Well, as a former STi owner, Ambystom I can tell you that the EJ20 is a much better engine (JDM STi engine) than the EJ25 USDM engine that we get over here. The main issue witht he STi's engine is that even though it has a .5 liter advantage, the design of the turbo manifold is garbage and it really kills the turbo spool and ruins the power band when the engine can't rev very high.

The turbo placement necessitates that the manifold be designed the way that it is, but alot of exhaust gas velocity is lost in that uber long up pipe and spool is hurt enough to negate the benefits of the extra liter of displacement. Another problem is that the stock turbo is TINY, and there is no top end power. However, I have to disagree with your comment about there being torque all over the powerband.

Because of the displacement and tiny turbo, there is a surge of torque down low that shoots up lik a monster, but it falls flat on it's face LONG before redline. The horsepower starts to pick up in the midrange but quickly takes a dive because the torque dies off too fast for it to develop. Perfect example, I had a catless TBE, an electronic boost cntrol solenoid, an APS cold air intake, and a custom reflash with several hours of dyno tuning and if you looked at my power band looked like a mountain; straight up and straight down.

How does this equate to the real world? I'll tell you. I raced my friend in his evo 9, which had a catless TBE, and a drop in filter, NO ECU TUNING OF ANY KIND. We did several rolls from 20 mph to about 100-120, and every time I would surge up about half a car in the first half of the gear and then he would make up the gap as my power fell off and his kept climbing towards redline. Each roll, he would put about a car and a half to two cars on me by the time we reached 100, and he didn't even have a reflash.

The STi's power band SUCKS. With a big turbo upgrade it still isn't fast because once the damn thing spools you have to shift because the EJ25 can't handle high revs. It's just a poorly designed engine IMO and I will never go back. EVO FTW.

 

I agree with a lot of what you said, stock the powerband is pretty bad, even despite the smaller turbo on the WRX, the powerband is absolute ****. With a reflash and a TBE exhaust though, the car is phenomenally different. I have power from about 2500 RPM to 5500 RPM which is pretty damn good. I completely agree that the VF39/43/48 is tiny, if you put it side by side to the Evo's 16G the difference is crazy (I'll find a picture). This isn't a big deal on the street but it does hamper track times, the car definitely feels like it's hitting a wall when the speeds get higher. I don't know about your experience but most of the cars in our local club have very different powerbands. There is that boost in torque but HP continues to rise.
This is an 06 STI with a TBE, SRI and a reflash.



The EJ25 can handle revs, the stock redline is 7000 RPM (6500 on the newer model) but you can raise that higher. The 6-speed slows it a bit since you have to shift more often. I don't think there's anything wrong with the motor, you just have to mod it intelligently.

 

Sam Hubinette is the driver...wouldn't exactly call him a joke.

 

i think we find one subaru fan here as being a moderator in the Mitsubishi forum.. How funny is that....

 

Somebody has to control the Mitsubishi fanboys :P.

 

that is true.

 

It's pretty common on a lot of forums, part of the reason is to be a mod you have to be around a long time which normally means you've switched cars at least once. I'm thinking of moving to an Evo in a few years though.

 

do not hesitate. The X rocks on road course. The STi wont matter which year , just cant keep up with the X.
Unless it is heavily over modified over the X.
You will see when the first time you will hit the track with at least a tuned X.

 

I noticed that too. Surprised noone has commented on it yet.

 

it started coming off for me too, at Lime Rock. Looks like with the high head wind and no front crash beam the bumper like to pop off.
I think because not enough support there, if you remove the crash beam. SO we working on the solution now, for me.
But mine wasn't even close to that one.

 

Yeah I know, a local guy set some pretty ridiculous times with his bone stock Evo.

 

Great thread Stephen!

 

Maybe he was, but knowing that track like the back of my hand, I know he drove the cars around it correctly.

 

Thanks for the support guys!

The front bumper on the Evo was coming off at one point during the day. What caused the bumper to come off was when Sam tried to drift the car. With the wheel locked all the way to one side and the car griping (not drifting), the passenger front tire pulled the corner clip out. We fixed it as soon as it happened. When we got back to the shop we made a permanent fix to the bumper and it is a lot stronger then before.

We contribute the success of the Evo to a well tuned car including motor, suspension, and brakes. Thanks to great parts like Stoptech brakes, Volk wheels, KW suspension, Sparco seats, Yokohama tires, Hotchkis sway bars and ACT clutches. Also thanks to Cosworth and Apex for partnering with us recently. The STI really did good as well, just not as good as the EVO…

 

What would have been an even bigger surprize if these two cars had gone against the 09 GTR. In short, GTR last, at least against the X! See EVO X General/ Congrs AMS for X vs GTR (and a bunch other mod'ed cars) for verification.
That said, I am a little shocked by the degree to which the X outperformed the STI. While the track results demonstrate the superior handling of the X, the "drag race" does not add up.
The STI, as pointed out above has more HP and Torque and weighs hundreds of pounds less. So how can the X have won the drag race? One of the reasons rests with the start; the STI boged down badly; they switched the camera quickly but it is there.
In short, driver error.
Later, Ken

AMS intake & Cat-back
Iveytune (322 all around)
Robispec K&W