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P100DL at the drag strip
- Thread starter SBDPlaid
- Start date
Ludalicious
Active Member
TexasTeslaRacing
Member
I've drag raced a lot of Teslas and the best times are when you have a warm battery between 88%-93%. Going higher than 93% has never produced a faster time. Lowering the tire pressure doesn't help if the track is well prepped. Keep the tire pressure at recommended levels, remove everything from the car, and mash the pedal as fast as possible. My best 1/4 mile in a 2016 MS P100D was 10.79. I've never understood how Tesla achieved a 10.5 and I've never seen an actual time slip any lower than a 10.6. Real world 1/4 mile times are 10.8 - 10.9 all day long.
zanary
Active Member
We do know that MaxBattery and Ludicrous + mode now become a regular acceleration mode so it's easier to activate. I think this was spotted in 2019.8.1 a week ago.
I don't know if that means Ludicrous + becomes something we can ride in all the time without feature of accelerated battery, drive unit and motor wear?
We will soon find out once 2019.8.x goes GA for all Model S and Model X.
I don't know if that means Ludicrous + becomes something we can ride in all the time without feature of accelerated battery, drive unit and motor wear?
We will soon find out once 2019.8.x goes GA for all Model S and Model X.
Ludalicious
Active Member
icefree
Member
GA = general availability
Ludicrous+ is really just Ludicrous w/max battery power turn on. It would be interesting to see if L+ also enables launch mode without going through the easter egg...but I doubt it, I think it just replaces the max battery option.
zanary
Active Member
I can't find the post, but someone mention that it turns on everything so you can do launch mode.
For those who have Insane Mode, they'll see Insane+.
zanary
Active Member
St Charles
Tesla, not TSLA!
This is correct. Lowering tire pressure may assist with traction on a poorly prepped track surface at the expense of additional rolling resistance. This is why Tesla cars and drag radials don't work out well. A sticky set of Mickey Thompson's have a massive rolling resistance when compared to the stock Michelin Primacy. TeslaRacingChannel did a fair amount of testing with drags on his P100D on youtube. His conclusion was to go back street tires.
Conventional wisdom says on a prepped surface you want to increase tire pressure until you get a small amt of wheel spin. That said, Tesla's get finicky about tire slip so it's probably best not to spin at all if possible.
St Charles
Tesla, not TSLA!
If you mean that the traction control system is designed to limit wheel spin, sure. At the drag strip, the traction control system gets in the way more than it helps.
I am saying that Tesla engineering has set a manual limit on the maximum torque of the motor. It isn't like the motor spins as fast as you press the pedal until traction control comes on. And a related group is picking the tires. On an ideal surface in ideal weather (a track day is pretty ideal) even at 100% L+ pedal why would the traction control come on? Do we think it comes on?
I am genuinely curious. I could see an engineering argument that as torque limits increase, at some point it is better to have some slip early (managed by traction control) in order to have lower rolling resistance for the rest of the performance run. But on contributed API data on the P100D and CANBus data on the P900D torque looks pretty linear, I.e. no traction control. Does anyone have data?
Does anyone lightening the car think it comes on at launch as weight decreases? That would be telling.
Also, does the rolling resistance of prepped drag tires that are stickier at launch get higher or lower over the length of one performance run?
I have a 75D so obviously my traction control doesn't come on much. Grin.
I am genuinely curious. I could see an engineering argument that as torque limits increase, at some point it is better to have some slip early (managed by traction control) in order to have lower rolling resistance for the rest of the performance run. But on contributed API data on the P100D and CANBus data on the P900D torque looks pretty linear, I.e. no traction control. Does anyone have data?
Does anyone lightening the car think it comes on at launch as weight decreases? That would be telling.
Also, does the rolling resistance of prepped drag tires that are stickier at launch get higher or lower over the length of one performance run?
I have a 75D so obviously my traction control doesn't come on much. Grin.
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That’s one thing that I wish Tesla would change; some indicator of traction control working (on the dash, etc) and possibly the ability to over ride if one so desired
St Charles
Tesla, not TSLA!
You are still just describing traction control. Tesla doesn't set an upper limit on motor output beyond what the battery can safely supply. The difference is that they do not allow this power to be supplied instantly, they ramp it at a programmed rate. This allows the tires to maintain traction and helps keep the suspension and differential from failure.
But, even on a Tesla it's not that difficult to defeat traction control. If memory serves, you pull the plug on a few wheel speed sensors and have at it! Here are some examples:
Electric motors can build torque as fast as they can generate a magnetic field. Your definition of 'instantaneous' might be a bit different than mine but I think we can both agree it's damn quick. faster than what we actually see on the road. The videos above should be good proof of that concept. Under normal conditions the car ramps power at a programmed rate. It's quick but not as quick as the motors are technically capable of. That is, until it detects wheelspin and cuts power.
Here is a video of Tesla discussing how their traction control works at length, with examples of TC enabled vs disabled:
It's interesting to note how Tesla engineers can tune TC to allow for some fun, and they do on the Model3 performance. That said, this isn't unique to Tesla. Porsche has been doing this for years and is a gold standard for traction control in performance scenarios. Now, this is all in very suboptimal conditions, to be sure. On a drag strip, the best 60' time I got in my P90DL was 1.52 seconds, similar to what a P100D is generally capable of. To me this shows that the two cars build torque at the same rate. The P100D keeps ramping to a higher power level and holds that power to higher RPM.
I know TeslaRacingChannel gutted his car and did a bunch of drag racing. I think he saw some minimal gains but it wasn't enough for him to keep the car gutted and he went back to a full interior. I don't think he discusses anywhere publicly where the improvements came from. I'd wager that less inertia amounts to better acceleration but the power increase stayed consistent.
Rolling resistance is higher across the board. This would depend heavily on how much of the track surface is prepped. Maybe it changes with speed but I have to think it's still going to be proportional to street tires in the same scenario. A good way to prove this out would be to drive a section of freeway on various tire compounds and measure the power consumption along a constant speed. I will say that I saw a 10% drop in wh/mi going from 21" pilot sport tires to 19" primacy's.
did they change that on D cars? My dash shows TC working if my car tires slip / displays TC indicator when you turn TC off (+ of no D)
zanary
Active Member
Page 58 of the manual shows a symbol that appears on your instrument cluster when TC kicks in.
Page 68 also tells you how it works, and using Slip Start to turn TC off.
Source = https://www.tesla.com/sites/default/files/model_s_owners_manual_north_america_en_us.PDF
I’ve never seen anything related to TC on my dash, so either the D/P models don’t show it or I’ve never had any slippage of any sort, which is hard to believe especially after doing multiple runs at the track last week and trying out Launch Mode multiple times on the street.
I also did not think there was a way to defeat or change TC in the Model S and only the Performance Model 3 had that availability?
