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I've been sifting through posts for an hour and didn't find any answers, so here's my questions:

Can I take a EJ22T shortblock, put Phase 1 DOHC Heads on, and a 1999 RS intake manifold? Will they bolt up?

Using the EJ22T head gaskets, also.

Someone said to me at one point that we can't use the DOHC heads because there is only a single exhaust port per head, whereas our exhast manifold has two exhaust ports per head. Is this true?

Thanks in advance.

It should bolt up, the only difference i can think of would be the cooling pockets or whatever they were called. I would run a thinner headgasket with RS heads tho to bump the compression back up a bit. A guy named mark that lives here has 2.5 heads on his EJ22T block.

Bump up compression? Then there's less boost to be had.

Depends on how much you plan on running, I've run a little over 20 psi on my engine with no knock or pinging on 91 octane with the 16G turbo.

But you could leave the gaskets EJ22T, from what i've heard, the change in compression isnt noticeable when driving.

What fueling/injectors are you running? Are you really leaned out?

I read that the EJ22T gasket will fill in for the misplaced head coolant pockets. What kind of compression, compared to stock, would the EJ22T block and DOHC heads give?

There are a bunch of threads on the compression.

At the time I was running the stock injectors with a walbro 255lph fuel pump. It was more than likely pretty lean

http://wac.addr.com/auto/obs/turbo/ejcalcs.html

this site has good info on head swapping.

You can run the DOHC EJ25 heads on the EJ22T and take your pick of head gaskets. If you run the stock EJ22T head gasket you will have a CR around 7.3:1. If you go with the EJ25 head gasket you will be around 8:1. Either way it works.

What will not work is the '99 EJ25 manifold with the '98 heads. The bolt pattern changed in '99. You must get a manifold from a set of '96-98 heads to make it work right...

And BTW, Marc has not had an EJ22T in his car for about a year now. He put the Ej257 in there last spring. But he ran the EJ22T from around '02 until spring of '04...

Which mark are you thinking of I know of two with imprezas and both were looking to switch to that swiss sounding turbo brand.

quote: "Bump up compression? Then there's less boost to be had."


for a street driven car having higher compression is almost always better than having higher boost. With ultra low compression you will not have any performance until the big turbo spools up and starts to deliver the cylinder pressures necessary for power.

But if the compression is raised instead of the boost you will have the cylinder pressure available at all rpm's. There was a guy on the team-integra.net forum that figured out a ratio to compare the performnce gained by raising compression instead of boost. i can't remember the exact figure but it was something like a .1 raise in compression was equal to 3 psi. of boost in terms of total area under the curve on a dyno chart. at least that's how it was for his integra.

Mileage too if anyone cares. Keep the boost down and the higher CR will allow for better possible mileage.

Steve

Matt Monson wrote:You can run the DOHC EJ25 heads on the EJ22T and take your pick of head gaskets. If you run the stock EJ22T head gasket you will have a CR around 7.3:1. If you go with the EJ25 head gasket you will be around 8:1. Either way it works.

What will not work is the '99 EJ25 manifold with the '98 heads. The bolt pattern changed in '99. You must get a manifold from a set of '96-98 heads to make it work right...

And BTW, Marc has not had an EJ22T in his car for about a year now. He put the Ej257 in there last spring. But he ran the EJ22T from around '02 until spring of '04...

Would the stock manifold work?