Jan 18, 2015
fiksegts Tesla Model S P85D Sets 1/4 Mile World Record While Challenger Hellcat Goes up in Smoke Drag Racing | StreetCarDrags.com�
Jan 18, 2015
PlanB That was awesome!�
Jan 18, 2015
EarlyAdopter The Hellcat is all show. The P85D is all go.�
Jan 18, 2015
Clprenz That was really cool... imagine if Tesla made some cooling changes and made the car lighter!�
Jan 18, 2015
fiksegts OR send out the update to release full power for the P85D....
�
Jan 18, 2015
gordo That whole clip was like straight out of a cartoon: The first guy is all Mr. super show off with his flashy paintjob and smoking tires, all spinning his wheels for the cameras and the P85D is just like ho-hum, quiet 4-door luxo-barge over here, don't mind me... and proceeds to beat the living crap out of Mr. neon green.�
Jan 18, 2015
scottm That hellcat did not have his head in the game.. what kind of a start was that!?�
Jan 18, 2015
Clprenz Very true... imagine if they did both!�
Jan 18, 2015
wiztecy The HellCat driver must have just bought that car, he didn't know what the hell he was doing. Jumpy at the start, whales on the gas and ends up spinning 1/3rd the way down the track just tach'ing the motor like crazy. Was like he didn't even know they're spinning like a wild Tasmanian devil down the track that he was so out of it. Lucky he didn't smash that damn smokey thing into the wall. If the car went sideways (which it started doing), then caught some good traction, that would have been crunch time. The poor guy was way overwhelmed and uncomfortable being lined up against P85D, and when it was right beside him he floundered.�
Jan 18, 2015
nwdiver I'd like to see a real match... looked like the hellcat driver didn't know how to shift*...
* Shifting was a how power was transferred to the wheels using a transmission; antique reciprocating engines have a poor power curve requiring multiple gears to keep the engine at it's optimum speed.�
Jan 18, 2015
bluenation i agree with the above sentiment: this was not exactly the fairest of matches, as the hellcat driver was all style, no skill. And unlike EVs, you do need real skills to drive an ICe on the level of the hellcat.
i mean, you can even see the hellcat wobbling side to side at one point.
id like to see motortrend or the like do a comprehensive rematch.
that said,
p85d is an absolute monster. they set a world record for fastest EV on that video....and 3.1sec for 0-60. one of the few times that tesla specs deliver more than promised. bravo.�
Jan 18, 2015
purplewalt Having that much power (707 HP) from a motor requires (some level of) skill to have it appropriately transferred to the ground.
The Hellcat might actually be the faster of the two cars, it just requires a more talented driver than the one in the video: Car and Driver got 11.1 sec. in 1/4 mile with stock tires.
Actually, Tesla tends to over-deliver regarding performance of their cars vs. their stated statistics.
I am not surprised by the 3.1 sec. 0-60 time.
However, timing wise for delivery of Model X and roll-out of Superchargers, yes, they have overstated their projections vs. deliverables.�
Jan 18, 2015
fiksegts magazine tests are one thing, at the end of the day, this is what happens in the real world from a stop... that Hellcat will leave the P85D for dead in a roll race....�
Jan 18, 2015
wiztecy He was waiting for the P85D to shift gears and follow his lead
�
Jan 18, 2015
sickfox W O W!�
Jan 18, 2015
larmor They really just need to send out some coding changes...
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Jan 18, 2015
Muzzman1 Finally a 60' time on the P85D!! Thank you!!
For me, that just showcases the p85d in a drag race. I've been waiting for this since the inception.
1.65 is pretty insane considering street tires and 4600lbs!!
11.60's. Pretty amazing as well.
Elon nailed it.�
Jan 19, 2015
Txy Would love to see this done again, but with a competent hellcat driver.�
Jan 19, 2015
artsci That's always the excuse when an ICE loses badly to a Tesla -- blame it on the driver not the antiquated ICE technology. Admittedly, the guy had a false start but he would've been smoked anyway with a clean start.
Electric cars will keep smoking ICEs (and without any poisonous smoke�
Jan 19, 2015
EarlyAdopter I can imagine similar conversations a hundred years ago:
Said the jockey to the driver, "I would have bested you, sir, but for the unruliness of my horse that day."
Said the driver to the jockey, "But sir, your horse is unruly every day."�
Jan 19, 2015
jerjozwik hey, electric drag cars can still make poisonous smoke.
Battery Powered Miata runs 9.61 @ 140mph - YouTube�
Jan 19, 2015
Soflason Drag Race: Tesla P85D vs. Dodge Hellcat
For comparison purposes, the P85D is powered by two electric motors with a combined output of 691 horsepower while the Hellcat has a 6.2L Supercharged HEMI V8 pumping out 707HP. According to Streetcardrags.com, during this run the Tesla Model S P85D set a new world record (verified by NEDRA) for being the quickest and fastest production electric car in the world running 11.6 @ 114.6 MPH down the 1/4 mile with a very impressive 1.65 60? time. 0-60 MPH came in at just 3.1 seconds during the run as per the VBOX. Although the Hellcat made a big, noisy show smoking its tires, it's driver choked at the race's start, and the silent killer, the Tesla P85D, easily prevailed.�
Jan 19, 2015
MartinAustin Exactly. The Tesla difference is that anyone can achieve those factory times, and with a minimum of fuss & effort. Even I beat the "4.2" figure on my P85 on my first serious try. (4.19, admittedly) With ICE "muscle cars" it requires the right track temperatures, tire temperatures, engine conditioning, driver skill, "launch" functions and a host of other stuff to get the manufacturer's claimed figure. Who needs all that crap!�
Jan 19, 2015
artsci I didn't see the Tesla driver creating all that burning rubber with his tires, yet he still "smoked" the Hellcat, even the the latter's smoking tires.�
Jan 19, 2015
Todd Burch Too much show...not enough go.�
Jan 19, 2015
deanb2 Two words for the Hellcat driver - Launch Control!
He still would have lost, but it wouldn't have been as embarrassing.�
Jan 19, 2015
bxr140 Dude...the hellcat ran a 17.4. Minivans do that. That was all driver error.
No way the tesla smokes the hellcat with a clean start. Beat? Sure, quite possibly. Especially with two amateur drivers and the very sophisticated tesla traction control.�
Jan 19, 2015
artsci Dude, ICE's days are numbered no matter who's driving them.�
Jan 19, 2015
tc4542 Agreed. When you get to a certain amount of power its simply doesn't mater anymore if you can't connect/hook up. The "D", GTR, and just a few others have mastered this and the results are documented. You simply can't just punch it with 700HP in a rear wheel car and expect to do anything but burn your tires up and/or loose complete control. He would have been a lot better of feathering it but that's where the "amateur" part comes in... Yes the good thing about the "D" is it does its thing drama free yet you still get the thrill. And anyone can accomplish the task without having to worry about killing themselves in the process. Its very unprecedented. We're going see some hideous accidents in the next couple of years from irresponsible US car manufactures putting this much HP in these cars without the ability to control that HP effectively, especially at the price point they will be sold at. These are wild and dangerous machines that only experienced drivers should be piloting. They should be mastering putting that power to the ground rather than putting more power in. More is not better, better is better.�
Jan 19, 2015
artsci Couldn't agree more. The instant power and torque available encourages a kind of reckless driving in the hands of imprudent, immature drivers. I'm afraid we'll be seeing more tragic consequences as more adolescent males get their hands on electric cars.�
Jan 19, 2015
bxr140 Indeed, though I'm not sure I understand the contextual relevance.
Chest thumping this "win" is like the high school bully beating up a 5 year old.�
Jan 19, 2015
tc4542 At least the "D" specifically is very controlled in the way it goes about its thing. My concern with it is people's inability to judge distance during inertia and not being able to stop in my time in the event warranted. The thing is like a controlled missile yet it doesn't act like it. The inability to stop during a launch in the event of an emergency (unexpected car or bicycle pulls out) would be nearly impossible for the brain to react to. This coupled with its "ease to launch" could cause some bad decision making on when and where to launch. In other words it would be easy to loose respect for the thing. At least radical ICE vehicles scare you.�
Jan 19, 2015
arondaniel lol hellcat! ...or would that just be lolcat?�
Jan 19, 2015
EarlyAdopter To anyone who says "the driver of the Hellcat didn't know what they were doing"
Do you think if they switched drivers and did the run again the outcome would be any different?�
Jan 19, 2015
tc4542 Did you guys see the BMW M4 lose it the other day at this "meet and greet" in CA? Although humorous and plain stupid, it wouldn't have been if someone would have been oncoming in the other lane...
BMW M4 Crash @ CARS COFFEE Blackhawk 2015 - YouTube
- - - Updated - - -
Yes probably. Be careful seeking out others to slay with this thing. It won't be you that loses, it will be the idiot ICE driver that literally loses it trying to think he can beat you. Of course that's when he loses it into you or some other innocent bystander, not good... Even if the results are injury and/or damage free, our insurance rates as a group will go through the ceiling... Simply put, there is really nothing that can beat this thing 0-60. We know that, but the idiot in the ICE vehicle doesn't. However that won't stop him from giving it his worst/best...
I'm not preaching, just being wise�
Jan 19, 2015
Dennis87 Should the outcome not be different? :/ The Hellcat did false start, brake and then just drive very slow to the finish. Off course a 700hp car does not run the 1/4 mile on 18 sec, a 300hp car runs 13 sec
The hellcat with a good driver does the 1/4 mile on 11.2 Seconds (10.8 Seconds with Drag Radials) so it should be able to beat the P85D time if the grip is good. But that is the problem with powerful 2wd cars, traction is always a problem. Personally I don't like cars without 4wd.
I hope the firmware update boost the hight speed performance for the P85D, it should be able to do the 1/4 mile a bit faster and have a higher trap speed of 120mph+ with all that power.�
Jan 19, 2015
tc4542 Hence is why I posted the video above, classic example of why you don't like RWD, especially one with too much power in the hands of one who can not drive.�
Jan 19, 2015
Todd Burch Agree.
Soon a video will come out with a close race with a Hellcat. The D will beat it to 60, and will slightly win or slightly lose at the quarter mile, depending on conditions and driver skill. That will be impressive enough. But this video--where the Hellcat driver was obviously not in his element, is not the video to chest-thump.�
Jan 19, 2015
bxr140 You can turn off the traction control in a Tesla just as easy as in the hellcat or any other modern car.
The bad accident rate wont be any different than the current death-by-automotive-excess rate. The same thing has been said about every step in the personal transportation timeline. Fast cars have always existed, and cheap fast cars have always existed.�
Jan 19, 2015
Tasdevil At least the tesla can make any driver look good�
Jan 19, 2015
Saghost Makes you wonder what a P85D could do on slicks, doesn't it?�
Jan 19, 2015
Mr X
waiting for LOLCAT license plate on a P85D�
Jan 19, 2015
ThirdMartini Make fun all you want but for a 700Hp Monster like the hellcat at just over $40K is a LOT of bang/$$. One drivers inexperience does not a trend make. And really it's not that HARD to handle that much power in an ICE car.�
Jan 19, 2015
Saghost Just over $40k?!? Last I saw the MSRP was a little over 58k before any options. Still a lot cheaper than a P85D, of course, but not $40k.
Walter�
Jan 19, 2015
ThirdMartini My Bad! .. I looked up pricing and said base is $41K ( but looking again that's for the 475HP SRT8 version .. 59K for Hellcat ).. still that's damn cheap for 700 ponies.�
Jan 19, 2015
linkster Maybe the M4 nav told him "make a left turn NOWW!!"�
Jan 19, 2015
David99 The Hellcat driver totally messed up the start. Makes it impossible to tell what the real performance would be. But it shows another thing that keeps being mentioned when it comes to drag races. People always blame the ICE driver for not having done a perfect start. Well if it's so hard to make a good start in an ICE car isn't that just another downside for ICE cars. Because any driver can sit in a Tesla and do a perfect start without any skills other than pressing the pedal down quick.�
Jan 19, 2015
Twiddler The Hellcat not only had no traction at the start, but for the rest of the drag. A shame, I would have enjoyed seeing the D destroy it in a more fair fight, but as said, it does really showcase how easy the Tesla can be operated. Heck, I bet the Tesla driver was quietly listening to NPR while sipping a flat white the whole time�
Jan 19, 2015
fiksegts the P85D does not spin off the line, slicks would not help.... a P85D with the 19" wheels and tires could be quicker though... who will give it a try?
�
Jan 19, 2015
Saghost It's been demonstrated on various occasions that the P85s are capable of breaking the rear end loose - and that Tesla's traction control is so quick and well made that you aren't necessarily aware of it while watching. There's no reason to think this has changed with the P85D, since the rear drivetrain is still the same.
If the car can break the wheels loose, it can benefit from more grip.�
Jan 19, 2015
breser Nope there's a post over on a BMW fan site from the driver here:
BMW M3 and BMW M4 Forum - View Single Post - M4 loses control leaving Cars and Coffee, hits median, gets airborne. Owner explains.�
Jan 19, 2015
SabrToothSqrl Any car can always benefit from more grip and less weight. Start stripping parts! Passenger seat alone is most likely 40 lbs!
rear seats. Trunk liner. Head liner. Strip everything! The floor carpets are too heavy!�
Jan 19, 2015
TNEVol I think I read in Motor Trend that they had the best times in the Hellcat starting in 2nd gear. Horsepower without traction IMO�
Jan 19, 2015
jerjozwik ive seen so many stripped out miatas, a low weight S would be a very unique unicorn.�
Jan 19, 2015
Vitaman With nicer seats and auto transmission and taxes, a realistic price is $70,000.
Still a lot of bang for the buck (but save some dollars for petrol...this cat is a thirsty one).
At that price a used Model S becomes a possibility. Completely different target group but still interesting.�
Jan 19, 2015
NigelM Earlier thread over here ---> Tesla-Model-S-P85D-Sets-1-4-Mile-World-Record-vs-Hellcat�
Jan 19, 2015
bluenation that's a very good analogy.
..is this a serious question?
i suggest you watch some more drag vids.�
Jan 19, 2015
EarlyAdopter Yes, it is.
If you took that Tesla driver and put him behind the wheel of that Hellcat, and that Hellcat driver behind the wheel of the Tesla, and ran again who do you think would win?�
Jan 20, 2015
Saghost I don't think EarlyAdopter is suggesting the Hellcat driver didn't screw up - it is certainly obvious they did.
Instead, I read his point as being about the relative skill level required to get the best from the car - the P85D driver AFAIK just had to time the light and floor the pedal, while flooring the pedal appears to be half the Hellcat's problem.�
Jan 20, 2015
mdevp I've seen a couple of 0-60 hellcat vids and I don't think anyone's gotten to the 3-4 sec range b/c everyone spins at the start and the launch control doesn't seem to really work. Then people comment how dumb the driver is, etc etc. I don't see how the hellcat can approach the P85D's 3.2secs, is there a vid showing someone getting a good hellcat 0-60?�
Jan 20, 2015
jerjozwik thats what sucks about the drag strip. a lot of the cars that run are under a "test and tune" mark. which means the owner is messing around with air fuel ratios and what not. and... in the case of my trips to the drag stip or the track, its learning HOW to drive your car in a controlled area.
...and then we get a video on the internet where everyone says "look how dumb that driver is."
im curious to see how many times that hellcat owner had attempted a drag run, because if jumping the light is any indication... i would say not many.�
Jan 20, 2015
Dennis87 P85D vs C7 Corvette Stingray
https://www.youtube.com/watch?v=HUWqYAcNP_I�
Jan 20, 2015
30seconds interesting that with a 3.1 0-60 and 11.6 quarter mile the P85D is pretty much right on top of the RS7, M6 Grand Coupe and the CLS63 AMG
2014 Audi RS7 vs. 2014 BMW M6 Gran Coupe, 2014 Mercedes-Benz CLS63 AMG S-model Comparison Tests - Page 5 - Car and Driver�
Jan 20, 2015
darthy001 Hmm... surprised that the Corvette didn't pull further ahead after keeping up so good from the start. But still weird to see all of these videos of the family sedan even in with a shot�
Jan 20, 2015
EarlyAdopter A family sedan a tenth of a second off from a 2 door, 2 seater, purpose built sports car. Love it.
The 'vette will still be more tossible in the corners, but you can certainly toss a lot more stuff (and people) in the Tesla.�
Jan 20, 2015
darthy001 Exactly�
Jan 20, 2015
gavine I can't wait for a P85D vs. Stock GT-R. THAT will be a good race.�
Jan 20, 2015
EarlyAdopter That still will be a family sedan vs. a purpose built, 2 door, 2 seat (effectively), sports car.
The drag race I'm really looking for is the P85D vs. an Audi RS7. That's as close to an apples to apples comparison as you can get.�
Jan 20, 2015
Mr X Looking forward to P85D vs. Veyron�
Jan 20, 2015
AWDtsla The Tesla will lose.�
Jan 21, 2015
Mayhemm Don't forget the Tesla's half-ton weight handicap. Really is remarkable what they've accomplished.�
Jan 21, 2015
Skotty I think the Hellcat driver was just messing around. Maybe after a poor launch he decided to just see how long of a peel out he could do. That, or maybe he needs a lesson in kinetic vs static friction.
Despite the fact that I love the Hellcat vs P85D matchup, I haven't passed this video around to show P85D performance because it looks more like skewed pro-EV propaganda than a real demonstration of EV potential in that context.�
Jan 21, 2015
gavine On MotorTrend Today: Why a Challenger Hellcat Lost Horribly to a Tesla Model S P85D�
Jan 21, 2015
jerjozwik meh... that car is WAY out of reach for so many people its almost like saying you want to see the P85D vs the red bull F1 car.�
Jan 21, 2015
andrewket Thanks for this. I got a good chuckle.�
Jan 21, 2015
wallet.dat The important thing to look at in the 1/4 mile is the trap speed and the 660ft speed. Those three cars are all doing low-mid 120mph range, while the 85D is at ~114mph. This tells you how hard the car is pulling on the roll (highway speeds). A 10mph delta on the big end is huge.�
Jan 21, 2015
John Luciano Comes to 1/4 mile it is time not speed. If you dropped a car on the track already doing 100 MPH it would beat a car that started from a stand still doing 150. The S got to terminal speed sooner .�
Jan 21, 2015
LetsGoFast It all depends on what metric you want to think about. Higher trap speeds equate to better hp to weight ratios. Elapsed times are almost all about the first 100 feet. The 6mph difference at the end of the track will have a very small effect on the ET. If you imagine the last 100 feet were traveled at the trap speed, the Tesla would cover it in .598 seconds and the 120 mph cars would cover it in .568 seconds. It is only going to cost the Tesla .03 seconds of ET. The quicker launch is going to yield an order of magnitude more time, more like 0.3 seconds.
It is certainly true that the cars with a higher trap speed are going to be faster from a 60mph start, but in the real world acceleration from 60-120 is not going to be something you actually get much use out of. Everyone will have their own subjective impressions, but to me the 0-30 performance of the P85D is absolutely jaw dropping when compared to essentially everything on the planet and the difference between 60-80 is really barely noticeable. Coming from a 911 TT, I don't really miss the high speed performance at all. I do miss the nimble, responsive steering -- but all in all, I'm very pleased with the upgrade.�
Feb 9, 2015
Krugerrand If you don't have a sense of humor or have sensitive ears (some foul language) don't watch this video.
Angry Dodge Hellcat owner sets 7 rules of ownership, with a nod to Tesla | Motoramic - Yahoo Autos�
Feb 9, 2015
artsci This is a hoot! He basically says don't race any car that will beat you including the P85 and P85D. Wisdom at it's best�
Feb 9, 2015
Saghost As I mentioned in the other thread on this video, what I like is the way he starts with a rant about how stupid owners are being and how unfair the drag race video was when they know the Hellcat is actually faster and that's why he's giving these rules - and then ends it with don't race a P85 or P85D because you'll lose.
Walter�
Feb 9, 2015
skilly uh....$40K? Where? Ill buy two for that price thank you...in fact, a full load Hellcat runs up and flirts with $70K and then tack on another $20K premium for even getting access to one...and thats only if you know people. Its very close to P85D costs - dont kid yourself.�
Feb 10, 2015
jerjozwik plus you gotta buy all that gas when you drop down to 3/4 tank after one hard pull...�
Feb 10, 2015
wallet.dat Has anybody timed a P85D after the Torque Sleep update?�
Feb 10, 2015
fiksegts I have.... 0-60 in 3.1-3.2 seconds...
�
Feb 11, 2015
wallet.dat What were you getting before that? Have you had the opportunity to time it before/after at the strip? I'm curious to know how the trap speed has been improved.�
Feb 13, 2015
Bj�rnNylandFan Ten-second Challenger Hellcat is ready for a P85D rematch
As interested outsider, I am hoping the Tesla can keep the pride up for model s owners come the exciting rematch :smile:
Any thoughts on road legal drag radials being used on the hellcat... does that spoil the fun?
Is the P85D? traction limited in any way at all , sticky rubber must be worth a few tenths! and the promised 0.1 0-60 reduction via over the air update what is that worth over a 1-4 mile?!
What ever happens hope the record of 11.6 gets beaten!�
Feb 14, 2015
sickfox I'm getting me some more popcorn! This just got interesting. Thanks Bjorn for posting this link.�
Feb 14, 2015
MikeL Yeeeah�
Feb 15, 2015
Todd Burch Tesla, the Ds could go for that 0.1sec 0-60 improvement and a significant improvement in 30mph+ acceleration right about now...�
Feb 15, 2015
fiksegts same, the update to increase acceleration/speed hasn't been sent out...
�
Feb 15, 2015
CalDreamin Has anyone put racing slicks on a P85D? I understand that the P85D with stock tires doesn't appear to lose traction on hard acceration, so the assumption is that stickier tires won't help. But I'm wondering if that's the super fast responding traction control at work.�
Feb 15, 2015
dsm363 Doing the test with the exact same tire compound would be the way to do it.�
Feb 16, 2015
mdevp Yes, good question. I've always wondered this, if you put drag radials on the P85D whether or not you could get a better 0-60 time.�
Feb 16, 2015
fiksegts the P85D doesn't spin off the line, so sticky tires would not help... the P85D could be quicker on the stock 19's since they might be lighter.... I think the difference would be pretty small though...
�
Feb 16, 2015
Saghost Correct me if I'm wrong, but my understanding is the P85D doesn't really spin noticeably at any time, including when on wet roads. That being the case, what makes you confident the traction control isn't silently pulling back power on street tires on dry roads? How would you tell?
It's not a cheap experiment, but for people who have the money for a P85D spending extra for another set of rims and racing tires might be worth trying to find out.
Walter�
Feb 16, 2015
mdevp Yes, but I was wondering if that was just the traction control working, so I'm guessing aP85D would spin but the stability control takes over. I saw a vid of someone pulling out that traction fuse on a p85 and he spun the heck outta his tires.
(Just read the post above) I was thinking the same thing, it wouldn't be cheap but some Nitto 555Rs on a P85D drag racing would be a sick sight.�
Feb 18, 2015
fiksegts when the tires spin, even the slightest, the traction control light blinks on the display... this is pretty easy to replicate when you accelerate around a corner in the P85D...
�
Feb 19, 2015
Saghost Huh. I have no personal experience with the car. The thing that confuses me here is this:
If the car isn't pulling back power during launches and isn't spinning, why is it that people report they can easily spin the wheels when they disable traction control?
Unless I'm confused - I'm pretty sure I saw several reports of being able to break wheels loose on dry pavement in a straight line with TC off a while back.
I know I've seen videos of forcing a P85 to spin while holding it with the brakes, and the D should be able to deliver the same rear wheel torque...
Walter�
Feb 19, 2015
Todd Burch In the P85, you can spin the wheels with TC off. I haven't heard of people doing that in the P85D because power is distributed to all four wheels, so it tends to grip the dry pavement.�
Feb 19, 2015
Saghost But it's not distributed to all four wheels - which was my point at the end there. The P85D rear motor is supposed to be exactly the same as the P85 drive motor, and it still only drives the rear wheels.
At low speeds, the battery can deliver far more power than both motors/inverters can take (from videos it looks like the D goes power limited at about 25 mph under current firmware.)
So in principle, the P85D should spin the rear wheels exactly as easily as the P85 does - the front motor adds additional torque and acceleration, but doesn't change anything about the situation at the rear.
That's why I'm still thinking the car is pulling back some power, though it apparently doesn't flash the TC light as some expect it to from other experiences.
Walter�
Feb 19, 2015
AndreyATC I'm not an expert in laws of physics, but i think there is a difference for rear wheel behavior when you have front motor
P85D is set to motion from the front motor as well, which in turn, squads the rear even more (applying more weight to the back, or more weight transfer front-to-back) which improves rear traction
Add the fact that the rear is now has to break loose while in motion (contributed by front) it's even harder to get a slip
We know it's easier to spin of the line than at 20-30mph for example
I'm running 285 PSS tires now and a cannot break the rear lose anymore, TC or not
My conclusion is that D might be traction limited, but it's not significant
I just dont see how the same rear motor can break loose the same way as on regular P
P.S. Can D run TC off in insane mode?
Let it spin if it can?�
Feb 19, 2015
Saghost That's an interesting point. I'm convinced that a P85D with the front motor disabled would spin, but I hadn't really considered that the front motor induced acceleration would produce additional weight transfer.Does P85 flash the traction light on hard straight acceleration when we know it is pulling power on dry roads?Walter�
Feb 19, 2015
mnx My car had 19" Goodyear OEM tires on it and I could easily spin them on public roads with the TC off. However at the drag strip they put traction compound down and the pavement is flatter and in better repair than most roadways. I had no hint of wheelspin at the strip with my P85 and the all season goodyears.�
Feb 19, 2015
Todd Burch You are correct in that a P85D with the front motor disabled is essentially the same as a P85 with an extra passenger--so it could spin its tires. However, with the additional front motor, you don't see it.
The coefficient of dynamic friction (the amount of friction when the tires are sliding on the pavement) is lower than the coefficient of static friction (the amount of friction when the tires are not sliding). So once tires are spinning, it requires much less torque to keep them spinning than would be required to get them spinning in the first place.
So suppose a P85's rear torque just barely puts it over the limits of static friction. This barely gets them spinning, but once the tires are spinning, the friction drops and less torque is required to keep them spinning. So they can stay spinning for quite awhile.
But now consider a P85D. The rear torque is the same, and *would* put the rear wheels just over the limit of static friction, but this time you've got the front motor pulling as well. Since the fronts help accelerate the car forward, this reduces the forces on the rear tires, putting them now below the limits for static friction. End result is the rear tires don't start spinning.�
Feb 20, 2015
mdevp I see what your saying, reminded me of high school physics, makes sense. With that said, wondering if anyone has tried to spin tires on a P85D w/TC disabled....�
Feb 20, 2015
Saghost I was with you right up until this last paragraph. I'm not seeing how the front motor pulling reduces rear ale loads at T=0 in this case - there's no mechanical connection, and plenty of battery power to go around, so it seems to me like there's no reason you wouldn't have the same torque at the rear wheels as the RWD case regardless of what the front motor is doing.
The only factors here at T=0 should be axle torque, wheel diameter, normal force (weight), and coefficient of friction. The front motor doesn't directly change any of that, and I ess therefore initially thinking it had no effect on the equation.
However, someone did make a valid point upthread that the faster acceleration and location of the CG above the wheels creates a greater weight transfer which will increase the normal force somewhat - meaning the loads on the rear wheels stay the same, but the effective increase in weight will allow them to carry somewhat more torque without slipping.
Given the lower power and reduced gearing of the front motor and the car's very low CG, it won't be a large effect, but it could be enough if as you postulate the P85 was barely past the traction limits.
Walter�
Feb 20, 2015
Todd Burch Walter,
I see what you're saying about t=0...but if we're close to the static friction limits on the rear wheels at t=0, the assistance in forward acceleration by the front motor could keep the rears just under the static friction limit. While this may be contributing, my guess is it's not the most significant reason why the D isn't breaking traction.
In addition to the weight transfer, one other thing is that we have no evidence that the rear motor in the P85D is producing the same amount of torque as the P85 *at t=0*. (This may be the main reason why the Ds don't break loose). While theoretically maximum torque for an electric motor can be produced at 0 RPM, and while the rear motor on the D has the same potential torque generation as that on the P85, the interverters may be splitting the power differently such that the highest torque in the rear wheels occurs at, for example, t=0.1sec.�
Feb 20, 2015
Saghost Why? What am I missing here? How does assistance from the front motor change the situation of the rear motor at all, aside from weight transfer, while in the RPM range where the rear motor can deliver full torque?
That's a valid point - we're all assuming things here. However, I only picked T=0 to make the situation simpler - I think the same argument more or less holds true up until you hit the battery power limit around 25 mph (my best guess from watching the videos that show the dash during hard acceleration.)
Above the battery power limit speed, the car has to split power - below it both inverters can have as much battery power as they want, and while Tesla certainly could program ramp rates into the inverters, with their remarkable traction control and the car's goal/role as a go fast halo car I have trouble seeing why they would add limits to it that weren't in prior models.
Walter�
Feb 21, 2015
mdevp Todd B, I understand your logic, makes complete sense, but after I saw this video, I had a few questions.
So, you are saying that if a P85D had the same traction control fuse removed like the P85 in the vid, it would not do a burnout b/c of the front motor pulling? (b/c of the friction coeff etc) I'll trust your logic but from seeing how easily and immediately the P85 spins I'm wondering if a P85D wouldn't do something similar. If the p85D did do a burnout, then theoretically would drag slicks etc improve a 0-60 time? Again I'm a novice w/this stuff, so bear with me :smile:�
May 5, 2015
DrGuest My S85 earned respect from a Red with 2 black racing stripes Dodge Charger Hellcat from 0-45 mph coming back to my office from lunch today.�
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