electric car motor

Discussion in 'The Projects Forum' started by yourownfree, Sep 13, 2011.

  1. yourownfree

    Thread Starter AAC Fanatic!

    Jul 16, 2008
    Any idea how much Horsepower is needed from an electric motor to run a VW car if you were to just replace the engine with a motor? Also what would the equivalent horsepower of an electric motor be compared to a gas engine? I know you dont need as much for electric. Is it based on torque for torque, electric vs gas?
    I have seen a kit that uses a motor that is suppose to develop 40 HP. My thinking is maybe a 15 -20 HP is plenty, but then again I suppose torque plays a role in this. Any experimenter out there already have figured it out?
  2. NM2008

    Senior Member

    Feb 9, 2008

    What type of VW car is it? Polo?, Passat, Golf?
    They all have different sizes/weights etc......
    You also need to take into account the type of engine previously in it,petrol or diesel?
    A diesel car have heavier running/transmission gear, stronger suspension........etc. Meaning more weight and will require more torque to move from still.

    Regard NM
  3. colinb

    Active Member

    Jun 15, 2011
    I am going to start counting the “ToS violation” posts on AAC... they are so frequent that it could even make a good drinking game.
  4. Smoke_Maker

    Active Member

    Sep 24, 2007

    There are 746 watts to a HP but the key is voltage and current, as voltage go's up your current from the batteries will go down. I have seen from 48 volts to over 240 volts in a Bug. Googly will give you lots of examples to study.

    Now to answer your question, a ADC 6.7 inch, 8 HP at 120 volts will be powerful enough to where you will want to drive it Bug, peppy. Use a 400 amp controller and you will get 64 HP which will feel like the gas engine.

    Batteries are the KEY/PROBLEM
  5. strantor

    AAC Fanatic!

    Oct 3, 2010
    The same as it had before, if you want the same performance

    hp = hp. What weighs more, a ton of bricks or a ton of feathers? hp = rpm X torque, whether you are talking about gas or electric.

    I had this misconception as well when I started looking into EVs. people tout that you can get away with swapping out your 200hp gas engine for a 15hp electric motor and all is good. People do do that, all the time, and their cars suck. It's the reason why people think electric cars are slow, and have no performance (suck). You can get away with putting a 15hp motor in there because electrics develop full torque at zero RPM, so you can actually get your sled in motion where you couldn't with a gas engine (but it's going to really suck). Look up the stats on the electrics that are winning at the drag strip. They have HP comparable to the ICE guys who are also winning at the drag strip.
  6. shortbus

    AAC Fanatic!

    Sep 30, 2009
    @yourownfree - drive a car similar to what your wanting to convert, make sure it has a tachometer in it. Watch the tach to see the RPM's as you drive, to get the range of RPM for all conditions, take off from a stop, cruising, and climbing a hill.

    After you have a good idea of the RPM's needed, then go on line and look for the "torque/horsepower" curves for the engine thats in the car you were testing. By comparing the torque/hp curve to you RPM data you can get a good idea of the electric motor power you will need.

    The one thing you need to remember is - torque makes you move... horsepower makes you fast.