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Natureboy

EJ22 versus EJ25

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Looks like the EJ22 is a common swap option for 80's DL's. Does anyone know what the weight difference is between the EJ22 and EJ25? What about dimensions-much larger or same size? Here's why I'm asking: Going to replace my worn out EA82 with either of these 2 choices and looking at pros and cons both ways. I'd like to swap in a dual range 5spd at the same time and I don't know if there are problems doing so with the EJ25. I had a Forester with the bigger motor and loved the torque it had at low rpms, which is ideal for off road use. That's my intent-larger tires and mild lift to get ground clearance and traction as a good daily driver with decent off road capability. Not interested in building a monster truck, just good dual sport usage. I'm sure someone is asking "why do you want to do such a thing?"-my response? Because I feel like it! If this irks you, console yourself by listening to Barry Manilow on your 8 track in your AMC Pacer plastered with Walter Mondale stickers.:Flame:

 

I know the EJ22 is bullet proof and has great power specs-I have access to both for my swap and would like good info before making the move. Is the power from the EJ25 overkill for such a light vehicle? Is the EJ22 a better match? I'd love to hear from those with actual experience, absolutely not interested in hearing about how wonderful the EA82 is and "how dare you mess with perfection and desecrate Subaru's honor and legacy by bastardizing it with an engine swap in your earth-destroying selfish baby-killing lust for power and world dominance and anytime you modify an 80's Subaru God kills a kitten."

 

Any thoughts?:)

Edited by Natureboy
I felt like it, dammit.

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EJ22 is the better match - the only phase-I EJ25 is a DOHC beast of an engine with a lot of problems. They also don't fit in the engine bay of the EA's very well. The later EJ25's (EJ253/EJ251) is wider than the EJ22 and the wireing is more complex.

 

Best of both worlds is the EJ25 "Frankenmotor" (as we call it) where you are basically doing a phase-I EJ22 swap but you sub in an EJ25D bottom end. That gives you a high-compression EJ25 pushing about 180 HP. It's a monster engine - more power than a stock EJ25 but fits in the same space as the EJ22 (no difference in size actually). This is the swap of choice IMO for the EA cars.

 

GD

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either will fit. mike and phil at subaruxt.com had an EJ25 in their RX, the size difference isn't all that substantial, but you don't have much room to play with either in an EA.

 

EJ25's throw plenty of block bearings too so i'd make sure it's a known great block if you go that route.

 

if an EJ22 sounds good, have delta cams make you a set of cams for extra grunt or torque.

 

either is going to feel awesome in lieu of the EAxx.

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Thanks GD. I'm sure someday I'll be well versed in Subaru-ness, but until then I appreciate your willingness to share the wealth of knowledge you have amassed thru hard work and experience. I have years of experience with mitsubishis, toyotas, nissans and isuzus but they don't convert well to these beasts. Looks like I'll be researching the Frankenmotor!:banana:

 

Thanks bro.

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either will fit. mike and phil at subaruxt.com had an EJ25 in their RX, the size difference isn't all that substantial, but you don't have much room to play with either in an EA.

 

EJ25's throw plenty of block bearings too so i'd make sure it's a known great block if you go that route.

 

if an EJ22 sounds good, have delta cams make you a set of cams for extra grunt or torque.

 

either is going to feel awesome in lieu of the EAxx.

 

Thanks, I appreciate your experience and input! Knowing what not to do is just as important as what is best to do.:)

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EJ22 is the better match - the only phase-I EJ25 is a DOHC beast of an engine with a lot of problems. They also don't fit in the engine bay of the EA's very well. The later EJ25's (EJ253/EJ251) is wider than the EJ22 and the wireing is more complex.

 

Best of both worlds is the EJ25 "Frankenmotor" (as we call it) where you are basically doing a phase-I EJ22 swap but you sub in an EJ25D bottom end. That gives you a high-compression EJ25 pushing about 180 HP. It's a monster engine - more power than a stock EJ25 but fits in the same space as the EJ22 (no difference in size actually). This is the swap of choice IMO for the EA cars.

 

GD

 

Which EJ25 is best to use, the 97 to 99? sounds like it's best to avoid the 96.

Thanks

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year is not a good way to talk about EJ engines because they didn't change Phases at the same time across models.

 

1996-1998 is Phase I EJ25 (as well as 99 Legacy and Impreza)

 

1999 Forester and Impreza RS and 2000+ everything else is Phase II EJ25

 

The Phase II's are better motors IMO and seem to have fewer issues. I say "seem" because while I see Phase I's far more frequently locked up or thrown rods, they are also older and more likely to be on the market, sold as is, not worth the fix etc verses newer stuff - so i'm assuming some things, but that does seem like a legitimate trends.

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For a frankenmotor you want a '96 to '99 EJ25 short block - doesn't matter what year. Even the '96 will work fine but newer is better as there were a couple generations of pistons used - they were trying to control the "piston slap" issue (benign but nice to have the newer pistons). Avoid the '99 Forester and Impreza as those are actually EJ253's (phase-II).

 

The frankenmotor has been done with the EJ251/EJ253 but the compression increase isn't as great because they don't have pop-up pistons that crest above the block. You can change out the pistons for the EJ25D units but that's more work for little gain.....

 

EJ25D block + head gasket + '90-'95 EJ22E heads + '97/'98 Roller rockers = :grin:

 

That's the best combo IMO.

 

GD

Edited by GeneralDisorder

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GD I think you are mistaken on the early DOHC and Phase II piston / compression thing. The Phase II pistons don't come out of the deck as you stated but they have a smaller dish volume in them than the early engines so you unless I'm mistaken (entirely possible) you actually have more compression with the Phase II shortblock / pistons. If I remember correctly the early dish volume is 14cc's and the Phase II 6cc's.

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