Model S vs Roadster on the Track

[smorgasbord]

We know Tesla was running betas at Laguna Seca and doing good lap times with them.

Well, that was "good" relative to us amateurs (rank amateur in my case). The Laguna Seca track record for any Tesla is still last year's effort in a Roadster Sport time by Joe Nuxoll, who has taught race driving in the past.

 

[Cottonwood]

Would the additional weight of the passenger have tipped the needed energy demand to cause the power to be lowered. I recall seeing most cars driven hard on a track being done by a single driver with no passenger.

I have informed the local rep and "ownership" via e-mail. I hope the problem is with my car and not endemic with the design. Note, that with my more conservative driving, I never got power limiting. It was Mike's (many track records) aggressive driving that triggered the problem.

The gross weight of the car and two passengers is about 5,000 lb. One less passenger at 200 lb is only 4%. That is enough to affect times, but a small number for cooling.

I did not take any pictures. I handed my camera to my friend. I will check the card to see if he got any decent ones.

 

[richkae]

I have informed the local rep and "ownership" via e-mail. I hope the problem is with my car and not endemic with the design. Note, that with my more conservative driving, I never got power limiting. It was Mike's (many track records) aggressive driving that triggered the problem.

The gross weight of the car and two passengers is about 5,000 lb. One less passenger at 200 lb is only 4%. That is enough to affect times, but a small number for cooling.

I did not take any pictures. I handed my camera to my friend. I will check the card to see if he got any decent ones.

Did you change the regen setting at all?
To reduce cooling load required for the motor and PEM ( and even the battery ) it might be best to turn regen off. I wonder if switching to the lower regen setting would help.

 

[TEG]

The Laguna Seca track record for any Tesla is still last year's effort in a Roadster Sport time by Joe Nolan, who has taught race driving in the past.

Joe Nuxoll...

Tesla Model S smokes the Tesla Roadster at REFUEL 2012 electric car race

Clearly both Tesla models are designed primarily as street cars with expected high performance only in short bursts.

With that said, most other EVs are far less competent on a track.

 

[Cottonwood]

Did you change the regen setting at all?
To reduce cooling load required for the motor and PEM ( and even the battery ) it might be best to turn regen off. I wonder if switching to the lower regen setting would help.

As I said in a previous post, it would be a good idea to set the regen to the light setting. That would heat the brakes a little more, but put a smaller load on the PEM, battery, and motor. Unfortunately, I did not think of that until I was driving home. :cursing:

 

[Johan]

As I said in a previous post, it would be a good idea to set the regen to the light setting. That would heat the brakes a little more, but put a smaller load on the PEM, battery, and motor. Unfortunately, I did not think of that until I was driving home. :cursing:

And as I suggested above, there really should be a user option to turn off regen completely. We know this can be done seeing as the car will turn of regen completely when the car is at a full range charge (until the SOC is down to is it around 90%?)

 

[donauker]

And as I suggested above, there really should be a user option to turn off regen completely. We know this can be done seeing as the car will turn of regen completely when the car is at a full range charge (until the SOC is down to is it around 90%?)

It actually didn't turn it off completely when I did a range charge, it just reduced it for a bit but ramped it up rather quickly. I expect it you did a range mode charge and then started a long descent it would probably reduce it nothing after further filling the battery.

I will say I really like the yellow indicator of the regen limit on high state of charge and of power limit on low state of charge though. It makes it quite apparent what to expect while driving.

 

[DaveVa]

I have informed the local rep and "ownership" via e-mail. I hope the problem is with my car and not endemic with the design. Note, that with my more conservative driving, I never got power limiting. It was Mike's (many track records) aggressive driving that triggered the problem.

Please let us know what you hear from Tesla in response to your inquiry. I really appreciate you exploring the limits of what the car can do.

 

[Cottonwood]

It actually didn't turn it off completely when I did a range charge, it just reduced it for a bit but ramped it up rather quickly. I expect it you did a range mode charge and then started a long descent it would probably reduce it nothing after further filling the battery.

I will say I really like the yellow indicator of the regen limit on high state of charge and of power limit on low state of charge though. It makes it quite apparent what to expect while driving.

+1 on the power limit indicators, both for power in and power out. However, having a screen somewhere even in the dumbed down Roadster view, that gives us a view of PEM, battery, and motor temps should be added by Tesla.

I have done a range charge twice at my Pagosa place. There, I start down a 600 ft in 2 mile descent to the highway immediately away from the garage. The car very quickly goes to a zero regen mode. Once on the highway, its uphill to the right and the regen limits disappear in a few miles. Its gentle downhill to the left. That direction, it took many (10-20) miles before the regen limits went away.

You can also get regen limits when well down on the SOC. I previously posted the picture below in the Supercharger area discussing charge rates at high state of charge. 218/265=82% SOC. I had been descending for over 2 miles down the east side of Wolf Creek Pass at 15-20 kW regen rate at about 40 mph. In terms of cooling, note the outside temperature of 46˚ F.

As you can see from the picture, a regen limit of a little over 30 kW had been created by the 15-20 kW regen for 3-4 minutes at 82% SOC. The limit went away quickly as the road got a little less steep and actual regen was reduced.

 

[jkirkebo]

My guess is it had to do with the batteries having a SOC of 35-40%. Losses are higher when SOC is lower, thus making more heat. Try again with a full standard charge and I'll bet the numbers get much better.

 

[DaveVa]

You can also get regen limits when well down on the SOC. I previously posted the picture below in the Supercharger area discussing charge rates at high state of charge. 218/265=82% SOC. I had been descending for over 2 miles down the east side of Wolf Creek Pass at 15-20 kW regen rate at about 40 mph. In terms of cooling, note the outside temperature of 46˚ F.

Interestingly enough, I got the same Regen limit yesterday. I went out to the car after work and had a Regen limit because it was cold (my car is generally not plugged in at work). Limit disappeared after a few minutes of driving.

 

[Cottonwood]

Finally found a good picture that my friend took. Here I am coming out of turn 13, going into turn 14. This is the rolling prairie of Colorado.

 

[DaveVa]

Finally found a good picture that my friend took. Here I am coming out of turn 13, going into turn 14. This is the rolling prairie of Colorado.

View attachment 11464

Nice picture! Any response from Tesla on the issues you encountered?

 

[VolkerP]

Finally found a good picture that my friend took. Here I am coming out of turn 13, going into turn 14. This is the rolling prairie of Colorado.

Nice picture! My first thought: "Wow, that silver Model S really looks like an Audi! Oh, wait... :redface:"

 

[DaveVa]

@Cottonwood Did you ever get a response from Tesla on what caused your car to be limited on the track? Would be great if the could look at logs to find out more detail on the limiting factors.

 

[chrisn]

I am confused how your results square with the Model S times (faster than Roadsters) at Laguna at Refuel 2012. I am wondering if the engineers there relaxed the safety envelope of the Refuel cars to test the limits, but ship customer cars with more conservative limits. If true, the real world results with customer cars is disappointing.

Please do let us know if you determine that this issue is unique to your car.

 

[Zextraterrestrial]

based on the first post - MSP overall higher top speed from track and the comment about better braking and handling through the curves I don't understand how the time/average speed could be less for the S?

 

[DaveN007]

Joe Nuxoll...

Tesla Model S smokes the Tesla Roadster at REFUEL 2012 electric car race

Clearly both Tesla models are designed primarily as street cars with expected high performance only in short bursts.

With that said, most other EVs are far less competent on a track.

So this is a 1:50 in a Roadster in the hands of a racing instructor who helped build the car? Again, this is an odd result that doesn't seem to line up with media reports and the "conventional wisdom" about the performance of these cars. On my first day at Laguna in my Cayman R I was running 1:47 following my brother's M5, and we are both novice drivers. When an experienced driver got in the Cayman he turned 1:41 at Laguna doing tests for a magazine. I think the logical conclusion is that the Roadster and Model S are phenomenal in short bursts, but really are not up to the task when it comes to actual track work. No big deal. Most people never drive on a race track, but let's keep it real.

 

[Cottonwood]

@Cottonwood Did you ever get a response from Tesla on what caused your car to be limited on the track? Would be great if the could look at logs to find out more detail on the limiting factors.

Nope, never heard back. The Model S shows a power limiting, but gives you no clue what is the cause. We can guess, but without access to the logs or some summary, we may never know. At least in the Roadster, there are the bar graphs for battery, PEM, and motor temps. In the S, we can only guess. :crying:

What is for sure, that for me comparing the R and the S on the same track, the same day, with a pro driving instructor doing all the driving (he holds many track records on this track), the R won because the S went into power limiting before we could finish a lap, well before the R. If it was the PEM, next time I will set the regen to light instead of standard, and Mike already suggested two foot driving to avoid most regen. If it was SOC (we were down to 100 miles), we will charge it up more next time. However, until Tesla gives us some info, in the S, we can only guess. :crying:

 

[brianman]

So this is a 1:50 in a Roadster in the hands of a racing instructor who helped build the car? Again, this is an odd result that doesn't seem to line up with media reports and the "conventional wisdom" about the performance of these cars. On my first day at Laguna in my Cayman R I was running 1:47 following my brother's M5, and we are both novice drivers. When an experienced driver got in the Cayman he turned 1:41 at Laguna doing tests for a magazine. I think the logical conclusion is that the Roadster and Model S are phenomenal in short bursts, but really are not up to the task when it comes to actual track work. No big deal. Most people never drive on a race track, but let's keep it real.

Perhaps weather and/or "traffic" on the track account for some of the discrepancies...