yep here is another one on how much boost.

[CacheHX]

what is your estimate on what my comp. is??? cause i dont really know

z6 head on y5 block
srp 9.0-1 low comp pistons
and a head gasket made for over 10 psi (not sure if its any thicker)


i tried that comp calculator but it doesnt have aftermarket stuff on it

 

[ryan89crx]

what is your estimate on what my comp. is??? cause i dont really know

z6 head on y5 block
srp 9.0-1 low comp pistons
and a head gasket made for over 10 psi (not sure if its any thicker)


i tried that comp calculator but it doesnt have aftermarket stuff on it

lol, im not trying to be rude, but common sense my man...

you said the pistons are from a z6 right?

all 1.6 share the same deck height and rod length. therefore a Y block with 1.6 rods and z6 pistons will be equal to a z6 compression wise

z6 9.0 pistons in a y block with a z6 head = 9.0:1 with a z6 HG

 

[CacheHX]

i broke it in without the turbo or injectors or anything just the stock maps and this is what happened:

could low compression be the reason why it is very sluggish on low to mid throttle but it rips when i hit WOT. it also backfires alot when i let off gas

 

[CacheHX]

they are y5 pistons, but your saying they are all the same?

 

[ryan89crx]

.2 difference in compression isnt going to make it very sluggish. id recheck your base timing and go from there.

backfire when you get off the gas could be because of free flowing exhaust, unless you are running stock exhaust. then i would go back to checking timing

 

[ryan89crx]

they are y5 pistons, but your saying they are all the same?

no they are not the same, whats the part # on the pistons?

 

[CacheHX]

ok thanks for the info.

its a greddy evo2 with DC headers

 

[ryan89crx]

i dont even see the y5 application on the SRP website...

are you sure thats the motor they are for? part #?

 

[CacheHX]

maybe they are for y8. my engine builder ordered them. there probably for a y8

 

[ryan89crx]

well throwing a z6 head on a y8 block(your y5 in essence is a y8 block with different pistons) will drop the compression .4 points. so figure that your 9.0:1 compression pistons will now be 8.6:1 with a z6 head. use a thinner HG and you can bring that number back up closer to 9:1

 

[CacheHX]

ehh its cool, i'll just run like 40 psi to make up for it. its all cool