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willysink

02 November 2008 12:17 AM

overbore

had my sti7 engine fitted with new forged pistons, with a 1mm overbore, can anyone tell me what size/cc my engine will be now with the 1mm overbore?
there must be a formula for working it out,
cheers

joz8968

02 November 2008 01:20 AM

swept volume = pi x r x r x h x 4

pi... 3.14285714 (pi taken as being 22/7)
r... radius of bore i.e half the new bore's diameter - in cm, to the nearest tenth (i.e. xx.x cm)
h... stroke i.e swept distance of piston from BDC to TDC - in cm, to the nearest tenth (i.e. xx.x cm)
4... total no. of cylinders

You'll end up with the new total displacement in millilitres or cubic centimetres (cc). Divide this by 1000 for litres.

merlin24

02 November 2008 01:27 AM

Not much of an increase in displacement -> 2038 cc

willysink

02 November 2008 05:52 PM

cheers guys, blimmey, i'd never of worked that out:brickwall :D
yeah, not many more cc's.
thanks again!!

joz8968

02 November 2008 07:52 PM

Quote:

Originally Posted by willysink (Post 8240319)

cheers guys, blimmey, i'd never of worked that out:brickwall :D
yeah, not many more cc's.
thanks again!!

pi x r (squared) x h is the fundamental formula for the volume of a cylinder. :)

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