Calculating compression ratio
Turbo Mini Forums

I have worked out my compression ration to be 12:1 though I am not sure, this is what i have used as calculations

These are my measurments:
cylinder head chamber 22cc
head gasket thickness:1.13mm
gasket bore diameter 73.5
combustion chamber volume 375cc I am not sure about this one.
stroke in inches 3.3 or 83.83mm, this is from the highest point of the piston.
piston deck clearance: .38mm
piston stroke length?? I am not sure about this
I think my piston cc is 11 but not sure.

any help would be appreciated. thanks

what CC or overbore is the engine?

JF.

1380

Righto..

1380 - 4 = 345

chamber = 22
Headgasket =3
below deck =1
Piston dish = 11
Combine the above makes = 37 cc

345 + 37 dived by 37 = 10.3

The head gasket and deck are ISH figures but better than 12 if for a turbo..

If you found another 5 cc in the head you'd be at 9.2 ish...

Hope that helps,

JF.

10.3 ish ? ooops .late again .

Edited by robert on 24th May, 2009.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

So we have confirmed low tens...

Is this an NA engine?

JF.

yes n/a

i was getting there!!!, i thought you wanted something else, hence my last post. So thankyou very much as always members of the forum have the answers

was that ok??

Manners cost nothing dear boy!

It'll do, a tad of sarcasm with it but I am the king of sarcasm myself!

JF.

Edited by giallofly on 24th May, 2009.

well aslong as you are happy i am happy.
I am sure there is room for argument on your last comment. lol. but if your happy, thats fine with me.
though seriously, I do appreciate the time and effort, as you can clearly see i struggle with numbers.

Well, I included the formula to you and other to keep..

I did not include the ringland, that is just far too keen.

So you have 10.3ish, alot less than you worked it out to be!

Glad to help.

JF,

i suppose it will do considering it is a n/a. again thanks. too much grovelling i think, so must crack on with gardening, cleaning cars and putting engine back together.