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J

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Discussion Starter #1
Hi Im rebulding my engine right now. I just ordered CP 86.5mm bore 9.0 CR pistons, Pauters rods and HKS 1.0mm Stopper type head gasket. My question is with the HKS head gasket install with CP pistons, how much CR will it be? Also, will the HKS head gasket work with CP pistons without any problems? Thanks
 

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Your fine. your a tad over 9.0:1. Maybe 9.2:1. The only way to really tell, get a cc kit and cc everything to be 100% sure. If your wanting an exact CR, then you will have to do it the hard way and cc it all. The JE pistons are off on the CR, but the CP's are pretty close.

Brian
 
J

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Discussion Starter #3
Thanks for you reply. But, I thought that when we put thicker head gasket it would help to reduce compression ratio....am I wrong or right? Don't get me lost here.
 

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J_Spec said:
Thanks for you reply. But, I thought that when we put thicker head gasket it would help to reduce compression ratio....am I wrong or right? Don't get me lost here.
yes, a thicker HG reduces static CR, however, OEM HG is also 1.0mm
 

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^ is it? i thought oem was 1mm, oh wlel, if it is thinner than stock, then you're static CR will increase slightly as you said earlier
 
J

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Discussion Starter #7
So, what can I do to get the static CR down to about 8.5-8.8? I thought using HKS 1mm HG would lower my CR down to 8.8.

By the way, is it a danger to run 9.0 CR with T4? I am thinking to boost it 18PSI daily after the car get tuned. Or I really need to get CR down with higher boost?
 

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what are you using to tune it with? if you plan on tuning with a stand alone, 9:1 cr is perfectly fine, all the tuner needs to do is cut back on timing advance if you start to see knock. but really, it's all in the tuning.
 
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Discussion Starter #9
Ahh, that's what I want to hear. I love you Boz! Thanks people
 

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Your fine, like Boz said, it's all in the tuning. The lower compression ratio just makes it easier and safer. I think the HKS is .002" thinner. I measured once a while back and it was slightly thinner.
 
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