I'm once again thinking about building some horsepower in my 2004 STI

As of today I'm running :
AVO Catted Downpipe
Stage II OTS Cobb tune
Cobb After MAF tube
Air Box Silencer

I know a custom tune is a big step, but want to get my combo SET before doing that.
I figure with the tune comes a bigger Fuel Pump and, depending on the tuner a manual boost controller.
What else should I be looking at?
I've heard good and bad about Crank Pulley
I've heard... meh about exhaust crossovers

No intention of doing a turbo swap and don't really want to mess with the intercooler.

At what point (if ever) does a cat back become anything more than a noisemaker for these cars?

 

I think, if you plan on staying stock turbo, you can stay stock fuel pump? What I really would recommend would be to find out who you want to tune your car and ask them.

However, to give my input:
From what I can think of, off the top of my head, since you want to stay stock turbo, the best thing would be to decrease under hood temps and smooth out airflow. Starting with the intake, a turbo inlet to go along with you already have an after maf? Or TGV deletes?

And then exhaust, hopefully you just forgot to put that you have a catless UP.

Then, move on to thermal coating or wrapping exhaust parts. Getting a turbo blanket. Getting thermal reflective tape and wrapping parts like the turbo inlet and tmic.

 

Fuel pump is a must have on the 04 STi. A 255lph pump is popular for stage 2 GD's.

 

A GR STI intercooler is a nice upgrade on the GD. I recommend a turbo blanket if you go to this route.

 

if you want some more power but dont want to change turbos go e85! theres a lot of pumps in san jose, i would go e85 if it was easier to find around here

 

Upgrade your cooling systems: radiator and oil cooler.. and instead of making the car go faster spend the $ on some track days and really see what you can do with the car, if you haven't already. . Itll give you new fun to have with the car..

 

Don't over think it! Just do the fuel pump, MBC and tune. It will make close to the power of a maxed out stock turbo with CAI, TGV deletes, header, etc. Plus, you already said you don't want a smog hassle.

If you want some real power on the stock turbo, you need e85, race gas or meth injection. Octane is the most limiting factor for us.

 

when i had my 04 sti i just did a catless dp and a protune. No intake, no fuel pump etc. Car lasted me a long time 175k miles with stock motor, turbo and drive train except clutch

 

Get a catback fuel pump Mbc and tune. Possibly intake of some sort. You'll be stoked. Crank pulley is do do as in poop. The header cross over porting n heat treating from grimmspeed is cool but costly and minimal gain.

 

fuel pump, 1000cc injectors, E85, Tune.......donzo

 

+1 best power mod you could ever do is change to a higher octane fuel.

 

^^^^^ yup

 

TBE+ CAI+ MBC+ fuel pump+ EWG and a tune... Your golden. Anything more would be injectors and E85.

 

I've got a call into GST right now for an estimate

MBT and Fuel Pump installed and Custom Tune.

 

I think, if my car were running, and I would be starting from scratch with it, I would focus on bracing, then suspension, then cooling/safety, and finally adding power. Starting with an STi would save some time for me since you are probably already at or around my power goal of 250whp.

For bracing, I would go with the rear X-Brace (I think you already did this, not sure), the Oswald front x-member, fender braces and I think that should do it for now. Suspension-wise, I would probably keep it simple on your car and do an ALK, Swift or RCE springs or none, replace the end-links and that is probably it. For power, I would try to stay as stock "looking" as possible, but that may just be because I have to try to figure out how to smog my car after getting it running, an I am really tired of that! I would go with a stock-replacement radiator, or better if needed, Spearco TMIC with the end tanks painted black and an STi stencil on top (to look as stock as possible), fuel pump, snorkus delete but keep the stock airbox, and maybe an inlet if you are feeling saucy. If you are really itching to do some mods, then maybe have the manifolds extrude-honed, and find an x-pipe. Have all of it coated by Swain-Tech, and put the shields all back on. Further bracing and such, go for a FSTB and a brake master cylinder brace.

Of course a tune. If you only do one thing, I would get it tuned. Personally I would not go E85 just because I find myself in odd places needing fuel here and there, but that is just me - I know lots of people have found joy with E85 or maybe just enjoy the whole "I need special fuel for my car, yo" thing. Raising octane or creating a situation where I need special fuel is the last thing I would do, but again, that is just me.

Does the STi have TGVs? I am not sure - but I have a philosophical disdain for these so I would say get them out if they are there. Great time to do an inlet and replace some hoses. Apologies if a lot of this has already been covered. Just saw your post and am waiting for some work stuff to happen.