V8

A V8 engine is a V engine with eight cylinders. In its simplest form it is basically two straight-4 engines sharing a common crankshaft. However, this simple configuration has the same secondary dynamic imbalance as two straight-4s, resulting in annoying vibrations in large-displacement engines. As a result, most modern passenger car V8s use a complex crossplane crankshaft with heavy counterweights to eliminate the vibrations. This results in a powerful engine which is almost as smooth as the straight-6, while being considerably less expensive than the even smoother and more powerful V12 engine. However, flat-plane crankshafts are still common in purpose-designed V8 engines for racing cars, since a crossplane crankshaft results in uneven firing into the exhaust manifolds, interfering with engine tuning, and the heavy counterweights prevent the engine from accelerating rapidly.
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