[Malibu73]

Hey all, I was just wondering if you all knew how MSN Autos got their HP/TQ measurements. Is it at the wheels or at the crank?

[lowROLLERchevy]

any new car site gets their specs from the manufacture

[firestone]

Most if not all cars from the factory are measured at the motor, not the wheels.

Adam

[SmallBlock_guy]

All,
as far as I know there will be a new rating criteria for SAE rating of the flywheel HP. They now have to do it with some accessories. I am not sure which ones, but I know some have to be on. GM has already started this, but others have not.

[farna]

There is a new rating criteria, but even the old one required accessories. The new J2723 standard mainly adds a third party witness. Here's the best article I could find on it, but it's a bit skimpy: http://www.canadiandriver.com/articles/jk/051026.htm
This article talks a bit about the standard, and dynop corrections:
http://www.land-and-sea.com/dyno-tec...horsepower.htm
The new standards have a "weather factor" in them as well. This prevents testing under ideal (for the engine combination) conditions and stating the highest possible (but not likely to happen very often) power rating.

SAE Net HP ratings require all accessories normally installed on an engine, to include air breather and a simulated stock exhasut system. The transmission is not connected, but the water pump must be pumpin water. This method has been used since 1972. That's why there is a big power difference between 71 and 72 engines. The engines didn't change (smog stuff wasn't added on most until 75-76), the rating method did. Before this manufacturers used Gross HP ratings. No exhaust, no air filter (in a clean room anyway), no belts driving anything -- just run tap water through it under pressure!