[Stan Weiss]

Originally Posted by Tom Vaught

Looks to me like Steve Linden matches everything I posted except for 1m FACT.
The rear wheel HP is not measured at the Axles/"Brakes" unless you take the tires and wheels off the vehicle. Tires do consume horsepower. A thing called rolling friction.
So the driveline has to include the tire contribution.

Emissions people (EPA and CARB) require on the track confirmation testing to assure the Coastdown) numbers used to dial in the dyno rolls matches the actual road measurements. I did Coastdown work for Ford and supplied the data under my name to the EPA as the "Coastdown Test Engineer".

I did the larger Trucks, F-150 thru F-350 vehicles and the Econoline vans.
Other Engineers did the Car platforms and the Small Truck and SUV type vehicles.

If the EPA/CARB was not happy with our numbers, they witnessed a reconfirmation of the track numbers. Most times it was vehicle to vehicle variability and the track numbers were the final numbers used.

So back on the HP numbers, Steve Linden is correct on 98% of his post.

Thanks Steve C for the link.

Tom V.

The AERO Contribution was confirmed at the Lockheed Wind Tunnel at Atlanta Georgia.

Tom,
This is exactly what they been doing for sometime on high HP cars. They use a hub dyno. It eliminates the tire slippage and give much better results

Stan