Of interest and related....
The new Feb issue of Popular Hot Rodding has a 15 page tech article written by David Vizard titled "The Spin Zone". Eight ways to get big rear-wheel power increases without having your engine make one hp more.
The big emphisis of the article discusses the subject of "flywheel moments of inertia" and the low/high moment moment of inertia flywheel controversy (or do I use a heavy flywheel or light flywheel, which is better?).
Other subjects are tackled... driveshaft, axles, wheels, etc ... and the other "flywheel" which is the crankshaft tortional vibration damper, or crank damper for short.
No matter what rules seem to apply to a given situation, there always seems to be an exception. The moment of inertia of an object up at the front end of the engine is just such an exception. Its the crank damper. Back in the '80's, even top drag racers were substituting heavy crank dampers for lightweight aluminum "hubs" in the belief they would go faster. The reality is these hubs, although having a vastly lower moment of inertia, actually cut power, even under high-acceleration conditions. The reason they did so is that they did not suppress crank tortional flexure. Such vibrations were transmitted directly to the cam via the timing chain and, as a result, the valve event timing was adversely effected and valve bounce was aggravated. All this led to reduction in power, and we are not talking about 0.5 to 1 hp here, but sometimes 12 to 14 hp on a 400-odd-hp engine. The bottom line here is, use a functional damper first and worry about its moment of inertia last. That way your motor will make more horsepower, longer.
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