Weight verses BHP

[Redcar]

Just come across a weight discussion whilst doing a search and noticed that cars range from 525kg to 650kg.

EDITED Sorry 760KG Gulp

Anyone know how much power is needed to accererate that extra 125kg

How do the lighter less powerful cars handle/accerate against the heavier more powerful cars?

anybody got any practical comparisons/experience.

Just wondering as when i'm next at the lights in my nimble 130BHP Xflow Narrow body      against something more modern!      

[Martin Keene]

I prefer the wieght route.

More Power = Spending Money

Less Weight = Making Money

Or at least to start with when you take bit off and sell them, when you get to the realms of buying carbon, aluminium, etc then it starts getting pricy. But, it's probably still cheaper than ****e loads more power...

[barney]

Hi,

Its horses for courses really,a lightweight car is great round the twisty stuff,but horsepower helps on the straights..  

just to bear in mind adding lightness is not always as cheap as it seems,but the money involved in some of the poweful car engined cars is not for the less than fully wedged    

cheers

Barney

a self confessed carbon tart..

[studbuckle]

try up to 760Kg for weight of a westfield

Weight is going to affect the handling but can also make for a more planted easier to drive car

[barney]

try up to 760Kg for weight of a westfield

Kinell...

Try 360Kgs instead,err slightly lively car..

but suspect Si`s got considerably ,more horses than 150 bhp    

[adhawkins]

try up to 760Kg for weight of a westfield

And close to a tonne fully loaded and two up

Andy

[windy]

Anyone know how much power is needed to accererate that extra 125kg

70kg of weight removed from the Westfield equates to a theoretical gain of 10 hp.

[ChrisG]

To only need 10bhp to accelerate 70kgs extra must mean its either a very heavy, and/or very low powered Westie though (I think)?

For example, my locost R1 weighs ~425kgs with around 160bhp, so I have a power to weight with me in it (~75kgs) of 320bhp/ton.

If I add a 70kg passenger, my power/weight drops to 280bhp/ton, so to regain my power to weight back up to 320bhp/ton I need 320 x 0.570 = 182.4bhp, ie 22bhp gain.

To only need 10bhp extra you'd need something like a 700kg car with 100bhp

100bhp/.7=143bhp/ton compares to 110bhp/.77=143bhp/ton

I know power to weight isnt necessarily a precise indicator as to the acceleration, but its probably the only calculation we can readily use to roughly compare acceleration without getting into complicated physics.

Chris

[neilb]

Just wondering as when i'm next at the lights in my nimble 130BHP Xflow Narrow body      against something more modern!      

Gearing will play a BIG part on the 0-legal limit sprint.

[detailer]

Agreed gearing crucial.  If you're dropping out of the zone between gears you're not making the most of what you have.

(especially when ringing a crossflows neck! New ratio's going in mine next week. LOL!