Much like the engine will define the characteristics of and ICE car the electric motor will for a EV.
I wish it was as simple as finding an electric motor with the same HP as the V8, however because its delivered in a very different powercurve it's not that easy.
They say 'The difference is torque is doing the work, while horsepower is how fast that work is being done.' Electric motors tend to have more torque but more importantly deliver it from 0RPM. Also there most likely won't be any gears in the system I choose so you don't have the power loss between gears.
So in short I have no clue on how much power to choose, but you can't have too much power can you?
Lets park the consideration of power and move onto the next consideration, how is the power mechanically output to the wheels?
Some motors like the hyper 9 are a direct output from a splined or keyway output shaft, so these would need a separate LSD to take the drive to the wheels. Motors like the tesla power unit include a differential so can be just mounted at the rear and custom length side shafts made to fit the rear hubs.
The splined or keyway output shaft would nice and easy, mainly most motors will fit in the tunnel where the gearbox once was, I can connect the propshaft to the stock GD LSD and minimal chassis changes needed. The downside of this is that's taking up valuable space where the batteries need to go in the tunnel, it's shocking how many batteries are needed.
Having a motor with an incorporated LSD is a very nice package this will deal with everything I just have to see if it will fit in the rear of the GD without having to do major surgery on things like wishbone mounting points. The GD with the euro chassis is renowned for its impeccable handling, I have neither the time or the knowledge to start re designing years of GD development.
Finding electric motors isn't as easy as you would hope, there are lots of startups out there with grants to make EV motors but if you get in contact with them they don't actually want to sell you a motor. They are mainly just developing technologies with the hope of being bought by an OEM.
Here was a quick table I knocked up looking at various motor options.
I think I have found my motor, the Swindon Powertrains 240!
Swindon Powertrains do 3 motor power options and 2 output types.
Motor power 128, 190 & 240Kw (Remember 1kw = 1.34HP) So 240kw = 320HP
Output types are either a LSD or reduction gearbox for a tunnel mount.
It would be ideal to use the LSD they do so I can mount this in the rear of the chassis and keep the tunnel empty for as many batteries as possible, keeping them low and in the centre of the vehicle.
However... Swindon don't offer their highest power motor with the LSD as its not rated to take the power. The brilliance of the EV motor is I can easily limit the power of the 240kw motor but then gain the benefits of a larger powercurve and larger area of efficiency. I also like the idea of the motor not having to run at 100%, logic dictates something running at less than its designed maximum will last longer, run cooler ect.
Also lets face it, once I am happy I'll crank it up to 11 and see if the LSD can actually take it. When I was on the phone to the good people at Swindon you could tell in their voices that it will most likely be fine, they just haven't done it yet. What's the worst that could happen? a new crown and pinion.
So here we have it, I've made a decision on my motor. Its liquid cooled so thats a huge plus. It's unfortunately a bit big so I will need to look at some modifications to the rear of the chassis. Although it would fit currently it would require a lot of swearing and bloody knuckles to get it out again. I always try and build something like I'm the one who is going to be taking it apart again.
It's 400V so falls in line nicely with what I was considering battery pack wise.
Swindon Powertrains supply a Cascadia controller also, this is a good proven controller so no worries there. It's CANbus compatible which is a must as I'm going to have to be doing lots of logical control over various modules in the vehicle.
The order has been placed, it should be with me by mid-end November 2022.
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