63 replies to this topic

[mariner]

I thnik Moto Gp bikes are cool, simple yet very subtle in many ways. I've just been  reading the KTM website claiming 270 bhp for their bike. The minimum weight for Moto Gp is 157kg excluding rider versus 702 kg with driver for F1 in 2016.

 

So with a , say, 63kg rider, the bike is 220kg versus 702kg for the car. At 270 bhp the car needs 860 bhp for an equal power to weight ratio. Now that is about where a F1 car sits in terms of power but surely the bikes very small frontal area, lack of wings  and semi-enclosed front tire gives it less drag?

 

So my guess is that from just  above traction limited speed , maybe 90 mph, to typical end of straight the Moto Gp bike would out-drag the F1 car. Am I right please?

 

 

I dont think th discusion is purely technical because teh way a car accelerates , with the noise, is a key part of the appeal of racing and not just corner speed.

Edited by mariner, 09 December 2016 - 16:47.

[munks]

Just noting: an F1 car's traction-limited speed may be significantly lower than the bike's due to those same wings that are causing drag.

 

But yes, I would lean towards agreeing with your statement from above both vehicle's traction-limited speeds.

[chunder27]

A moto GP bike is far from simple to be honest.

 

They used to be far more complicated than they are now with live GPS making adjustments as the bike was moving to TC and the like. I wouldn't believe KTM's figures. 250 is about as much as you need, any more is simply unnecessary, plus would put massive stress on the engines that are limited as they are in F1 for costs

 

An F1 car would pull initially, then the GP bike would go again as the electronics give up and the bike has pure power to weight going to the track. If there were no electronics it would take the bike longer to catch up. 

 

Biggest limiting factor for a bike is starting it and wheelie control initially, after that it would probably pull away.
 

Aero would slow down the F1 car and weight.

[Kelpiecross]

I saw on TV a while back a side-by-side standing start demonstration at a Top Gear day at Eastern Creek. Stoner on a MotoGP bike, Webber in a Red Bull F1 car and (I think) Lowndes in a Holden V8 Supercar.
From the start the MotoGP bike was away like a shot - way quicker in initial acceleration than the two cars. It was a bit hard to pick but I think the Supercar was a bit faster than the F1 car over the first 50 feet or so. Over the full lap the F1 car was about 30 seconds quicker than the other two.

MotoGP bikes and F1 cars seem to reach about the same top speed on a straight but the car probably comes out of the corner before the straight seemingly twice as fast as the bike - so presumably the bike accelerates a bit faster than the car even at higher speeds.

I think it has been noted before on the forum that F1 cars are surprisingly sluggish in their initial acceleration - compared to other fast vehicle anyway.

Just found this:


It was Whincup - not Lowndes. Cars about equal initially.

Edited by Kelpiecross, 10 December 2016 - 04:05.

[Wuzak]

I saw on TV a while back a side-by-side standing start demonstration at a Top Gear day at Eastern Creek. Stoner on a MotoGP bike, Webber in a Red Bull F1 car and (I think) Lowndes in a Holden V8 Supercar.
From the start the MotoGP bike was away like a shot - way quicker in initial acceleration than the two cars. It was a bit hard to pick but I think the Supercar was a bit faster than the F1 car over the first 50 feet or so. Over the full lap the F1 car was about 30 seconds quicker than the other two.

MotoGP bikes and F1 cars seem to reach about the same top speed on a straight but the car probably comes out of the corner before the straight seemingly twice as fast as the bike - so presumably the bike accelerates a bit faster than the car even at higher speeds.

I think it has been noted before on the forum that F1 cars are surprisingly sluggish in their initial acceleration - compared to other fast vehicle anyway.

Just found this:


It was Whincup - not Lowndes. Cars about equal initially.

 

It looked to me that the V8Supercar and teh F1 got off the line roughly the same initially, but then the F1 car took off.

 

The motorcycle was, of course, gone. The F1 seemed to catch the bike towards the end of the straight, but that may be because the bike was braking for the corner.

 

Amazing that it took just over 2 laps for the F1 car to catch the bike and V8. A V8 lap of Eastern Creak is around 90-95s, from memory. The cart was probably held up a little by the bike.

[Wuzak]

This is an interesting set of tests between an F1 car and a TT bike.

 

[Greg Locock]

Initial acceleration should be tire limited, and without AWD a racing car will lose because the weight transfer favours the bike, if the tires are similar. It'll also depend on how the traction control is set for each machine, a wise f1 team might decide that burnouts off the starting line are a pretty silly move, for example. for the race cal, but for qualifying it might be a good move. 

[Kelpiecross]

This is an interesting set of tests between an F1 car and a TT bike.
 

I think it was pretty clear Stoner was braking hard for the corner.

As for the F1 with DC driving - 10.29 for the 1/4 mile? I think an F1 car should be in the mid-8s at least. The V8 Supercar could probably do mid-10s.

I would guess that a MotoGP bike and an F1 car would have similar 1/4 mile times - in the 8s but with the bike probably a bit quicker and winning because of its initial acceleration off the line.

[Wuzak]

The 1/4 mile times did seem slow.

 

I wonder about the condition of the track. The Red Bull was using full wets - whether that was because of the track condition or some sort of handicap is not clear.

 

Also, in the braking test DC locked up the front tyres pretty hard. He should have stopped in an even shorter distance.

[chunder27]

I watched some footage recently of import drag racing in the USA.

 

There were front wheel drive Civics running mid 8's!  lol

 

And a bloke on a street tyres Mustang running high 5's, quite the most sorted drag car I have ever seen. Astonishing engineering.

[scolbourne]

Have we any other times for an F1 car over a 1/4 mile ?

It is possible the track in the video  was longer or the grip was poor compared with a drag strip. Maybe Coulthards reactions are not upto it anymore. (I still have not forgiven him for losing me my bet on the Australian GP when he let his team mate win)

Edited by scolbourne, 15 December 2016 - 11:01.

[gruntguru]

Have we any other times for an F1 car over a 1/4 mile ?

It is possible the track in the video  was longer or the grip was poor compared with a drag strip. Maybe Coulthards reactions are not upto it anymore. (I still have not forgiven him for losing me my bet on the Australian GP when he let his team mate win)

An F1 definitely out-accelerates a V8 supercar at all speeds (including zero). Even a Tesla Model S beats a V8 supercar. https://www.youtube....h?v=6eGhjhx8O9M

 

Formula One race cars have been recorded to reach 0-60 as fast as 1.6 seconds, however the typical range for modern day F1 cars is between 2.1 to 2.7 seconds. The 2007 Honda RA107 f1 race car goes 0-100 mph in a blistering 4 seconds flat.  The 2015 Infiniti Red Bull RB11 Formula One race car jets 0 to 60 in only 1.7 seconds, and perhaps even more impressive can reach 190 mph in under 10 seconds.  http://www.zeroto60t...-f1-0-60-times/

[Kelpiecross]

An F1 definitely out-accelerates a V8 supercar at all speeds (including zero). Even a Tesla Model S beats a V8 supercar. https://www.youtube....h?v=6eGhjhx8O9M
 
Formula One race cars have been [/size]recorded to reach 0-60 as fast as 1.6 seconds[/size], however the typical range for modern day F1 cars is between 2.1 to 2.7 seconds. The 2007 Honda RA107 f1 race car goes 0-100 mph in a blistering 4 seconds flat.  The 2015 Infiniti Red Bull RB11 Formula One race car jets 0 to 60 in only 1.7 seconds, and perhaps even more impressive can reach 190 mph in under 10 seconds.  http://www.zeroto60t...-f1-0-60-times/[/size]

I don't think anybody said (or implied) that a V8 Supercar was faster than an F1 car?

What they didn't show in the video was putting the Tesla on a trailer to be taken home with a flat battery.

[imaginesix]

I don't think anybody said (or implied) that a V8 Supercar was faster than an F1 car?

What they didn't show in the video was putting the Tesla on a trailer to be taken home with a flat battery.

I always figured Australia was a third-world country, but not even having power outlets at a race track, well that's just dumb!

[chunder27]

Err, the discussion has nothing to do with V8 Supercars!!

 

And surely anyone with any sense would realise an F1 car would out accelerate one.

 

Let's be frank here, when it comes to acceleration, there are plenty of things quicker than an F1 car, rallycross cars, most forms of top dragster that race with slicks, I would think that even a motocross or speedway bike on dirt would manage to beat an F1 car for 100 yards until  the thing got up to speed.

Edited by chunder27, 16 December 2016 - 09:29.

[Briancoat]

To really add value to a technical discussion like this, it is necessary to have access to a library of authoritative academic works on the subject of advanced automotive comparisons ... 😀

Edited by Briancoat, 16 December 2016 - 10:51.

[thegforcemaybewithyou]

I8 or V8 what is better? 😉

[Kelpiecross]

I always figured Australia was a third-world country, but not even having power outlets at a race track, well that's just dumb!

If they did have power outlets at the track they could have camped overnight while the battery charged up enough to get home.

Where the hell is Canadia anyhow? I read in the paper that the new PM is a fervent supporter of (and idolises) the late Mr. Castro - you must be very proud of the PM.

[Kelpiecross]

Err, the discussion has nothing to do with V8 Supercars!!
 
And surely anyone with any sense would realise an F1 car would out accelerate one.
 
Let's be frank here, when it comes to acceleration, there are plenty of things quicker than an F1 car, rallycross cars, most forms of top dragster that race with slicks, I would think that even a motocross or speedway bike on dirt would manage to beat an F1 car for 100 yards until  the thing got up to speed.

Very true.

[imaginesix]

If they did have power outlets at the track they could have camped overnight while the battery charged up enough to get home.

Where the hell is Canadia anyhow? I read in the paper that the new PM is a fervent supporter of (and idolises) the late Mr. Castro - you must be very proud of the PM.

"The paper", how quaint.

 

One day when you guys enjoy the widespread benefits of electricity you can read up on all the great things that happen in the rest of the world, including treating dead people with respect.

 

As for where we're located, we're in the same direction you're currently gazing - your navel - just much, much, further away (mercifully).

[gruntguru]

I don't think anybody said (or implied) that a V8 Supercar was faster than an F1 car?

Well the video (and somebody's post) said the Supercar launched better that the F1. Oh wait it was you!!!

 

It was a bit hard to pick but I think the Supercar was a bit faster than the F1 car over the first 50 feet or so.

The main point of my post was "An F1 definitely out-accelerates a V8 supercar at all speeds (including zero)." ie an F1 car launches harder than a V8 supercar and probably also a Moto GP bike and even a P85D (no info on what the Tesla is capable of wearing slicks - its probably close to its torque limit with road tyres).

[Kelpiecross]

Well the video (and somebody's post) said the Supercar launched better that the F1. Oh wait it was you!!!
 
The main point of my post was "An F1 definitely out-accelerates a V8 supercar at all speeds (including zero)." [/size]ie an F1 car launches harder than a V8 supercar and probably also a Moto GP bike and even a P85D (no info on what the Tesla is capable of wearing slicks - its probably close to its torque limit with road tyres).[/size]

Well - there certainly was not much difference between the V8 and the F1 car over the first 50 feet or so. And I think that is my main point - the Supercar is twice the weight of the F1 car and has 100HP less (I presume the F1 car was of the 2.4l variety).
The F1 car should have should have disappeared into the distance like the 'bike did - but it didn't. If the 'bike got to 60mph in 2 seconds (or maybe a bit less) - the F1 car certainly had a slower time to 60mph.

Why was the F1 car so sluggish off the line? It was only a demonstration run - maybe Webber wanted to demonstrate that from being a bit behind from the start he could pass the other two by (or in) the first corner. Maybe his gear ratios were all wrong? The close finish was certainly "contrived" - maybe the start was also.

Do you agree that the F1 car appeared sluggish off the line?

It seems just about impossible to get accurate figures on 0-60 times for both F1 cars and MotoGP 'bikes - presumably they are kept as secret as possible.

[Kelpiecross]

"The paper", how quaint.
 
One day when you guys enjoy the widespread benefits of electricity you can read up on all the great things that happen in the rest of the world, including treating dead people with respect.
 
As for where we're located, we're in the same direction you're currently gazing - your navel - just much, much, further away (mercifully).

Really some dead people don't deserve respect. It's a bit like saying Hitler wasn't so bad - after all he did cure unemployment and build nice roads.

I shouldn't say too much about your PM - our PM is possibly an even bigger ******** - and I voted for his party.

We'll have electricity one day - just you watch!

[gruntguru]

Well - there certainly was not much difference between the V8 and the F1 car over the first 50 feet or so. And I think that is my main point - the Supercar is twice the weight of the F1 car and has 100HP less (I presume the F1 car was of the 2.4l variety).
The F1 car should have should have disappeared into the distance like the 'bike did - but it didn't. If the 'bike got to 60mph in 2 seconds (or maybe a bit less) - the F1 car certainly had a slower time to 60mph.

Why was the F1 car so sluggish off the line? It was only a demonstration run - maybe Webber wanted to demonstrate that from being a bit behind from the start he could pass the other two by (or in) the first corner. Maybe his gear ratios were all wrong? The close finish was certainly "contrived" - maybe the start was also.

Do you agree that the F1 car appeared sluggish off the line?

It seems just about impossible to get accurate figures on 0-60 times for both F1 cars and MotoGP 'bikes - presumably they are kept as secret as possible.

I agree with all that. I only posted to make sure no one thought that was a normal launch for an F1.

[Joe Bosworth]

I like to use standing start quarter mile times as a very good measure of acceration capability between vehicles. There is so much uncontroverted data available that it strips most all of the BS out of the question.

There is nothing between them using this measure:

A MotoGP bike on the line with a 63 kg rider and 270 HP available can be expected to do the quarter in 7.48 seconds.

An F1 car on the line at minimum class weight and 850 HP available can be expected to do it in 7.51 seconds.

What you see off the line is seen in position times in the first 60 feet. This performance is virtually dominated by the forces that the driven tyre(s) are capapble of transmitting as both vehicles have enough torque available through the clutch and gears to overwhelm the rubber/road interface.

It is very unlikely that the Mu factor for the
tyrers on either Gp bikes or F12 cars will vary be any significant factor, say 1.4 or so. The bike has the advantage that they are ridden at incipient wheely initially off the line so 90% plus of total weight is working for it, say 200 kg plus bearing down. It is unlikely that the F1 car in normal race tune sees more than about 225 kg bearing down on each driven tyre before aero forces develope.

If you apply our basic F=ma formula we can see that the F1 car might put 10% or so more force initially through the driving tyres but is pushing 3.9 times the mass give or take a bit considering rotating mass.

It is liitle wonder that the Moto GP bike gets off the line faster.

Regards

Edited by Joe Bosworth, 18 December 2016 - 12:52.

[imaginesix]

Point of order.

 

None of the times we've seen in this thread are from a MotoGP bike.

 

Carry on.

[Lee Nicolle]

A drag race like Guy Martin and DC on a piece of racetrack is fairly indicative. The car was faster and so it should be with a LOT more traction.

as for F1 being fast as a drag racer, sorry there is street cars faster [on a drag strip] than F1. The F1 however does everything better afterwards, which is what it is designed to do.

I too have seen the clip about Tesla beating a Stupidcar,, no great feat as a 1400kg Stupid car with 600hp and 420 ft lbs of torque struggles against the massive torque of the electric motor. But the Supercar is about a week a lap faster around the race track. As for electricity every pit area I have ever visited as well as most speedways as well have 240v in the pit area.

But when your electric toy is used very hard the battery life goes from hours to minutes. Then you may need a gen set to feed your electric toy.

Again the word is practicality. 

[chunder27]

Lithium ion batteries actually do not wear out as easily as you think.

 

Only if you drain them to nothing. If you charge them without them going flat you get a decent return.

[Lee Nicolle]

Lithium ion batteries actually do not wear out as easily as you think.

 

Only if you drain them to nothing. If you charge them without them going flat you get a decent return.

But the Tesla tested did ride off on a trailer as per quoted by Kelpiecross #13.

[Kelpiecross]

But the Tesla tested did ride off on a trailer as per quoted by Kelpiecross #13.

Sorry to mislead you - but putting the Tesla on a trailer was what I imagined happened after the runs - meant to be sarcastic. But even after the two runs shown the Tesla would have been getting a pretty flat.

[gruntguru]

But even after the two runs shown the Tesla would have been getting a pretty flat.

How do you come to that conclusion?

[Pierce89]

I watched some footage recently of import drag racing in the USA.

There were front wheel drive Civics running mid 8's! lol

And a bloke on a street tyres Mustang running high 5's, quite the most sorted drag car I have ever seen. Astonishing engineering.

You're qouting 1/8 mile times. No street tyre has ever gotten close to 5 second 1/4 mile. Top fuelers run about 4 seconds on a 1/4 mile with 11000 hp and only 1000 kilos.

[Kelpiecross]

You're qouting 1/8 mile times. No street tyre has ever gotten close to 5 second 1/4 mile. Top fuelers run about 4 seconds on a 1/4 mile with 11000 hp and only 1000 kilos.

Believe it or not FWD Civics in the US do run in the 8's for the full 1/4 mile. Beats me how they get enough grip off the line.

I am also doubtful about the high 5 sec/street tyres story - in Oz the alcohol funny cars run times like this.

[Kelpiecross]

How do you come to that conclusion?

How many runs would you guess/estimate?

Maybe we (you) should work out (roughly) theoretically just how much energy is needed for the Tesla S to do a 1/4 mile.

Car weight about 2200Kg? (About right for a 85kWh battery pack I think).
1/4 mile time about 11secs?

Energy needed to accelerate a mass of 2200Kg over 400m in 11 secs from a standing start?
Energy needed to overcome air resistance over the 1/4 mile? (I imaging this would involve summing the integral etc. etc. - too hard for me).
Energy for rolling resistance? (I would think quite a lot for a 2200Kg vehicle with wide tyres)
Efficiency of the motors/driveline?
On the plus side - energy recovered slowing down - presumably with no braking from the discs etc. - but again minus air and rolling resistance slowing down.

Also to be taken into consideration is the increasing time taken to do the 1/4 as the battery charge drops. No use considering a 1/4 mile time about as fast as an old bloke on a pushbike - nly the maximum energy runs?

Anyhow - away you go - I will check your calculations. (You didn't expect me to do it did you?)

Edited by Kelpiecross, 21 December 2016 - 06:59.

[chunder27]

Guy in a Mustang running a stupidly well sorted twin turbo 4000hp in the import vs whatever series. Blue Mustang, runs high 5's in competition. OK fair enough maybe nothose times on street tyres, but according to the team they can get very close on street rubber.

 

In the Pro fwd class a few years ago they were running low 6's in the works Cobalts. But these were factory cars running works engines and Pro Stock setups, damn quick.

 

The Civics in the fwd class that run 8's are few and far between, but there are a few of them. Yes they get off the line slowly, but once they get going they can hit nearly 200mph at the line. They have 1000hp plus and low drag hence the speeds. Some of the import stuff the Puerto Ricans run is damn trick.

 

They are not 8th mile times, please don't patronise me.

[Greg Locock]

Well let's do the maths. 5 seconds 1/4 mile, say 400m, s=1/2*a*t^2. so 400=1/2*a*25. a=800/25=32 m/s/s

 

That's just over 3g. sustained. On street tires. Unh huh.

 

I think I've seen 1.4 g or so on real tires.

 

Now, you can argue decimal points. But come on.

[thegforcemaybewithyou]

Those 5s are for a 1/4 mile, 1/8 mile or 1000 ft track?

 

The best indication for the initial acceleration should be the 60 ft time. A Tesla can do times of 1,65s for that what equates to an average acceleration of 1,37G.

[OO7]

That didn't look like a standard F1 launch to me and it was Webber driving for goodness sake, he has never been the most sprightly off the line.

 

The following involves a V10 (900+ bhp and 600kg including the driver) vs a Super Bike:

http://www.youtube.c...-c57SMU&t=7m46s

 

Current F1 cars are in the 950+ bhp ballpark, have DRS, slicks and gobs of torque, albeit with a 100kg weight penalty (705kg including the driver).

Edited by OO7, 21 December 2016 - 11:08.

[chunder27]

The car I am talking about ran a 5.94 at the import vs extreme event at Maryland in the last few weeks.

 

It might not have been running road tyres to get that time I admit. But it was running insane times and did it two or three times over the weekend, the thing is basically a Pro Mod!

 

And if it was running those times on slicks it would not be seconds slower on road tyres.  There is a guy in the UK than can run mid to high 6's on road tyres.

[Wuzak]

Current F1 cars are in the 950+ bhp ballpark, have DRS, slicks and gobs of torque, albeit with a 100kg weight penalty (705kg including the driver).

 

Current cars aren't allowed to use the MGUK of the line until they have hit 100km/h. SO they would have to make do with around 800hp for the first few seconds. 

[Wuzak]

How many runs would you guess/estimate?

Maybe we (you) should work out (roughly) theoretically just how much energy is needed for the Tesla S to do a 1/4 mile.

Car weight about 2200Kg? (About right for a 85kWh battery pack I think).
1/4 mile time about 11secs?

Energy needed to accelerate a mass of 2200Kg over 400m in 11 secs from a standing start?
Energy needed to overcome air resistance over the 1/4 mile? (I imaging this would involve summing the integral etc. etc. - too hard for me).
Energy for rolling resistance? (I would think quite a lot for a 2200Kg vehicle with wide tyres)
Efficiency of the motors/driveline?
On the plus side - energy recovered slowing down - presumably with no braking from the discs etc. - but again minus air and rolling resistance slowing down.

Also to be taken into consideration is the increasing time taken to do the 1/4 as the battery charge drops. No use considering a 1/4 mile time about as fast as an old bloke on a pushbike - nly the maximum energy runs?

Anyhow - away you go - I will check your calculations. (You didn't expect me to do it did you?)

 

Maximum power for a P85D is 568kW. Quarter mile time is 10.8s. Energy used is 1.7kWh.

 

85kWh would give 50 runs at max power, but usable battery would be less, so probably about 38 runs (using 75% of battery capacity).

 

I'm not 100%, but so long as there is some degree of charge in the batteries the performance should be the same.

[scolbourne]

This was the fastest "Street Legal" car back in 2015. I dont know the rules and tyres that have to be used.

 

 

The 2014 record holder

 

http://www.enthusias...-rod-drag-week/

[Wuzak]

Oh, and it would take less than half an hour to recharge that energy using 240V, 15A mains power, or 3/4 of an hour with 240V and 10A.

[scolbourne]

And the electric record holder

 

 

Jonny Smith in the Flux Capacitor 74 Enfield 8000 broke the world record at Santa Pod Raceway for the quickest street legal electric vehicle. This clip shows his run of 10.1 @ 121.77mph. He then went on to run a mind blowing time of 9.86 @ 121.73mph.
Go to http://www.flux-capacitor.co.uk for full details on the car. Main stats are.....
Twin 9" DC motors
188 Kokam/Hyperdrive lithium-ion military pouch cells.
Over 800hp
Over 1200lbft
0-113mph in 6.15 seconds.

[thegforcemaybewithyou]

Based on the speed data from

 

 

i get the following acceleration(m/s²) vs. speed(km/h) chart.

 

 

The acceleration for the very first part is a bit under 1G, then rises to almost 1,4G at about 150km/h and then falls after the traction limit.

 

With that acceleration assumed, the car would need just ~9s to complete the quarter mile and finish with a speed of 287km/h. 60ft time is ~1,9s and 1/8 mile time ~6,2s. That is of course with the fuel load for the race, with a bit of slipstreaming and without DRS.

[imaginesix]

How many runs would you guess/estimate?

Maybe we (you) should work out (roughly) theoretically just how much energy is needed for the Tesla S to do a 1/4 mile.

Car weight about 2200Kg? (About right for a 85kWh battery pack I think).
1/4 mile time about 11secs?

Energy needed to accelerate a mass of 2200Kg over 400m in 11 secs from a standing start?
Energy needed to overcome air resistance over the 1/4 mile? (I imaging this would involve summing the integral etc. etc. - too hard for me).
Energy for rolling resistance? (I would think quite a lot for a 2200Kg vehicle with wide tyres)
Efficiency of the motors/driveline?
On the plus side - energy recovered slowing down - presumably with no braking from the discs etc. - but again minus air and rolling resistance slowing down.

Also to be taken into consideration is the increasing time taken to do the 1/4 as the battery charge drops. No use considering a 1/4 mile time about as fast as an old bloke on a pushbike - nly the maximum energy runs?

Anyhow - away you go - I will check your calculations. (You didn't expect me to do it did you?)

In other words, you don't know but you don't let that stop you from talking like you do. Shocker.

[imaginesix]

Maximum power for a P85D is 568kW. Quarter mile time is 10.8s. Energy used is 1.7kWh.

 

85kWh would give 50 runs at max power, but usable battery would be less, so probably about 38 runs (using 75% of battery capacity).

 

I'm not 100%, but so long as there is some degree of charge in the batteries the performance should be the same.

No way man, they get much lighter as their batteries drain. Obviously! That's the only way they can do such fast times, by having only a few kWh to work with, and that's why they can never make it home under their own power. Just ask Kelpie with a K.

 

If I'm being hard on you Kelpie, at least it means I have enough faith in your intellect to point out your (glaring) incongruities. If I didn't think well enough of you I'd have you on ignore.

Edited by imaginesix, 21 December 2016 - 22:43.

[Kelpiecross]

No way man, they get much lighter as their batteries drain. Obviously! That's the only way they can do such fast times, by having only a few kWh to work with, and that's why they can never make it home under their own power. Just ask Kelpie with a K.
 
If I'm being hard on you Kelpie, at least it means I have enough faith in your intellect to point out your (glaring) incongruities. If I didn't think well enough of you I'd have you on ignore.

That's (almost) very kind of you Six old mate - it must be the Christmas spirit.

[Kelpiecross]

Maximum power for a P85D is 568kW. Quarter mile time is 10.8s. Energy used is 1.7kWh.
 
85kWh would give 50 runs at max power, but usable battery would be less, so probably about 38 runs (using 75% of battery capacity).
 
I'm not 100%, but so long as there is some degree of charge in the batteries the performance should be the same.

Where did you get the 1.7kWh figure from? I worked it out (very roughly) and got a figure even lower than this - about 70 runs worth on 100% battery drain. I assumed I had made a slightly large (enormous) error in units etc. If true I am (almost) impressed.

I would like to see it actually demonstrated.

Edited by Kelpiecross, 22 December 2016 - 02:39.

[Wuzak]

Where did you get the 1.7kWh figure from? I worked it out (very roughly) and got a figure even lower than this - about 70 runs worth on 100% battery drain. I assumed I had made a slightly large (enormous) error in units etc. If true I am (almost) impressed.

I would like to see it actually demonstrated.

 

Powertrain Electric motor Front and rear motor combined output up to 762 bhp (568 kW), 687 ft·lb (931 N·m), 3-phase AC induction motor Transmission 1-speed fixed gear (9.73:1) Battery 60, 70, 75, 85, 90 or 100 kWhlithium ion^[4] Electric range

• 70 kWh (250 MJ)
  240 mi (390 km) (EPA)
• 85 kWh (310 MJ)
  265 mi (426 km) (EPA)
  310 mi (500 km) (NEDC)

Plug-in charging

• 11 kW 85–265 V onboard charger for 1ϕ 40 A or 3ϕ 16 A^[5] on IEC Type 2 inlet^[6]
• Optional Dual Charger for 22 kW for 1ϕ 80 A or 3ϕ 32 A^[5]
• Supercharger for 120 kW DC offboard charging, adapters for domestic AC sockets (110–240 V)

 

https://en.wikipedia...i/Tesla_Model_S

 

Best time I saw was 10.8s - but that may have been for the P100 (100kWh) rather than the P85 (85kWh).

 

In any case, 568kW * 10.8s / 3600s/h = 1.704kWh.

 

85/1.7 = 50.

100/1.7 =  58.8