What motor (4g63 vs. ej257) will prove to hold more power on the stock shortblock. Also, please back up your answer with facts or reasoning. I will also post this over at clubwrx.net. It will be interesting to see the outcome from two different perspectives.


(my opinion- both will hold about 450 whp)

 

the AMS EVO 8 put down 530 on the stock block. i think that even though both engines might have a similar threshold, it is much easier to get that kind of power out of the 4g63 because you can't boost the ej25 higher than 15 pounds

 

JUN who has been tuning both ej20's and and 4g63's alway had higher power on the Mitsubishi powered cars. If anything, the maximum horsepower ptential for the ej257 is probably slightly less than for the ej20 in a turbo application as it is going top be slightly less rigid because of bigger holes and less potential for rpm.

 

15 pounds?? Wered you get that mystery meat #? The 4g is a better engine period the Al subie blocks are very finicky and the head design blows a big one compares to the 4g excellent ability to not det like the suby

 

God from Godspeed racing says he thinks the sti block will support up to 450 hp reliably. He said they should start to break at about 500whp. Just keep that in mind.

 

Dan and his newfound STi celebrity status doesnt really know. The 205s ovaled the stis will oval too when taken off that healthy diet of racegas

 

So far the ej257 is winning over at clubwrx

 

There are a wad of dynos of "stock block" 500+whp 4g63s on the DSM boards due to very careful tuning... and I'm not talking of one run wonders. I don't think there are nearly as many stockers holding together at over 500 in the Scooby camp. Now don't get me wrong at all, I'm thinking an STI would look real good with my wife in it... sharing the garage next to the EVO. I just can't convince her that it is not ugly

 

It took me a long time to get out of that Subie underdog mentality also. I can see only one of them has the ***** to put it to the test

 

I know, I just though it would be fun to see what they had to say

 

Call me Mr. Obvious, but in either forums, I think the answers you'll get will be biased opinions rather than facts.

 

I just wanted to hear everyone's reasoning for picking one or the other, but no one seems to be posting why they chose either one. Of course you will not be able to take the results and say, "well, I guess the 4g63 will handle more power because evolutionm said so", but that's not the point of this thread.

 

In our experience the 4g63 is almost unrivaled in the "stock block" hp holding capacity race, at least for a 4 cyl. We are now 500 dyno pulls into our car, and at least 1/3 of those are above 480 whp with 50-75 at or above the 525 whp mark. Leakdown at this point is right around 2-3% for all 4 cyl, which is better than alot of new cars in the last few years.

-kris

 

Awesome

thats the kind of response I was looking for.

BTW, on what dyno were these pulls made on, and what have you done to the head?

 

You asked about block; at the myevo site there is a Swede who is pulling 710HP from the mitsu.. The Evo head allows more boost than the Sub before pre-ignition, the mitsu rolling assembly is proven to support over 400HP. The way the engine is tunned will determine what fails first. RPM and cylinder pressure must both be considered as they will cause different failure points like piston collapse, rod collapse, rod cap faliure. The cast pistons are light and well designed but poreous. For this reasn they may be the weak link as the steel crank peened rods seem solid and stout for stock units. Assuming no detonation, the crank should reach bending moment before shear at high rpm (dynamic load) or from pressure (static loading). The rods should bend before the caps or bolts fracture under pressure but the revese should occur it the engine is reved beyond limits. The absolute values can be calculated using strength of matterials and mass (static and dynamic) parameters for both engines being compared. Hope this helps. Evo wins the head design comparison and that is proven by the boost it can support. I believe the head is the key to making power so I bought what I bought.