IW STi Forum banner
1 - 20 of 26 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter · #1 · (Edited)
Well I'm a proud owner of a 2005 Arctic White STI. I previously owned a 412 rwhp 406 rwtq 2004 Mustang GT. Know everything there is to know about mustangs and little about STIs. Just trying to find a few things out.

First off. How much hp will the stock block and tranny hold on the STI. I hear that the wrx has a serious problem with handling power on their trannys.

Other than that, what should I do first? I was looking at the Turbo XS turbo-back exhaust. Looks and sounds great! Which turbo-back will give me the most hp and sound the best?

Thanks guys!

Brandon
 

·
Premium Member
Joined
·
1,324 Posts
Turbo XS makes a nice TBE. Sound wise, it's all a matter of opinion. If you get a turboback however, you have to get some sort of engine management. Personally, I like the Cobb AP because it's flexible and user friendly. Some others are Utec, and Ecutek.

Stock block, some STis are chugging along at 450+whp, but don't quote me on reliability. Tranny, I am not really sure. Welcome to the site though, you'll learn a lot in little time.
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #3 ·
Tomerville said:
Turbo XS makes a nice TBE. Sound wise, it's all a matter of opinion. If you get a turboback however, you have to get some sort of engine management. Personally, I like the Cobb AP because it's flexible and user friendly. Some others are Utec, and Ecutek.

Stock block, some STis are chugging along at 450+whp, but don't quote me on reliability. Tranny, I am not really sure. Welcome to the site though, you'll learn a lot in little time.

Which Utec system do I need to you know? And why will I need a engine management for the turboback?


Thanks!
 

·
Registered
Joined
·
4,244 Posts
protune is highly reccomended as well, as OTS maps can be dangerous
 

·
Registered
Joined
·
6,488 Posts
Heh, another converted mustang guy. I came from a 95 gt with a supercharged 306 that made similar numbers at the wheels. You have a lot of former mustangers on here.

As for how much power the stock 2.5 block will hold, that really depends on a lot of things, but the conventional wisdom seems to be a little under 400wheel hp. Usually people start popping their block when they get large new turbos or forget that flat engines burn oil and dont keep the oil topped off between oil changes. As for the transmission I have no idea, but it is a very robust 6 speed, though maybe not as robust as a viper/cobra t-56. Though there are a lot of people running rotated turbos on stock short blocks and stock transmissions, so you are a ways away from the breaking threshhold.

Good luck with the car and enjoy the traction of AWD I know I do.
 

·
Premium Member
Joined
·
1,324 Posts
whiteO5STI said:
Ok well if I want to do the turboback exhaust, what else do I need idealy?


Thanks!
Gauges would be good. Defi, Maddad...
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #10 ·
Tomerville said:
Gauges would be good. Defi, Maddad...

Yeah. But do I need anything else that would really help with the turboback. You were saying I need engine management for just the exhaust? I don't see why?
 

·
Registered
Joined
·
4,244 Posts
THis is what most people do stage 2:

Cobb AP
TURBOBACK EXHAUST with heatshield
Protune
Guages (defi guagepod is popular but do cost some $$$
 

·
Registered
Joined
·
479 Posts
You don't "have" to get anything to go with the exhaust, but some people have had problems in cold weather of their turbo overboosting (too much psi and the ECU cuts fuel) when they go with a catless aftermarket exhaust by itself.

You're not getting too much help b/c you're asking the same types of questions that 75% of new people coming onto this forum have already asked. People would just rather you search than answer it again in yet another thread.
 

·
Registered
Joined
·
479 Posts
P.S. The tranny problems were with the WRX 5 speeds, you won't find the limit on the STi 6 speed without a built block.
 

·
Registered
Joined
·
890 Posts
Quite a few people have ran 500+whp and abused it and the engine still holds, but some people have blown their motors on the stock turbo, it really depends on how you drive and how good your tune is. I've been running a rotated mount turbo for 3K miles so far so good (knock on wood), so IMO the STI stock bottom end is pretty strong.
 

·
Registered
Joined
·
154 Posts
as far as the drivetrain the transmission is rated to 550 ft lbs but i have heard that subaru over engineered the drivetrain it is stout
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #18 ·
WolfPlayer said:
Did you tune your own Mustang? If so, what programs did you use?

t
I didn't myself. I had it professionally tuned at a place up here in NOVA that does just Mustangs. They used a custom SCT tune and piggy backed right off the stock ECU.
 

·
Registered
Joined
·
18 Posts
Placing a downpipe or full catless turboback exhaust on the STI will increase your power somewhat, but engine management software is essential to truly receive the full potential of these mods. Subaru's ECU is very smart and quite picky. It will adjust to your driving habits and mods in a matter of days, but usually tones down the power over time. With EM, the ECU is much more controlled and kept happy. Happy ECU = more powa!

As far a mods are concerned....here's the best way to get the most power (on the stock turbo)...

1) Downpipe
2) EM (Cobb AP -off the shelf map or custom tune, Utec -custom tune, ecutek -custom tune)
3) K&N filter (or whatever brand you like - most tuners say the stock airbox works best with the stock turbo)

Those things can give you anywhere from 30-50whp and 50-80wtq. If you want more, you'll need a bigger snail with supporting mods (injectors, FMIC, fuel pump, custom tune, tumble delete, ewg, etc.). Welcome to our world!!! lol
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #20 ·
nimbus said:
Placing a downpipe or full catless turboback exhaust on the STI will increase your power somewhat, but engine management software is essential to truly receive the full potential of these mods. Subaru's ECU is very smart and quite picky. It will adjust to your driving habits and mods in a matter of days, but usually tones down the power over time. With EM, the ECU is much more controlled and kept happy. Happy ECU = more powa!

As far a mods are concerned....here's the best way to get the most power (on the stock turbo)...

1) Downpipe
2) EM (Cobb AP -off the shelf map or custom tune, Utec -custom tune, ecutek -custom tune)
3) K&N filter (or whatever brand you like - most tuners say the stock airbox works best with the stock turbo)

Those things can give you anywhere from 30-50whp and 50-80wtq. If you want more, you'll need a bigger snail with supporting mods (injectors, FMIC, fuel pump, custom tune, tumble delete, ewg, etc.). Welcome to our world!!! lol

Thanks a lot man! I think im going to do turbo-back, up pipe, intake and BOV to start of with. Oh yeah, and a custom tune. Turbo XS headquarters is about 30 mins from me!
 
1 - 20 of 26 Posts
Top