Subaru Impreza GC8 & RS Forum & Community banner

what can i do to my 2.5 motor to make more power

4K views 43 replies 25 participants last post by  Qman 
#1 ·
hey i have a 00 2.5 and all i have done to it is all the suspension, light weight pulley, intake, and exhaust. what else can i do to make it go alittle bit quicker not using turbo just little up grades until my swap. please give me some ideas. thanks!!!!
 
#9 ·
Here's a list of what I'm in the process of doing to my '99 RS. Might be useful info for you.

Exedy LW flywheel
Exedy sport clutch
Delta 2000 grind cams
3 angle valve job
Stromung Type XA axle-back exhaust
Cobb Tuning Cold Air Intake
Cobb Equal Length Headers
Magnaflow 2.5” High Flow Cat
Stroumung mid-pipe with flex pipe and turbo-tube welded in


I'm getting an Ispeed USA SRS-30 ECU reflash later down the road.


All said and done, it should be able to hang with stock WRX's. People underestimate the N/A subies. Not blazingly fast, but very fun.
 
#11 ·
I say stock WRX is reasonable with that. Most people only run like a 14.3 in a stock WRX. I ran a 15.0 with just headers on my car.

I now have Delta 2000 cams and LOVE IT! Would love an SRS-30 reflash but its real expensive...
 
#16 ·
Not exactly an Impreza, but...

On my old XT (yes, the wedge on wheels XT), I found that porting and polishing the heads, coupled with a Delta Cam regrind did wonders for the performance of the vehicle. My current OBW has the following installed: CAI using the factory air box and a TrueFlow filter; Borla headers, Stromung track pipe, a Fujitsubo muffler, and an STi short shifter - it runs very well. I just had a tune up (NGK plugs and wires, new coil pack) and have an underdrive pulley waiting to be installed (I'm having it put on when I get my timing belt and water pump replaced next week). It's surprising how well the EJ25 responds to modification, and even if the car doesn't gain a lot of HP, it certainly becomes more responsive and more fun to drive (I also have no desire to take my OBW to the track, although I hear they can make fine auto-x cars).
 
#23 ·
looks like 2.2 heads on a 2.5?
EJ25 heads rebuilt by Delta cam with the 2000 grind aggressive cams, carbon nitrated valves, and 3 angle valvejob.

You could buy my COBB CAI:). sounds siick and give you a little extra kick in your pants:p
I have a cobb CAI and it really does nothing other than add noise. Once you open up the breathing with cams and heads, the CAI along with header back exhaust becomes much more effective.

By itself, though, its relatively pointless.
 
#26 ·
I'm no expert, just an aircraft technician, but unless your altering the CR with the forged pistons you not going to gain anything accept the piece-of-mind that your pistons are ready for a turbo, extremely high compression or some big RPMs.
I'm about to start my project which is max power for lowest dollar. Heads are getting pulled i'm buying a $100 die-grinder to P+P the heads and port match them to intake and headers. No good to have flow w/o demand so then comes the $1300 TWE race cams and a tune. You may get a small chunk of hp w/o the cams. Is anyone running P+P heads with a stock cam that can shed some light on that idea?
 
#27 ·
I have a cobb CAI and it really does nothing other than add noise. Once you open up the breathing with cams and heads, the CAI along with header back exhaust becomes much more effective.

By itself, though, its relatively pointless.



...Key word in my statement; Little. And it actually does make a difference in the power band.:clap:
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top