ej22 convert to dohc

[calvin6199]

i just bought a 1998 impreza outback with a ej22 i want to put dohc heads on it and also want to turbo it what do i need to do and what heads to use do i need to change the pistons

[subiekid]

search on http://bbs.legacycentral.org

[calvin6199]

thanks

[Zefy]

you can muck around with making a hybrid frankenstein motor but it's really just easiest to do a full motor swap.

 

and just to clarify, subarus are not hondas. DOHC isn't always the answer.

 

read over on legacy central or go to nasioc.com. oodles of people have done swaps like this.

[calvin6199]

i already have the motor i got it for a deal hole car for $300 runs great with 130k milesit had got hit in the front lightly going to put the motor in my vw beetle but thaught i would do a little to it first and i was looking on there it seams the ej25 sohc head would be a good head for what i want to do. But need to know what head gaskets and pistons to use im not very familar with the subaru i have built many v8 and vw type 1 motors. thanks for the sites they are helping

[Numbchux]

even the 2.2 SOHC heads are good up to about 300hp (turbo, of course). I don't think there's much to be gained N/A for the switch. Also, keep in mind that the quench volume of a 2.5 head is larger than a 2.2 head. so using a 2.5 head on a 2.2 block will lower your compression ratio. definitely means a drop in power N/A.

 

 

I love to see subie motors in VWs! I've done the wiring for more than a few of them, and if things go well will be very involved in another one this winter. But you really need to narrow your desires in order for anyone to help. Almost every combination you can dream of has been done and documented. read up, research parts, decide on a budget, a hp goal. you know the saying, "fast, cheap, reliable. pick 2", so find where your priorities lie in that triangle. THEN we might be able to point you in the right direction.

 

generally, though. all EJ heads are pretty much interchangeable. you will run into a few issues if you try to put 1.8 heads on a 2.5 and vice versa, as the bore diameter is so drastically different....but even then, the bolts will line up.

 

as a rule of thumb, intake manifold has to match the heads (not 100% true...but frequently). So when you talk about swapping heads onto your motor, you're really talking more about swapping your shortblock into another motor. at which point.....why not just start with a different motor?

 

fuel injectors are dependent on the rails, which are dependent on the intake manifold. so if these need upgrading, consider those options as you're considering the rest of the build.

 

head gaskets, again, are all pretty similar. there are a couple different thicknesses (effect compression/interference). some have different cooling holes in them, and different materials. but....very similar. probably only about 4 or 5 different OEM designs.

 

management. depending on your power desires....you may want an engine management system. the stock ECU is surprisingly intelligent, but it has it's limits. specifically when it comes time to adjust your ignition timing.

 

 

 

 

IMHO. if you already have an entire 2.2 donor car. and want more power than the 2.2 offers, turbo it. don't mess with the heads and stuff. just throw ~6psi of boost at it, and be done with it. the 2.2 is the most reliable subaru motor ever, why mess with it?

 

or, if you're going to piece together a swap. start over. your N/A 2.2 parts car will have little use.

Edited November 14, 2009 by Numbchux