How about if I use 2.5 RS heads with WRX cams?

 

hmm, ... I'd have to look that up to be sure, ... but my senses are telling me no for some reason. The RS heads aren't going to flow as much either, I Think. :shrug:

 

..... oh, and I'm tired as hell right now, .... so I probably don't know what I'm talking about at the moment.

 

I wouldn't expect the 2.5RS heads to flow very well. I have no factual data to back that up though.

It seems as if the compressio ratio bump is nominal with the WRX heads on the STi block.

It's not going to be a real high-revver, but I bet it'll be a heckuva stump puller and make the car MUCH more tractable in the low revs.

I'm sure it'll still yank hard when you feed it some boost too...
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Just thought of something too... I recall the older EJ25 being quite a compression beast (10:1 IIRC). They achieved that with a thinner head gasket (.058cm vs. .08cm) and a smaller quench volume in the head combustion chamber (4.5cc vs. 5.3cc).

The EJ25 would probably pump the compression sky high with a STi block...
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Oh, and wouldn't the biggest stumbling block be that the RS is SOHC and not DOHC?
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The 98's are DOHC, whil;e the 99's to 01's are SOHC.

 

"- Both Ecu's are completely stock, no reflash on either block
- Blue and Red are the 2.4 Liter Block, Green is the 2.0 Liter Block"


I've posted that a zillion times, ... but that the dyno chart i-speedusa did. It's obvious to me where the gains are!


"- Blue and Red are the 2.4 Liter Block (EcuTeK reflash *), Green and Purple are the the 2.4 Liter Block (no reflash)
- * The EcuTeK reflash is the base reflash on a US 2.0 Liter WRX Engine (more power can easily be obtained)"

And as that one shows, .... the swap will be perty nice! And of course, this is with their 2.4L block they have built, ... but I would expect very similar gains.

Seán

 

Thanks for the helpful info. guys!

 

What'sthat? Are you a French chef now?

 

no, it's Seán, .... not Seen.
go look it up
Your kid's gonna have the same problem from all the dumb uneducated supposed-to-be-smart people in this world. plus it's the 'true' Irish way to write it lol