EJ18 heads on EJ22 is that ok? or dumb idea?

[jedz123]

Hello my fellow Legacy enthusiests. I have a question for you all that may, well sound odd. I have recenlty pulled my EJ18 motor out of my of 93 Impreza. I plan on using the motor for my legacy down the road. (My summer project) I am going to turbocharge the 1.8 after a 2.2 head swap. I have seen this done before by a few guys on NASIOC so I know it works. The head swap drops the 1.8 down to a turbo friendly 8:1 compression ratio. I can't wait to get strated on this project. However the donor heads are coming from my Legacy...I can't start the project until I have the heads soooo.. The question for you all is this? will it be a wise descison to use the 1.8 heads on my 2.2? I know the compresion will jump up drasticlly, but with 93 octane gas will it be ok? Can I expect any kind of hp gains? or expect a blown motor? I was wondering if anyone has ever been down this road before. I want to start my turbo project but I still want to be able to drive my Legacy. Any ideas would be greatly apreciated. I start ripping apart the 1.8 on thrusday and thats when I plan on doing the head swap...If my Leg is going to be ok. Thanks guys

[bmxpunk]

I was under the impression that the 1.8, 2.2, and 2.2t heads (phase 1) were all the same core. Matt could answer this for sure, but I think the only reason to change to the 2.2 heads on the 1.8 is that the valves are bigger and you have the plumbing on the back of the head for the turbos oil and coolant.

[206er]

the combustion chambers have got to be different. EJCALCS doesnt list the ej18 head combustion chamber, but if they are both 9.5:1 stock, and ej22e heads lower the CR on an EJ18 block, it stands to reason that they are different volumes.
I do know that the ej18 cams are a bit bigger than the ej22 cams.
I have heard but dont really know the ej18's flow less and have smaller valves.
the manifolds are the same, gears the same, etc.
as far as wether or not to do it, I would vote no. would probably be 10 hp gain max and you would have to run premium.
source some more ej22e heads if you were planning to use the ones from your legacy for a turbo build.
an NA build makes sense for an impreza or other light car, but heavy cars like a legacy need a turbo.

[sammydafish]

lots of stuff on that EJCALS page is wrong, so jut FYI on that note. The gasket specs for almost all of the heads is wrong, so that makes a bunch of the calcs wrong too.

anyway, if you're 100% sure that swaping to the EJ22 head will lower the EJ18 compression (using the same head gasket, it could just be the gasket that's different) then yes, the oposite must be true. But like 206er said, even with more compression, the smaller valves would probably hurt you more than help.

Oh, and one more note, EJ18 manifold is different from the EJ22.



If you want a set of EJ22e heads I have a set you can have real cheap. You'd need to hot tank and surface them.

[jedz123]

Sweet guys thanks for the info. I would love to avoid the Swap If I need to, but I know if I let the motor just sit I'll lose my motivation to do something with it. I need to start this peroject NOW! So yeah I am interested in the EJ22E heads So please message me about the terms and price for them (Idon't know what you mean by tanking but I have had to have a cyl head from a turbo daytona resurfaced cause I warpped the shit out of it...ahh I love boost). So now does this mean I have to source an Intake manifold? I can't use the one from the 1.8? For I was under the impression you could... oh well thanks guys for the help and info.

[sammydafish]

The manifold will bolt on, but it's different, the IAC valve is on the TB on a 1.8, not sure what else is different.

[supernoob]

I just put my spare ej18 heads on my spare ej22 block just for fun. I used the 22 manifold after porting the heads to match. This was going to go in my friends 90 Leg, but I busted the crank pulley bolt off inside the crank. So after I tap a new one, it'll be going in my 98 wagon shortly, with the 98 manifold of course. I'll let you know how it turns out.

Stephen

[Matt Monson]

The EJ18 heads appear externally the same as Ej22 heads, but there are 3 key difference.
#1 Ej18 combustion chamber is smaller
#2 Ej18 valves are smaller (same size as Ej22T valves). I can never remember which, but it is only the ehxaust or the intake valves that are smaller. I want to say it was the exhaust valves.
#3 Ej18 intake ports are 1/8" smaller than Ej22 ports.

Go over NASIOC and search for Subachad. He used to run Unique Motorsports, but his site is down right now. He ran the Ej18 bottom end with Ej22 heads for quite a while and really liked it. He used a stock WRX turbo, with his own custom plumbing and ran 13-14psi. It was track car that he did pretty well with in the local Las Vegas race scene.

You can use whichever manifold you want with it. If it's going in the Legacy, use the Ej22 manifold and all it's sensors and harness.

Also, the Ej18 cams have something like 5-6 more duration to them. To use them in the Ej22 heads, you need to swap over the roller rockers from the Ej18 as well. But they bolt right up. I just don't know if this would offer any gains.

We just put together an Ej18-T and used the Ej22T cams and rockers. Comparing this to previous Ej18-t's we have done, the turbo cams seem to be an upgrade for it. It feels more solid in the 4000-6000rpm range. This in on an otherwise stock Ej18 running 5-7psi on a Vf-22...

[douglas vincent]

Subachad site

http://www.vincentfurniture.com/subachad/

[jedz123]

Awsome thanks!