Horsepower ratings

[Mark E.]

Re: Horsepower ratings

My layman's distinction:

Rear Wheel HP- Just that; includes drive line loss

SAE Net HP- Measured at the flywheel (not the drive wheels) so no drive line loss. As stated above, includes losses due to exhaust, induction, fan, alternator,... The rating used after 1971.

SAE Gross HP- Measured at the flywheel. Basic engine with with minimal parasitic loss. The rating used prior to 1972.

[Michael W.]

Re: Horsepower ratings

So, Michael,
on a new car that says has such and such horsepower, that's rear wheel horsepower, like it's calculated with car in it's entirety tied down and run on a chassis dyno? Not just the engine on a stand but with stock exhaust and all accessories installed??

No, it's still just engine dyno horsepower, (net as per SAE xxx) been that way since the early 70s.

[William F.]

Re: Horsepower ratings

But Michael, you said it was "rear wheel horsepower" Others say, (and now you seem to correct your previous statement) to say today's and back to 72 advertised "net" horsepower' is just the engine at flywheel but with with all components in place.

[Michael W.]

Re: Horsepower ratings

But Michael, you said it was "rear wheel horsepower" Others say, (and now you seem to correct your previous statement) to say today's and back to 72 advertised "net" horsepower' is just the engine at flywheel but with with all components in place.

Punctuation changes everything. I said:

"No OEM uses rear wheel horsepower, back then or now."

not

"No, OEM uses rear wheel horsepower, back then or now."

The latter also makes no grammatical sense.

Eats shoots and leaves.