STI is undertuned ??
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Joined: Dec 2002
Posts: 134
From: columbia,md
Car Info: 03 wrx,944 turbo racecar, Lexus is300
STI is undertuned ??
Calculate this.....low compression 2.5 makes 155 hp ( 8.5:1)
variable valve timing is worth 15 hp, and the STI intercooler should be capable of making the industry standard of at least 10hp per psi (130 hp) THERE IS YOUR 300 HP.
So the STI will most likely run 13 psi......think back to the 2.5 rs in sport compact, in the end they ran like 14 lbs of boost to make around 300 hp from a 2.5 turbo. The STI internals are much stronger than the sport compact car so 18 psi would maybe ( depending on which turbo we get ) equal 350 hp, add a uppipe and turbo back ,.and it should push close to 400.
My 944 turbo is a 2.5 liter 4 and with 19 lbs of boost and biggg turbo, it makes 395 at the wheels.
Keep in mind the shape of the combustion chambers have been reworked for forced induction so the STI IS very UNDERTUNED !!
The potential is incredible, good luck on the electronics though, you know Subaru Technica International is'nt gonna let anyone other than Prodrive-USA have a crack at the ECU.
944 turbo guy
what you guys think,..mav,.rhdude,..etc..
variable valve timing is worth 15 hp, and the STI intercooler should be capable of making the industry standard of at least 10hp per psi (130 hp) THERE IS YOUR 300 HP.
So the STI will most likely run 13 psi......think back to the 2.5 rs in sport compact, in the end they ran like 14 lbs of boost to make around 300 hp from a 2.5 turbo. The STI internals are much stronger than the sport compact car so 18 psi would maybe ( depending on which turbo we get ) equal 350 hp, add a uppipe and turbo back ,.and it should push close to 400.
My 944 turbo is a 2.5 liter 4 and with 19 lbs of boost and biggg turbo, it makes 395 at the wheels.
Keep in mind the shape of the combustion chambers have been reworked for forced induction so the STI IS very UNDERTUNED !!
The potential is incredible, good luck on the electronics though, you know Subaru Technica International is'nt gonna let anyone other than Prodrive-USA have a crack at the ECU.
944 turbo guy
what you guys think,..mav,.rhdude,..etc..
Guest
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Yep..
...I totally agree, I don't believe they would give us a car that isn't undertuned, + the internals on this STI alone are plenty strong enough to handle a **** load more boost, even with someone like me tunning it 
I would be willing to bet you could get 400hp eaaasy with mediocre "home grown" bolt ons!
As far as electronic's go's, Subaru Int Tech. isn't dumb there ECU is probably going to be able to take use farther then we believe.
~B
I would be willing to bet you could get 400hp eaaasy with mediocre "home grown" bolt ons!
As far as electronic's go's, Subaru Int Tech. isn't dumb there ECU is probably going to be able to take use farther then we believe.
~B
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Why do you assume that the STi will only run 13psi? The current one runs 17 IIRC.
As far as undertuned, I'm sure it is a bit. Subaru has to sell a car that is 50 state legal, and able to run in all 50 states. Last I knew, the best gas you could get at the pump in CA was 91 octane. You wanna put that in a car that's tuned to it's maximum on 93? I wouldn't.
I agree that 400hp is possible with bolt on's, but that should be a gimme...show me one turbo car that doesn't respond well to intake and exhaust mods.
Jim
As far as undertuned, I'm sure it is a bit. Subaru has to sell a car that is 50 state legal, and able to run in all 50 states. Last I knew, the best gas you could get at the pump in CA was 91 octane. You wanna put that in a car that's tuned to it's maximum on 93? I wouldn't.
I agree that 400hp is possible with bolt on's, but that should be a gimme...show me one turbo car that doesn't respond well to intake and exhaust mods.
Jim
Thread Starter
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Joined: Dec 2002
Posts: 134
From: columbia,md
Car Info: 03 wrx,944 turbo racecar, Lexus is300
IMPREZARIDER--
I didnt assume it will run 13 psi, its a calculation. did you read the first thread line? The current j-spec and uk-spec run 17.5 lbs of boost because they are 2.0 liters. That means they start out with
115 hp of motor power and the 17.5 lbs of boost makes up the
170 or so hp of "on boost " power. Based on an average of 8-11 hp per psi (lb per sq inch) . but because they are small displacement engines there isnt much torque. The STI on the other hand is a very large displacement 4 cylinder, and boxer engine at that, so it makes equal torque as horsepower.
944 turbo guy.
I didnt assume it will run 13 psi, its a calculation. did you read the first thread line? The current j-spec and uk-spec run 17.5 lbs of boost because they are 2.0 liters. That means they start out with
115 hp of motor power and the 17.5 lbs of boost makes up the
170 or so hp of "on boost " power. Based on an average of 8-11 hp per psi (lb per sq inch) . but because they are small displacement engines there isnt much torque. The STI on the other hand is a very large displacement 4 cylinder, and boxer engine at that, so it makes equal torque as horsepower.
944 turbo guy.
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i am interested about the sti like everyone else, but at the same time im pissed off. i just bought my damn car because it was the top of the market. jan 02 when i got mine. i dont have money to keep jumping up. so no matter how much i am in love with it, i cant be all over it, or i'll get myself into even more debt and pick one up. besides the non sti can get 400hp also, if you want to tune it that way. deffinately not as reliably as the sti would, but hell, you could.
Thread Starter
Registered User
Joined: Dec 2002
Posts: 134
From: columbia,md
Car Info: 03 wrx,944 turbo racecar, Lexus is300
I had a feeling that was the case,'cause it just seems like no-one from mid atlantic give a flying sh-- ...
I just got my o3' in Sept, but my soon to be father in law is gonna buy it,...
944tg
I just got my o3' in Sept, but my soon to be father in law is gonna buy it,...
944tg
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Isn't the Japanese STi only a 2.0L boxer with top and front mounted intercoolers? If so, then the US STi is a freak version, lack of front intercooler they had to make up the power some where so they just boosted the engine size. As far as I know, the reason the WRX lacks a front intercooler is because of crash test issues, hence the reason the WRX only put out 227hp. Or am I just completely wrong?
But that's the reason I don't really care quite that much. Though I'm more curious what I could get out of my 03 RS if I added a turbo kit.
But that's the reason I don't really care quite that much. Though I'm more curious what I could get out of my 03 RS if I added a turbo kit.
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Originally posted by Jabzilla
As far as I know, the reason the WRX lacks a front intercooler is because of crash test issues, hence the reason the WRX only put out 227hp. Or am I just completely wrong?
As far as I know, the reason the WRX lacks a front intercooler is because of crash test issues, hence the reason the WRX only put out 227hp. Or am I just completely wrong?
Jim
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Originally posted by Impreza Rider
Completely wrong. The WRX has never come from the factory with a FMIC. Also, it would be stupid to do a front and top mount intercooler. Can anyone say lag?
Jim
Completely wrong. The WRX has never come from the factory with a FMIC. Also, it would be stupid to do a front and top mount intercooler. Can anyone say lag?
Jim
Your correct in that the WRX never came with a FMIC, but your incorrect about the FMIC and lag issue. Corky Bell, a well known engineer for his knowledge of turbo charged cars, wrote a book specifically about this topic and after reseaching found that one would have to have almost 25' of intercooler piping in order for the intercooler of loose efficiancy (hense "lag"). So the FMIC will not cause your car to have more lag, only a bigger turbo would. There was also research done on intercoolers being too big and it was found that this would also loose efficiancy, but this is more common knowledge.
Ernie
'93 Mazda RX7
516rwhp @ 20psi SR Motorsports KKK stage 2 turbo
10.73@128mph....
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Re: STI is undertuned ??
Originally posted by 944 turbo guy
variable valve timing is worth 15 hp,
variable valve timing is worth 15 hp,
Subaru AVCS is an extremely basic implementation of VVT, and I seriously doubt it is worth anywhere close to 15hp.
In addition, according to some people, the AVCS is tuned for better throttle response and turbo spool
I agree that it is under-tuned, a 300/300 split means that there is plenty of room to grow in the top end. Not to mention those 3 damn cats again
Last edited by Elgorey; Feb 10, 2003 at 05:54 PM.