[bgoner]

I got this old DC motor which should be 100V X 25A = 2.5kW ... which is about 3HP.

I read somewhere that for each 1000lbs you need 6-8hp. My car would be around 2200lbs - so minimum of 15hp.

My first gear ratio is about 1:10 and my 4th gear is about 1:3 (opel corsa 88').
Does that mean that in first gear I could have 3HP X 10 = 30hp?

or am I mixing torque with power?

I don't need the car to go beyond 35mph, it would be prototype for city use. Ment to learn from the project. Is this motor suitable?

 

[Yabert]

My first gear ratio is about 1:10 and my 4th gear is about 1:3 (opel corsa 88').
Does that mean that in first gear I could have 3HP X 10 = 30hp?

Hi

You can't have more HP with ratio. Only torque change when you change ratio.

3HP @ 1000 rpm = 15.76 lbs-ft of torque.
3HP @ 100 rpm = 157.6 lbs-ft.