wondering what the CR is for a usdm ej205 w/ 98 rs heads?

wouldn't the issue be the weird quench area ...

wouldn't the issue be the weird quench area ...


i thoguht this too unitl fuji K brought it to our attention that the combustion chamber is actually smaller on these heads then the ej205 heads..therefore enabling the rs heads to be implemented right/

im contemplating just picking up an ej205 SB and doing this instead of buying an ej22e and rebuilding it and using it with the ej25d heads..

i wanted to do the low compression build but i think id be happy with a decent 290-300 whp out of a smaller turbo then 350ish+ out of a big turbo + lots of lag

im looking for balance here, not a full top end drag motor for tons of boost

Put an Ej20 head gasket up against that head before you fully commit. I am sure that SOHC Ej25 heads won't make a seal. I suspect that Ej25d heads may be the same way. It's not about the size of the combustion chamber. It's about the bore of the mating surface.

Furthermore, what makes you think that an Ej205 block is any better than an Ej22e shortblock? I'd personally take the greater displacement. The strength of the internals are comparable and the compression ratio is just fine for boosting.

well, id rather get the 2.0 and be done with it then get an ej22 then have to tear it down

Then find a good used Ej22e bottom end with a known history. I'd personally trust it more than I would any take out Ej205 block. It's also likely to be cheaper. Hell, I'd take an Ej22e with unknown history and 150k mi and put it in and boost before I would put any unknown 50K mi Ej205 block in my car. Ej22 powered late 90's legacies see a lot less abuse than any WRX that I've ever seen.

Then find a good used Ej22e bottom end with a known history. I'd personally trust it more than I would any take out Ej205 block. It's also likely to be cheaper. Hell, I'd take an Ej22e with unknown history and 150k mi and put it in and boost before I would put any unknown 50K mi Ej205 block in my car. Ej22 powered late 90's legacies see a lot less abuse than any WRX that I've ever seen.


valid points for sure, the ej22e is a solid motor and im sure with t-leg pistons can support a good 350 whp or more.

sometimes i get cocky and think im gonna do this and rev the thing to 7.5K and put an td06-20G snail on it but then i realize a 1.8ECU plus piggyback wont be able to handle this :banana:

t-leg pistons aren't any better than na leg pistons. Same cast pistons just different compression ratio. If mating Ej25 heads to it, you actually want to keep the Ej22e na pistons. If you go with Ej22t pistons, you run a compression ratio in the low 7's. With the NA pistons and DOHC Ej25 heads you are at an almost perfect 8.6:1.

As far as 350whp? Hitting that is going to be all about the tune. As I kind of alluded to in my PM, you will want a standalone if that number is your real goal.

thanks matt, helpful as always