Tesla owner Emmanuel Chang had his 2013 Black Tesla Model S P85 dyno tested on a mobile CCMR Dynojet recently at some generic car show.
The Model S P85 is officially rated 416 HP at the motor shaft. This particular combination of dyno and P85 recorded 436 HP at the wheels. (there is usually a significant drivetrain loss between motor and wheels)
A few details regarding this test:
1) The tech couldn't attach a sensor to the motor's crank so "engine rpm" has to be recalculated as he took the wheel RPM (so multiply the RPM by 1000, then by 9.71 *approx*) 2) The dyno maxed out at 2000 lbs·ft but math from the specs indicates 4301 lbs·ft at the wheels. 3) Horsepower and torque number are inaccurate as the car smoked the tires on the dyno's drum so the wheels were not spinning 1:1 for the computer to measure accurately, basically it has slightly more power than what the computer thinks it has. Source: TMC