TESLA high performance tuning discusion

Doctorbass said:
Tesla are using induction motor that run over 10krpm if i remember..

so 3 time 3050rpm is 9150rpm and 3 time 84kmh is likely close to the max speed of the Tesla S right

Doc
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As Arlo said, the Tesla is software limited to 18,000 rpm @155 mph (240 kph)
So 84kph would be about 6100 rpm at the motor.
...But i dont know how that affects their motor torque (Nm) figure , which may be calculated from some other input.
Isnt there some formula relating power, rpm and torque ?
 
Hillhater said:
Doctorbass said:
Tesla are using induction motor that run over 10krpm if i remember..

so 3 time 3050rpm is 9150rpm and 3 time 84kmh is likely close to the max speed of the Tesla S right

Doc
Click to expand...
As Arlo said, the Tesla is software limited to 18,000 rpm @155 mph (240 kph)
So 84kph would be about 6100 rpm at the motor.
...But i dont know how that affects their motor torque (Nm) figure , which may be calculated from some other input.
Isnt there some formula relating power, rpm and torque ?
Click to expand...


Lol Torque = HP x 5252/RPM
Or HP=RPM x Torque/5252

The dyno measures how fast the weight of the roller is accelerated and might have a partial load on it with an eddy brake but really the dyno knows the HP and roller rpm calculates the rest.
 
OK ...but with a traditional ICE on the dyno, its easy to directly get the motor rpm and plot it against power at the wheels etc
Not so simple with the tesla i suspect ?
But recording road speed (kph) is easy, so i expect the 84.5kph figure is correct for peak torque, which correlates to 6100 motor rpm ( approx)
Using your formula, if we take that 1400Nm at 84.5 kph (6100rpm), that gives a hp figure of 1177 (871kW) ...clearly an impossible figure !
But, if we assume their 394 kW (at the wheels)..at 89.3 kph (6400rpm),
Allowing 10-15% for transmission losses, thats more like 450kW at the motors, then the formula gives approx 700Nm Torque.
That is a much more realistic figure.
How does that sound ?
 
Hillhater said:
OK ...but with a traditional ICE on the dyno, its easy to directly get the motor rpm and plot it against power at the wheels etc
Not so simple with the tesla i suspect ?
But recording road speed (kph) is easy, so i expect the 84.5kph figure is correct for peak torque, which correlates to 6100 motor rpm ( approx)
Using your formula, if we take that 1400Nm at 84.5 kph (6100rpm), that gives a hp figure of 1177 (871kW) ...clearly an impossible figure !
But, if we assume their 394 kW (at the wheels)..at 89.3 kph (6400rpm),
Allowing 10-15% for transmission losses, thats more like 450kW at the motors, then the formula gives approx 700Nm Torque.
That is a much more realistic figure.
How does that sound ?
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Not even close.
The P100DL is limited by battery and it makes ~700hp peak that's all the battery can do. Thats about 522kw at the motors.

Working math for this is not worth the time because we are guessing at to many numbers. You need to know the EXACT motor RPM to calculate KW or Hp. You can give me a torque number at roughly a rpm but it all you have.
 
Arlo1 said:
Not even close.
The P100DL is limited by battery and it makes ~700hp peak that's all the battery can do. Thats about 522kw at the motors.

Working math for this is not worth the time because we are guessing at to many numbers. You need to know the EXACT motor RPM to calculate KW or Hp. You can give me a torque number at roughly a rpm but it all you have.
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I am not trying to accurately calculate the power/or torque of the Tesla, i am simply checking the validity of those published dyno Torque results.
M Not worried about +_ 10%, i am thinking in the order of +_ 100%. !
Any figure quoted for motor output has to be a calculation, but i would hope any dyno monkey can record road speed and wheel HP fairly accurately, so i suspect the peak wheel HP at 394kW @ 89kmh, is what they got on the day.
BUT ,..that 1406 Nm is definitely not correct...and like i said ..closer to 700Nm

To do it properly for any EV , you would need to log the battery voltage and amp draw during the run also,, then you might have some useful data !
(Doesn the Tesla log all that sort of data anyway ?)
 
Maybe that simply the various version of the model S ( S, P, PD, PL PDL etc... PD+ have different gear ratio...

Doc
 
If we make the tesla 1000 pounds lighter with the same power output and use the same tyre and gearing, The tyre will have less dynamic load of the mark giving less traction and a slower 0-60mph time but once the car get upto speed and grip it will then accelerate harder than the heavier version.

This is due to the tyres being at the limits of their grip it's not possible to get the traction down through the stock tyre, so you have to use a drag tyre to get the width and stickyness to go any faster than 2.8 seconds or so it's limiting all the hypercars, tesla only manages to get the 2.3secs by using its mass as dynamic load off the line with a trunk full of torque she pulls hard with no gaps in power delivery unlike an ice engine so it has the luxury of being as torquey as a diesel and will rev up like a 2 stroke when it's an inrunner design.

I've noticed this with my old car it run a 185/65/13 tyre weighed 850kg and had 160bhp with this setup I had 0-60 times around 6.5 seconds and pull to 145mph, when I fitted a turbo new rods and pistons it had 200bhp the same tyre and got 6.5 seconds with lots of fethering the tyre just could not get me launched any quicker I needed to go to 195/45/14 to get me close to 6 seconds but then even these meet their limits.

Question does the tesla use the largest available road legal tyres ?
 
Ianhill said:
If we make the tesla 1000 pounds lighter with the same power output and use the same tyre and gearing, The tyre will have less dynamic load of the mark giving less traction and a slower 0-60mph time but once the car get upto speed and grip it will then accelerate harder than the heavier version.
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I know where you're going with this, but in practice you would just drop the air pressure by 30-50% or so and the 1000lbs lighter car would destroy the stock weight car.

They aren't that close to the limits of what a tire can handle after ~30-35mph, and the lighter car would be dominating from that moment onward even with stock tire pressures.
 
.....Question does the tesla use the largest available road legal tyres ?
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:lol: You are joking..right ?
No, is the short answer.
There are options , but the largest factory option is 265/35/21
There are much wider , larger diameter, grippier compounds, semi slick, etc ..road tyres available .
 
I would still take the 1000 pounds out though, being over the top even if I got like .4 of a second quicker stock to say 30 there on in the lighter one is going to be pulling much harder and pull on by and any race has one start some rolling so the weights got to go no brainer.
The skylines are a good argument for 4wd setups efficency losses they are hovering around 7 second 1/4 miles and the same setup in a rwd would pull low 6's.

A 265/35/21 doesn't seem that wide or great to me I suspect this has been engineered for a good wh/mile rather than a sticky fat boy creating more drag so it's all about efficiency where as the drag boys soon sort that out but then they come unstuck with the motors and controller limiting the sucker.

I like the idea of a lipo drag killer but I think the setup itself is flawed for drag racing but highly suitable to track racing, the grip that's available through a bend with torque vectoring (electric lsd) is amazing, but by using the brakes through a bend it becomes wasteful to any system for an electric one this is where we need to improve disc brakes are old fashioned :mrgreen:

Theres no regeneration available while torque vectoring so a traditional mechanical type system with traction control would be more suited to electric as it would allow max power through to each wheel and no more so there less energy wasted by the brakes, for a normal car it makes no sence having the extra drag and complexity of the added lsd on normal day driving where torque vectoring rarely takes place but in an electric race car it's slipping all the time and energy will be wasted heating the discs killing the run time.
 
Ianhill said:
If we make the tesla 1000 pounds lighter with the same power output and use the same tyre and gearing, The tyre will have less dynamic load of the mark giving less traction and a slower 0-60mph time but once the car get upto speed and grip it will then accelerate harder than the heavier version.
Click to expand...


This is a big misconception. As the torque needed to accelerate the car is lower MUCH LOWER. In fact the car needs so much less torque that a small loss in traction still makes the car MUCH FASTER 0-60 not slower. Remember a car weighing less then .01 lb (hypothetically speaking) would need only a fraction of a NM or FT-LB to accelerate 0-60 in less then 1 second.

When you make claims like this (based on some BS thread from Reddit) you need to understand all the forces at play here.

As a rule 100 lbs off the weight of a car makes it .1 sec FASTER in the 1/4 mile.
 
a little more data.
Dyno results for S60, S85, and S85P (700hp) from a Russian test. https://geektimes.ru/post/279758/
Whilst they are obviously not comparable to a P100D in several respects, they do have many similarities..
peak power in the similar 50+ mph (80kmh) road speed range
peak power of the P85 was 310 kW ( presumably at the wheels)..and steady between 40 to 75 mph
Max torque, at 600 Nm ( at the motor ?) for the P85...that 40% more than the S85 !
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Arlo1 said:
This is a big misconception. As the torque needed to accelerate the car is lower MUCH LOWER. In fact the car needs so much less torque that a small loss in traction still makes the car MUCH FASTER 0-60 not slower. Remember a car weighing less then .01 lb (hypothetically speaking) would need only a fraction of a NM or FT-LB to accelerate 0-60 in less then 1 second.

When you make claims like this (based on some BS thread from Reddit) you need to understand all the forces at play here.

As a rule 100 lbs off the weight of a car makes it .1 sec FASTER in the 1/4 mile.
Click to expand...
U blast me then say this :roll:

Calm down :lol: I'm having general chit chat and made no reference to reddit I've not read it :) I used my personal experience admittedly ive not mentioned the scientifics of it but check out engineering explained on youtube if you want to see the science of it all.
 
Ianhill said:
If we make the tesla 1000 pounds lighter with the same power output and use the same tyre and gearing, The tyre will have less dynamic load of the mark giving less traction and a slower 0-60mph time but once the car get upto speed and grip it will then accelerate harder than the heavier version.
Click to expand...

We are back to the dynamic weight transfer thing again. For maximum acceleration you need to reduce drag and mass and increase power and weight transfer to the rear. If you did the following there is absolutely no question the lighter Tesla would launch faster and trap higher:

1. Aired down the tires as luke said
2. Programmed the smart suspension to raise the back fully and drop the front with as little valving as necessary for a nice, squatty launch - there is room for a lot of tuning here alone!

Arlo1 said:
As a rule 100 lbs off the weight of a car makes it .1 sec FASTER in the 1/4 mile.
Click to expand...

This is pretty well a fact for cars in the 11-13 second range. Many people go by the 100lbs = 10hp = .1s formula, but I have found with my faster machines it very much matters where the weight is removed. Also, don't forget that rotational weight makes a much bigger difference than sprung mass.
 
There's a trend showing weight off the line wins as long as you have the torque to back it up, the lighter cars pull harder up top, I'm surprised a 911 beats the la ferrari for max gs pulled but then again it is heavier ?
 
Ianhill said:
I'm surprised a 911 beats the la ferrari for max gs pulled but then again it is heavier ?
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No it has a better suspension design/setup and lower CG etc.
 
Ianhill said:
There's a trend showing weight off the line wins as long as you have the torque to back it up, the lighter cars pull harder up top,
Click to expand...

Lighter is always better.
You will always have limited torque and always have limited traction.
As you reduce the weight of the vehicle you reduce the amount of inertia there for requiring less power to make it accelerate at the same rate.
When you apply the same limited torque to the limited traction it will accelerate faster.

The reason the wheels spin is because the inertia of the vehicle will fight the change in speed. But if it has less inertia it will fight the change in speed less.


A good example is TOP FUEL or F1 they make them as light as the rules allow then add ballast where they can only to comply with the rules.

If you were to add 500 lbs to either one they would be slower! That's why the make them as light as they can in the first place.
 
La ferrari specs mounting the batteries as low as possible gives an impossibly low center of gravity that’s 1.4 inches superior to the Enzo’s so it's lower than the 911 as is the Enzo but the weight is more rear biased on the 911, the la ferrari uses a 345/30R-20 tire on the back and still can't beat the limosine tesla.

To me the first graph looks doctored the hellcat is all over the place yet the tesla is holding a steady G on graph one, while in the second graph the tesla is more erratic up top and looks more realistic.
 
Off the mark it's a bit more complex than just inertia the preload to the rear wheels and initial torque created makes a big diff.
The 911 is the example look how well it launches when it's got the power to do so if it was electric the tesla would be mince meat it's initial inertia needed to move is lower but the weight transfer and preloaded to the rear rubber is just as high giving max traction available but less steeeing input too.
 
1. The consumer reports graph needs to be thrown away. Clearly that hellcat was in the hands of a moron who had no clue how to launch an 800hp car. Perhaps that is what they were trying to show and it was taken out of context?
2. Speedmd, can you please post a link to the article where you gained that graph? I am very curious to see how they measured these readings as they don't seem quite correct. Also is this a 2017 turbo s?

The turbo s and p100d are perfect to compare to approximate the p100d's torque and hp output. Both run a 10.8ish quarter mile time, the p100d traps around 125 and the Pcar closer to 130. Both are AWD. Both have a pretty sophisticated launch mode.

In stock form, the Turbo S is known to make 580hp and a bit over 500ftlbs of torque. Seeing as the 911 traps a bit higher and has a a slightly lower 60 foot and 1/8th mile times are similar enough it can be asserted fairly accurately how much hp/torque the Tesla is putting down by factoring in the extra weight it heaves around. Both are amazingly fun in their own rights. I am looking forward to comparing Porsche's coming electric car and the next generation Tesla on a road course in the not too distant future!
 
Agree the Hellcat run was wasted..looks like he was digging for traction until he got to 3rd gear !
..but from the tesla P90 consumer report run you can clearly see how the accelleration is limited by the torque curve ( flat up to 1.5 secs,(50mph) 50 mph, then tails off.
I dont understand why the other graph of the P100D shows the accelleration tailing off just 0.5 sec into the run ?
Thats a long way before the torque drops off, or the power peaks...it ought to have held that accelleration beyond the 1.5 sec mark.
 
Hillhater said:
I dont understand why the other graph of the P100D shows the accelleration tailing off just 0.5 sec into the run ?
Thats a long way before the torque drops off, or the power peaks...it ought to have held that accelleration beyond the 1.5 sec mark.
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Because 1.5g of accel is not sustainable without something for added down-force and was likely a spike from weight transfer or something.
 
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