Compression Ratio - Calculation

[fairmorn308]

Hi Guys

Can someone help me work out my engine compression ratio.

Spec

1.4 8v xsi bottom end with skimmed block
1.3 8v Rallye Head - Skimmed
High Compression Pistons

:)

I can try and get sizes etc but i dont fancy sending everything away so it can be checked

[Mathias]

why high compression for your build mate? what inlet are you using?

[adamskiTNR]

well you say it's been skimmed. by how much on each? that changes it

[AXracing]

How long is a bit of string? You would have to give a lot more details to work it out. The early XSI and Rallye heads are the same or close enough if makes no difference depending on the models they came off so it would really depend on how much you skim off them, How much you take off the block, what thickness head gasket your using and what pistons your using. A word of warning you can run to much compression. Your normal better lowing compression slightly then having to retard the ignition.

[axsaxoman]

he will ever get a vtr up to where comp ratio will cause aa det problem ,no matter what he does
piston /valve clearance will be a problem long before comp ratio,

[fairmorn308]

why high compression for your build mate? what inlet are you using?

Cause you cant get low compression pistons for this engine

Running S1 Rallye Inlet

[fairmorn308]

How long is a bit of string? You would have to give a lot more details to work it out. The early XSI and Rallye heads are the same or close enough if makes no difference depending on the models they came off so it would really depend on how much you skim off them, How much you take off the block, what thickness head gasket your using and what pistons your using. A word of warning you can run to much compression. Your normal better lowing compression slightly then having to retard the ignition.

You tell me what info you need.

Head and block skim where just a clean up I can find out exact amount when i call them on monday.

Thickness of gasket will relate on what compression ratio am getting with each thickness etc, I know i can lower it by using a decompression plate but i want to know what am running also