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Old 10-07-2010, 06:23 PM   #1
flyguyeddy
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Default head choices for ej22et: 25d or 251?

im building an ej22e with a turbo. ill be using wiseco off the shelf pistons (.020 overbore) and sti rods. i have the choice between the ej251 heads that have 270k or some junkyard heads from a local yard that have 60k or so. the condition of the j/y heads is unknown, the ej251 WAS running in my car until the ecu (i think) died.

anyway, im building that ej22e and i want to know which heads to use.

any thoughts? i currently have the 251 heads, id have to buy the 25d heads.
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Old 10-08-2010, 09:52 AM   #2
flyguyeddy
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I find it hard to believe that nobody has an opinion on this matter. Come on guys, help a guy out with his decision
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Old 10-08-2010, 10:13 AM   #3
FuJi K
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ECU died, have you looked into doing a simple USDM 02-05 WRX harness/ecu? That's like the most efficient way to go about it. THings are getting cheaper nowadays compared to what I had to go through back in the day.
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Old 10-08-2010, 12:04 PM   #4
flyguyeddy
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No, im using megasquirt for engine control. Gonna use the 36-2-2-2 wheel for a crank pickup and batch fire the injectors.
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Old 10-08-2010, 01:30 PM   #5
eg33GC
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revs/top end with marginal taper
torque/bottom end with solid midrange

pick one.
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Old 10-08-2010, 04:30 PM   #6
flyguyeddy
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Torque/bottom end is my preference. But im not so sure how a td04 will spool with a 2.2. I will be gasket matching everything on the exhaust side so the turbo spools nice and smooth.
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Old 10-10-2010, 06:24 PM   #7
flyguyeddy
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i assume that would mean the ej251 heads?
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Old 10-10-2010, 06:42 PM   #8
trxdam
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I would have to say ej20k/r heads hands down if you are buying, way bigger ports, cams, valvetrain was made to rev to 8000+rpms..... I saw a set for 400 bucks a little while back....
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Old 10-10-2010, 07:55 PM   #9
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25D pretty much already has turbo provisions as far as an oil feed location, you can drill and tap the head for return.

As for the 251s having "assumed" less top end capability, this is a huge fallacy.
I have flow tested the 25D, the 251 and the 20K in stock form.
The SOHC 251 heads had better low lift numbers and better peak flow numbers than the "D" or the "K"
They will be a hell of alot more reliable if set up right.
People crow and crow about how great EJ20K heads are....
1. They're really not much better than 25D heads, when flow tested back to back the JDM big port 20K heads outflowed the 25D heads by an average of 5 cfm across the board and only about 10 CFM more peak.
2. "Yeah but shim under bucket dude." Yeah they'll take 8000 shifting as long you never use anything bigger than a VF series turbo. Throw a healthy TD06-20G on some EJ20K heads that uses stock valvetrain and rap the **** out of it, valve float like a butterfly, valve locks poppin out stingin like a bee.
The stock springs from an EJ20K are deceiving, they're super tall and have a boatload of seat pressure but they have no spring rate; AMOF they have less on the nose pressure than a 25D.

Verdict:
It's probably cheaper and easier to run a 25D setup but if you're after more than easy like easy maintenance and superior flow, the 251 wins.
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Old 10-10-2010, 10:11 PM   #10
trxdam
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25d heads go to ~6500 rpms im assuming what does the chart say about 20k/r heads past that? I got rid of my 257/20r combo a long time ago.....
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Old 10-11-2010, 11:24 AM   #11
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Flow charts scale flow with valve lift, not RPM, so I can't tell you.
Peak to peak was a a difference of only 10 cfm.
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Old 10-11-2010, 02:15 PM   #12
trxdam
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I guess i should say 20k cams are what really give it the omph..... Sorry for thread jack...... If you can make that sohc put down some good #'s go for it.
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Old 10-11-2010, 02:46 PM   #13
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Quote:
Originally Posted by trxdam View Post
I guess i should say 20k cams are what really give it the omph..... Sorry for thread jack...... If you can make that sohc put down some good #'s go for it.
Yeah, they're quite a bit more aggressive than the EJ20G or 25D.
Right around 246* & 248* intake and exhaust adv. duration
.323 & .327" lift for the STI models.
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