Compression ratio and displacement

phunk

Whos good at math? Tell me if this is right. I feel like math should tell us combustion chamber size if we assume the compression ratio is exactly 11:1. Each cylinder is 616cc displacement to get our 3696cc total displacement.

(616 + X) / X = 11
X should be our combustion chamber size.

616 / 10 = X

(616 + 61.6) / 61.6 = 11

So when the piston is at BDC we have 616cc cylinder displacement and the combustion chamber is 61.6cc for a total of 677.6cc area. Compressed 11:1 would leave the 61.6cc chamber.



So to solve for your 9:1 ratio...
(616 + X) / X = 9
616 / 8 = 77cc
(616 + 77) / 77 = 9

So you need to make the combustion chamber 15.4cc larger without changing the bore or stroke. To do this, you would dish the surface of the piston a total displacement of 15.4cc.

Ami right?

EDIT: these equations would include the headgasket area and piston dome/relief in the combustion chamber volume, and provide final chamber size, not just the measured CCs in the cylinder heads.

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