David N Waldmann wrote:
>
> I think you're confused.
Nope, sorry. :)
>
> Power to weight ratio can and will be anything, as you showed in your
> example.
>
> What was being asked/suggested is a formula or statement that says "for
> every ____ pounds removed or added it is the equivilent of 1 HP" (actually
> should be lb/ft, as the "midget racer" expressed).
Right, I wasn't referring to the validity of the thought that power =
acceleration (torque makes the world go 'round, y'know :). But saying X
lb. = Y bhp is *exactly* the power to weight ratio. So gaining 1 bhp has
the *exact* effect as losing 26.667 lb. of weight on the p/w ratio. As
to the 40 billion variables that determine how the power, torque,
gearing, and weight effect the acceleration of the car is a matter WAY
over the simple (and genuinely meaningless, as you said) ratio that all
the magazines like to list.
>
> HP is what determines your speed, because HP is an expression of
> time/distance work. It makes no difference how heavy your car is if you are
> trying to make it go 120 MPH (well, actually you do increase the rolling
> resistance very slightly), the only forces you have to overcome are wind
> resistance and rolling resistance.
>
> However, Torque, expressed as lbs/ft, describes a weight/distance work, and
> will therefore determine how _long_ it will take you to get to 120 MPH, or
> how fast you can go up a hill (adding the overcoming of gravity to the
> wind/rolling resistance force).
I'm pretty sure the "up a hill" example would be determination of
power. I'd have to think about it, maybe even read. . . Fizzix was a
while back. :)
--
~
'94 FZR-600: Wants a brain.
'90 GS-500E: Wants a heart.
'LXIX Sprite: Wants courage.
'93 B-2200: Wants to go home.
'87 RX-7 TII: Please ignore what's behind the curtain.
Getting caught is the mother of invention.
~
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