Original Posted By: MacklemAW(at)aol.com
Sorry it a few days to reply, I have my junk mail filter set pretty highand you got thrown in with the junk mail. I just happen to be browsingin that file looking for something else.The interesting thing about the horsepower curve and torque curve isthat they are the same curve. Horsepower is torque multiplied by rpm. So if you took the "x" axis of the graph and rotated it up 45 degrees sothat the torque curve warps, it would be the horsepower curve (sorry,it's really hard to explain). The reason the horsepower curve keepsincreasing as the torque curve starts falling is due to the fact thatit's being multiplied by an increasing rpm. The point where thehorsepower curve starts falling is at the point where the torque curveis falling faster than the increasing rpm. Whew.Now to answer your question. There is no simple formula to calculatetorque/horsepower for and engine. You could calculate the ideal level,by first determining the volume of air/fuel mix pumped: ( displacementx rpm ) / 2 (because it's a four stroke engine and fires half the time) volume pumped. Then determine the quantity of energy in the volumeof air/fuel mix (I need a chemist for this). Then multiply those twonumbers. In an actual engine, you loose energy by: friction of therings, friction here, friction there, heat lost in a heated exhaust gas,work required to turn the alternator, fan, waterpump, power lost due toan inefficient intake system that limits the air/fuel intake, incompletecombustion, bla, bla, bla. Now all of these particulars are differentfor each engine due to about a million design decisions made whenbuilding the engine. That's why they just put it on a dynometer togenerate a curve.If you look in any hot rod magazine, I think you should easily find anadvertisement for a "software dyno". There is software that has theparticulars for engine blocks, carbs, manifolds, headers, and can give ahorsepower curve for a combination of those. I've never tried it.Robert HainesDu Quoin, Illinois ----- Original Message -----
Pietenpol-List: Re: HP & TORQUE
HP & TORQUE
Original Posted By: Fisherman Caye