Originally Posted by jadcock

Auto makers usually publish "crank horsepower", or horsepower measured at the end of the crankshaft. This is the true power of the engine. WHP, or Wheel HorsePower, is measured on a chassis dyno, using rolling drums driven by the vehicle's drive wheels. So the chassis dyno measured 272 WHP in this case, or 272 hp at the wheels. It's usually stated that an average drivetrain will "absorb" 15-20% of the power of the engine, due to many things like equipment mass, friction, etc. So given a range of 15-20%, that Titan would be making anywhere from 312.8 to 326.4 hp at the crank (remember Nissan publishes 305 hp at the crank).

Also realize that 15-20% drivetrain efficiency figure is just a general benchmark. Let's say for the sake of argument that Nissan's drivetrain is very efficient, and there's only a 10% loss between the crank and the wheels. In that case, 272 WHP equals 299.2 hp at the crank. We'd really need to know the ACTUAL drivetrain efficiency figure for that particular Titan to know what the ACTUAL power is at the crankshaft.