Traction on hard acceleration

[12Pack]

I don’t see that from that acceleration plot. It looks like full torque is available at very low speeds. Also, it takes the same amount of torque to skid the tires no matter what the speed. Torque just translates to force at the point where the tire touches the road.

Unfortunately going back to the previous part of the discussion - those plots however they were generated - do not reflect the real world experience of several (I count at least 3 separate contributors) non-P MS owners.

I will re-iterate - my previous non-P MS85 did NOT experience full, linear acceleration from standstill when you stomped on the throttle, but it ramped up in a non-linear way as if there was a bit of "turbo-lag". My current P100D explodes off the line with immediate acceleration (I'm sure the AWD helps, but so does the immediate power delivery).

If this is the same situation on the M3, then it could be down to the PEM not making the theoretical torque immediately available - allowing the car to get off the line without wheelspin.

 

[Daniel in SD]

Unfortunately going back to the previous part of the discussion - those plots however they were generated - do not reflect the real world experience of several (I count at least 3 separate contributors) non-P MS owners.

I will re-iterate - my previous non-P MS85 did NOT experience full, linear acceleration from standstill when you stomped on the throttle, but it ramped up in a non-linear way as if there was a bit of "turbo-lag". My current P100D explodes off the line with immediate acceleration (I'm sure the AWD helps, but so does the immediate power delivery).

If this is the same situation on the M3, then it could be down to the PEM not making the theoretical torque immediately available - allowing the car to get off the line without wheelspin.

It is very mysterious. Maybe Tesla gave "hot" cars to reviewers (manufacturers have been known to do that). The runlogs that Krash posted earlier in the thread are only for D models but they all show the same acceleration curve as the Model 3 plot (Constant acceleration/torque at lower speeds tapering off at higher speeds (becoming constant HP)). That model 3 data was taken with a VBOX accelerometer. Skidmark has a similar device so it will be interesting to see if he can repeat those results.

 

[Krash]

...The runlogs that Krash posted earlier in the thread are only for D models but they all show the same acceleration...Constant acceleration/torque at lower speeds tapering off at higher speeds...

Forum members have provided samples from eight RWD cars: corked, uncorked, new drive unit, old drive unit, 75, 85. They all have linear torque and power acceleration, but yes I don't have an S85+ or SP85+. Here is how an uncorked RWD 75 stacks up against a RWD 85...

 

[insaneoctane]

Everything I have read simply indicates Tesla has dialed in the Model 3 very conservatively for the first 0.5 seconds of WOT. Even if someone disabled ABS sensor to defeat TC, I don't know if you would still get instant full torque. Tesla controls this. I would be very interested to see if a model 3 owner would unplug ABS thereby defeating TC and performing a 0-60 VBox run. I'm guessing that it would be hard not to light up the tires and I would love to compare the first second acceleration . I suspect that the model 3 does 10 - 30 mph faster than 0 - 20 mph only because Tesla says so ...

 

[Krash]

...I would be very interested to see if a model 3 owner would unplug ABS thereby defeating TC...I'm guessing that it would be hard not to light up the tires ...

Unplugging ABS would not change the torque setting. Tesla doesn't watch the wheels and slow them down when they get too fast. Tesla watches the motor torque and limits something like the current to keep torque below the torque setting.

 

[Daniel in SD]

Everything I have read simply indicates Tesla has dialed in the Model 3 very conservatively for the first 0.5 seconds of WOT. Even if someone disabled ABS sensor to defeat TC, I don't know if you would still get instant full torque. Tesla controls this. I would be very interested to see if a model 3 owner would unplug ABS thereby defeating TC and performing a 0-60 VBox run. I'm guessing that it would be hard not to light up the tires and I would love to compare the first second acceleration . I suspect that the model 3 does 10 - 30 mph faster than 0 - 20 mph only because Tesla says so ...

Again, it could be wrong but the VBOX data shows 0-20mph time being exactly the same at 10-30mph time. I want to see more instrumented tests to confirm. It's really sounding like some cars are different.
I could see people being used to the acceleration of ICE cars with a drag race type launch feeling that the Model 3 is slow off the line but almost everyone who currently owns a Model 3 is a current Tesla owner.

 

[Daniel in SD]

Another data point showing linear acceleration: http://www.motortrend.com/cars/tesl...la-m3-v-ms-v-bmw-330i-accel-graph-time-to-mph
Shows what I'm talking about with an ICE vehicle being faster off the line due to gearing but MUCH slower after shifting into second gear (at about 35mph). So, relatively speaking the Model 3 is much quicker at 35mph.

 

[insaneoctane]

I'm really surprised by that graph. It shows ICE hanging with the EVs until 40MPH. The only explanation that makes sense to me is that the 330i must have been launched with violent clutch dumping maneuvers..

 

[Daniel in SD]

I'm really surprised by that graph. It shows ICE hanging with the EVs until 40MPH. The only explanation that makes sense to me is that the 330i must have been launched with violent clutch dumping maneuvers..

It's an 8 speed automatic (automatic transmissions are really good these days though). The reason is it has much shorter gearing in 1st gear than the Model 3. You can see the shifts at 35mph and 55mph where it's acceleration drops (slope decreases). It's all about torque to the wheels.

 

[DarthPierce]

I'm really surprised by that graph. It shows ICE hanging with the EVs until 40MPH. The only explanation that makes sense to me is that the 330i must have been launched with violent clutch dumping maneuvers..

Yes, it was absolutely launched with the BMW at full throttle, turbo spooled up, with left foot fully depressing the brake - it's attention grabbingly loud and pretty abusive to the torque converter, but the only way it's going to be moving ~4MPH at T=0 as on the chart.

 

[Daniel in SD]

Yes, it was absolutely launched with the BMW at full throttle, turbo spooled up, with left foot fully depressing the brake - it's attention grabbingly loud and pretty abusive to the torque converter, but the only way it's going to be moving ~4MPH at T=0 as on the chart.

All three cars start at 4mph. Maybe they're doing a 1 foot rollout or maybe they just lined them up the way. Anyway I think this perfectly illustrates why the Model 3 doesn't spin its tires. The BMW 330i can accelerate faster at low speeds because it has shorter gearing even though it's much slower at higher speeds.
P.S. Do modern BMWs even let you press the brake and gas at the same time? I thought car manufacturers stopped that after all the recent unintended acceleration lawsuits.