Electric Supercar

If you are starting assembly, does that mean that you have worked out the placement and mounting of all of the EV components?

I've seen the advertising material on the kit manufacturer's website, but I didn't see any technical details. Do you have an illustration or clear description of the rear suspension? That's critical to fitting the Tesla drive unit in.

Update:
After some online research, I see that the kit uses the front suspension of the FWD donor at the rear, which is normal practice for mid-engine kits of this century. In this case, this means the double A-arm system of the donor Accord.

That's generally a good thing, but it is designed to fit around the conventional transverse placement of the engine, ahead of the axle line. In this case it seems to include the cross members from the Accord, to locate and mount the lower control arm and the steering rack (which is presumably replaced by fixed track rods). The rear cross member will probably go right through the bottom of the motor and inverter of a Tesla Model S or X drive unit (because they are behind the axle), although the Tesla front drive unit places the motor higher to clear the front of the battery case, which might help.

Your post in another forum says that you have motor mounting information from another builder; what's the plan to make the drive unit fit with the suspension and structure?

Also, maybe I wasn't clear. I will be sourcing the entire tesla subframe (control arms in all). I just need to mate it with the frame.

snowdog said:

I obtained the frame dimensions from the kit manufacturer. I sourced the Tesla dimensions from GrabCad. It will fit.
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I am waiting on the battery purchase for now as it will take me some time to assemble the car. I am planning on ~30kW. Batteries can fit up front as well as between seats and behind the seats. Much of the other electrical, contactors, DC-DC converter, Tesla controller, etc. will be in the back.

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It sounds like you're well along in planning. I think I understand the general intent and approach, although it sounds like Tesla components were the only option considered; was that because a ready-to-run product is required, and EV West and others promise that with Tesla drive units?

I assume that you meant 30 kWh (not kW). That's not much capacity for a high-powered application, so range (assuming aggressive driving, given the nature of the vehicle) will be short. It is difficult fit in more in a car not designed to accommodate battery volume.

I'm impressed that the kit manufacturer provided frame dimensions. That's helpful. I see that their order options include "electric drive"; I assume that just means that (compared to their Honda and Toyota options) they just omit the fuel tank, cooling system, and shift linkage. Since the others are set up to bolt in suspension parts from the donor, and there is presumably no donor for the electric drive, does it just have plain frame tubes with no mounting points for any suspension?

snowdog said:

Obviously I will need to modify the frame to meet up with Tesla subrame and I may need to modify the suspension points. I may need to widen the rear fenders depending on what size tires/rims I end up going with.

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snowdog said:

Also, maybe I wasn't clear. I will be sourcing the entire tesla subframe (control arms in all). I just need to mate it with the frame.

Click to expand...

I wondered when you mentioned the Tesla subframe earlier if you were planning on using it, complete with the whole Tesla suspension (like Chris Hazell's drift car project - see Tesla Powered Nissan r32 skyline). That can make sense and avoids several compatibility issues, but it will involve substantial frame modification and will result in a very wide car. Chris discussed the details of the width issue; fortunately, the K1 Attack body is designed to fit over an Accord front end which is a little wider than the Skyline, so the additional fender width won't be as extreme.

Keep in mind that to "just mate it with the frame" is not trivial, since the frame needs to support and locate the subframe at four specific points (relatively low in the vehicle), plus the rear suspension spring and shock struts (relatively high in the vehicle). The subframe will pull down on the frame at the four mounts (with the weight of the subframe and drive unit), while the struts will push up on the frame with the entire weight of the rear of the vehicle.

This is a reminder that the Tesla "skateboard" idea is nonsense: the car is a conventional unibody (the tube frame will take the place of that in this case) with front and rear subframes that support nothing but themselves, and a battery in between which supports nothing but itself.

I suggest taking suspension modification seriously. Pickup points can't just be moved without consequences, and most people in this forum don't seem to realize that. On the other hand, if you use the complete subframe with suspension, I don't know why you would need to modify the Tesla suspension (other than changing to softer springs and shocks for the lighter vehicle); the Honda (or Toyota) suspension likely would require modification.

I'm old school Jaguar vs BMW/Audi knockoff.

Seems there's one German suspension designer that keeps getting himself fired, and is making the rounds -- latest stop, Tesla.

Take a look at the "lightning rods" in the Tesla skateboard pics. Ridiculous, IMO. Makes a low slung sportscar derivative next to impossible because you have to look through the strut towers.

Done right, the top of the springs is no taller than the outboard brake rotors would be...

Tuck a Tesla drive unit into an XKE rear suspension assembly and you have the makings of a sportscar.

I'm not tickled by the bazillion rubber bushings and no parallel link on the Tesla rear knuckle to keep it where it needs to stay in free space. Rube Goldberg and it's no wonder it clunks.

EDIT: finally at the computer and looked up a K-1. A cutie worth adding to my never-get-done project queue. It's gunna look funny with Tesla struts poking up through the rear quarters, lol.