horsepower and weight loss and acceleration

[Armand]

Does anybody know of a simple way to figure how much weight loss (through diet or removing parts) equals a "horsepower"? I realize that a lot of things come into play, but assuming everything else is the same (the same bike, conditions, modifications). I'd like to say "if you could cut 10lbs off the weight , it would be equal to X horsepower" . Thanks

[stevo]

I used ta know roughly what it equated to for a sporty but I can't recall offhand..

have a play with these formula to find out what ya want around the weights and power outputs you're looking at ...


Weight from 1/4 mile speed =

= (223/mph) cubed * HP


HP from 1/4 mile speed

= (mph/223) cubed * weight..




If you plug figures into this formula and change the weight and HP one up and the other down to give the same elapsed time then that should give you an idea what ya after

elapsed time from HP and weight

5.92 * cubed root of weight/HP

[Gold951]

Wouln't it be easier to work with the HP to weight ratio (HP : pounds)?

[sportsterrific]

I believe the simplest formula is 10 pound=1 horsepower. At least this is what I've read.
So call Jenny Craig, and you'll be getting speeding tickets in no time!

[cadiero]

Don't forget that rotating wheel wieght = more horspower than static wieght.

unsprung wheel wieght is also most more important than static wheel wieght in improving handling.

Smokey Yunick, wrote in one of his books reguarding this for dirt track cars. He claimed that unsprung wieght 1 lb = 1 HP, rotating wieght, 1lb = 3-5 HP.
This is for dirt track race cars, not motorycles. But, it does show how important loosing wieght can be!

[stevo]

ahh Smokey ... i've got some of his books ... read 'em and digested 'em many years ago...

They were THE hot up bible..


As I said I used to know it but I've forgotten....

[Narley]

Try these formulas by typing in some variables.
http://www.nightrider.com/biketech/calc_estimatehp.htm

[cwissler]

Here's another site that offers a horsepower calculator and many others calculations and converters: http://www.rbracing-rsr.com/calculations.htm http://i101.photobucket.com/albums/m54/cwissler/dragracewheelie.jpg

[Armand]

Thanks. All good formulas but they require 1/4 mile times etc. Per the above 1 HP = 1 lb or 10lbs depending. What would you guys guess is the best estimate? I would like to be able to tell my friend "If you'd loose X pounds, it would be like gaining X horsepower" (30lbs = 883 to 1200 conversion???). Keep in mind that this is in reference to acceleration and not top speed.

[grizz420]

if you know the bikes wieght and power you can figure out the power to wieght ratio example my 05 wieghs 560 now with fluids and I'm pushing 75 horse power ...divide 560 by 75 you get 7.466 pounds per HP ....by loseing pounds or gaining HP you can change this number{power to wieght}the smaller the # the better you will accellerate

[stevo]

just use 13 seconds as a 1/4 mile time....

[Narley]

then use 12 and compare to see if there is a consistent change of hp versus weight and et.

[biknut]

I've been led to believe that 7lbs of rotating mass = 1 hp

I installed a 18" PM wheel that is 2lbs lighter than stock and the tire is 8lbs lighter. I can feel the slight difference.