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Old 02-22-2008, 12:32 PM   #1
Gr3en
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Default STi headgaskets?

I am doing cams in my 05 RS and am thinking of doing STi headgaskets to up compression. What kind of a difference in power will I see? What are the pros and cons.

Thanks!
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Old 02-22-2008, 01:22 PM   #2
LTracer
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What are the physical differences in the EJ257 headgasket versus the stock one for your EJ253? Thicker, thinner, different material? I saw your post over at 2.5rs and was curious.
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Old 02-22-2008, 01:39 PM   #3
Gr3en
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The STi gaskets are thinner, about half thickness on the RS gaskets.
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Old 02-22-2008, 02:16 PM   #4
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Any thoughts guru's?
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Old 02-22-2008, 02:53 PM   #5
FuJi K
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I thought that the PHASE 2's are all the SINGLE layer HG??
The '96-'99 2.5L DOHC HG are THICK. '99-'01 2.5L SOHC are a SINGLE THIN HG. I remember seeing the STi HG and it's not THIN at all.
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Old 02-22-2008, 04:05 PM   #6
Gr3en
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Huh. Maybe I misheard my mechanic and he said thicker. That does make sense.
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Old 02-22-2008, 08:55 PM   #7
GrundleJuice
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isnt the STi HG to fit a closed deck or semi closed deck? Will it work ok with the open deck design in terms of allowing coolant to circulate properly? im not very familiar with the open deck ej25's vs the closed decks as far as cooling between the block and heads, just the first thing i thought of when thinking about STi motor vs n/a motor.
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Old 02-24-2008, 11:50 PM   #8
Matt Monson
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Unless I remember incorrectly, the STi HG's are .058, just like the '99-02 SOHC Ej25 HG. It's what I've used on my last couple of engines. However, I don't know what the thickness on an '05 EJ25 uses for a gasket. I know that engine has different pistons than mine and a different intake manifold but haven't followed the last couple of years of production closely enough to know of any other differences...
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Old 02-26-2008, 06:22 AM   #9
subyboy
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I don't belive using STI hgs will raise the cr if anything it will lower it, as with the coolent circulation it has to deal with the heads it really wont matter on the block. For what ever hgs you do decide to use make sure that the coolant holes/ports on the heads and the gaskets line up. If they don't but are close you will have to moddify them.
My .02

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Old 02-26-2008, 11:20 AM   #10
FuJi K
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The coolant passeges are ALL in the SAME SPOT as always. Only difference are they moved a little left or right, and PHASE2 heads the passeges are BIGGER at the middle and around. They have NOT moved to anywhere where it's going to effect cooling.

If you've seen phase1, phase 2 heads, you'll know.
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