Help.....problem with lowering my compression.....
#1
Help.....problem with lowering my compression.....
So here's my deal: I really do not want to change my pistons.....
I had my AES 390ci built with Flat top pistons. I want to use a single PT88 turbo.
My engine info and planned parts:
Iron LQ9
4.030" bore
3.825" crank
6.125" rod ((1.180 pin height))
LS9 .051 gaskets
74cc chambered heads
Flat Top pistons
9.225 deck height
The compression calculator at http://www.eaglerod.com/....IF I DID IT CORRECTLY.....says 10.28:1 compression.
I'm trying to get it to 9.8:1.......
How thick can I go on the head gaskets ((Brand and part number)) and still have the gasket be very strong and reliable.......? That the only place I see any possible wiggle room to lower cr any more.
I know 10.28:1 cr is fine if I use full time E85....but Id rather not if I don't have to.
Thanks...
.
I had my AES 390ci built with Flat top pistons. I want to use a single PT88 turbo.
My engine info and planned parts:
Iron LQ9
4.030" bore
3.825" crank
6.125" rod ((1.180 pin height))
LS9 .051 gaskets
74cc chambered heads
Flat Top pistons
9.225 deck height
The compression calculator at http://www.eaglerod.com/....IF I DID IT CORRECTLY.....says 10.28:1 compression.
I'm trying to get it to 9.8:1.......
How thick can I go on the head gaskets ((Brand and part number)) and still have the gasket be very strong and reliable.......? That the only place I see any possible wiggle room to lower cr any more.
I know 10.28:1 cr is fine if I use full time E85....but Id rather not if I don't have to.
Thanks...
.
#2
8 Second Club
iTrader: (4)
If you have good deck and head surfaces cometic can make you a custom head gasket to hit most any compression you want, there is no limit really. Very common for the import crowd to run 3.5+mm thick HG's (.138" thick). I believe they sell a cheaper .070 shelf LS gasket as well.
#3
9 Second Club
How thick are the piston crowns ? Could they be machined ?
Likewise can chambers be opened out more ?
Cant say I've ever seen anyone using a gasket more than 2mm thick, and even that's rare.
Likewise can chambers be opened out more ?
Cant say I've ever seen anyone using a gasket more than 2mm thick, and even that's rare.
#4
8 Second Club
iTrader: (4)
Wouldn't need that thick of a gasket to drop a half point of compression.
3.5mm is common in the BMW turbo crowd…
http://www.jegs.com/i/Cometic+Gasket...FZSKaQodNWoAwg
I ran a 3mm thick gasket on my Sc300 2JZGE setup as well.
3.5mm is common in the BMW turbo crowd…
http://www.jegs.com/i/Cometic+Gasket...FZSKaQodNWoAwg
I ran a 3mm thick gasket on my Sc300 2JZGE setup as well.
#5
If you have good deck and head surfaces cometic can make you a custom head gasket to hit most any compression you want, there is no limit really. Very common for the import crowd to run 3.5+mm thick HG's (.138" thick). I believe they sell a cheaper .070 shelf LS gasket as well.
That should be good......
Again...if I am figuri it all out correctly with calculator. I used the one here:
http://www.eaglerod.com/
.
#7
Would this be the proper gasket to use for 4.030" bore....?
http://www.netgaskets.com/COMETIC_He...%20c5751-b.htm
Is .070 thickness perfectly fine for 18-20 psi.......???
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http://www.netgaskets.com/COMETIC_He...%20c5751-b.htm
Is .070 thickness perfectly fine for 18-20 psi.......???
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