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View Full Version : 2.2 Turbo Build tripped up Need advice


Cubdriver
12-10-2011, 04:02 PM
Hey Guys,

As some of you guys know my 16yr old son (Granny on this forum) and i are adding a turbo to his 97' Legacy. We have been gathering parts for the past month and this is what we have:

STi injectors
wrx intercooler
wrx down pipe
headers for twin port heads (our current problem)
18G turbo
various fittings and hoses

Still Need:
Turbo cross member
e-manage Ultimate

I have been a tinker my whole life but have had only one other Subaru bought new (04 sti 375rwh) now sold.

I have been swamped at work and jumped into this with Granny without doing all my homework. I had him put the car on jack stands last night and when i took a look underneath at 12:15am (damn kids) first thing i noticed is we have single port heads and need dual port for the headers. Not wanting to tell him last night cause i know he would'nt let me get any sleep i waited until this morning. I guess all i can do is find an earlier year 2.2 dual port head right? How about a later model 2.5 head? I would imagine the 2.5 head would have lower compression but since we are adding the turbo does it really matter? Will the dual port heads bolt to our block? Thoughts?

Sorry, I know its a stupid mistake but thats what i get for not doing my homework. Also this motor is not the original but apparently since it has single ports must be a 97' or newer.

Thanks,

Hank
Garrison
12-10-2011, 06:02 PM
viewtopic.php?f=11&t=23349 (http://www.sl-i.net/FORUM/viewtopic.php?f=11&t=23349)

That thread ought to help.

To answer your questions specifically:
Yes, 2.5 heads will bolt up but you won't gain as much safely as you would from a 99+ 2.2L block. The difference is in the rods and crank; the later year models share rods and crank with the WRX, but due to their displacement increase over the WRX, need less boost to get more equal (or greater) power. The compression ratio of a frankenmotor (2.2 block + 2.5 [DOHC] heads) is about 8.5-9.0. Perfect for a turbo motor.
anothernord
12-10-2011, 06:59 PM
What Garrison said. If you can stand the car being offline for a long time, go ahead and pull the engine, install some DOHC 2.5 heads on there, and put it all back together.

If you choose to use the phase II 2.2 out of the 99+, then you have to swap the crank sprocket over since the cam sensor pickups for it are different, if I recall.
Cubdriver
12-10-2011, 07:31 PM
http://www.sl-i.net/FORUM/viewtopic.php?f=11&t=23349

That thread ought to help.

To answer your questions specifically:
Yes, 2.5 heads will bolt up but you won't gain as much safely as you would from a 99+ 2.2L block. The difference is in the rods and crank; the later year models share rods and crank with the WRX, but due to their displacement increase over the WRX, need less boost to get more equal (or greater) power. The compression ratio of a frankenmotor (2.2 block + 2.5 [DOHC] heads) is about 8.5-9.0. Perfect for a turbo motor.

Garrison, thanks for the thread it was very informative. I just checked and it looks like our motor is a 98'. Does it matter which year 2.5 DOHC heads should i look for? Does it matter?

Thanks,
Hank
Cubdriver
12-10-2011, 07:34 PM
What Garrison said. If you can stand the car being offline for a long time, go ahead and pull the engine, install some DOHC 2.5 heads on there, and put it all back together.

If you choose to use the phase II 2.2 out of the 99+, then you have to swap the crank sprocket over since the cam sensor pickups for it are different, if I recall.

Thanks Nord, there goes my easy build. :smt021 You are probably right, i should just yank it and get it over with. Will my intake work on the 2.5 heads?

Thanks,

H
anothernord
12-10-2011, 11:06 PM
Yep all phase 1 intake manifolds will bolt up.
Cubdriver
12-11-2011, 01:08 AM
Yep all phase 1 intake manifolds will bolt up.


Cool thanks,

H
susiemk
12-28-2011, 12:26 PM
PI sohc Intake manifolds do not fit on PI or PII DOHC Heads :(...

I wish you were close to NYC as I have 2.5l DOHC heads & intake manifold I was saving for a PI MAF ej22 DOHC conversion that will never happen now as I have MAP ej22's + I have dual port ej22t & ej22e heads all for sale...

Easiest solution is a custom up-pipe & downpipe see ej16 turbo in the turbo section of RS25 - the guy has pics of how he made his up-pipe.
I did this so I could keep my OEM N/A crossmember & e-manifold - it took about a day to complete/install & lasted forever (2004-2011+).
We used schedule-40 pipe (1/8" wall thickness) for the uppipe I upgraded it this year & it was still A-OK no leaks or holes!