Testing 0-60 time question

[moswissa]

Hey guys, been spending a lot of time on Reddit reading about how apparently Tesla’s 0-60 specs are based on no roll out, But then u hear they do use roll out because that’s industry standard. I was curious to see what my MYP is doing 0-60 roughly. I posted this thread on their sub section but it’s dead over there.

I did my own tests using my GoPro at120fps and playing it back watching the speedo and my video in milliseconds and seems that I’m getting 3.65 as my fastest time with no roll out. I start the timer when the speeding goes from 0-1 and stop the count at 60mph. I understand that the speedo isn’t 100% accurate nor is my method but I can live with a tough estimate, so I don’t need any engineers to over analyze my little experiment.

My question is, at what speed does a Tesla do a 1ft rollout? Ive read anywhere from 3-5mph, but Ive also seen youtubers start their timer at 7-9mph. If that’s the case, I want to reanalyze my video just to see where the MYP stands with the rest of the Tesla line up. See what quarantine does to ppl?

thanks !

 

[Dolemite]

lol Reddit

 

[Knightshade]

Hey guys, been spending a lot of time on Reddit reading about how apparently Tesla’s 0-60 specs are based on no roll out, But then u hear they do use roll out because that’s industry standard. I was curious to see what my MYP is doing 0-60 roughly. I posted this thread on their sub section but it’s dead over there.

Tesla posts 0-60 times using 1 foot rollout for P versions of their cars only.

Unlike everyone else on earth- they dishonestly measure ONLY their P cars that way- and publish times for all their non-P cars without rollout....thus making the non-P cars look worse than they really are in comparison.

I did my own tests using my GoPro at120fps and playing it back watching the speedo and my video in milliseconds and seems that I’m getting 3.65 as my fastest time with no roll out. I start the timer when the speeding goes from 0-1 and stop the count at 60mph. I understand that the speedo isn’t 100% accurate nor is my method but I can live with a tough estimate, so I don’t need any engineers to over analyze my little experiment.

Yeah- you're gonna need to buy a high resolution GPS based performance measuring device like a Draggy if you want accurate numbers.

A P3 should be doing for example (assuming good flat roads and high state of charge) roughly 3 flat with 1 foot rollout, or around 3.2ish without it.

You seem to be posting about a performance Y though? Quickest on the draggy leaderboards I see at a glancel is 3.75 (no rollout) and 3.55 with 1' rollout... so just barely slower than the quickest non-P 3s (LR AWD with boost upgrade)

My question is, at what speed does a Tesla do a 1ft rollout? Ive read anywhere from 3-5mph, but Ive also seen youtubers start their timer at 7-9mph. If that’s the case, I want to reanalyze my video just to see where the MYP stands with the rest of the Tesla line up. See what quarantine does to ppl?

thanks !

The question doesn't make any sense as such things are measured in the modern era...

Back in the day different race tracks used different methods to measure rollout- some were speed based, others pure distance base, etc... and so you got inconsistent readings depending where you measured.

With precision GPS measuring being easily available now such measurements are standardized by accurately measuring a complete acceleration run, then subtracting the time taken for the first 1 foot (30 cm) of vehicle movement.

If you really want accurate measurement, and accurate rollout/non-rollout times- buy a Draggy.

 

[Mash]

Draggy is not precise at all. It still uses regular GPS, so margin of error is quite high. Most accurate way is to drive on flat surface with cruise control and calculate average speed from gps on that distance. This gives correction multiplier for speedometer.

Afterwards make Scan My Tesla log with just speed measured. Then convert speedometer speed to real speed. Then repeat same drive in opposite direction - that will give headwind and inclination influence. Then calculate running average acceleration from speed change. Calculate 1 foot time. That should give roughly 30-50 times more precise speed curve considering there was no wheel spin.

 

[Knightshade]

Draggy is not precise at all. It still uses regular GPS, so margin of error is quite high.

I mean, it's not though.

It's not just a dumb GPS device polling one satellite- it's using timing delay from multiple satellites to calculate a much higher degree of precision.


Tested against actual precision timing lights at race tracks it generally provides the most accurate measure available- even moreso than the VBOX GPS device most car mags used for years before that.


Track vs vbox vs Dragy results

Draggy was exactly .01 seconds different from the actual track timing lights at 330', 1/8th mile, and 1/4 mile...

Vbox was off by over 20x that difference (.262, .227, and .215) at those points compared to physical timing lights.

Even the "worst" score of any timing comparison for Draggy was only a difference of a few hundreths of a second, versus the several tenths off Vbox showed.

Vbox was also off by about 2x as much on trap speed compared to Draggy.



Lest you think that's just one guy doing one test- here's another doing multiple runs-
Quick Tech: Dragy GPS-Based Performance Meter - DSPORT Magazine


Again draggy is never off by more than hundreds of a second from the actual timing lights.

 

[FlyNavy01]

Draggy is not precise at all. It still uses regular GPS, so margin of error is quite high. Most accurate way is to drive on flat surface with cruise control and calculate average speed from gps on that distance. This gives correction multiplier for speedometer.

Afterwards make Scan My Tesla log with just speed measured. Then convert speedometer speed to real speed. Then repeat same drive in opposite direction - that will give headwind and inclination influence. Then calculate running average acceleration from speed change. Calculate 1 foot time. That should give roughly 30-50 times more precise speed curve considering there was no wheel spin.

Dragy is 10Hz GPS and is plenty accurate for 99% of people. Typically within +/- .01 seconds of most drag strip laser timing systems as can be seen on a lot of youtube reviews. The method you describe above seems pretty convoluted and unnecessary.

 

[MagnusMako]

Draggy is not precise at all. It still uses regular GPS, so margin of error is quite high. Most accurate way is to drive on flat surface with cruise control and calculate average speed from gps on that distance. This gives correction multiplier for speedometer.

Afterwards make Scan My Tesla log with just speed measured. Then convert speedometer speed to real speed. Then repeat same drive in opposite direction - that will give headwind and inclination influence. Then calculate running average acceleration from speed change. Calculate 1 foot time. That should give roughly 30-50 times more precise speed curve considering there was no wheel spin.

Dragy uses 10ghz resolution - this is the precision needed to get accurate results. If you look at comparisons of people who use both a Vbox and a Dragy - they are extremely close to each other. (Dragtimes as one example). I've also done tons of track runs (a few are on my youtube as well) and the time differences of the track versus my Dragy in 1/4 mile are almost always within 1/100th of a second of each other.

 

[holmgang]

It's not just a dumb GPS device polling one satellite- it's using timing delay from multiple satellites to calculate a much higher degree of precision.

.

What is an example of a dumb single-satellite polling GPS device? Anything behaving like that would't be able to provide any nGPS functionality

 

[moswissa]

ok so back to my question, at what average mph do most Tesla's hit 1ft roll out lol

 

[Roaddkill]

0 ~ 60 times

My accuracy exceeds my precision

 

[Paddy3101]

Don't confuse positional accuracy with Speed/Time accuracy, they are calculated differently

GPS.gov: GPS Accuracy

How accurate is GPS for speed measurement?
As with positioning, the speed accuracy of GPS depends on many factors.

The government provides the GPS signal in space with a global average user range rate error (URRE) of ≤0.006 m/sec over any 3-second interval, with 95% probability.

This measure must be combined with other factors outside the government's control, including satellite geometry, signal blockage, atmospheric conditions, and receiver design features/quality, to calculate a particular receiver's speed accuracy.

How accurate is GPS for timing?
GPS time transfer is a common method for synchronizing clocks and networks to Coordinated Universal Time (UTC). The government distributes UTC as maintained by the U.S. Naval Observatory (USNO) via the GPS signal in space with a time transfer accuracy relative to UTC(USNO) of ≤40 nanoseconds (billionths of a second), 95% of the time. This performance standard assumes the use of a specialized time transfer receiver at a fixed location.

 

[Mash]

Guys, dragy is not fpga based high cost phase shift measuring unit like some expensive vbox stuff. It's regular 10hz GPS, but they doing approximation calculation since it assumes that you doing only one activity - going straight as fast as you can. I believe that this approximation is 2x better than 15 year old vbox.

Dragy never said they accurate to 0.01. They said it's resolution. Precision from publicly available data is just somewhat better than 0.1 second on a whole run. But smaller distance measurements have to suffer more than that inevitably.

Precision and resolution of wheel speed sensor is much higher, but accuracy is not good - you have to calibrate with current temperatures to GPS data over longer run.

50ghz GPS probably can add 2x more precision. And phase shift measuring GPS that costs 20-100 times more can beat any of that stuff.

But honestly, buying even dragy for Tesla makes zero sense. To measure quality of the road and tire temps you're testing it on today? Influence of the surface, inclination and wind is more than precision of the unit anyway.

Vbox sport at least works as regular GPS for actual tracks instead of drag strips and can measure your performance and improvements.

 

[UncleCreepy]

I might be missing the point here, but why not just floor it and enjoy the acceleration? Forget about ns and Hz and have a little fun .