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Compression Ratio & Displacement
Building or refreshing an engine? Compute the static compression ratio and total swept capacity from the real measured volumes.
Engine geometry
Volumes & clearances
10.51 : 1
Static compression ratio
2,993 cc
Total displacement (3.0 L)
498.8 cc
Swept volume / cylinder
52.5 cc
Total clearance volume
Breakdown: chamber 44 cc · gasket 6.81 cc · deck 1.66 cc · piston dish +0 cc.
Rule of thumb: ~10.0–11.0 suits naturally-aspirated petrol on pump fuel; turbo builds usually sit around 8.5–9.5. Always verify with a real measurement before machining.
Good to know
- Use measured chamber volumes (burette or pipette) — a 1 cc error moves the ratio by roughly 0.1–0.2.
- Piston volume is entered as +dish (adds clearance) or −dome (reduces it).
- This is the static ratio — camshaft timing changes the dynamic (effective) ratio a lot at low rpm.