Power to weight ratio of your car?

Lotus Exige

710kg currently but aiming for about 680-690kg

285bhp but should be 320bhp by within the next few months

Current power to weight is 401bhp/ton but final will be 470bhp/ton
 
RedvGreen said:
Unsure if you're being sarcastic or otherwise?

Performance comes from many factors, so a willy-waving BHP/ton is pretty moot unless you somehow develop some way to represent gearing, torque, drive systems etc.

Oh wait, we do, it's called 0-60 times :rolleyes:
Click to expand...
I'm not being sarcastic. Engines produce a twisting force (torque) that is pushed through a gearbox (gearing) that drives the wheels. Virtually every motor vehicle is set up this way. A Mazda RX-8 gets its performance from the torque and the gearing. A Suzuki Hyabusa gets its performance from the torque and the gearing. A Volvo FH16 750 gets its performance from the torque and the gearing.

BHP/ton is reasonably effective at representing performance as the simplest factors in acceleration at 'regular speeds' are 1) weight and 2) power, with that being ultimately derived from the torque and the RPM.

0-60 times are a pretty poor performance metric, unless you exclusively do lots of random full bore standing start launches to 60. It's too heavily influenced by drivetrain, the spacing of 1st and 2nd gears and the shifting speed of the gearbox. More interesting would be something like 50-100 for regular cars driving on regular roads.
 
I had my car weighed today and 2 weeks before was on the rolling road, so thought I might as well post on here.

'97 Vauxhall Astra

1220Kg (Full tank of fuel)
354bhp

290bhp/ton, that'll do me. For now :D
 
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