MarcG
Active Member
I fully expect a few 1/4-mile runs with Launch Mode enabled within the week (with videos and V-Box data, of course!) :biggrin:
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New Launch Mode - firmware 2.9.40
- Thread starter PatP
- Start date
I fully expect a few 1/4-mile runs with Launch Mode enabled within the week (with videos and V-Box data, of course!) :biggrin:
Like others noted, now that it was actually a reasonable temperature (almost 50F, or so the car thought), launch mode works just fine for me now. Max Power just needs to be on, not batteries ready. Same firmware yesterday, hovering around 2F, no dice (and no error stating that... WTF... it isn't a secret code sequence if it is in the manual...)
It is kind of a pain to engage if you wanted to do it quickly, or on a timed start... it is a really unnatural sequence.
It is kind of a pain to engage if you wanted to do it quickly, or on a timed start... it is a really unnatural sequence.
As I promised took my P85D to Irwindale 1/8th dragstrip to test Launch Mode. I was disappointed in the results. My previous best was 7.37 at 93.0 mph and on first run did 7.43 at 93.5 at 85% with launch. But my reaction time was poor and this turned out to be my best run. It seemed to hesitate a little bit. Made a total of 4 runs, one without launch at 7.497 and 92.86 and 79%. My last run was 7.501 at 92.25 at 74% and 56 degrees. So maybe cold weather did not help.
The highlight was my run against a new Z01 Corvette with 650 hp. I smoked him with a .126 reaction time (no launch) to his .839 and his 8.935 compared to my 7.497, but his speed was 95.82. He smoked his tires and the announcer made a big deal with the fastest Corvette against the worlds quickest production car.
The highlight was my run against a new Z01 Corvette with 650 hp. I smoked him with a .126 reaction time (no launch) to his .839 and his 8.935 compared to my 7.497, but his speed was 95.82. He smoked his tires and the announcer made a big deal with the fastest Corvette against the worlds quickest production car.
I think the hesitation you are experiencing is related to the traction control I previously alluded to taking over immediately after launch mode. Given my 19in tires have 32k miles on them, but when I use launch mode I feel the tires begin breaking and then traction control takes over and allows the front end to drop. If there was just a second more of slip before traction control kicked in I think you would see a nice improvement in times.
Carspotter Daily
Tesla > ICE
Especially because drag strips have rubber on the track, "slip start" would benefit your times, the car's traction control acts as if your on normal roads and limits the power output as a result. I'd be surprised if you got any wheelspin at all, considering the weight of MS.
Andyw2100
Well-Known Member
This is not my area of expertise at all, but my understanding is that the traction control only kicks in if it senses that the wheels are actually losing traction. I don't believe the traction control would be limiting power before any traction is lost, and I don't believe slip start would allow any more power to be delivered initially.
I'm sure someone like lola or fiksegts or someone will elaborate on this and / or correct what I got completely wrong.
Andyw2100
Well-Known Member
I was responding to Carspotter Daily (as evidenced by my quoting him) who suggested that you would have benefited from using slip start, because the drag strip has rubber on the track. I posted because I don't believe that is correct.
On the all-seasons slip start will get you more power output than launch mode. If you have "enough" traction already it may do nothing. But it's clear that you can't tell without trying it, the car will silently pull down output torque long before the traction control indicator lights up.
lolachampcar
Well-Known Member
Working on a CAN bus data logger using front and rear motor torque values along with wheel speed, battery voltage and battery current all at 100 Hz frame rate. This will provide a nice graphic picture of Tesla's TC at work 
Cottonwood
Roadster#433, Model S#S37
So the Limitations state that the ambient temperature needs to be above 3˚C.
Is this really an ambient temperature limitation, a battery temperature limitation, or both?
I apologize in advance that I have not read all 40 pages of this thread, but I had two questions:
1) Can somebody help explain to me the "Max Battery Power" mode? I know it doesn't have to be "ready" for launch mode, but would it really make sense to drive around for 1 hour and burn extra energy to heat up your battery pack since now your SOC would be much lower? Or wouldn't it be better to hop in at 95% and punch it cold? It would seem much more practical if you could enable it while plugged in at home, or from the mobile app, etc.
2) Any tips on how to properly time launch mode at a traffic light without timing out? Can you have a long pause for any part of the sequence? For example can I do "launch mode enabled" and not hit the gas the second time until the light is about to turn green?
1) Can somebody help explain to me the "Max Battery Power" mode? I know it doesn't have to be "ready" for launch mode, but would it really make sense to drive around for 1 hour and burn extra energy to heat up your battery pack since now your SOC would be much lower? Or wouldn't it be better to hop in at 95% and punch it cold? It would seem much more practical if you could enable it while plugged in at home, or from the mobile app, etc.
2) Any tips on how to properly time launch mode at a traffic light without timing out? Can you have a long pause for any part of the sequence? For example can I do "launch mode enabled" and not hit the gas the second time until the light is about to turn green?
Well, after initially not being able to get it to work, I tried it a few days ago when the temp was around 45* and it did work.
Max battery, full press and hold of the brake pedal, then full press and hold of the go pedal, and launch mode is activated.
MarcG
Active Member
I would venture to say that it's not a battery temp limitation, since enabling Max Battery Power heats it up.
In most cars there is an icy road warning a few degrees above freezing, so I'm guessing that Tesla doesn't want us to use Launch Mode if there's a chance roads may be icy/slippery.
- - - Updated - - -
1) Max Battery Power heats up the battery so that it reaches a point where it has less impedance, so more power is available (less power is lost in battery resistance)
2) You can enable Launch Mode and keep it enabled for a while by "stabbing" the accelerator pedal once, but not pressing it again until you get an idea that your light will go green within 4 seconds (for example, keep an eye on cross lights)
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