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Tesla P85D does sub 9 minute BTG run at Nurburgring

He started to hit some heat-related limiting at 1:41, but didn't get seriously choked down until about the 8 minute mark. This is from an amateur driver in pretty heavy traffic. Its far from super-car territory, but better than the 10 minute+ runs I've seen from the P85.
 
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Thanks for posting! The car did a lot better than I would have expected. Tesla has made a lot of improvements from the initial P85's to the P85D. I think the main factors holding the car back now are the cooling system and the lack of a two-speed transmission. Roadster 2.0 Elon?
Any idea what he had the regen set to? It looks like it might be in the high regen mode.
 

Doug_G

Lead Moderator
Global Moderator
Apr 2, 2010
17,888
3,414
Ottawa, Canada
Wow, that is significantly better than a P85. He got his first power limit about 1-1/2 minutes in, but it was mild - about 240 kW, which is plenty of power. It only really ramped back around the 8 minute mark.

On our local track that would be good for several fast laps. In my P85 I get about one hot lap.

Definitely want to set the regen to low for a track. Regen messes up the corner balance, and even more significantly it heats up the drive train faster.
 
I would think that there is a lot of optimizing you can do by knowing the track.
Heat management is super important to the Model S, so you would plan to use more power where it is worthwhile, and ease up where it is not.
In an ICE you can apply full power for any short section, even if it only gains you fractions of a second. In the Model S you would sacrifice those fractions to not heat up your drivetrain.
Use that power on other sections where you gain much more time.
Proper instrumentation of your heat budget would be a huge help.
 
It's a bit unfair to compare amateur times on a crowded track to those of professionals on a closed course, but it's pretty clear that there is some room for improvement in execution there. It would be interesting to see what happens with less regen or no regen. With no regen, you might overheat the brakes instead of the battery. Nonetheless, this is a big improvement on the P85 video we saw last year.
 
I wonder if any of the heat limitations would be reduced by the Inconel fuse upgrade. I suspect what's triggering the heat limit here is the motor/inverter temp, but maybe the fuse temperature has been the bottleneck for everything up to and including the P85D? I imagine the repeated application of high power would get that fuse running pretty hot over time.
 
nice video, I wouldn't call that driver an amateur....

He self-identified that way. He's clearly pretty familiar with the course, anticipating many of the curves quite well. Every video he posts appears to be at the ring, although this one he specifically describes the car as "his."

From the comments, I believe he also owned the P85+ which did a 9:14. I'd never seen that until today, only having seen much slower laps. Subjectively, I'd say he had better lines in the P85+.
 
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fiksegts

Active Member
Jan 6, 2013
1,287
1,196
Miami
I guess technically any non pro driver is an amateur, but that guy can clearly drive... he's being modest...



He self-identified that way. He's clearly pretty familiar with the course, anticipating many of the curves quite well. Every video he posts appears to be at the ring, although this one he specifically describes the car as "his."

From the comments, I believe he also owned the P85+ which did a 9:14. I'd never seen that until today, only having seen much slower laps. Subjectively, I'd say he had better lines in the P85+.
 
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7racer

Member
Jun 13, 2011
766
81
I just got back from the Ring (and Germany) yesterday.

Indeed the ring is a blast...and suggested for anyone that wants to run.

For your information, almost everyday is the TF (or touristenfahrten) sessions. That is the tourist sessions.
What's crazy about this is that ANYONE with ANY car can come out and drive. So on any given day you will see super fast Porsches but then pass a bus, or sedan with tons of people in it.
Its INSANE!

Here are the times
Opening times Nordschleife- Nürburgring

also on the TFs, the distance is what is called "Bridge to Gantry"....so you don't go flat out or complete the whole course on the TF.

I also did a two day track day there which I did get to run the full Nordschleife including the GP track.
Boat loads of fun!

I wish I had my roadster or even my GT-R but ended up rental a track car at rent4ring.de

here is a vid and you can see the traffic and bus at 1:49 (not worth watching the whole video.
I do hope that the next gen roadster will be track capable though. EVs for the track need a bit more top end and a way to recharge quickly and stay cool on a track day.

Nurburgring 2015 on Vimeo

- - - Updated - - -

on and on my Harry's laptimer overlay, you can see the Bridge to Gantry layout (lower left hand corner of the vid)
 

Ingineer

Electrical Engineer
Aug 8, 2012
1,510
3,724
He clearly is running a lot of regen. I also see the traction/yaw control constantly triggering. I wonder if it's good enough to help or hinder on a track like this? I bet it can be disabled with a simple fuse pull.

Hmm, would adding a beefier pump with more flow help? Seems like with the size of the radiator and A/C there should be enough heat transfer to get rid of it all. Maybe it's not even kicking in the A/C?

Yeah, getting the inverter, rotor and stator temps would help a lot. While we're at it, add in the pump RPM's, A/C compressor target, valve positions, etc. Seeing these would help us to devise a system to keep them cooler for track use. Tesla probably doesn't care about such things, but maybe there's an Engineer or two that would be interested enough to help off-hours. I bet Elon would be ok with this, even though I don't see him officially tasking engineering with such a project.

I devised a hack to the LEAF's HVAC controller to allow direct control of the system's cabin fluid heater. This was before the addition of the heat pump. Their HVAC team had (badly) engineered the system to turn on the heater anytime the glycol loop was below a certain temp, which led to a LOT of wasted energy consumption. When you only have about 21kWh usable, that ~5kW heater load is a serious issue. Luckily Nissan listened to us when we asked for a heat-pump in 2011. They added it in 2013, which is pretty awesome. Now it only Tesla would do it...
 
He clearly is running a lot of regen. I also see the traction/yaw control constantly triggering. I wonder if it's good enough to help or hinder on a track like this? I bet it can be disabled with a simple fuse pull.

Hmm, would adding a beefier pump with more flow help? Seems like with the size of the radiator and A/C there should be enough heat transfer to get rid of it all. Maybe it's not even kicking in the A/C?

From what I've seen reported elsewhere, it is no longer as easy to disable the traction control as it used to be, but I don't know for sure that has been demonstrated conclusively.

There is no chance that the system hasn't maximized its efforts to cool the car down by running the compressor full tilt. However, one of the systems has clearly exceeded its cooling capacity. There are at least three loops of sealed coolant for the battery, the motor/inverters and the cabin. I don't know if the dual motor cars have added a fourth loop or if they just use the same loop for both drivetrains. In order of ease of execution, the possible hacks for performance driving would be to add external cooling to the coolant loops with dry ice or similar, beef up the heat exchangers or beef up the compressor. Changing the compressor would run a considerable risk that you would need to update the firmware driving the process, which as far as I know if beyond the capabilities of anyone hacking the car today. Improving the heat exchangers has less risk, but assumes that you know something about the space/performance trade-offs that Tesla's designers did not. Putting dry ice around the the coolant loops seems to me fairly likely to work for a limited time. You'd have to study the situation to make sure that you didn't fool the sensors into reading inaccurate temps too close to the external input, but if you did it near the heat exchangers, I feel pretty confident that Telsa would instrument their temp readings nearer to the drive units themselves.

I'm also curious about the two levels of power draw down. I wonder if one is when the battery temps spike and the other is when the drive units spike.
 

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