Need specs on SOHC swap to Australian DOHC heads

[Nitemare1]

The compression will drop because the heads have larger chamber. If you machine the heads more than the Subaru recommended maximum, you will adversely effect the cam timing because the cam sprockets will now be closer to the crank pulley, but the timing belt is the same length.

The only proper way to raise compression is to use custom pistons. I would run it as is and decide for yourself if the compression is really too low.

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ughhh lol this is becoming a pain in the ass. I think im just going to look into delta cam options for now. ill pop these heads off and while the cams are being re ground port the heads...

So it seems as if doing this swap is going to cost more than what its worth.....

I mean, anyone swapped out stock ej22 heads for ej20 heads and noticed such a reduction in compression that the car just sucked? if so cant you just crank up the boost?

[cj91legss]

I have that problem right now. Low compression and poor off boost power.

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[Nitemare1]

I have that problem right now. Low compression and poor off boost power.

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hmmmm... well essentially less compression = you can run more boost, however its how quick we can get it to make boost will be the main issue. may be a re ground set of cams in these ej20 heads will help the boost come on faster? IDK, I think ill do the delta sohc's for now, then gather everything I need for the ej20 head swap and have some reground cams put in them when I put the heads on and Ill do a little write up on if the cams help to counteract the slow boost/compression issue and turn up the boost a little more : )

[cj91legss]

yeah and let me know. Im sure I just need some pistons. I would like to get back up in compression. Im either 7 or 7.5:1. More boost would be nice tho....

I havent installed my 20g ecu yet tho. I have a bunch of stuff to do just haven't had the time.

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