Tesla Powered Cobra Race Car

[tiger82]

Thought you might be interested in seeing our Tesla powered race car that we hope to have on track this summer.
The chassis and suspension were custom designed in 3D CAD, the drivetrain is from a P85, the battery pack is from a Kia Soul EV, and the body is from a classic 427 Shelby Cobra

Here's a link to a YouTube Video with more information and pictures:

 

[TurboFroggy]

Great project! However, Isn't there some limitations on maximum C discharge on those Kia batteries? I wouldn't think they would like anything over about 4C which would be around 100KW. That would limit you to around 135HP or so. Or are you counting on the maximum pulse current? The doc here shows that around 420KW, which would certainly make for a serious race car: https://avt.inl.gov/sites/default/files/pdf/fsev/batterySoul1918.pdf

 

[tiger82]

Yes, we are largely basing our assessment of the Kia battery on that report. The discharge test is 10 seconds discharge/10 seconds rest until the pack is discharged. Our application is road racing, where the throttle is on/off. That being said, we think the real issue is going to be power limiting by the Tesla motor due to motor/inverter overheating. Every report I have seen about Tesla track days talk about Power Limiting after a couple of laps.

 

[jaguar36]

Awesome project!
Whats your plan on dealing with the overheating of the rotor, stator and inverter (specificly the IBGTs) that have typically limited Tesla track performance?

 

[tiger82]

We are using a very large radiator and fan with an inline ice reservoir. However, it is possible that the Tesla inverter limits power based on Power demand history as opposed to actual temperatures. We are also looking at both fixed and variable power limiting strategies (i.e. allowing full power out of a corner for brief spurts, then limiting it). In road race applications, average power around a track may only be 1/3 to 1/2 max anyways. The car will still be very fast even if we have to limit max power to 200 kW peak.

 

[jeremyz]

That's really cool. Did you consider using a LiFePO4 battery pack? I think in the United States the only option for such a pack would be the first year Spark EV. I think that there was an option to buy the i-Miev in Japan with a LiFePO4 battery as well. The energy density isn't as good as a conventional Li+ battery, but there isn't as much voltage drop as you discharge the battery.

I agree with your assessment that the drivetrain with having fewer cooling problems when put in a lightweight race car than when it's installed in a giant boat of a car.

 

[jeff mccabe]

We are using a very large radiator and fan with an inline ice reservoir. However, it is possible that the Tesla inverter limits power based on Power demand history as opposed to actual temperatures. We are also looking at both fixed and variable power limiting strategies (i.e. allowing full power out of a corner for brief spurts, then limiting it). In road race applications, average power around a track may only be 1/3 to 1/2 max anyways. The car will still be very fast even if we have to limit max power to 200 kW peak.

Hello from your competition
Im real jealous with your Drive-train. It is my plan also as soon as I melt my dc motors and you and Jack Rickard fully workout the bugs
My first track day with my Cobra was last years Refuel. Its old school, series DC GE11" .
Thats as high as I ran it , 200kw. That was more than enough to be a real handful.
I'm recovering from back fusion surgery and hope to be back on the track in a few months.
I geared the car wrong and only had about 95 mph top speed. Im building a new rear gear to solve this and plan on changing up my trans setup also.
Please keep posting on your progress ! You have a really cool project on your hands.
Thanks

, Jeff McCabe

 

[tiger82]

The Spark pack is a little small (18 kw-hr) and according to DOE testing is only capable of putting out about 200kW.

 

[wycolo]

So DOE tests for max output, which might be more than just i@max accel? Reference?
--

 

[tiger82]

Here's a link to testing done on one vehicle by Idaho National Labs. They've got test results for all major EV's - but unfortunately not any Teslas.

https://avt.inl.gov/sites/default/files/pdf/fsev/batterySoul1920.pdf

 

[Ampster]

Yes to the question at the beginning of this thread. There will always be hobby examples as noted above.
I converted this VW to electric in 2012. It cost almost $20k including the roller. This picture is in July while delivering it to a buyer. He paid $2500.

 

[RacerX]

Yes to the question at the beginning of this thread. There will always be hobby examples as noted above.
I converted this VW to electric in 2012. It cost almost $20k including the roller. This picture is in July while delivering it to a buyer. He paid $2500.

Darn, late again ... Would have paid $2999 wish I could make it back to the time tunnel.
It looks very nice. The family would have loved it. Memories.

 

[zag2me]

Nice project indeed, but that rollbar ruins the cobra's lines

 

[SabrToothSqrl]

Well.. hot damn! Me wanty!

Can you do a 40s slant back ford?