[Rdstrblk]

Hello all! I have been lurking for a while now, feeding off the grand information here while also assessing my own plans for the racecar I own. It is nothing special, probably no good even for a chumpcar race, but I have decided to convert the 63HP engine to an electric motor system.

I can see that there have been a few festy builds.. I am now researching parts feasibility and logistics to make sure I don't buy too big of a motor.

Anyways, just wanted to get started, dive in, and say hello!

-Blake

 

[Duncan]

Hi Blake
It's not a racecar but it's fun and it does get used on the track occasionally

http://www.diyelectriccar.com/forum...dubious-device-44370p15.html?highlight=duncan

 

[Rdstrblk]

Looks like 50kW will get me to my power goals ~67HP

How realistic is fitting a motor of this power? How big will it have to be? Logistically will it even fit without huge modification to the frame?

 

[Duncan]

In a race car you will not be pulling full power continuously
The motor in my "Device" is 10 Kw in the forklift - I can put 400 Kw through it
That motor is 11 inched diameter about 14 inches long and weighs 102 Kg

I would suggest it's little brother a 9 inch forklift motor for your application

 

[brian_]

I don't think fitting in the motor is the big packaging issue... that's the battery.

 

[Rdstrblk]

I read that a 9" motor was as big as could fit in the festy. And WRT the forklift motor rated at 10kW, how do you increase the anticipated power output? Increased system voltage? Higher amperage? To what extent can this rated power be extended?

Getting 400kw from a 10kw motor sounds like a lot..

Thankfully the car is completely gutted so fitting batteries will be a sinch

 

[Rdstrblk]

http://myshared.photos/a-wild-and-wily-little-runt-my-1990-ford-festiva/

 

[Duncan]

Hi
Forklift motors are rated very conservatively!

The limitation is heat and brushes

My motor - Hitachi - was 48v and 208 amps in the forklift - running at about 1400 rpm

Running it at the same current and a higher speed gives more power - so at 4000 rpm and 200 amps it will produce 30Kw - and run COOLER than at 1400 rpm and 200 amps

The next question is how much current will it take? - and for how long?

My controller gives 1200 amps - that will melt the motor if it is continuous - BUT at that current the motor gives a tonne of torque and will spin my tires on good tarmac

So my car accelerates - at the end of our 1/8th mile its doing about 87 mph

You simply can't keep applying that much power - the next corner comes up fast!

Voltage
You controller reduces the voltage - you demand a certain current and the controller sets the voltage to get that current

BUT as the rpms rise it takes more voltage to get to a certain current

With 130v and 1000 amps my car took off like a scalded rat - but as the revs rise the amount of current that 130v could push across the motor dropped so at 100 kph I only had 200 amps

With 340v - I don't get that problem!

Running my 48v 10 Kw forklift motor at 1200 amps and 340v is not a formula for long life!
But so far so good!

In normal driving I have a switch that limits me to 48% - 576 amps

My last grass autotest I got my best time at 40% power - 480 amps

Full power on grass is spin city!