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But people report power increase when they have a 2.5 DOHC in their car and then swap on 2.2 heads. Therefor it must increase power. Unless their butt dyno is broken...

 

none of us know anything because renob said so...

 

and yes a 2.5l does gain HP when swapping on 2.2l heads. Did this to a 2.5 that went interference but didn't trash the pistons and it was a substantial (maybe 20+hp) difference. 2.2 heads are cheap and plentiful down here in texas.

 

I am not here to get in a pissing match but i found the thread and on page 3 matt monson said himself that it makes the ej25 go from 9.7:1 to over 11:1. THAT makes power, and its not icing on the cake.

 

here is the link if you don't believe me.

http://forums.nasioc.com/forums/showthread.php?t=631527&page=3

 

:banghead:

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I don't want to get in a pissing match either, but on the other hand, it looks like I'm getting flamed in here for questioning peoples' butt dynos.

 

Here's Matt's post that I'm talking about: http://forums.nasioc.com/forums/showpost.php?p=32176687&postcount=303

 

I don't know everything about everything, but I know I've read that thread a number of times, and my Frankenmotor was a substantial improvement over my old 2.2. It's so powerful that my doors don't shut the same anymore.

 

Jacob

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  • 5 months later...
Frankemotor:

 

EJ25: short block and head gaskets.

 

EJ22: EVERYTHING ELSE.

 

Got it?

 

GD

 

Proper Frankenmotor:

 

EJ25: Short block and injectors (unless you already have the 280s) and flywheel if you are off roading.

 

Cosmetic hybrid head gaskets

 

EJ255: Oil pump

 

EJ22: Everything else.

 

More compression = more heat, 10mm oil pump is the ticket. The 22 flywheel is about 4 pounds lighter than the 25 so you lose a little torque/rev a bit quicker.

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Proper Frankenmotor:

 

EJ25: Short block and injectors (unless you already have the 280s) and flywheel if you are off roading.

 

Cosmetic hybrid head gaskets

 

EJ255: Oil pump

 

EJ22: Everything else.

 

More compression = more heat, 10mm oil pump is the ticket. The 22 flywheel is about 4 pounds lighter than the 25 so you lose a little torque/rev a bit quicker.

 

What year/model for EJ255 oil pump? Is this the STi "high volume" pump?

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What year/model for EJ255 oil pump? Is this the STi "high volume" pump?

 

From what I gather, the 11mm+ STi pumps are too much and can cause a starvation if you're using a stock pickup tube. Not interested in finding out, but I'm running a 10mm pump off of a WRX. At least the guy I bought it from said it was off his 06 WRX. The whole argument on NASIOC became confusing as to what sizes were what, I just know it flows a whole lot better than the stock 8mm pump.

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I had a previous dealing with oil pumps, and I learned the 97-99 DOHC EJ25 oil pump is thicker than the later 00- SOHC 2.5 oil pump.

I had accidentally put a later thinner oil pump on my DOHC engine when I did headgaskets, but I found out and corrected the problem before I ever ran the engine.

 

A correct guide with all the different sizes/differences/years of EJ oil pumps all listed would be helpful.

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I had a previous dealing with oil pumps, and I learned the 97-99 DOHC EJ25 oil pump is thicker than the later 00- SOHC 2.5 oil pump.

I had accidentally put a later thinner oil pump on my DOHC engine when I did headgaskets, but I found out and corrected the problem before I ever ran the engine.

 

A correct guide with all the different sizes/differences/years of EJ oil pumps all listed would be helpful.

 

Hmm, are you sure that 99 is included in that? And what about 96?

 

The 99 DOHC is actually the same block as the SOHC, the only difference is it has different pistons for the sohc heads.

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Yeah the info I got, was all DOHC EJ25 blocks.

the early '96 EJ25's would be included, phase I engines.

 

All DOHC oil pumps should be same, and the 00+ SOHC should be different. If I can remember I was told the SOHC pump rotor was 70% the size, positive-displacement oil pump, so maybe the DOHC pump has up to 30% more flow? Even with 'blocks' the same, oil pumps used should be different part numbers.

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Yeah the info I got, was all DOHC EJ25 blocks.

the early '96 EJ25's would be included, phase I engines.

 

All DOHC oil pumps should be same, and the 00+ SOHC should be different. If I can remember I was told the SOHC pump rotor was 70% the size, positive-displacement oil pump, so maybe the DOHC pump has up to 30% more flow? Even with 'blocks' the same, oil pumps used should be different part numbers.

 

Well a 99DOHC leagcy motor and 99SOHC impreza motor are the same block. Just different pistons and heads. The 99 DOHC motors have the bigger rod bearings and the thrust bearing in the new location.

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Hey,

 

I've been following this thread...having read extensivly the NASIOC Frankenmotor stuff and a few thoughts.

 

The DOHC motors may very well have a larger pump for more volume. It needs more oil in it because there are more places for or to be. Will probably have a little more capacity in the oil pan tool. I've read there of several different EJ oil pans and pickup tube arrangments.

 

The whole power thing with this engine and the debate...from what I gather and find having looking at some Dyno sheets what happens is that you get a flatter more linear torque curve with it. More displacemenmt, higher compression ratio. And I was thinking if one of those is stock out there, you wouldn't expect to rev it to the moon or have anything fancy to get the torque that you all say feels pretty good.

 

Doug

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  • 4 weeks later...

After 5k miles on my EJ25D/Singleport 2.2 heads, I have the following to report.

 

Improved fuel mileage over my 2.2; about 1.5mpg. Surprised me as well.

 

Obvious huge power increase over stock 2.2

 

Consistent P0304 that never goes away for more than a week. PRE has informed me that it's a result of running a light flywheel, and is nothing to worry about based on the tests I've performed.

 

Powerband is 2000-5500rpm. Does have power from 5500 to fuel cut around 6k, but not as balls to the wall as pre 5500. Torque is ridiculous, I may need to go to a stronger clutch than the KSB04.

 

You absolutely need a grounding kit. Something about the config of the engine really requires a more stable electrical system.

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