# Motor torque vs engine torque?



## somanywelps (Jan 25, 2012)

If the engine you're talking about is an ICE, the torque peak is somewhere at 1/2 to 3/4 the way up the RPM and peak power is generally close (~5/6) to the redline.

DC series motors have a pretty flat torque curve to RPM with a drop off at the very high end generally. Imagine that you always had the power of your engine at peak torque, even from 0 rpm. Even if you have the same numbers, it's going to be quicker.


----------



## Guest (Apr 6, 2012)

What are you driving that only makes 50 ft-lbs of torque at the peak? Sounds like an old 1131 cc VW air cooled engine. That produces 50 ft-lbs of torque at 2000 rpm. Something like that? 

Pete 

A good 9" motor and 96 volts with a controller that will provide at least 600 amps should do the trick. That is speaking of course if you are talking about a car. A small car.


----------



## electricdominic (Apr 3, 2012)

gottdi said:


> What are you driving that only makes 50 ft-lbs of torque at the peak? Sounds like an old 1131 cc VW air cooled engine. That produces 50 ft-lbs of torque at 2000 rpm. Something like that?
> 
> Pete
> 
> A good 9" motor and 96 volts with a controller that will provide at least 600 amps should do the trick. That is speaking of course if you are talking about a car. A small car.


1988 Suzuki Samurai 1.3l engine. Those torque nbrs are from a fresh engine, which mine is not, lol.

Thanksfor the info. Do you know if it is a 1:1 torque relationship?


----------



## Guest (Apr 6, 2012)

Na! the Series DC motor will do better than the stock engine in performance and torque. 

Check out this stuff. 
http://www.evalbum.com/
http://www.evalbum.com/2026
http://www.evalbum.com/3016


----------



## somanywelps (Jan 25, 2012)

electricdominic said:


> 1988 Suzuki Samurai 1.3l engine. Those torque nbrs are from a fresh engine, which mine is not, lol.
> 
> Thanksfor the info. Do you know if it is a 1:1 torque relationship?


1:1 Torque to what? 

Also almost any electric motor will destroy that engine.


----------



## electricdominic (Apr 3, 2012)

somanywelps said:


> 1:1 Torque to what?
> 
> Also almost any electric motor will destroy that engine.


Let me see if I can clarify. My ICE puts out 60ft-lbs of torque max. Do I also need to find a electric motor also with 60ft-lbs of torque? Meaning if I replace a X ft-lbs ICE there is a 1:1 torque relationship to the amount of torque rating on it's replacement motor. Is this correct?


----------



## Guest (Apr 6, 2012)

The larger the diameter the armature of the motor the more torque will be applied. So you need to figure your power then figure your torque. 

A 9" motor will produce more torque than a 6 1/2 inch motor. A 13" motor will produce more torque than either the other two mentioned. The larger the motor the less available RPM due to physical constraints of the series motor. A typical 9" motor can do 5500 rpm while the typical 11" motor can do 4800 rpm. Some even slower.

Others can better explain the process. It is not a simple answer. 

Pete 

A 9" motor and 120 volts and 750 amps will do you fine if you have good batteries. The more AH you have the better. Lithium Cells are best. More expensive yes but best. You can go more but I would not go less. It will provide you with more power than your little 1300 engine. About the same RPM range too. Plenty of grunt which is what you need in a 4X4. 


http://en.wikipedia.org/wiki/Torque
http://www.diyelectriccar.com/forums/showthread.php?t=11708
http://www.diyelectriccar.com/forums/showthread.php?t=6535


----------



## Guest (Apr 6, 2012)

You can't compare the gas engine to an electric motor. They work differently.


----------



## electricdominic (Apr 3, 2012)

gottdi said:


> You can't compare the gas engine to an electric motor. They work differently.


Can you explain how? So the torque ratings are not 1:1 between them?


----------



## Guest (Apr 6, 2012)

In simple terms the gas engine must work up to the max torque while the Electric motor has max torque right out of the gate. The way the motor work is with voltage and amperage to equal HP but the torque from your motor will be like right now. Depending upon the voltage you have and the amperage you feed it and the size of the motor you will have your answer. There is no clear cut This equals that compared to that. Electric motors are also rated at a continuous rate rather than a peak rate. Your gas engine is rated at a peak power range. Not the continuous rate. 

Don't compare the two. A set up like I described will give you better performance and power over the gas engine currently in the vehicle. To get even more you increase your voltage and amperage. Re-gearing can help too to some degree. Many no longer need 1st and some don't even need 2nd any longer when converted to electric. There is so much torque that you just don't need it. I use all my gears but 1st is really not needed. 

My Leaf does not shift. The VW does.


----------



## Guest (Apr 6, 2012)

You really need to see if you can get a ride or drive an electric car. Then you will be hooked for life. Electric Golf Carts or GEM vehicles don't count.


----------



## electricdominic (Apr 3, 2012)

gottdi said:


> You really need to see if you can get a ride or drive an electric car. Then you will be hooked for life. Electric Golf Carts or GEM vehicles don't count.


I got the opportunity to drive the Leaf before they were available for purchase. Also 10 years ago I got to drive the EV-1. It was the EV-1 that got me hooked. Now I have the financial resources to take action. BTW, I value your information in your other posts.


----------



## subcooledheatpump (Mar 5, 2012)

Torque is Torque, there is no comparison ratio between electric vs gas. 

If a gas engine outputs 50 ft-lbs, then it outputs 50 ft-lbs. 

If an electric motor outputs 50 ft-lbs, then it outputs 50 ft-lbs. 

The difference between gas and electric, gasoline engines output peak torque at a certain RPM, the "torque band". Whereas electric motors output torque over a much larger torque band, and it starts at 0 speed. 


Power is torque and speed 

Power= RPM X Torque/ 5252

If an electric motor makes more torque at a higer speed, then it will be more powerful than a gas engine, and will make the vehicle go faster. 

From what it sounds like, your original gas engine isn't very powerful; about 34 HP. Making 100+ HP with an electric system isn't really that hard so you should be able to get better performance with an electric system.


----------

