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Old 12-03-2012, 11:07 AM   #1
EJ207RSTi
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Default ej207 v8 to ej257 shotblock

I'm replacing my ej207 version 8 shortblock with a ej257. Plan to use the version 8 heads. My concerns are, my car has been completely redone to run the version 8. I know all of my wiring is for the jdm engine. And will all of the sensors work? a/c, p/s? Anone know any problems I will run into?
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Old 12-03-2012, 11:51 AM   #2
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The shortblock should be relatively invisible to your car. Keeping the V8 heads will make life much easier.

You'll need a tune though.

Last edited by kpluiten; 12-03-2012 at 11:57 AM.
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Old 12-03-2012, 12:15 PM   #3
WhatTurboLag?
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Everything will work, you will need a tune like he said. Might have to lower the redline It's a stock piston and stock rod motor.
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Old 12-03-2012, 12:35 PM   #4
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i thought that there is a lot of problems with the heads and the cylinders matching up. i remember messing with a 22r and putting a 20r head on a toyota and it uped the compression a good amount. there are alot of posts about that too.
you might want to talk to a tuner first before yous start yoru project. also just a side note, I have a 20 and when its my time i am going to go with the 2.19 stroker motor it looks like a better option for the 2.0
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Old 12-03-2012, 08:26 PM   #5
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If you want the 2.5 just get your heads milled to better match the 2.5L bore, much better solution compared to thick head gaskets http://forums.nasioc.com/forums/show....php?t=1942615

2.1L stroker (2L block W/79mm stroke crank) is an option as well but the "stroke" is relatively mild. There has been a slight spool increase reported but most of these engines end with a 8.5+/1 CR in addition to the 4mm stroke increase so where the gains are coming from is not totally clear.

If you want more displacement and are a touch crazy you can do a destroked 2.35L(2.5L block 75mm crank) with the milled 207 heads and have a crazy top end power band.

Last edited by lukeskywrx; 12-03-2012 at 08:34 PM.
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Old 12-04-2012, 04:11 AM   #6
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I just need it to run healthy really. I am going to use drop in forged pistons in the 257 shortblock. Hopefully everything works out.
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Old 12-04-2012, 08:47 AM   #7
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might as well do rods as well since its apart. my friend just found that out the hard way. bent a rod and spun a bearing. entire build costs down the tube. take the time to do it right the FIRST time now.
dont forget the 207 heads are slightly larger if i recall compared to ej205 heads so with a stock ej257 bottom end the compression will go up but not as substantially as it would if it was a usdm hybrid. getting the heads milled requires a basic overhaul of the heads keep that in mind as well. maybe try calling CP and see what they have for the lowest possible compression ej257 pistons.
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Old 12-04-2012, 09:01 AM   #8
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I would expect you would still want to have the combustion chamber enlarged to match the 257's. It is still a hybrid after all.
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Old 12-04-2012, 11:40 AM   #9
lukeskywrx
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Quote:
Originally Posted by EJ207RSTi View Post
I just need it to run healthy really. I am going to use drop in forged pistons in the 257 shortblock. Hopefully everything works out.
Dropping in forged pistons is the last thing you want to do for it to run healthy. That is like playing russian roulette with the clearances.
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Old 12-04-2012, 01:26 PM   #10
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Quote:
Originally Posted by WhiteBgeye02 View Post
might as well do rods as well since its apart. .
why the rods? the stock 257 rods are the same as on the 207. Plenty strong unless he wants to spend for the overkill on H or I beams.
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Old 12-06-2012, 12:10 PM   #11
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Well I hear more about the 2008 STi motors breaking ringlands than anything. And I have some plans to make a decent amount of power. I plan to get the work done at Akuma in NJ
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Old 12-06-2012, 03:03 PM   #12
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Pistons do no matter what, rods are cheap insurance. Might as well so if/when you break one you won't regret not doing it the first time
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