Compressio Ratio

[Goran 3]

I have skimmed the head by 0,7 milimeters ( converter i found on google says its about 0,027 inches )

 

So what could the compression ratio be now .. original was 9.18

 

thanks

 

i tried but the search isn't working

Edited April 27, 2011 by Goran

[kyepan 291]

look up calculating compression ratio on google, and the engine swept volume, combustion chamber volume, and you should be able to do a rough calculation.

 

cheers

 

J

[Goran 3]

look up calculating compression ratio on google, and the engine swept volume, combustion chamber volume, and you should be able to do a rough calculation.

 

cheers

 

J

 

so i have this

 

Vs = 1905/4 = 476.25cc (swept volume of one cylinder)

 

Vc = ? (volume in chamber, head gasket etc.) ...here i cant find the original data, and if i do how do i calculate the 0,7 milimeters/0.02 inches lowered cylinder head?

 

CR = (476.25+Vc)/Vc =

[petert 588]

I use this program called DCR Calculator. It's imperial but that doesn't bother me as I'm old. If you'd have taken 0.027" off the gasket thickness your new CR would be 9.78:1. As it's off the head/chamber, which is not the full bore diameter, it will be slightly less. Probably around 9.5:1. The only way to know for sure is to measure the new chamber volume.

[Iain-gti 6]

Anywhere you can download this, searched Google couldn't find anything!

 

 

Thanks

 

Iain

[petert 588]

Here's an interesting page I just found the link on:

http://hemrickperformance.com/dynamiccompression.aspx

 

The download:

http://cochise.uia.net/pkelley2/dcrvb6.zip

 

I think more importantly is to keep the cranking pressures under 220psi. Use this great tool:

http://www.rbracing-rsr.com/comprAdvHD.htm

Edited May 2, 2011 by petert