SolidSpruce

i bought some new 9.8:1 JE's for a B18 off a friend, and put them in my B16. Do i still retain the 9.8:1 compression ratio? or did it drop?

I know the bore is the same on both motor, and the stroke is the difference......does anyone know of a compression ratio calculator online or something?

thanks

TTWS6.

yes 9.8:1 GSR pistons is 8:8:1 in a b16.. the deck height of the b16 is shorter, thats why

hoya_10fintec

a stock GSR pistons in a B16 = 8.?:1
but 9.8:1 GSR forged pistons in a B16 = maybe lower than 8.?:1...?

bump.. I wanna know too..

SolidSpruce

if the deck is shorter....wouldnt that INCREASE compression, since now there would be less volume in the combustion chamber? i figured it might be something in the head, the depth of the dish....now im confused

hoya_10fintec

if I put a GSR head on a B16 block, it will raise the compression..

SuperTeg95

Yes a GSR head has a smaller combustion chamber. A b16 head will drop the cr.

tegasaurus

i believe its the stroke and rod height that changes the compression, but am not sure if it increases or decreases. I know a b18c to a b18a/b decreases about 6 pts.

there is a calculator on c-speedracing.com, check it out

boosted92

9.8:1 JE's will give you 8.8:1 in a stock bore B16, 9:1 with gsr head . Almost 8.9:1 in an 81.5MM B16, and 9.05:1 with GSR head .

Stock GSR's in a B16 will give you 9:1. Stock GSR's in a B16 with a GSR head will give you 9.15:1.

hoya_10fintec

I read that if you put GSR pistons in a B16, it will be lower CR less than 9:1..
somewhere around 8.5:1 or something... can't remember exactly..

someone confirm me on this?

thid92

i would be careful because the intake valves are bigger on a b16 than a b18b (which will cause major damage ) i hope ur talking about LS pistons if not dont worry.

boosted92

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hoya_10fintec &raquo;</TD></TR><TR><TD CLASS="quote">I read that if you put GSR pistons in a B16, it will be lower CR less than 9:1..
somewhere around 8.5:1 or something... can't remember exactly..

someone confirm me on this? </TD></TR></TABLE>

Nope.

81MM B16 w/B16 Head + GSR Pistons = 8.98:1 compression, so basically 9:1.

SolidSpruce

ok, wow, that pretty wild, ok ok, so what if u put stock b16 pistons in a b18 block? with a gsr head? somewhere in the 11 cr maybe? if thats the case, for those people wanting to run all motor w/ higher cr stock b16 pistons would be a cheap way to increase compression!

boosted92

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SolidSpruce &raquo;</TD></TR><TR><TD CLASS="quote">ok, wow, that pretty wild, ok ok, so what if u put stock b16 pistons in a b18 block? with a gsr head? somewhere in the 11 cr maybe? if thats the case, for those people wanting to run all motor w/ higher cr stock b16 pistons would be a cheap way to increase compression!</TD></TR></TABLE>

Yep, you could do that. Stock B16 pistons in a GSR would make 11.7:1 compression, and 11.4:1 with an ITR. Most people looking for something cheap would go with CTR pistons though, giving you 12.4:1 and 12:1 with a GSR and ITR, respectivly.

hoya_10fintec

damn!! that's pretty good than... maybe I should just throw in a set of GSR pistons. I'm only gonna be boosting up to 10psi w/hack..

Thanks

11psiTurboSI

I have JE 9.8:1 pistons for a gsr and in my b16a2 with stock headgasket its 8.8:1 and i hate it way too low

SolidSpruce

yeah same here! i just realized this after having the motor built and running for 6 months now! what kind of power are u making? and how much boost are u running?