Quote:
Originally Posted by JohnnyBfromPeoria
And, again, the vehicle's exhaust isn't the one connected to the engine during engine dyno testing, therefore, there isn't a difference in rated power.
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That seems at odds with the definition of SAE net horsepower posted above. Here's another definition that I found that spells it out even more clearly:
"However, the SAE net power testing protocol calls for standard production-type belt-driven accessories, air cleaner, emission controls, exhaust system, and other power-consuming accessories. This produces ratings in closer alignment with the power produced by the engine as it is actually configured and sold."
Also, if they don't use the exhaust as sold on the car how does GM know that NPP makes 6 additional hp on the Corvette?
All that said, I've never witnessed an engine being dyno'ed on a stand, only in the car on a chassis dyno. If you have some sources or industry experience on how its actually done I'd like to learn more.