I'm asking this because I keep getting different results on the various online compression calculators. The engine build includes new rod bolts, ringset, gaskets, 3 angle valve job, etc.

<U>Scenario 1:</U>
B18c5 block bored .25 os
OS PCT pistons
Skunk2 pro 1 cams
stock head

<U>Scenario 2:</U>
Same as above with .015 milled off the head

This is a track only car (road racing). Once I know the CORRECT compression figures, then I'll be able to determine the best octane to use.

Thanks for any help.

 

The numbers i get assuming you are using stock HG (.026) and valves are....12.6 for first scenario and around ~12.9 for the second scenario

 

Yes, stock HG and valves.

How did you calculate the cr's? I'm just trying to determine a good, reliable method that gives me the correct answer.

Thanks

 

edit: oops.