Dear all,

hope some can help..

I would need to know the cylinder head volume.

GDB Sti ... MY02.. with AVCS.
Standard 92mm x 75mm stroke cylinder.

has anyone measured before and might have the information?

please enlighten!

thanks

 

Someone will have to check my math, but here's how it calculates out:

radius of the bore squared --->R^2
stroke--->h

the volume of the cylinder is Pi*R^2*h, in this case 4.6^2*Pi*7.5= 498.57075

Since your compression ratio, if you have an EJ207, should be 9.5:1, you can solve backwards for the combustion chamber volume using this:

V(cylinder)+V(head)/V(head)=9.5

substitute to get:
[498.57075+V(h)]/V(h)=9.5
V(h)=58.6554

58.6554 is the combustion chamber volume in CC, with the piston at TDC. However, the actual volume of the head is that number plus or minus any dome or dish on the piston. Unfortunately, I don't have that information around.

If I've screwed up any of the equations, please post the corrected numbers here. Thanks.

Also, a footnote- the published CR is 9.5:1, but I doubt it's 9.500000:1, so bear in mind that the above calculations are probably off by a couple CCs.

 

hey pal.. thanks.. i know the caculations. the only thing i dun have is the cylinder head volume. ( meaning the dome shape where spark plug + valves are)
if having that i would know how to caculated backward..

hey!! really thanks for yr help tot! i apprecitae that!

 

Try calling around to shops that have replaced pistons in STi engines... maybe you can talk one into CC'ing one piston to determine the dome volume. If you find out, please post back to me.

 

hey pal...

i m in singapore.. where support for subaru is limited as well.
anyway.. fyi... Ej207 gdb my02 . compression ratio is 8.0:1. this i can cfm.

based on my caculations, i worked out to b 22cc.
i just need confirmations on this!

u may try to work it backwards as well.
cheers!

 

I found a bit of info on head and piston volumes here:


Unfortunately, since you have neither a US WRX EJ205 nor a Spec C EJ207, it still leaves you in the dark.

 

hey cool pal.. thanks for your information.

i got it!