90mm bore and boost
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Joined: Dec 2008
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From: Oxnard, CA
I don't think anyone is running 90mm with F/I... Only the hardcore N/A people run 90mm bore sizes.. And there are only a handful of those guys too.
I wouldn't think a gasket that thin could hold out past 15psi....even with lower compression pistons.
Would the slightly improved displacement really yield higher performance than the ability to up the boost safely/reliably, even if you bored to 88mm?
I wouldn't think a gasket that thin could hold out past 15psi....even with lower compression pistons.
Would the slightly improved displacement really yield higher performance than the ability to up the boost safely/reliably, even if you bored to 88mm?
Joined: Apr 2002
Posts: 4,857
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From: Gold Coast
Originally Posted by ERL_S2000,Aug 27 2009, 01:45 PM
1. Past 89mm you can not o-ring the head and you will run into major issues with gaskets because of the big bore size. Sealing area becomes very small. This is not a big problem with N/A engines but being FI we have very little room to work. I am using a OEM gasket @ 89.5mm. The thickness is .030". Given your deck height after your new setup is install and how much comes off the head if you have it reworked ect ect ect may require you to modify the piston spec before installation do to having a limited amount of gaskets to use. I personally did not want to use cometic in any way esp @ that bore size. I see nothing wrong with a 88mm bore.
listen to ERLDont go past 89.5mm
Stick with 89mm or less if you want less headache.
My builder was able to O-ring the block at 89.5mm and I am using a copper SCE headgasket.
Whether this will hold with good boost...time will tell.
FINGERS crossed!
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