72MachOne99GT

Flywheel horsepower = the HP the engine makes before accounting for driveline loss.
And RWHP = #'s to the ground..
GROSS=????

badspork told me in chat it was w/o accessories,exhaust, and it was a baseline for what the engine 'was capable of; or something like that

anyone else have any input?

anthonydalrymple

From what I understand.....

Gross horsepower=no acessoiries of any kind on the front of the motor, no transmision, driveline,etc.

BHP=Acessories attached(alt, power steering, etc). Still no transmission\ driveline.

Gross horsepower; standard American measure for advertising up until about 1972.

Bhp; standard for all auto manufacturers since '72.

I do not profess to know this as fact since it really never meant very much to me; i believe in rwhp numbers....

waxyourboard

Here's one thing I don't understand -- well I do, it's just kinda dumb. Why does it matter if you have a 300 horsepower engine, when if you add the accessories that are always going to be on it, and add the exhaust and drivetrain that are always going to be on it, you only get 270 to the ground?

Flywheel horsepower is what all the manufacturers use today (also known as net horsepower) - it's with all the accessories attached, no drivetrain.

Gross horsepower is just the engine itself and the water pump. Not a very good way to measure how much horsepower you really have

RWHP is also known as BHP (brake horsepower) - this is what you're actually putting down to the ground in the fully setup car with engine trans exhaust and accessories.

Some shops don't have a chassis dyno to find out BHP, so some only use an engine dyno which is cheaper, but can only tell you Flywheel horsepower or Gross horsepower

72MachOne99GT

are you sure brake horsepower is the same as rwhp

i assumed that todays rating system was brakehorspower/which is the same as net

rwhp is obvious

and gross was what spork told me, the engine with no accessories, and no exhaust

(what i think would be neat, would be to compare todays 4.6 2v's 260 net hp against the 335 underrated gross hp from a 428, just to see how much more power is made from todays smaller engines,,,, well, not MORE, but more per CI)

anthonydalrymple

I remember seeing an artical or two over the years comparing some "old" vehicle versus "new" vehicle power at the rear tires via dynojet. All that I can recall is that the owner's of the older "muscle" is that they didn't have near as much rear wheel horsepower as they expected or thought....

waxyourboard

Brake Horsepower
n. abbr bhp or b.hp.

The actual or useful horsepower of an engine usually dedtermined from the force exerted on a friction brake or dynamometer connected to the driveshaft