i have gsr motor with usdm itr pistons and the compression is about 10-8-1 to 10-9-1 i want to raise it to 11-5-1 to 11-7-1 should i mill the head or buy a cometic headgasket. just look for info thanks

 

That's an awful big gain you're looking to get. You'd probably need both a thinner head gasket and have the head milled to increase the compression that much. If you're serious about raising the compression that much, then consider different pistons.

 

u should buy b16 pistons
pr3= 11.3cr
p30=11.6cr
ctr= 12.1cr

 

just had it rebuilt with the itr pistons.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kendall &raquo;</TD></TR><TR><TD CLASS="quote">That's an awful big gain you're looking to get. You'd probably need both a thinner head gasket and have the head milled to increase the compression that much. If you're serious about raising the compression that much, then consider different pistons.</TD></TR></TABLE>

yeah you will need both the 2 layer mugen/spoon headgasket will get you to around 11:1 if you mill the head about 10 then you ll be at 11:4 mill it 20 and you ll be at 11:7.

 

HG before mill always