Hi, I hv a 06 2.5i. Wondering how you can build a 2.5i engine that goes as fast as the WRX (without engine swap or turbo)? Or wt mods are needed to squeeze power out of a 2.5i N/A engine without blowing up the engine? thx for helping

 

Forget it! It can't be done. You should sell what ever you have and buy a Prius.

 

Your first steps, which might actually get you there to very close would be intake, exhaust, headers (arguable on the 06's), main pully (arguable), cams and ECU, the last 2 gaining the most power, but also requiring the others to get to thier peak. If that doesn't get you there i'm not sure what else might help, to maybe a light flywheel as well.

 

Go pick up a copy of Subie Sport and flip to "Project 2.5RS: Zero to hero." To some it up they're trying to get the same performance from a 2.5 i, as in a STI.

 

...and they missed. Counting on a NOS squirt now to get them to run with the STI. But, I'll be there (Subiefest) to watch!

 

I'd like to add in the high flow cat and ignition..

i checked the cobb site and they're selling stage 1-3 cylinder heads. they are too expensive though.

 

i think rewsupal is right...thats my thoughts too...supposedly the pp6 gets u to 200 at the crank then once u at a cat and intake and pulley, maybe a short shifter, youll be keepin up with a wrx maybe, at cams too and i bet youll keepin up noooo prob...sti is a dif story haha. but anybody that says u cant build a impreza that beats an sti is an idiot...it can be done and ive seen it done...and with the 06 2.5i its more likely than ever...the AVO turbo without the front mount on the stock engine puts 265 at the crank and they say that since ours is lighter and such that it kills a wrx and beats a stock sti but i dont believe that...buuttt, once u add the front mount along with other mods ecu, cams, cat, etc. then youll pass 300 hp nooo prob...the front mount alone will put u near 300...once u do those other mods youll be killin sti's...it would take a lot of work but it can be done...but as far as not turboin it or swapin, i think u could get around a wrxs performance out of it without extensive mods

 

I've been told that with high flows on ours we'd be lucky to get 5 HP, if you don't mind the noise go for it, but i passed on doing that myself because i didn't want to go to loud.