Audi's run a Torsen center, and some guys swap the rear to a torsen as well. I always thought running Torsen's in the front, center, and rear differentials would be awesome in a daily driver.

#3:

What do I have to watch out for? I've heard WRX transmissions are made of glass and don't put up with abuse. It also sounds like the engine has a bit of a knock when it's cold out, but that goes away when it warms up.

#4:

What are the most popular mods? I've read about Cobb Accessport, MBC, swapping in STI goodies.

#5:

How much power can this EJ205 make before internals have to be addressed? I don't want to build the engine, but I wouldn't mind grabbing injectors and a chip tune if the engine puts up with it

[Mitsu3000gt]

If I recall, that car has a cat PRE-turbo, and a couple more after. Removing those along with the COBB gets you 50+ HP if I am remembering correctly. I almost bought one of those before my first S4.

[4WARNED]

You sir need to direct yourself over to western Subaru club.

wsc.com

[Mibz]

If it's a manual then you've got viscous coupling center and rear diffs. If it's an auto then you've got an electronic center diff.

http://en.wikipedia.org/wiki/Subaru_Impreza_%28second_generation%29#North_America

[cherpintow]

Originally posted by 4WARNED
You sir need to direct yourself over to western Subaru club.

wsc.com

This. Tons of info over there and some good stickies to read through. Also, have fun this winter, they are a blast to drive in the snow.

[zipdoa]

Awesome. Thanks for the info guys!

[KRyn]

Don't forget NASIOC (http://forums.nasioc.com/)!

[Perfect Dark]

We're lucky to have one of the best Subaru tuners out there located right here in Calgary. PM Airboy over at the WSC forums or check out his site. He can guide you through what mods will give you the best bang for the buck and then give you a custom dyno tune.

02-03 transmissions are fairly brittle, I wouldn't push any more than stage 2 power at it (turboback exhaust and an STi uppipe to get rid of the cat). Some people have no issues but the consensus is to be careful unless you really want to try a transmission swap haha.

The 2.0L isn't the torquey beast that the 2.5L is but it's a decent little engine...great daily driver car.

[jsn]

Yea like mentioned, talk to airboy on wsc. Stage 2 is probably the best bang for the buck mod you can get power wise. You don't even really need a full turbo back exhaust. You really only need to get a 3 inch downpipe and you're good to go for stage 2.

I currently run an OTS cobb stage 2 map, but airboys custom tunes are way better. I just found an accessport for dirt cheap so I went that route. If you're buying an accessport new, I'd probably just go get a custom tune from airboy instead.

[dimi]

I'd say get a downpipe/upipe, keep the stock exhaust to keep noise levels in check. Maybe get a VF39/48/52 from an Sti and throw that on. Take it to airboy, get a quick compression check done to get an idea of engine health, maybe a leakdown, get a tune and you should be good to go. Custom tune is worlds better as has been mentioned.

Viscous center and rear, although my viscous rear R160 acts like an open diff. Still you'll have more than enough traction, so I wouldn't worry about it. If you're upgrading diffs, save your money and get an Sti with a DCCD or evo with ACD. However what you could try is sourcing a R160 mechanical LSD (plated) that was in some early JDM GC8 cars. Those lock up a lot more aggressively, just make sure the diff has the same FD as your tranny.

The cold "knock" is probably piston slap. I have a NA EJ25, not a 205, but it slaps when cold and then once pistons warm up and expand into cylinders, its fine. Very prevalent in subarus due to the engine configuration and short piston skirts.

Oh yes, go to WSC.

[zieg]

The transmission is only brittle if you expect it to hold up to repeated full on rally launches. And to answer you're questions #1 and #2, they are both a yes.