ShapeGSX

Personally, I feel that the Evo is in better shape than the STI in terms of ultimate power output. Something about the STI engine is really limiting top end power.

Look at any Evo power and torque graph. The power just keeps on increasing to the power peak at 6500RPMs. Perfect. The high RPM allows you to take advantage of steep gearing.

The STI's peak power is at 5300RPMs. After that, power drops like a rock. The cause of this is the torque that drops like a rock after the peak.

With the STI's close ratio gearing, you want a lot of torque and power in the high RPM ranges. But as it stands, with the stock turbo, cams and intake manifold, there is no prayer of having the power peak hitting anywhere north of 5500RPMs. What does this mean? Might as well block out the tach past 6200RPMs, because there is no point in revving that high. So with the close ratio gearbox, which already forces you to shift a lot to stay in the torque band, you have to shift even more because the torque band is so damn small.

dlowman

So far Dan (god) is running 16.8 psi and his only mods are a downpipe, boost controller and blitz SUS.

300 hp at the flywheel!

Thats damn scary!

vegetta

Boost is falling off. Volumetrically 16.8 psi of boost must be near the turbo's limit. It's cranking the equiv of 20 psi on the EVo 2 liter.

So that means you need a bigger turbo, but dang....once they get one you are talkin' fofifty at the crank.

Speedlimit

Well..... his crank HP is much higher than that with 286 whp and don't forget the rest of the story. That is the max boost he is getting out of the stock turbo and even with that, the compressor is wind milling at high rpm. I wondered how the STI could achieve low lag with a larger turbo and the answer is .... they did it with a smaller turbo. The AVCS certainly helps but quick spool up is predominantly turbo design.

I agree with Shape that the EVO torque curve is sweeter on this comparison. It will be fun to see how much boost the 2.5L can handle with a larger turbo.

Speedlimit..

ShapeGSX

Nate from TurboXS says that the torque falloff isn't due to the turbo. Rather it is due to the cam profiles and the intake manifold.

Unfortuantely, cams for an STI are $2400!

The HKS cams for my 4G63 cost me $400. Of course, I bought them used.

Alfriedesq

iTrader: (6)

You could always use some aftermarket WRX cams without the avcs function - - - in any event - like i've been saying all along - the subaru upgrade path is a costly one

vegetta

Man the STI is a torque monster if they are telling the truth. They are now saying they are over 312 ft lbs of torque at the wheels and over the 300 hp as well. And they still haven't done anything except exhaust and a little more boost. It wasn't supposed to be this way. How long have they even had the car?

Speedlimit

Hi,

Dan didn't add a little more boost, he maxed out the turbo at under 17psi bud. That means that real hp on the STI is step 1: replace the turbo and most owners are not going to jump on that one quickly. Plus the STI ECU is another new adventure.

The argument is that the EVO is much cheaper to mod than the STI. So far that is exactly how it is panning out and the way it is supposed to be.

Speedlimit..

vlasnos

That is awesome. Some guys are mad here because they don't like to be proven wrong but look at it this way soon there will be some monster Evo's and monster STI's. No one can say at this point which one is better to mod unless they are trolling or bs'ing.

Alfriedesq

iTrader: (6)

The track will tell all - - so far many evos are in the mid 12's - from 12.4 to 12.6 with minimal mods - - - from my experience it will take a significant amount of work to get an STI into that range - PARTICULARLY IF you still have to shift into 5th gear to run the 1/4

vlasnos

Increasing horsepower wouldn't change the gear ratios so why wouldn't you still have to shift into 5th? And since the car pulls as fast as 13 flat stock while shifting into 5th already, you can logically calculate that 50 wheel horspower would translate into another 3 - 7 tenths off of the 1/4. Esp. since 300 whp wrx's generally pull mid 12's. And if they are making all that torque they could actually shift from 3rd to 5th and possibly still be faster than your car. It seems that you have continually underestimated STI and are confusing wishful thinking with objective analysis. That's always bad strategy in any compettition. Best of luck.

Alfriedesq

iTrader: (6)

I already had an sti with 412 wheel HP and know what that 6 spd is capable of

trs94

Al, the better question is probably why aren't the Evos going faster yet? One week after the STi is released and it is making essentially the same as your setup for less than half the price. I guess I don't see how knocking .75 seconds off a stock STi ET is going to be that hard. And as far as shifts goes, STis already shift into 5th stock in the 1/4, so there isn't going to be any additional time penalty here with mods.

As far as cams vs. a maxed out turbo, time will tell. Remember, the STi turbo is feeding a 2.5l, not a 2.0l so comparing turbos just based on PSI is misleading. What will the stock Evo turbo flow CFM-wise? Probably not a whole lot more than the VF39.

Anyone who has driven the STi will tell you the stock turbo spools _very_ quickly...it feels small, which is why it has basically no lag, even stock. To make big power you'll need a new turbo in either car. Which will be easier in the STi. Unless you can get larger reverse rotation twin-scroll turbos for the Evo, you'll be losing some of that good stock torque curve. The STi's AVCS will benefit any turbo.

TRS

trs94

Your 6 speed had different 5th and 6th speed ratios, shorter ones.

TRS

ShapeGSX

The peaks are close to the same. However, given that Al's car is making the torque over a wider range, I feel that his car will have the upper hand.

Anyone that races knows that peaks mean nothing. You want to be able to hold torque at a high value for a wide RPM range. Al's car does a better job at this.