legacycentral bbs

did anyone ever figure out what exactly the comp ratio was for these? I need to CC my heads still but was wondering if someone else has already done it.

this is of course assuming stock 22t bottom end/pistons

thx

pish posh

again with the pish posh....

go get that GTI ready!!

ok,

I cc'd the heads 4 times tonite, consistantly got 56cc's , although that does not sound like a volume size I have heard of , that appears to be what these heads are.

anyone seen specs of 56cc's? ( or thereabouts )

duh,

newer liberty heads....

anywho.. lets see what I can hodge podge together with these parts that wont sell

ok.

sti block
arias forged pistons @ 22 cc volume
sti stock gasket @ .21 compressed
deck clearance of -.254mm
20g heads @ 57cc volume
std stroke/bore for 2.5
nets :

compression ratio of 8.06/1 <- acceptable
however
if I chose to run the ej22t block unmodified I would end up with somewhere around 7.2 / 1

nico must have found some of the 49cc heads for his to work, as this seems way too low to be functional.

anyway, figured I would post what I figured out. and it seems that ( barring anyone buying my stuff) I am going to build my 2.5l w ej20 heads.

I have the ej22t turbo pistons in an NA block with the twin turbo heads which are much much much bigger combustion chamber than the stock ej22t heads. I am betting 7.5-1 or less. Pretty doggy NA.

ack! that would suck NA , I assume that was a "need to get a motor running out of this pile of spare parts " project?

57cc is the published number that I have seen for those heads.

Yea, I figure that my 1 cc vairiance could have been from a little carbon on the valves etc. considering I got that close consistantly I say 57's it is.

anyone know if putting 95 leggy twinscroll 20g heads on the 22t block w/ stock internals is worth doing? any work required beyond moding turbo feed lines, new dohc t-belt, and 22t headgaskets (assuming it is paired with a proper intake mani)?

would depend on the chamber volume, it could work if they are the smaller norm ( around 49cc ) and I still think that your comp ratio with stock gaskets will be too low. If you ran the thin gaskets it makes it better, but there isnt a good thin option for the 2.2 either.

i dont no about you guys but dont do anything, just stick the heads on the ej22t-block.

i heard from so many pepole that its going to be slow your nuts, you will have no low end power. well they where all wrong, not only do i have foot pound stopping 1st 2nd gear mid and high is just the same.

at 7psi i had a tunner tell me that this car is insane, when i boost it to a easy 19psi i will leave any car bike plane trian 0-100kms looking like there is no life in there motor.

1st an 2nd gear want to rip my tires tranny apart, plus tryin to steer the crazy ness in a stright line is impossible.

but do you know what heads you have? if you have a small combustion chamber head it will be much better than if you had the ones I had. I seriously doubt you have 57cc chambers.

also,

what gasket did you use?

Blast, this is what i feared, so unless im planning on using new pistons the new heads are not a good idea?

best bet would be to CC the heads and find an accurate chamber size, seems there were quite a few. Once you have that you can do the calcs to figure out what it is you need to do .

But yes, most likely you would end up with a very low comp ratio, while it would work, it would definitly be sub-optimal.

Anyone have the displacment specs on the stock 22t pistons and heads?

there is that ejspecs page, although I dont know how much to trust it,
I saw 28cc for the pistons and 40cc for the chamber.

I think the head gasket compressed is ~1.5 mm for the 2.2 gasket

I have sohc 22T heads on my shelf at home, if I get a chance tonite I will cc them.

Here’s what I got…

First stock:
Displaced volume = 554cc (97mm bore x 75mm stroke)
Piston volume = 28cc (published value, I have not confirmed)
Gasket volume = 11.1cc (1.5mm thick, stock EJ22T)
Head volume = 40cc (back calculated from published CR)
[554 + (28 + 11.1 + 40)]/(79.1) = 8.00:1 CR

I cc’d my EJ20G heads at 56cc, so 56-57 looks to be a good number:
[554 + (28 + 11.1 + 56)]/(95.1) = 6.83:1 CR

Now if you go with the “thin” 0.5mm head gasket you get:
[554 + (28 + 3.7 + 56)]/(87.7) = 7.32:1 CR
But I believe the EJ22T pistons come above deck height by about 0.25mm (0.010”), so that leaves only 0.25mm of deck clearance… to close for me.

I have heard there is a 1mm HG (from the phase II 2.5 DOHC?), which would give .039” deck clearance (.040 is considered optimal by many performance engine builders). Which yields: [554 + (28 + 7.4 + 56)]/(91.4) = 7.06:1 CR

You could use N/A pistons, 14.5cc?, but you get narrower (weaker) ring lands and the rings are closer to the piston crown and subject to more heat:
[554 + (14.5 + 11.1 + 56)]/(81.6) = 7.79:1 CR w/1.5mm HG
Or [554 + (14.5 + 7.4 + 56)]/(77.9) = 8.11:1 w/1mm HG
Might be an option for lower boost levels… but who wants that.

Best option is still custom piston, which means you can go forged… yeah, big boost here I come. But adds about $500 to the build, plus maybe the cost of a bore job… Booo, Hisss.

It all makes fitting the later, smaller chamber, DOHC heads & manifold look better… until you have try and fit up the EJ22T sensors so you can use the stock ECU & wiring. Then you could transfer a later ECU and wiring harness, or port the stock heads or go with the RS SOHC heads, and on, and on, and on… its all just time & money. But remember… if it was easy, every one would do it.

For now my EJ20G heads sit on my bench... decisions, decisions.
Gary

bah,,

just go standalone and call it good.


I wish hydra would make a damn wire in.....


oh well, looks like I will haltech it.

the heads i used are from a ej20k 2.0l turbo vf22 480cc injectors motor. the heads come stock ported the same size as the gaskets, even the intakemanifold is the same size match as the heads ports.

i am useing stock ej22t head gaskets, there is a little meat from the heads not being a 2.2l.

did you cc the heads ever? were they shim/bucket lifters or hydro w rockers?

dont no what the cc could be on these heads, it must say it on the internet some where. they where shim/bucket lifters.

im going to try a search.

problem is without actually cc THOSE heads, you dont really know what they are ( from my experiance so far , looking at the available charts havent been so accurate ) . I would be interested to see exactly what you have, and see what your car is really running for a compression ratio.

Nico's heads are virtually identical to USDM DOHC Ej25 heads, with the exception of his cam profiles. They will be right around 49cc. '97-98 WRX or Ej25 heads really would be optimum for this kind of build, but I personally don't see an issue with the lower CR numbers that the 89-96 Ej20G heads give you. But that's just me...