Horsepower SAE Net/SAE Gross/DIN

[metoo]

Here's some info a freind of my got from somewhere.

"SAE Gross:
Horsepower is measured at the crank with a brake dynometer (bhp), without any accessories (exhaust system, air cleaner, air-conditioning compressor, and power-steering pump). This method was used in the United States until 1972.

SAE Net:
Horsepower is measured at the crank with a brake dynometer (bhp). The engine is set up just like it will be installed in the car. This method has been used since 1972 in the United States, and is what most manufactures use in their published HP figures. This value can range from 20-40 percent less than the same engine rated by SAE Gross.

DIN:
Horsepower is measured at the crank with all of its accessories. It is set up like it will be installed in the car, and is always a 'NET' figure. The SAE Net horsepower is roughly the same as DIN, with some minor uncertainties and a small 1.0139 scaling factor. The 1.0139 factor comes from the conversion of the 'standard' horsepower (745.7W) used in SAE to the metric horsepower (735.5W) used in DIN. Additionally, the two standards differ on the temperature/pressure conditions and exactly which accessories must be on the engine at the time of rating. Typically the DIN figures are slightly higher, but not by much. DIN ratings are common in Europe and Japan. DIN ratings have been used in other countries prior to the adoption of SAE Net.

RWHP:
Horsepower is measured at the driving wheels, with the engine installed in the car (along with all of its accessories). This value can be approximately 15-20 percent less than the same engine rated by SAE Net, due to the loss through the driveline."

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