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compression into bmep? (brake mean effective pressure) and how much do i need to skim off to change thecompression from 10.5 to 11.5?
 

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a) who cares
b) feck loads lmao

get pistons from a 16v and skim the head about 15thou and you might be in that region of CR
 

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A i care, need it for a spreadsheet i'm doing
B a mil or two?
 

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Compression into BMEP?

BMEP is a measure of how efficient the engine is.

The formula bmep= hp x 13000/ L x rpm

or bmep= lbf/ft x 2.475/ L

L is capacity in litres my man.

This in only effective in telling the BMEP at the most effective point i.e. highest torque. It will work for other parts of the power/torque range but will not be as effective.

Average road cars run BMEP's of about 140 - 170 ish PSI. Real evil engines will run over 200 PSI and a few rewal mean F1 engines will run 250PSi. All NA.

As for the CC lowering, you need to measure the combustion chamber volume. To work out the CR this formula is used,

CR= CV +CCV/CCV

CV is the cyl volume, CCV is the combustion chamber volume.

CV is basically the capacity of the engine divided by the number of cyls (4 in your case).

CCV is less easy to calculate, you need the combustion chamber volume of the head and the space between the piston and the head, i.e. gasket clearence and top of the piston in bore clearence.

You can work it out from that fomula.

Chris
 
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