I have a b18b block that i am building for forced induction. I bought 8.5:1 compression pistons, and have since thrown on a gsr head. I am wondering what the compression ratio will be now.

Also i am nervous to rev the motor too high. What do u guys normally go to? I got pistons and eagle rods, and will have a gsr oil pump also. I am gonna stay at a 7200 limit for now. what would be safe?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by streetlvlhatch &raquo;</TD></TR><TR><TD CLASS="quote">I have a b18b block that i am building for forced induction. I bought 8.5:1 compression pistons, and have since thrown on a gsr head. I am wondering what the compression ratio will be now.

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If the 8.5 compression piston was made for b18b block/head, then putting a p72 head in will yield about .45 more compression so you will be about 8.9/9. This is counting that the piston that you have has stock compression height.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by streetlvlhatch &raquo;</TD></TR><TR><TD CLASS="quote">
Also i am nervous to rev the motor too high. What do u guys normally go to? I got pistons and eagle rods, and will have a gsr oil pump also. I am gonna stay at a 7200 limit for now. what would be safe?</TD></TR></TABLE>

depending on cams you can rev higher...the only limit for revs in a stock b18b block is the rod bolts, but since you dont have those any more go ahead and rev like a vtec engine...dont be squeerd.

 

Put the car on the dyno and see were the power rolls. You will then know how high to rev it. As for compression You would need to post the piston dome/dish cc, bore, stroke, and so forth. then honda-tech member can give you an estimate. But im going to take a wild guess and say you are close to 8.5:1.

 

i have srp pistons with 8.5:1 compression runnung eagle rods for an ls

 

help!!!

 

anything else about the compression?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by streetlvlhatch &raquo;</TD></TR><TR><TD CLASS="quote">anything else about the compression?</TD></TR></TABLE>

 

with the stock LS stroke and the 8.5:1 pistons and a stock (assumed) P72 head, you're going to yield about 8.7:1-8.9:1. If you have a thicker head gasket of course that will drop it to about 8.6:1. These estimates are not calculated, just from past experience with LSVTECs.

assuming you didn't shave your block deck nor the head. did you re-sleeve your block while you were at it? Even if you're not going to boost more than 1 bar you should re-sleeve it for security and strength.,