Compression For mixed matched head and blocks

Samurai_Blue

Yolo Whippin'
Below is a list of compression for different block and head and piston combinations.
credit goes to redlsteg @ B20Vtec

B16A block, B16 head and:
GS-R pistons 8.7
USDM ITR pistons 9.5
92-93 GS-R pistons 9.56
JDM ITR pistons 9.9
B16A pistons 10.2
CTR pistons 10.8

B16A block, GS-R head and:
GS-R pistons 9.0
USDM ITR pistons 9.9
92-93 GS-R pistons 9.94
JDM ITR pistons 10.3
B16A pistons 10.6
CTR pistons 11.3

B18C block, B16/ITR head and:
GS-R pistons 9.65
USDM ITR pistons 10.6
92-93 GS-R pistons 10.64
JDM ITR pistons 11.0
B16A pistons 11.36
CTR pistons 12.0

B18C block, GS-R head and:
GS-R pistons 10.0
USDM ITR pistons 11.0
92-93 GS-R pistons 11.1
JDM ITR pistons 11.5
B16A pistons 11.9
CTR pistons 12.6

B18B (LS) block, B16/ITR head and:
GS-R pistons 9.8
USDM ITR pistons 10.8
92-93 GS-R pistons 10.84
JDM ITR pistons 11.2
B16A pistons 11.6
CTR pistons 12.3

B18B (LS) block, GS-R head and:
GS-R pistons 10.2
USDM ITR pistons 11.2
92-93 GS-R pistons 11.3
JDM ITR pistons 11.7
B16A pistons 12.1
CTR pistons 12.85


http://www.b20vtec.com/forums/b-series-tech/72854-ctr-pct-piston-compression-clarification.html
 

Samurai_Blue

Yolo Whippin'
mirrorimg said:
Needs more LS block, P75/P8R head with different pistons!
Click to expand...
yeah it does, these compressions were done without the use of the compression calculators though, so i dont know how off they are. These compressions are supposed to be "true compression ratios" at sea level. It was also off of a hybrid site

ill do a quick test to double check the numbers to see what i get

EDIT: just ran tests the gsr numbers were off for a GSR with 81mm bore with p72 head. and PCT pistons at over 13:1 and c speed was at 12:1
 
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mirrorimg

Well-Known Member
Pretty funny that the numbers came from B20VTEC and dont have an B20's listed. I would expect the slightly increased quench area because of the 84mm bore would lower the compression slightly.
 


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