ej18 heads on ej22t block

Heads, valves, pistons, rods, crankshaft, etc...

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NICO
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ej18 heads on ej22t block

Post by NICO »

need help is it true that ej18 cams are better then ej22t cams becuse they open more and longer

anyone please
1993 Subaru Legacy 44B STi 4Cam 16Valve Turbo Intercooled AWD
EJ22T, STi EJ207 DOHC, Vi-PEC (Spare Autronic) @ 426.20HP / 394.94ft lb @ 00psi
Tuned By: Franz Diebold ( DIEBOLD AUTOSPORT ) @ NVauto
dzx
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Post by dzx »

I would think it depends on if its naturally aspirated or forced induction.
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evolutionmovement
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Post by evolutionmovement »

Yeah, you don't want the big overlap performance-minded N/A cams would have on a turbo motor. The overlap helps a N/A engine suck more air into the cyminder at higher rpm, but on a turbo engine, it just wastes power out the exhaust.

Steve
Midnight in a Perfect World on Amazon or order anywhere. The first book in a quartet chronicling the rise of a man from angry criminal to philanthropist. Midnight... is a distopic noirish novel featuring 'Duchess', a modified 1990 Subaru Legacy wagon.
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Post by tris91ricer »

..but on an N/A, the EJ18 heads and cams would do something useful? Should I be looking for a set? That would up the CR, right?
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NICO
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Post by NICO »

ok so dont put them on the turbo motor. got it evolutionmovement.
1993 Subaru Legacy 44B STi 4Cam 16Valve Turbo Intercooled AWD
EJ22T, STi EJ207 DOHC, Vi-PEC (Spare Autronic) @ 426.20HP / 394.94ft lb @ 00psi
Tuned By: Franz Diebold ( DIEBOLD AUTOSPORT ) @ NVauto
evolutionmovement
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Post by evolutionmovement »

I don't know if they have large overlap, It's just an educated guess. I could be wrong, but if they are cams optimized for N/A performance, especially in a small engine where you'd want more top end to make up for the inevitable less bottom end they would almost definitely have fair overlap.

Steve
Midnight in a Perfect World on Amazon or order anywhere. The first book in a quartet chronicling the rise of a man from angry criminal to philanthropist. Midnight... is a distopic noirish novel featuring 'Duchess', a modified 1990 Subaru Legacy wagon.
Matt Monson
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Post by Matt Monson »

The EJ18 heads are substantially different than the EJ22 heads and would be a downgrade for either a turbo or NA build. The valves are smaller, and the combustion chamber is significantly smaller. Even on an EJ22T block, you would still be in the realm of 9.5:1 CR. And then there is the issue of a couple of extra breathers on the backside of the heads for EGR and some other stuff. Don't waste your time playing with these heads at all.

But you might look into the cam thing a little more. The cams will likely fit into a set of EJ22 heads. We are tearing down an EJ18 this weekend, and maybe I will get a chance to pull the cams out and compare...
1974 Porsche 914 Cam Am Limted Edition AKA the Bumble Bee
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NICO
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Post by NICO »

evolutionmovement you think they would give me more top end i have the durations on both of them and i will show you and then you tell me what you think

Matt Monson thanks let me no what you find out it could help use all out.
1993 Subaru Legacy 44B STi 4Cam 16Valve Turbo Intercooled AWD
EJ22T, STi EJ207 DOHC, Vi-PEC (Spare Autronic) @ 426.20HP / 394.94ft lb @ 00psi
Tuned By: Franz Diebold ( DIEBOLD AUTOSPORT ) @ NVauto
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Post by dzx »

It's quite possible. The 2.5RS heads apparently help quite a bit on the EJ22T. The car that i rode in the other day had some 2.5RS heads on his turbo motor and it pulled pretty hard. I think a 12.9 at this altitude is pretty good for an automatic awd car.
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evolutionmovement
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Post by evolutionmovement »

Large overlap will only help an N/A car's top end. Turbo cars will just loose boost as the exhaust valve is open at the same time as the intake. Low end N/A power suffers, too. The idea behind the overlap is that at higher rpm the open exhaust valve with it's escaping exhaust pulse creates a low pressure zone behind the pulse which helps pull more air through the open intake valve and into the combustion chamber.

Steve
Midnight in a Perfect World on Amazon or order anywhere. The first book in a quartet chronicling the rise of a man from angry criminal to philanthropist. Midnight... is a distopic noirish novel featuring 'Duchess', a modified 1990 Subaru Legacy wagon.
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Post by Matt Monson »

Ok,
So, the EJ18's intake ports are a full 1/4" smaller than the EJ22T's, even though the valve size is the same. Also, the EJ18 has roller rockers, and because of that the width of the cam lobes is substantially different than the EJ22T's. You could take the whole rocker assembly and cams from an EJ18 and put them into an EJ22T head, but putting the whole head into your car would be a waste of time...
1974 Porsche 914 Cam Am Limted Edition AKA the Bumble Bee
1973 Porsche 914 2.0 l -Suby swap pending
1968 Porsche 911t survivor 47k original miles
2000 2.5RS daily driver.
1999 2.5RS w/ 50+ extra whp
Suby Hai!
91l-t
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Post by 91l-t »

i actually tried 1.8 cams and rockers on my 2.2n/a, no power and it sounded like a v-tec at high rpm. imo useless, maybe just the cams would work but i lost patience and put the originals back.
91 legacy l blue ej22t
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Post by free5ty1e »

is any 2.5 head the desired upgrade for the ej22t's, or is there consensus on what is the best / most cost efficient head upgrade would be? I'm thinking head/headers/turbo change all in one upgrade... probably port/polish/3-angle valve job standard dealie for the head, coating for the header, coating for the turbo (obviously this is not going to be a quick upgrade). Suggestions?

So far, jet hot or hi per coat for the coating, and a td05-16g for the turbo. perhaps even a ported monster 16g.
-Chris
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93TW 4EAT, Forester lift, 3" TBE, 11psi, 200k mi
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Matt Monson
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Post by Matt Monson »

Free5tyle
Read the sticky at the top for Xephyr's set up... ;)
1974 Porsche 914 Cam Am Limted Edition AKA the Bumble Bee
1973 Porsche 914 2.0 l -Suby swap pending
1968 Porsche 911t survivor 47k original miles
2000 2.5RS daily driver.
1999 2.5RS w/ 50+ extra whp
Suby Hai!
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