Hi
I made an Excel chart with a lot of cars' data and it showed a lot of anomalies regarding total engine displacements, just one example:
SSC Aero SC/8T:
bore: 99.0 mm,
stroke: 101.6 mm,
number of cylinders: 8.
So displacement should be (99/2)^2 x pi x 101.6 x 8 / 1000 = 6256 ccm instead of 6187. This is just 69 ccm, with some other cars the difference was almost half a liter.
Some other differences with their scale in ccm (without sign):
Aston Martin DB9: 18,
Audi TTS concept: 445,
BMW Nazca C2: 622 (okay this had many version, maybe non-matching data),
Chevrolet Corvette C2: 46,
Isdera Imperator 108i: 568,
Jaguar XJ220 V12 prototype: 56,
Lotec Sirius: 46,
Porsche 911 GT2 S (1996): 73,
Porsche 911 GT2 R (1998): 158,
1965 Shelby Cobra 427: 39.
These are too big for conversion or rounding errors. Input data comes from various (generally reliable) places.
Is it more complex to calculate total displacement? I think the combustion chamber should be ignored here, and this method works precisely with the majority of cars, but there are several major errors in it. Why?