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Old 05-23-2001, 09:25 AM   #1
advance
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Question EJ22 vs. EJ25

I have the EJ22 and was wondering the differences in the EJ25 for instance can heads be swapped (any gains), can the 25 work with my 22 tranny, is the hp differences in the block or the head. Feel free to tell me anything else about the differences.
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Old 05-23-2001, 11:12 AM   #2
mrbell
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Most of the HP gains come from the larger displacement of the block. A 2.5L block should bolt to your tranny, I think, w/o problems(you may have a few unused bolts, but I dont' think it'll be a problem). The 2.5L heads probably flow more(speculating) so you might see an increase in power. Personally, I'd kind of like the smaller displacement block for turbo charging. But I might switch to the larger heads. Go for it. =)
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Old 05-23-2001, 11:20 AM   #3
Blindeye_03
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Sounds like it wouldnt be a pain in the arse...do it .
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Old 05-23-2001, 07:31 PM   #4
bobjr94
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I know on the late 90's 2.5 the chambers are much bigger, and just a guess Id drop the compression 1 point at least
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Old 05-24-2001, 12:33 AM   #5
ColinL
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On a 99+ EJ22 the heads are very similar to a 99+ EJ25, but they are not identical. Smaller valves, smaller ports, smaller bumpsticks.

I couldn't tell you what the chamber volume is, sorry. I do know that the quench area is different because of the bore differences, and that could very well lead to some sealing / head gasket issues.
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Old 05-24-2001, 06:31 AM   #6
pottsie350
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I have a 2.2 as well, and from what I've gathered the EJ22E used in the new impreza is the same block used in the 89/94 Legacy turbo, except with higher compression pistons. The heads on the phaseII (99 and newer) EJ22E are different than the heads on the phaseI (89/98 EJ22E). The PhaseII heads flow a bit more air.

I would venture to guess that by sticking a set of 2.5 L heads on the 2.2 you wouldn't see much difference, unless you decided to go with a higher flowing set of cams, or a turbo/supercharger. To get noticable power without using cams and or air pressure I would suggest installing the block too.

I have no definitive proof but I think the 2.2 should be stronger if you decided to use some forced induction.
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Old 05-24-2001, 04:53 PM   #7
pottsie350
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You may be right, I'm only going by the part numbers for remanufactured engines. There may be a lot of resellers selling the newer 2.2 block as a replacement for the older legacy block. The engine model codes are the same, both being EJ22E. The differences I have been able to substantiate are the Legacy turbo motors having lower compression dished pistons and single exhaust ports, vs the NA motors dual exhaust ports and higher comproession pistons.

I haven't seen any pictures of the decks to prove otherwise, and nobody has been able to show me a comparison of the two engines. I would very much like to find some proof somewhere. But info seems hard to come by.

[This message has been edited by pottsie350 (edited May 24, 2001).]
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Old 05-25-2001, 12:34 AM   #8
bill harvey
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the "new 2.2 " is not the same block as the turbo block because the n/a 2.2 is opne deck and the turbo one was closed deck there fore not the same block.
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Old 05-25-2001, 07:17 AM   #9
svxtrem
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Actually, the '99 2.2 has the same size ports and valves as the 2.5. The cam is smaller. So, easy mod is to put 2.5 cams in the SOHC 2.2 lose some torque, but gain hp.

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Old 05-25-2001, 07:35 AM   #10
ColinL
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Aha, good knowledge sharing there... thanks.
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