Rated engine power
How do manufacturers, presently, determine how to rate their engine's crankshaft horsepower? Is the cooling fan engaged and drawing air? Alternator charging? Power steering pump and A/C installed and ...
Forum Discussion
as mentioned today engine power is determined with the alternator, water pump, fan etc. all connected and operating along with the factory air intake, air filter, exhaust system installed etc. Often referred to as SAE Net HP. This was instituted sometime in the 1970's for U.S. sold cars and Light trucks.
AFAIK there isn't any load added to the alternator to represent what power might be needed for other electric loads in the car, nor do I think the AC is on, but the AC belt and pulley are connected.
Before that there was SAE Gross HP which was used by U.S. mfg which was determined without driving water pump, alternator, an open air intake system, and no muffler installed, and in some cases running non factory header pipes. At the Same time many european vehicles coming to the U.S. were advertizing DIN HP which was much closer to the SAE net rating.
AFAIK there isn't any load added to the alternator to represent what power might be needed for other electric loads in the car, nor do I think the AC is on, but the AC belt and pulley are connected.
Before that there was SAE Gross HP which was used by U.S. mfg which was determined without driving water pump, alternator, an open air intake system, and no muffler installed, and in some cases running non factory header pipes. At the Same time many european vehicles coming to the U.S. were advertizing DIN HP which was much closer to the SAE net rating.
