i just blew my motor and am thinking of replacing the short block with a 2.5 sti short block with je pistons. since the 2003 WRX heads flow more than the sti heads will i be making more power than a stock sti with the same mods - vf34, 565cc inj, walboro fp, TMIC, catless turbo back, tune, spt intake. at the same time, if you put a 2.5 in a stock 2003 wrx would you have more than the sti's stock 300hp
??

 

That's going to be interesting. Currently i am at just about 300whp and 260tq. I think having the 2.5 bottom would help a lot in the tq dept. GL on the build. Let us know how it turns out.

Sorry i dont have the info or answers you seek.

 

Fact. I have a EJ257 in my bugeye. Stage 2, Invidia up and down, Apexi NOIR cat-back, protuned.

I make more TQ then a stock STi, but my top end is crap. Due to the TD04 still on there. But with a 2.5L bottom end, you can boost a lot more through it. lol, and I cant upgrade that until I upgrade my transmission, as the 02 transmission is the weakest of them all, and the 03 is just a little better.

You might want to think about upgrading the transmission in the near future.

 

MindzeyeWRX02 did you put in a stock sti block or did you put in a built one?

 

Stocker block. I don't plan to push more the 350whp in the end... but none of that can happen until i upgrade my transmission. Still driving the glass box around. lol

 

^ do you have the dyno sheet?

 

Somewhere. lol.
Just bought a house and all my things are in boxes. It was tuned at GST. Heartbreak dyno, lol.

 

what were the numbers?

 

i have RA gears 1-5 ACT 6 puck clutch

 

How is that treating you? The only thing i hate about the idea of dropping in new gear sets is the tranny case still flexes. but i do love the gear rations of 5mt.

But i only want to do this once, so a 6mt is where i'm going. With a R180 rear, sti axels, hubs, etc.

OP. EJ257 SB, G35R and supporting mods. You'll smash on a STi. Just remember, supporting mods. You can't upgrade one system without eventually upgrading another. Breaks, transmission, suspension are all related in that sense.

 

RAs are still VERY breakable if you shock load which is more then likely if your running a 6 puck.. Power levels don't "Break" gears.. Shock breaks gears.. There are guys out there with a stock 02 glass box running 11s with GT35Rs. Make sure you preload man..

I've heard it both ways about the WRX heads.. However I have never seen flow charts to prove either. The STI however toes have the timing advantage which aids in low end TQ unlike most timing mechanisms which are top end like Vtec and Toyotas VVTL-i..

As for the power.. You should be in line with a stock STI.. At that point it's almost Apples to Apples.. Really it comes down to Tuning.. Just keep in mind that HP is HP but TQ is where your power is.. Think of it this way.. HP helps, but TQ is what really moves the car.. I have almost 450whp but I get beat by a local with less then 400whp because I have 375TQ and he is over 425TQ..

 

i love my RA gearset sometimes its annoying to shift so much cuz its close ratio and my highway gas mileage is not too great... 3250 rpms at 70mph. but other than that i LOVE the gears. i feel like im cheating when i dont tell people i have them because of the difference it gave me... its like unaccounted for hp/trq