Horsepower at the flywheel or wheels? It's an important distinction in powertrain bragging rights. Thanks to dyno wizardry from Hyper Power International, you can now know both. MT's tried it first with the GT-R.
It's always been tough to stack up raw engine power output of the car against at-the-pavement performance. This has been the problem with dynos in the past, you either measure power on an engine dyno and don't know the power to the wheels or measure on a chassis dyno and don't know how much power the engine really makes. Rule of thumb driveline losses are never satisfying in either case and that's where Hyper Power International comes in.
Apparently, their dyno looks like any other four-wheel chassis dyno, with four big rollers to strap a car onto and sophisticated measurement equipment to test maximum output. The trick comes in when you've finished a pull and the system asks you to put the car in neutral. As the wheels and the rollers slow down, the dyno which was just used to measure power is now able to measure losses. By comparing the normal slowdown of the rollers against the slowdown with the car and all of its drag from gears, bearings, differentials and so on it can determine real driveline losses.
Motor Trend's Frank Markus was the first journo to test out the system and considering the constant automaker slap-fight surrounding the Nissan GT-R, Godzilla was the only choice for the test. The results are pretty interesting — it looks like the initial Nissan HP claims have been accurate. Of course, now there will just be naysayers wanting to see engine dyno versus chassis dyno versus Hyper Power dyno results now just to confirm Nissan isn't a den of cheaters. And by naysayers we mean Porsche. [MotorTrend]