Dynamometer tests are used to measure a car's torque and rpm response. But how do they get that information? And how reliable is what they get?

Starting engine dynamometer pulls at low rpm is hard on the dyno and hard on the engine. Today, engine dynamometer testing is an integral part of many HOT ROD engine buildups and product tests.

Dyno testing pushes engines to the limit — and sometimes beyond it. This video shows what happens when performance testing turns into failure.