Weight = HP ? what is the formula?

[twobone]

The light weight religion on this forum is quite strong.

Before I start any campaign of weight reduction at the expense of sound deadening, safety or comfort.....what is each pound worth?

[mark 74 carrera]

I have always read that it is more about power to weight ratio. So obviously losing weight will not increase HP, but it will positively impact how the same HP pushes the car around.

I once saw a video where some guys were running a Japanese car in the 1/4 mile. As they continuously took weight off the car, the 1/4 mi times came down. It got ridiculous in the end where the car was basically a shell and an engine.

Mark

[island911]

what is each pound is worth changes depending on how many pounds/HP you've got. --it's one of those 'math story problems."

[Kevin Stewart]

you will never get more hp by loosing weight, but you will free up the hp to weight, Kevin

[randywebb]

What is it worth?

- This really depends on what performance crterion you are evaluating -- is it acceleration, braking, roll, pitch, yaw? or some amalgam of them all that comes out as type of subjective feel?

Wt. removed from the rear and from up high is the best place to remove wt. if it is already sprung.

Unsprung wt. is great to remove b/c that is what allows the tires to follw the road better (esp. on bumps).

Reciprocating wt. and rotating wt. can affect the ability of the motor to attain high rpms, longevity at high rpm, and the ability to change speeds quickly ('rev it up' aka revability).

That's the Wheaties version - summarized. For an even shorter summary (with consequent loss of explanatory power, fit to reality, yada yada) you can figure 10 lbs. = 1 hp.

[DUK]

When we were racing go-karts an old man told us 10 lbs. was worth one hp. Then when I was in ASA we did some acceleration testing for GM at the prooving grounds and the data pretty much backed that up. Wish I still had the data but I believe it is on one of their engineering websites.

[Bill Verburg]

a pound is a pound the world round, except when it comes to it's effect on performance. Each pound ansd is effect depends on where it comes from.

from most to least significant weight
engine speed recipricating
engine speed rotating
wheel speed recipricating aka unsprung weight
wheel speed rotating
sprung weight at the ends
sprung weight up high

[afterburn 549]

My 2 cents. everyone wants performance. Performance coast $$$. You need to get the car near 10 to 1 to have performance. ( As you see I am not there yet).
So money is the issue with most people. You can ezly get 300 lbs out of your 81 w.o. making it look like a track whore. from there you need to add to the power plant.
Its a individual puzzle