Filed under: EV/Plug-in, Tesla Motors
Revisiting the Tesla Roadster as a track car: it could happen
click the Roadster for a high res gallery
A few weeks back we addressed the question of using the Tesla Roadster as a track car. Discussing the topic with Tesla VP Darryl Siry during my first ride-along in the car, he made it clear that the Roadster in its current form wouldn't be very suitable for track use. The sustained loads on the electric motor in that kind of situation would cause the air-cooled unit to get too hot. When the temperature rises, the power electronics module (PEM) automatically cuts the power output. However, the arrival of DriveTrain 1.5 could provide the ideal basis for a track special.
With the air-cooled motor soon to be supplanted by a liquid-cooled version, capable of sustaining significantly higher continuous power levels, the single biggest stumbling block may have been overcome. In combination with the upgraded PEM, the only other major issue to address would be the vehicle weight. To that end, Tesla engineers are contemplating a Roadster 120, with 120 referring to the range. They could use a battery pack with only half the capacity and chemistry balanced more toward power than energy. That would drop nearly 500 lbs of mass, improving handling, acceleration, and braking capability. The reduced mass would also reduce the loads on the motor allowing it run at speed even longer. Of course none of this will happen until the standard Roadster is in steady production.
Gallery: First Drive: Tesla Roadster
[Source: Tesla Motors]
Reader Comments (Page 1 of 1)
tankd0g 3:42PM (1/28/2008)
Just what I want, less than an hour of track time before I have to call the fork lift to put it back on it's trailer. Didn't we just have a long heated discussion about how this is not a track car so it shouldn't be expected perform as one?
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Darryl 8:02PM (1/28/2008)
I wouldn't say Tesla engineers are considering this yet. It is just an idea I have that I think might appeal to some buyers. You are right in saying that we are focused on one thing only now - the current Roadster, but I would be interested in hearing what people think about the idea.
i also would de-couple the notion of a "Roadster 120" from a Roadster track car. Two different things.
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Cliff 8:25PM (1/28/2008)
Hmmm...I think Tesla is aiming at a killer autocross car rather than a track car. Lighter is faster and autocrosses do not require any range.
We run the ProEV Kokam Lithium Polymer powered Electric Imp on the race track and need all of our 35 kW-hr pack to compete in Sport Car Club of America (SCCA) regional races which tend to be under 35 miles.
Our .225 kW-hr per mile street mileage goes to about 1.2 kW-hrs per mile on the track.
So if the Roadster gets anywhere similar mileage and they drop the battery pack capacity to 25 kW-hrs, then the pack will be empty in less than 10 laps on most tracks.
For road racing, get the larger pack and learn to work with the weight.
Cliff
Driver
ProEV's Kokam battery powered Electric Imp
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dv 9:14AM (1/29/2008)
ABG, you missed this yesterday afternoon:
http://origin.mercurynews.com/breakingnews/ci_8102047
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Lad 9:42AM (1/29/2008)
If I may be allowed to repeat myself:
I can assure you that if TMC doesn't put the car on the track, others will. So why not control the process to assure positive PR...if nothing else, this is a smart move to protect the brand. Hey! This is an exciting car and has world class acceleration. You add 500lbs of lightness and you have a hellacious responsive car that can set new standards for electric race cars. When the race guys see all you need is to replace the drive-line to get a more responsive race car, the rush will be to BEVs.
On the racing version, I would like to see TMC consider super caps along with the batteries to store more of the braking regen energy for even faster acceleration. As you know if you have ever done a lap full-on. It's wide open acceleration as early out of the turn as possible followed by braking into the turn as late as possible. Running the roadster on the track is the best worse case engineering test I can think of. If it does well at Sears Point, the streets are a cinch.
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GoodCheer 10:49AM (1/29/2008)
I agree with Lad. Any trackable EV would surely want banks of supercaps to provide power rather than batteries (unless your batteries can handle the power both out and in). I would think to capitalize on the potential regen, you'd want the front wheels driven as well as the rear, so the Tesla would not be an ideal place to start... unless they fit wheel-motors in front.
But if you get to the point that you can capture a reasonable fraction of deceleration energy, you might be able to bring the power use down from Cliff's 1.2 kWh/mile, at which point a track EV might really be a blast.
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Cliff 7:45PM (1/29/2008)
Goodcheer and Lad,
You might enjoy checking out our website at www.ProEV.com. There are lots of technical details about the car. We are running all-wheel-drive so that we can use the maximum regenerative braking possible. We are putting 300 amps into the batteries under braking. The Kokam cells can be recharged at 200 amps continuously (30 minutes to full charge) so we are trying even higher peak 'regen' currents. We do not see an advantage to 'super caps'.
The 1.2 kWh per mile figure would be 20% higher if we had not been using massive regenerative braking.
Cliff
Driver
ProEV's Kokam battery powered Electric Imp
Reply