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Calculating CR

Posted: Tue May 06, 2008 10:00 pm
by Imprezive
Calculating CR!!!


Ok so I did a little more research... And found Cometic.com (they sell head gaskets and whatnot)

They list 2 head gaskets, one for a "EJ22ET" and an "EJ22E", both for 98mm bore.

Specs:

EJ22ET - .051" crushed thickness (Stock thickness of legacy SS HG's)
Volume: 0.595 cubic inches

EJ22E - .040" crushed thickness
Volume: 0.467 cubic inches

So you lose lose 0.011" which equates to a loss of 0.128 cubic inches (or 2.068cc) of combustion chamber volume.

Now I just need to CC my heads as well as get the piston dome vol.

Posted: Wed May 07, 2008 4:09 am
by 93forestpearl
Why are you considering doing this? If you want higher cylinder pressures, get a larger turbo.



I don't know if you'll have contact or not. People use beeswax, playdough, silly putty and other stuff to check that clearance.

Posted: Wed May 07, 2008 6:15 am
by Richard
Note - silly puddy does not taste like peanut butter. Trust me.

Posted: Wed May 07, 2008 4:43 pm
by Imprezive
I want to bump the compression because with my ported heads I will most likely lose some bottom end. Now couple that with the fact that this car will be predominately used on the street where driveability and off boost power are important.

Generally speaking, silly puddy often tastes like hands or dirt because everything sticks to it.

Richard, don't eat any more silly puddy.