Performance of P85D with Ludicrous upgrade review

[Cottonwood]

Cottonwood, like you, I understood the torque limit to be one of traction limits which are there to minimize wheel/tire spin. At best you get a chirp or a scuffing.
Are we not understanding this correctly Lola?
Is this just a static power mapping that has no feedback from the wheels?

this could be easy to test... just throw a nice patch of sand ahead of the tire patches for about 10 feet with a broom and then do a launch with your CAN bus and see what the result would be... Some loss of traction should occur and power diminished to match the coefficient of traction available.

Here is an icy test comparing a P85 to a P85D, both on good snow tires. The AWD P85D out accelerated the 2WD P85, but both had deceleration (using all 4 wheels) that approximately equalled the acceleration of the AWD P85D. From this, it appears to me that, when not power limited, the Model S is using all the traction that the tires have.

Nokian Hakkapeliitta R2 Snow Tire Report - Page 7

 

[rays427]

What kind of 60ft times were you getting Ray?

First run was 11.345 with at 60ft of 1.640. Second run was 11.342 with a 60ft of 1.653. Third run was the best 60 ft of 1.629 and 11.367 quarter. Fourth run was 11.513 with 60 ft of 1.712. I think I staged deeper on the last run which hurts the 60 ft time. I red lighted on that run which can also be caused by staging deep. I think the battery charge started affecting the results by the 3rd and fourth runs.

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First run was 11.345 with at 60ft of 1.640. Second run was 11.342 with a 60ft of 1.653. Third run was the best 60 ft of 1.629 and 11.367 quarter. Fourth run was 11.513 with 60 ft of 1.712. I think I staged deeper on the last run which hurts the 60 ft time. I red lighted on that run which can also be caused by staging deep. I think the battery charge started affecting the results by the 3rd and fourth runs.

I should have pointed out that both cars were running original 19 inch tires. I did not feel any loss of traction. I would think that for the computer would have to detect some slip to limit output so I don't think better tires would make any difference.

 

[P85DEE]

First run was 11.345 with at 60ft of 1.640. Second run was 11.342 with a 60ft of 1.653. Third run was the best 60 ft of 1.629 and 11.367 quarter. Fourth run was 11.513 with 60 ft of 1.712. I think I staged deeper on the last run which hurts the 60 ft time. I red lighted on that run which can also be caused by staging deep. I think the battery charge started affecting the results by the 3rd and fourth runs.

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I should have pointed out that both cars were running original 19 inch tires. I did not feel any loss of traction. I would think that for the computer would have to detect some slip to limit output so I don't think better tires would make any difference.

Thanks Ray. As I suspected, 60ft times above the 1.61x range and up to around the 1.7xx range will usually produce a best of around 11.3xx quarter mile times in these cars.

Breaking 11.3 seems to require a 1.61x 60 and greater than a 90% SOC.

 

[NSX1992]

Ray can you also post the 1/8 mile results? Last Sunday I did 11.546 @113.70, 60 ft 1.641, 1/8 7.311 @92.63. On 4th run did 11.765 @ 115.39 (0.2 sec slower but almost 2 mph faster). Who knows when I will get Ludicrous but your results indicate 0.2 sec expected improvement as promised.

 

[sorka]

It looks a lot like Tesla is very purposefully controlling power for the first second of every run and that the amount of power they are allowing is the same from P85D to P85DL. Check out the plataeu on torque and very steady current rise for the first second of this D to L comparison #166. I believe the battery can source current faster so the it would be possible to get more torque in that early period (assuming Tesla's HP numbers for the motors themselves is accurate). If Tesla is tightly controlling the first second as it appears, there will never be much of a difference in low speed performance no matter what is done (drag radials, prepped track, etc.).

The next real data point for me will be a XDL run. If a faster current ramp is possible, I would think that is where Tesla would employ it

I agree they're controlling power before 35 MPH. If they added a track mode that would allow more power to be put down on say slicks, it would improve the 1/4 mile time. Yes I know that's not stock.

 

[NOLA_Mike]

I agree they're controlling power before 35 MPH. If they added a track mode that would allow more power to be put down on say slicks, it would improve the 1/4 mile time. Yes I know that's not stock.

They should just let the traction/stability control take care of if on all production cars. I don't understand why they would "hard code" a torque limit when they brag about (rightfully so) having the best and quickest reacting dynamic stability control due to the responsiveness of the electric drivetrain versus an ICE drivetrain.

So, I can only assume if they are doing this there is another weak link in the drive train they are protecting.

Mike

 

[sorka]

They should just let the traction/stability control take care of if on all production cars. I don't understand why they would "hard code" a torque limit when they brag about (rightfully so) having the best and quickest reacting dynamic stability control due to the responsiveness of the electric drivetrain versus an ICE drivetrain.

So, I can only assume if they are doing this there is another weak link in the drive train they are protecting.

Mike

I've never had a car that when traction control actually engaged didn't result in massive power cuts. Maybe they could be smart and have a learn mode for the track that progressively increases power on lunch to hunt out the traction limit of your current wheel/tire set and then pull back a few percent for actual runs.

 

[Andyw2100]

Cottonwood, like you, I understood the torque limit to be one of traction limits which are there to minimize wheel/tire spin. At best you get a chirp or a scuffing.
Are we not understanding this correctly Lola?
Is this just a static power mapping that has no feedback from the wheels?

this could be easy to test... just throw a nice patch of sand ahead of the tire patches for about 10 feet with a broom and then do a launch with your CAN bus and see what the result would be... Some loss of traction should occur and power diminished to match the coefficient of traction available.

If I understand what lola, sorka, and the others suggesting that the initial limitation is torque based are saying they are not saying that it can not also be limited by traction. So in your example, the car would limit power when a loss of traction was detected. I believe what those guys is saying is that initially the car could actually produce more power, but it is not.

In other words they are not saying the traction limit is not there, or is not functional at the start. What they are saying is that the traction limit is not actually responsible for the limit on power at the start, and Tesla is limiting it by design.

 

[lolachampcar]

It appears to me that there is a maximum amount of available front and rear motor torque for the first 1 second of a start from zero. If there is insufficient traction, the TC will step in and modulate torque. I've done some launches on wet roads and the logs show very active traction control at lower speeds although the power cuts and/or time constant seems larger when there is wheel slip within the first second. After the first second, torque comes down with the battery limit.

My guess is that there is a maximum amount of torque that Tesla will provide either the front or the rear. In the case of the P85D and similar cars, this maximum allowable torque is less than the battery could supply if asked within the first second. Banging out the exact same amount of torque with enough traction that there is not wheel slip would explain why the torque profile is the same car to car and all cars have nearly identical 60 foot times (varying by staging only??).

Data from a Model X should tell us a bit more as I suspect the X is getting more torque allowed within the first second. This would explain why the X is as close to the S in performance as, beyond the first second, the battery seems to dictate available power.

 

[ArtInCT]

Ok then, that said, and looking on the positive side, it looks like there could be a few more "enhancements" coming our way from Tesla by easing or removing "the First Second Governor".... unless those enhancements provide a certain amount of brittleness or detriment to the drive train(s).

 

[rays427]

I made a mistake my best run was the first run. We made 4 runs in just under hour. After my last run I parked the car for a minute or so and when I got back in the screens were blank except for a message that was something in the effect "car shut down will restart when this message disappears". I rebooted the computer and it still had the message with blank screens. About 20 seconds later the message disappeared and everything came back online. I assume something overheated and shut the car down. For those that asked about the 1/8 mile etc. I have attached a picture of the time slips for our first two runs with all the information. We raced each other each time.

 

[gordo]

Did three 0-100 runs today with my recently upgraded P85D @ 92, 90, 88 SoC, all with Max Battery prepping but not 'ready'...

Hit 454kW max at both 90 and 88 SoC. Excel screenshot of 3rd run below...

Tried to SC at San Mateo for a few minutes to achieve Max Battery and higher SoC between runs, but gave up after waiting around 15 minutes for the Whole Foods crowd.

 

[MarcG]

Did three 0-100 runs today with my recently upgraded P85D @ 92, 90, 88 SoC, all with Max Battery prepping but not 'ready'...

Hit 454kW max at both 90 and 88 SoC. Excel screenshot of 3rd run below...

Tried to SC at San Mateo for a few minutes to achieve Max Battery and higher SoC between runs, but gave up after waiting around 15 minutes for the Whole Foods crowd.

Thanks for sharing! I think I saw you pass the line of cars waiting to charge (I was first in line by that point). Around 1:30pm, yes?

 

[gordo]

Thanks for sharing! I think I saw you pass the line of cars waiting to charge (I was first in line by that point). Around 1:30pm, yes?

I thought that plate looked familiar... I think I was behind you for a bit until i gave up. Didn't make the connection otherwise I would have said hello.

 

[MarcG]

I thought that plate looked familiar... I think I was behind you for a bit until i gave up. Didn't make the connection otherwise I would have said hello.

No worries, next time! I ended up waiting about 15 min. myself (and of course 20 min. later when coming back to my car to unplug, there were 3 spots available... Murphy's law!)

 

[George L Parrott]

60 ft times

What kind of 60ft times were you getting Ray?

Here are the 60 ft times for both of us with P85D(Ludicrous upgrades) on 24 February

George Ray
5:09 pm 1.637 1.653
5:22 pm 1.771 1.640
5:42 pm 1.702 1.629
6:08 pm 1.712 1.712 (not a typo, equal to the 3rd decimal!)

 

[KyP85D]

I had not noticed this prior to the upgrade but now when I turn on max battery power it adds four miles to my rated range. As soon as turn it off they go away. I wonder what that's all about.

 

[benjiejr]

I had not noticed this prior to the upgrade but now when I turn on max battery power it adds four miles to my rated range. As soon as turn it off they go away. I wonder what that's all about.

FYI, I noticed increased range when using max battery too but I don't have the Luda upgrade yet.

 

[kennybobby]

A warmer battery is happy to supply current and is more efficient at it than a colder one.

 

[sorka]

A warmer battery is happy to supply current and is more efficient at it than a colder one.

Yea, but it disappears as soon as you turn it off EVEN if max battery was already in ready mode.