This guy has some interesting info, insights and views on WRX & Impreza tuning and engine history.

http://www.spdusa.com/wrx_intro.htm

Hope you find it as entertaining as I did.

 

Very informative indeed.


:banana:

 

Nice link. Better than blowing $20 on an issue of Hyper Rev

 

This is great!

Apparently, according to this website. You can safely tune the wrx 2002-2004 to 240-280 hp on stock 91 gas. With minimal changes.

It warns to:

1) Change rear muffler to 2.5" restriction exhaust pipe (Going as big as 3" does not help)
2) Replace the up-pipe cat with a sturdy heat protective pipe, keep the 2nd and 3rd cat, they encourage using em.
3) Get an ECU (brand they are use i guess)
4) Do not change turbo boost pressure (psi stuff)
5) Modify the ECU because of changing air pressure and air heat because of up-pipe replacement
6) Change to an STi intercooler or ARC Top mount intercooler.

This gives me a start where to do modifications to my02 wrx ^_^

- Ulysses

=====

Thought I'd extend this and add notes as I go along. This is a great way of learning all this car stuff. I'll just edit here, and add. My car is still bone stock and Im wondering what to do. MY2002 WRX.

- If I follow step one (1) above. This limits the use of the types of muffler to get.
2.5" inches is roughly 63.5 mm converted. So, the target is 63.5 mm.

The aftermarket mufflers Im seeing are:

Helix Catback - 80 mm Pipe
HKS Carbon-Ti - 75 mm Pipe (Confirmed on http://www.hksusa.com/)
HKS Hi-power - 75 mm Pipe (Confirmed on http://www.hksusa.com/)

A'Pexi N1 - 65 mm Pipe
(According to their application chart, only for the Subaru RS)
(However, on the Price List pdf file, there is one for the WRX Model 161-KF01)
(Confirmed on http://www.apexi-usa.com/)

A'Pex GT Spec - 74.7mm to 85mm Pipe
(Application chart does not have Subaru in it)
(According to their price list, model 171-KF01 is for the WRX)
(Confirmed on http://www.apexi-usa.com/)

A'Pexi WS (World Sport) - 65mm to 65mm to 80 mm Pipe
(Application chart does not have Subaru in it)
(According to their price list, model 103-KF01 is for the WRX)
(Confirmed on http://www.apexi-usa.com/)

A'Pexi WS2 (World Sport) - 65mm to 65mm to 80 mm Pipe
(No application charts available)
(According to their price list, model 116-KF01 is for the WRX)
(Confirmed on http://www.apexi-usa.com/)

Greddy EVO - 80 mm Pipe
Greddy EVO2 - Not made for the WRX, for RS apprently according their websit. 60 - 70 mm Pipe
Greddy SP2 - 80 mm Pipe
Blitz NUR Spec Racing - 80 mm Pipe

So, pretty much. Its gonna be hard to find a muffler to meet the requirements mentioned on the spdusa site.

75mm is 2.95 inches.
80mm is 3.14 inches.

Either way 75mm or 80mm is wayyyy to close to 3 inches.

I'm guessing a lot of you are wonder why stay at 2.5" or 63.5mm piping? Im wondering that too. To quote SPDusa.com website:


So, pretty much, im guessing that means, your gonna be slow at low rpms.

I'll continue this off a little bit later when i have a little more time. I want to research more on this.

 

That's some good stuff. I added it to my favorites so that i can read some more of it when i have time.

 

The original Borla cat-back (not the Hush) is 2.5" if you can find it. I've got it and I love it.

 

useful, the Apex N1 is 2.5 inch piping and of good quality. I recommend it if you want a 2.5 inch catback.

 

Its funny that you mention that because according to A'PEXi's website, they dont have it mentioned as a recommended application for the wrx. they have it recommended for the subaru rs.

This is wierd because in the pricing guide has a wrx model for sale, even though the application page say its only for the RS. A bit of conflicting info there.

Good point you mention there. Since 63.5 mm vs 65 mm isnt quite the same (im being a bit **** at this point), does it make much of a difference?

It also seems like a good size to get because in spd's website, they mention that this size muffler is good enough to get to 300 hp before doing any kind of engine modifications (strengthening valves, pistons)

 

That was one of the first Websites recommended to me when I bought my WRX a few years ago. While there is definitely some good info on that site, their view on modifications is VERY conservative and most of their thoughts relative to going past Stage II have been proven wrong by hundreds of members. I can't tell you how many members have properly tuned Stage IV setups that safely deliver 260-300HP to the wheels. Take everything you read on the Internet with a grain of salt.

Jimbo

 

I suppose that's why we post these things to forums...to get a concensus.

What I liked about the site was the author's conservative approach. I, personally, don't plan to ever make major mods to my car so a lot of what he was saying kinda jibed with what I had planned for my car...inexpensive Streetable Performance. (I doubt I'll ever go past stage II)

I don't know how many vendor sites I've visited which don't give you one iota of information other than hp gains or a simple statement as to what their product does without any explanation of how it does it. To me, that's annoying. I wanna know what makes someone's product so desirable that I'd blow hundreds of dollars on it or choose it over the competition...other than "our product is superior to all others!"

 

Clint - You sound just like me two years ago. I remember telling my wife that I was not going to modify my WRX. Mmm hmm. She knew better. First it was an exhaust, then it was engine management and now I have a VF34 and STi injectors sitting in my garage waiting for an AccessPort. Keep reading the forums and you will learn just like I did.

Jimbo

 

You right, man.

I ordered a swaybar and kartboy endlinks last week and have checked the stupid DHL tracking number like 20 times already, hehe.

Once I get the check for the airgun I just sold (badass $950 airgun), I'm gonna get an AP too...and some SS brakelines... muahahahaha!!!

I'm shoppin catbacks as I write this too....ahahahahhaha...somebody help me.

If my wife can spend $5k on friggin window coverings for our house, why can't I buy a crate engine??? WHY!!!???!!!!

 

useful, exhausts between the 2.5RS and WRX are for the most part interchangeable. The Apexi' N1 will fit fine.

 

I read just about all of the WRX info on spdusa.com and it seems like not only are his recommendations modest, but to me (and I could be wrong here) it seems like he also gears tunning for longevity.

How many people out there have been running their WRXs with ECU mods and for how many miles?
I am really curious to know if ECU mods will last 100K miles, or if they just beat the snot out of the engine.

I just bought an 04' WRX wagon and am loving it, though I really want more low end power.

The 'mods' I have planned in order are:
1) stereo upgrade cause I love music and drive too much (just need to wire my sub & amp, and get some infinity speakers)
2) Rims and tires (Rota Subzeros or torques)
3) Tint
4) Exhaust (probably something from spdusa.com unless I can find a local dealer or another 2.5" muffler)