Stuno1

RC-F hits 60 in 4.17 seconds...

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60 on the speedo isn't 60 

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Potbetially the case. Given he hit 4.4 on two other runs it seems a fair test. Also he is in a warm country with dry conditions. 

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I mean looking at the owner I did not expect much anyway... timing 0-60 with a phone in the hand whilst driving based on speed indicated on speedometer.... I probably can tell speed more accurately from the smell of the coffee in the morning.

2 minutes ago, Stuno1 said:

Potbetially the case. Given he hit 4.4 on two other runs it seems a fair test. Also he is in a warm country with dry conditions. 

That is kind of the point - he never hit 60. He hit something in 4.4s, but that is not 60MPH. Speedometers does not show speed accurately - normally at least 5-10% overstates it. So he potentially hit, 54-57MPH in some time +/- his own clicking on the button early or late.

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I wouldn’t use the phone but the way he analysed the footage in post production. Agree accuracy of the Speedo is a question but so is gps tracking etc. He hit 4.4 which is stated by then hit 4.17 using the same method. Even if that is 4.2 it’s still good and shows what the car can do in idea conditions. 

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Yes.. appreciate he can just delta on time post production and timing inaccuracy can be somewhat mitigated.

However speedo are very inaccurate (It is mandated that speed overstates speed by law!). I woudl be happier with results if he would have attempted to at least adjust for speedo inaccuracy i.e. drive at constant 30, 50 and 70 MPH compare it against GPS speed and then average the difference e.g. maybe his speedo is ~4% overstating, so he has to get to 62MPH to reach 60MPH. Obviously, there are no way to mitigate display error on digital display, but at least we can say he had "tried"... 

In which case we could take his results with pinch of salt... now he is measuring fat content in milk not his 0-60...

GPS inaccuracy is +/- 0.2 KMH for a record. so at 60MPH that makes up maybe ~ 0.2%... not 5-10%.

Finally, I know all Lexus cars 0-60 is understated, but the method he uses to prove it just wrong.

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Don’t disagree with anything you have said chap and I would expect 4.2 a 4.3 in ideal conditions. 

 

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On 2/24/2019 at 12:10 PM, Linas.P said:

Finally, I know all Lexus cars 0-60 is understated, but the method he uses to prove it just wrong.

Lexus never provide 0-60 times, it is always 0-62mph (100 km/h).

That may not sound a big difference but a car capable of 0-60 in 6.0 seconds would need another 0.2 seconds to get to 62 mph if acceleration was linear, which it isn't and would actually need > 0.2 seconds extra.

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2 minutes ago, ColinBarber said:

Lexus never provide 0-60 times, it is always 0-62mph (100 km/h).

That may not sound a big difference but a car capable of 0-60 in 6.0 seconds would need another 0.2 seconds to get to 62 mph if acceleration was linear, which it isn't and would actually need > 0.2 seconds extra.

That is not actually true, in US they indeed provide 0-60. In countries using metric they provide 0-100KM/h or like UK translates that to miles which makes it 0-62.

536988443_usmph.thumb.jpg.4c473be6482bd4b701840fa0b0169931.jpg2008248557_UKmph.thumb.jpg.4f0046d3f69437fb9fcce7918427cbe3.jpg

The rest is true it is important to note whenever quoted speed is 0-60 or 0-62, because as you said it does make a difference.

In this particular case it does not matter which official speed he is quoting - maybe he is quoting american 0-60 in 4.4s, or 0-62 in 4.5s - my point was that when his speedometer displayed 60MPH, it wasn't actually 60MPH... it was certainly less. What he could have done was to drive the car and compare speedo vs. gps and then factor the difference out... 

Anyway, I don't think there is any point to argue - there are much more accurate ways to measure acceleration and one in the video is not once of them. Basically pointless video... 

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12 hours ago, Linas.P said:

Anyway, I don't think there is any point to argue - there are much more accurate ways to measure acceleration and one in the video is not once of them. Basically pointless video... 

I agree it isn't 100% accurate but I wouldn't say pointless. It shows that the car is pretty quick, and that the different modes make a difference as the speed of gear shifting is increased etc. Using the frames of the video was a good way to improve accuracy, he just doesn't have an absolute starting point or a totally accurate speed measurement but is probably within 0.3 sec.

Re 0-62, I meant in the UK but if we want to talk about the US then your statement about the speedo isn't totally correct. They have a tolerance somewhere around -6% to +10% accuracy at 60 mph and typically read in the middle of that range which means there is the possibility of the indicated speed being totally accurate, rather than ours which is about +4% to +10% accuracy and so always reads over, never the correct speed.

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3 hours ago, ColinBarber said:

I agree it isn't 100% accurate but I wouldn't say pointless. It shows that the car is pretty quick, and that the different modes make a difference as the speed of gear shifting is increased etc. Using the frames of the video was a good way to improve accuracy, he just doesn't have an absolute starting point or a totally accurate speed measurement but is probably within 0.3 sec.

Re 0-62, I meant in the UK but if we want to talk about the US then your statement about the speedo isn't totally correct. They have a tolerance somewhere around -6% to +10% accuracy at 60 mph and typically read in the middle of that range which means there is the possibility of the indicated speed being totally accurate, rather than ours which is about +4% to +10% accuracy and so always reads over, never the correct speed.

So if Lexus says that RC-F does 0-60 in 4.4s and this guy got his RC-F to do it in 4.17s, but is within 0.3s... doesn't it make it 4.4s then? I mean isn't it pointless to say you recorded 0.3s quicker time when your accuracy is within 0.3s? I would argue that his results are accurate to closest second, which really becomes hilerious when he puts the end result with 2 decimal places.

He is in US, so I would expect him to use US measurements and not UK. Secondly, even his video states 0-60, so I reckon that is what he was measuring. Even in UK it is easier to measure to 60, not to 62 if you going speedometer. 

And finally when it comes to standards - most cars are made to UN standard (+10% +4km max), same applies to cars in US, EU an anywhere else. It doesn't mean every car/manufacturer will use maximum allowance and then it again changes based on the car spec e.g. same speedometer is fitted to RC200t, 300h, 350 and RC-F - I ten to believe the margin on speedometer will be the same, but because all cars have different engine, gearbox and whee sizes the actual difference on road will be different. Most cars I had were always ~10% over-reading.

Again as I said, it is possible to improve the accuracy of his results, but it is not even worth it. The only real way to get somewhat accurate results is to get somewhere even and straight like airfield and do say 3-5 runs using GPS and then average the results. Ideally using dedicated device, but even app on the phone would be 10 times more accurate than his approach (and I mean it - GPS is accurate to 0.2m provided good circumstances).

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2 hours ago, Linas.P said:

And finally when it comes to standards - most cars are made to UN standard (+10% +4km max), same applies to cars in US, EU an anywhere else. It doesn't mean every car/manufacturer will use maximum allowance and then it again changes based on the car spec e.g. same speedometer is fitted to RC200t, 300h, 350 and RC-F - I ten to believe the margin on speedometer will be the same, but because all cars have different engine, gearbox and whee sizes the actual difference on road will be different. Most cars I had were always ~10% over-reading.

Why do you insist on posting things you know nothing about? Where is you proof that most cars are made to a UN standard?

There are many different rules and regulations in different territories. EU, US, Canada, AUS etc. all have different requirements. But rather than just making stuff up, the following has extracts from actual Toyota service manuals which give tolerances, which if aren't met means the speedo should be replaced as it is faulty:

 

 

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9 minutes ago, ColinBarber said:

 you know nothing about?

How do you know that and why you insist on posting something which does not matter? If they not made to UN standards, then at least in theory they should. 

...and anyway - how does that matter in this case where inaccuracy is in the method and not in the speedometer itself? 

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18 minutes ago, Linas.P said:

If they not made to UN standards, then at least in theory they should. 

What theory? Maybe you should offer your services to Toyota, they obviously can save themselves millions in your consultancy by not having to use different parts in different countries and go through multiple homologation exercises.

 

The method used is very accurate, down to whatever video frame rate was used in the video. 1/30 second is 0.033 sec, so accurate to within 0.07 sec once you factor in a frame either way on the start and the finish, and he probably used 60 frames per second to half that inaccuracy.

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Few issues you doesn't seems to understand (I am not even sure why you trying to argue about it):

1. as long as actual speed is adjusted for (which is not the case in this video), speedometer is not an issue here (seems like you primarily worried about that),

2. he did not say he has used frames to count acceleration, it is my assumption he could have done that and it would have been somewhat accurate.

Your questions in itself is pointless - UN is international organisation which defines the standards (beyond many other things) ... I mean things like how long is the meter... you know that little pesky little thing we base all our calculations on? If they have directive on how speedometer should work, then it is how it should work. Go ahead and argue with UN that physical contact of meter is not correct... good luck!

And finally, UN directive is the law, because of EU directive, which UK is part of as well. This is most strict rule worldwide so by complying with it you have good chances you would comply with any other rules worldwide. I do not know if Toyota varies their equipment in different regions and frankly I don't care. It is true that they need to homologate their cars in different regions, but it does not mean they need to change equipment if it exceed the specifications in that region. I do not know if they do it or they don't and again I don't care, because in the end this is not the point here!

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17 minutes ago, Linas.P said:

And finally, UN directive is the law, because of EU directive, which UK is part of as well. This is most strict rule worldwide so by complying with it you have good chances you would comply with any other rules worldwide.

I think you have completely the wrong idea what the United Nations actually does and stands for... It's certainly nothing to do with setting standards.

https://www.un.org/en/sections/what-we-do/

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Even if I am wrong (which I am not) it does not matter.. UNECE is part of UNESC, which is part of UN... I call them all UN, because they all part of same organisation. UNECE in this case set the standard for how speedometer should be adjusted, known as directive 39.. again none of that matter in this case.

The only point I was making - when the speedometer displayed 60MPH in the video nobody knows what was actual speed at that time, because whoever recorded and posted the video have not checked how much their speedometer over reads. The real speed could have been 56MPH, 54MPH or even actually 60MPH - we don't know!.. and that is why this video was pointless, because it has proven nothing.

What you 2 are trying to argue is the legislature in place for speedometer calibration... which makes no difference here. 

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40 minutes ago, Linas.P said:

The only point, I was making when the speedometer displayed 60MPH in the video nobody knows what was actual speed at that time, because whoever recorded and posted the video have not checked how much their speedometer over reads. The real speed could have been 56MPH, 54MPH or even actually 60MPH - we don't know!.. and that is why this video was pointless, because it has proven nothing.

And the very next day he did the same thing and got values differing by 0.6sec, all because the wind changed direction...

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Well I guess, he did not claim RC-F does 0-60 in 4.17s  "all day everyday", but even then failed to prove the point it does that "ever".

When it comes to 0-60 acceleration I think having any decimal places is kind of pointless.. Yes probably there is difference between 4.1s and 4.9s even for rough guide to compare, but as you said every car, every single time will make different speed based on environment. 4.17.. lets just call it 4.2.. or as Lexus now doing with new 2020 RC-F track edition - 3.96s... that sounds too desperate to be "under 4s club"... just call it 4s.

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1 hour ago, Linas.P said:

2. he did not say he has used frames to count acceleration, it is my assumption he could have done that and it would have been somewhat accurate.

What are you talking about? There is a whole section of the video where is goes frame by frame in a video editor to get the start and end points and adjusts the time accordingly.

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I did it 3.7 seconds yesterday - but I haven't got a Lexus anymore. 😶

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6 minutes ago, ColinBarber said:

What are you talking about? There is a whole section of the video where is goes frame by frame in a video editor to get the start and end points and adjusts the time accordingly.

I probably did not survive that long... yes your right he does that... which is good. Yet we haven't established what speed does 60MPH indicated means on his car.

If he would have done 1 more step and compared indicated versus GPS speeds and then reached GPS speed using same "frame counting" method... I woudl be happy enough.

 

 

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3 minutes ago, Flytvr said:

I did it 3.7 seconds yesterday - but I haven't got a Lexus anymore. 😶

Those 1196cc Opel Kadetts are damn fast cars :horse:

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it was probably vertical acceleration.. or the speed of rust spreading 😀

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