BHP and torque calculations

You wouldn't with that information you need the CdA and frontal area.

The air resistance is the main concern when moving at a constant velocity and that's roughly

Fd = Cd x 0.5 x rho x A x V-squared

Fd = The drag force (in Newtons) Cd = Coefficient of drag rho = Density of the air (normaly about 1.22) A = Frontal area in sq.m V = Forward speed in m/sec

now you have the Fd you can work out power (P) in watts

P = Fd x V

or in a single system

P = Cd x 0.61 x A x V-cubed

The power required to travel at a constant speed is defined by the aerodynamics, as described in depresions email.

You could. Actually, you can measure the average power over a period of acceleration quite easily:

P_avg = (vel1^2 - vel2^2)*mass/(2*time-taken)

where vel1 & vel2 are in meters/sec and mass is in kg, this gives the average power in watts. 1Hp = approx 746watts.

So, for example accelerating from 30mph (13.4m/s) to 40 mph (17.88m/s), with a car mass of 1200kg, the avg power is given by:

P=(17.88^2-13.4^2)/(2*1200*time)=400*1200/(2*time) watts

say time=3s, this gives P=16.8kW = 64Hp

Note; this is the average power between the two engine speeds corresponding to the two speeds.

Doh. Got my sums wrong... 28kW, 37Hp

Thanks! That gives me something to go on.