hey guys, im thinking about upgrading to a 2.5 shortblock in my wrx, I have the wrx utec, would I have to get the sti utec? or what would I have to do, because im sure the wrx utec wouldn't work good with the 2.5 considering it would be measuring 2.0 liters, correct?


ron

The Utec you use depends on the ECU you use. It has nothing to do with the mechanicals in the car.
If you are using the 04 WRX ECU you use a 04 WRX Utec.

TMS

my understanding is you would need a sti utec

No, you dont. You use the UTEC that is made for the ECU you are using.
The STI utec wouldnt even plug into the WRX ECU.


<< Had a 2.5 in his WRX, used the same WRX utec he ran on the 2.0. The displacement of the motor has nothing to do with UTEC choice.

my understanding is you would need a sti utec
As Dave said, that is incorrect. What you DO need to use is the STi knock parameters.

Ya might wanna look into a reflash.

peace

so I have a 2003 2.0L wrx with a UTEC I'm using...

when my engine goes, I can swap in a 2.5 bottom end and be good to go for the most part?

For the most part, sure. Why would your engine "go"? Don't run it past its limits...

After I run it hard I hear some tapping sounds... valve tap, rod knock, piston slap... it's anyone's guess...

I use mobil one every 3,000... prob should get a black labs test... I'm at 70,000 miles and everyday I've taken the car to red line... Been through a few trannies and a few rear diff's figure it's just a matter of time.

Now I'm upping the boost to 16 16.5 pounds with a UTEC that's not gonna make it last longer. Obviously with this power I've been trying not to shift after 6K or 6,500