legacycentral bbs

Hi, im wondering if turbo heads would be a direct replacement for n/a heads in my 91. in other words, will the intake and exhaust manifolds bolt up fine. Other than having to plug up the returns of course. Also is there anything I need to know about putting the delta cams in turbo heads? Thanks Matt

I dont see why it wouldnt work.
I also dont see why you would want to. They do have smaller EX valves than the NA.
Why not just put the Delta Cams in the NA heads?

I dont have any N/A heads

the reason I ask becuase I am finishing up a 2.5 block with 2.2 heads and only have a set of turbo heads available. After some searching I found out that the coolant passages are different on turbo and n/a motors. I guess Ill have to get a set of n/a heads then?

i was just about to ask a similar question about puting N/A 2.5 heads on a N/A 2.2

try the N/A heads and ill just find the answer from you, but i dont think the 2.5 and 2.2 (N/A or F/I) coolant lines match up exactly but they do enough to work properly.....i think thats right, i may be wrong

but have you looked at it to realy know or did you just read that?

I remember Matt saying that SOHC 2.5 heads on a ej22t block are a good option despite the mismatched coolant lines, ipso facto ej22t heads on a SOHC (p2) block will work just as well. So I guess I figured it out on my own.

to answer your questions, yes, the turbo heads will bolt up to the NA intake and exhaust from a 2.2 (as long as they are both dual port exhaust)

as has already been said, the turbo heads have smaller ex valves.

another note, if you're using an open deck block, the difference between the coolant holes doesn't matter since the block is open. Only if you're using a EJ22t closed deck block is it an issue. This is an issue for you though, see the nexe note for details.

An important note, running EJ22 heads on an EJ25 you'll need to run EJ25 head gaskets or the gasket hole will be smaller than the bore. If you run the EJ25 gaskets on the EJ22 heads, the coolant holes in the gaskets will not line up with the coolant holes in the heads. This might be an issue for you. Same as the issues with the EJ25 heads on EJ22 closed deck block. the holes are close, but not exact.

One more note with this configuration. The EJ22 heads flow a lot less than EJ25 heads. Plus add to the scenario that you've got more displacement, this might be a pretty big issue for you, not to sure what your goal is for putting the heads on, but it proboable won't get you whatever you're looking for.

An one last note, the EJ22 heads are only 40cc chambers, so depending on what gaskets you run and what pistons are in your EJ25 block, you could be running a compressions ratio as high as 13:1

The valves are only 1/16" smaller and the ports are the same size. Also the turbo cam has more duration, and as such would probably make more power than n/a heads anyway. But like I said im going to be using delta regrinds. As for gasket I am using STi headgaskets, the same thickness as phase II gaskets, and probably have to be modified for this setup. Thanks for the info.

is the STi head gaskets thick gaskets? i know you can throw on a thick gasket and get that compression down lower.

I don't see any reason not to use turbo Ej22T heads on an NA build. If you've got Ej22e heads, I would consider it better, but don't see a problem with using the turbo heads.

I built a phase I Ej25 with Ej22E heads and used the phase I Ej25 head gasket with it. The coolant passages were not an issue. Tired rod bearings were an issue, and we onlt got 10k mi out of it before the bottom end gave up the ghost, but that's another story.

I got the heads last night, pulled the cams and sent them off to delta today. Its going to take a week to get there though

3 day UPS is your friend. Delta does 24 hour turnaround most of the time, and you can ship 'em out on a Monday and have them back the next Monday...

3 day ups was $33 compared to $13 for ground. I was disappointed in that. Where I go to school there is a DHL, I like that service the most. Oh well

I noticed that the oil feed and return are on the cam backng plate on the back of the driver side head. I wonder if I can swap a n/a plate on there?

the na plate has 2 less bolts i think.

im using turbo heads on my 95 2.2 na block. everything runs good.

I'm pretty sure this is gonna cause a problem. It's not the NA -vs- turbo heads that is the issue, it's the 2.2 heads on a 2.5 block that creates the problem.... what are you going to do for a head gasket?

MRtuningCO wrote:the na plate has 2 less bolts i think.

im using turbo heads on my 95 2.2 na block. everything runs good.

ooohh, so did you use the n/a plate, or it just doesnt work? If so what do you do to plug up the lines? Thanks!

sammydafish wrote:I'm pretty sure this is gonna cause a problem. It's not the NA -vs- turbo heads that is the issue, it's the 2.2 heads on a 2.5 block that creates the problem.... what are you going to do for a head gasket?

Im going to use STi 2.5 head gaskets.