WRX EJ20 vs STi Motor

cadprowrx · 08-13-2003, 12:18 AM

As far as hardware goes, what's the difference between my WRX motor and the STi motor. I know that they bumped the ccs to 2.5l, but did they increase bore or stroke or both? Also, what other things did they do? Different rods? Compression?

I know it has variable valve timing... so you don't have to include that!

Cosmo · 08-13-2003, 07:12 AM

Compression is slightly higher in the STi (I believe 8.5:1 as opposed to the WRX's 8:1). Bore and stroke are larger/longer. As far as internals, I believe the rods are the different because of the different crankshaft. And, naturally since it has larger bore, the pistons are different.

jwtarbaj · 08-13-2003, 11:21 AM

If I'm not mistaken I read that the block is different too. I'm not sure how. Anyway if you want a bigger motor for your Rex you could do a stroker kit and perhaps even an overbore. The stroker is good for 2.2L I believe and the overbore would add a little more. This is expensive work though.

cadprowrx · 08-13-2003, 11:36 PM

Thanks for the replys. Not interested in punching out my motor, just had a friend ask what the difference was between my WRX and the STi...

Zullard · 08-15-2003, 04:15 PM

Aluminum engine block and forged pistons and rods.