[snowdog]

Hey Friends,

I am starting on the journey of building another electric supercar.

Still in the planning stages. Here is my thought...I would like to take the cockpit of a modern car and strip most of the exterior for my own unique exterior design. As far as drivetrain, I was thinking all wheel drive. My first thoughts go to tesla as I have done that before but anything is on the table. Also looking for battery suggestions. My thought is something smaller and more modular and smaller (less weight) than the tesla packs, but that is also an option.

If you are looking for more details, check out the video.

I look forward to your suggestions.

 

[brian_]

Interesting, but how do you see this as being meaningfully different from a body kit on an AWD Tesla?

 

[snowdog]

Interesting, but how do you see this as being meaningfully different from a body kit on an AWD Tesla?

Ahh Brian...

Almost all builds fall into 2 categories.

Rebuilding/restoring something old or broken to return it to its former glory
or
Trying to improve looks, performance, or functionality

My build would fall into the later category. In many ways this is what the majority of kit cars are; taking the drivetrain/power unit from a donor vehicle and create some more pleasing/aggressive styling (granted very subjective). Sometimes they try to improve the performance with different suspension, or with reduced weight.

To answer your question...It might be very similar if I do something like Vaydor (Infiniti G35) or Valarra (Corvette). I do not love the Tesla interior (or exterior for that matter) so I am likely not doing a body kit on a Tesla.

 

[brian_]

Almost all builds fall into 2 categories.

Rebuilding/restoring something old or broken to return it to its former glory
or
Trying to improve looks, performance, or functionality

My build would fall into the later category.

I would agree that those are reasonable categories for car builds (the first being restoration and the second being custom cars), but most EV conversions (including the first Electric Supercar) are neither of those (unless you count operating on a different energy source an improvement in functionality); they are conversions to a different type of powertrain of an existing vehicle, which may or may not be "old" or "broken" and isn't being returned to its former glory, looks are typically not improved (or even changed in most cases) and performance is rarely the target. That's why I was wondering what was intended other than cosmetics, since the idea seems to be to start with an AWD EV and make an AWD EV.

In many ways this is what the majority of kit cars are; taking the drivetrain/power unit from a donor vehicle and create some more pleasing/aggressive styling (granted very subjective).

Yes, kit cars tend to be either moving a production powertrain (and often major parts of the chassis) into a different body, or replacing external bodywork on a complete production vehicle for aesthetic purposes (such as the many Fiero kits). Without a custom body structure, a project to give a production EV platform a different appearance would be the latter case.

To answer your question...It might be very similar if I do something like Vaydor (Infiniti G35) or Valarra (Corvette). I do not love the Tesla interior (or exterior for that matter) so I am likely not doing a body kit on a Tesla.

Okay, the second category of kits... the body kit that I asked about. Apparently a Tesla isn't the right base vehicle, but if you use any EV and change only body, it's an interesting custom car project, but not really a conversion, right?

 

[Electric Land Cruiser]

After listening to your goals of having less fiddly things like doors and interiors to do but still having a go at exterior design I was thinking about the Porsche 996 chassis. They can still be had relatively cheap (for a Porsche) and the IMS failure might be a good candidate. Also they made AWD versions in the Carerra 4 and Turbos so you could either adapt the physical driveline, or possibly put a Tesla drive unit up front for AWD. Lastly, there are limitless suspension and upgrade parts for the chassis as well as tons of bodykits that could serve as a base for your project.

 

[snowdog]

After listening to your goals of having less fiddly things like doors and interiors to do but still having a go at exterior design I was thinking about the Porsche 996 chassis. They can still be had relatively cheap (for a Porsche) and the IMS failure might be a good candidate. Also they made AWD versions in the Carerra 4 and Turbos so you could either adapt the physical driveline, or possibly put a Tesla drive unit up front for AWD. Lastly, there are limitless suspension and upgrade parts for the chassis as well as tons of bodykits that could serve as a base for your project.

Yes the 996 is a top candidate

 

[snowdog]

Okay, the second category of kits... the body kit that I asked about. Apparently a Tesla isn't the right base vehicle, but if you use any EV and change only body, it's an interesting custom car project, but not really a conversion, right?

It will be a conversion of sorts, but not a traditional conversion

 

[snowdog]

Working through motor selection

 

[MattsAwesomeStuff]

As someone who typically builds on the thrifty side... yeah you're very much not giving the Warp9 a fair shake, but you're right, getting actual data on it is almost impossible. Also, it's really no better than a junkyard forklift motor the same size. Duncan gets something like 400kW out of his in the 1/8th mile, and I think does some time attacks too, and is competative at them. But I can't see how a motor from the EV meta 10 years ago is going to accomplish your goals anyway. You're not really worried much about cost, which is a major factor in going with a simple DC build. Back when it was almost impossible to build your own inverter for an AC controller, or repurpose an existing one, they were the way to go. But today none of those things are true.

Maybe some day if you get bored of nice supercar and you want to do "Poor Man's EV Supercar", then maybe consider still doing a forklift build but otherwise nope.

You could use a Prius transaxle, or a Lexus GS450H trans/motor, and while plenty zippy, neither of those say "supercar" to me. They say "As fast as you'd ever want it for street use", but not supercar.

Your goals for the project build and end result matter too. Does your familiarity with Tesla interest you to not reinvent the wheel? Or, does it feel like "No reason to do that, I've already been there done that"? Are you at all focused on the joy of the project as a project, or are you just thinking about what is the most interesting end result?

Are you thinking about the ways your current car is lacking and what you might want your next build to be that could be used in a different situation?

Far as I know Model 3 motors have been reverse engineered by Damien and you can buy boards for them and... maybe the inverters too perhaps?

I'd stay away from anything too proprietary, it locks you too heavily into a brand that might not still exist when your project is finished. Tesla and Leafs are safe because the community support is there for them.

Are you interested in this from a video content perspective? If so the most interesting might be the Mustang crate motor, it's the most catchy and that car is making waves where Tesla isn't as attention-getting as it once was.

 

[snowdog]

Thanks for your insights and questions. I have much to think about.

 

[57Chevy]

A car with enough torque to break traction on any wheel at any speed, and the software finesse to prevent it from doing so. That would be my definition of a supercar. Two Tesla LDUs is a quick, cheap and somewhat dirty way of achieving that. You can buy a wrecked car, take out the motor and then on-sell the rest of the parts for what it cost, so the hardware is essentially free other than the hassle of having carcasses and mountains of junk to deal with. The control equipment will cost some extra of course.

Take the Emrax numbers with a fair bit of salt if they come from the manufacturer only. Has anyone externally verified them?

 

[brian_]

Far as I know Model 3 motors have been reverse engineered by Damien and you can buy boards for them and... maybe the inverters too perhaps?

There's no need to dig into Model 3 controller internals (although you can if you want) - the Model 3 drive unit is controllable with external boxes, such as the Ingenext controller. tiger82 is running one in his Cobra-based race car; it is from

 

[brian_]

I wouldn't have watched the video, but since it was mentioned that the oddball Emrax was being considered, I had a look...

The NetGain brushed DC motor specs are terrible - and I mean that the lack of information and the poor presentation are the problems, not the actual motor performance. The one specific problem mentioned is the low power rating; that is due to the lack of cooling. Perhaps that could be fixed (if someone wants to build a "supercar" out of museum pieces), but more importantly it identifies the importance of considering cooling and duty cycle.

Listing the Leaf as 80 kW is problematic. The stock controller limits the Leaf motor power to protect the battery. Even if using the controller with the stock limits, the current generation of the Leaf is limited to 110 kW, and with the largest battery it is limited to 160 kW.

Since cost is being tracked, the inverter - or a suitable inverter - should be included. Just as the reason for years for using brushed DC motors was the availability and cost of controllers, it makes sense to select the combination of motor and controller, rather than picking a motor then potentially being forced by that decision into an expensive (or homebuilt, or modified) inverter.

"Motor" weights are being shown which include the transaxle in some cases - that makes a huge difference to the weight. Those apples-and-oranges weights appear to go into the table without adjustment: the transaxle weight is not removed from the complete drive units, and a gearbox weight is not added to the bare motors. In some cases the inverter is probably included in these weights, too.

The Tesla Model S Plaid rear unit has two motors, but they are not connected. All of the Plaid motors are related to the rear motor of the Model 3, but none are identical - for one thing, the Plaid rotors of the Plaid motors are wrapped in carbon fibre reinforcement to hold them together at higher speed.

AWD can be achieved by any number of motors. The assumption is using separate front and rear motors (which makes sense), but at each axle there can be one motor with one reduction gear set and a differential, or two separate motors with their own reduction gear sets (no differential). No inexpensive mass production vehicle has used separate motors at an axle yet, but it is possible (and it will be possible with salvaged components).


Oh, and about the Emrax: the case of the motor rotates. It is a strange thing to attempt to use in anything other than an aircraft (directly driving a propeller).

 

[joekitch]

only just realized you're using a full model S rear suspension and subframe
do you find that doesn't really corner well? I've heard since its designed for a 5000lb luxury sedan, it has very little adjustment and doesn't like to take hard corners and doesn't feel good to drive.

 

[brian_]

only just realized you're using a full model S rear suspension and subframe
... I've heard since its designed for a 5000lb luxury sedan, it has very little adjustment and doesn't like to take hard corners and doesn't feel good to drive.

The vehicle mass difference could be largely accounted for by selecting appropriate springs and dampers (shock absorbers). The bushings will be stiffer than required, but that's good for a sports car. It has little adjustment - some Model S owners have complained that only toe can be adjusted, and they want to adjust camber... but there are aftermarket adjustable arms for that if it is an issue.

I have no idea what "doesn't like to take hard corners" would mean.

 

[joekitch]

what I mean is the fundamental focus of its design is comfortable heavy car, which sort of taints the entire thing to not be particularly good at cornering no matter what you do, the lack of adjustment is just another symptom of that

but if electric supercar guy has it on his setup and has been thrashing it, and still likes it, that would be a good sign that it's more than good enough for most (performance minded) conversions...hopefully...

An example of a rear suspension design that'll be sporty would be the taycan's, but there's very few wrecked examples so getting a rear clip is basically impossible for now.
still, this guy did an excellent write up on everything he could see about it
I wonder if this rear clip could be adapter to have a tesla LDU nestle within it?

2020 Porsche Taycan Suspension Deep Dive | How it works - Autoblog

Contributing writer and engineer Dan Edmunds climbs under the 2020 Porsche Taycan to explain what everything is and what it does.

www.autoblog.com

 

[57Chevy]

the fundamental focus of its design is comfortable heavy car

Model S suspension is early 90s BMW E39 which is pretty good for its time. The S adds 12 degrees anti-squat in the rear and 12 deg anti-dive in the front which is definitely a lot, and the non-adjustable 1-2deg camber on the rear is the real bugbear because it chops out the tires in very short order. A better camber on the rear would be adjustable -0.5 to -1. Dial down the anti-dive and anti-squat to 8deg, take a rear toe-adjuster bolt and put it in the camber arm inner end and it should be a pretty good setup. That is what I'm doing. Either way it is going to be a barge.

 

[brian_]

Model S suspension is early 90s BMW E39 which is pretty good for its time.
...

View attachment 125574

Essentially... except that the BMW has McPherson struts at the front, while Tesla uses upper control arms - both use two converging links to form a virtual lower A-arm. BMW calls the rear suspension design "Integral IV" (they have generations of the "Integral" type); most manufacturers using this design use some variation of the term "integral link" to describe the caster control link design.

 

[brian_]

what I mean is the fundamental focus of its design is comfortable heavy car, which sort of taints the entire thing to not be particularly good at cornering no matter what you do, the lack of adjustment is just another symptom of that

But that's mostly a matter of tuning, not fundamental design.

An example of a rear suspension design that'll be sporty would be the taycan's, but there's very few wrecked examples so getting a rear clip is basically impossible for now.
still, this guy did an excellent write up on everything he could see about it
I wonder if this rear clip could be adapter to have a tesla LDU nestle within it?

2020 Porsche Taycan Suspension Deep Dive | How it works - Autoblog

Contributing writer and engineer Dan Edmunds climbs under the 2020 Porsche Taycan to explain what everything is and what it does.

www.autoblog.com

Yes, the Taycan's rear suspension should be good. That sort of multilink (any combination of converging links and A-arms, plus a toe link) is pretty common (although of course the Taycan parts are particularly nice), so there are lot of options... including the Tesla Model 3 and latest variants (at least the Plaid) of the Model S.

Edmunds has excellent suspension walkarounds for quite a few vehicles.

 

[snowdog]

I am finally getting around to starting this build

More to come