0-100 Km/h Times Are Useless, So Stop Asking For Them

[hrd-hr30]

I can't agree with you Big Rizza. Too much theory poorly applied that doesn't even come close to modelling the real world.

one quick example of how poorly applied you estimations are from your last example...

0-1 second

The V8 accelerates harder than the turbo over this increment because of its strong torque. The V8 gains 20km/h compared to the turbo’s 10km/h. The V8 is accelerating harder than the turbo (speed rising at 20km/h per second vs 10km/h per second). The speed of the V8 at this point is now 20km/h, the speed of the turbo at this point is 10km/h, so the V8 is pulling away from the turbo.

At 20km/h for one second, the V8 will travel 5.5 meters. At 10km/h for one second, the turbo will travel 2.8 meters. So the V8 will be 2.7 meters ahead of the skyline after 1 second

the V8 wasn't doing 20kph for one second - that was its instantaneous velocity at the end of that second. A much more reasonable estimation (though still terribly innacurate) would be to average the speed for that second. ie the diffference between the speed at the beginning of that time period and the end of it. in this case 10kph. So the V8 would have travelled much closer to 2.7m instead of 5.5m as you state. And the innacuracies just keep on compounding from there with each subsequent time period.

I'll Leave aside the completely unrealistic modelling of the cars' accellerations and complete disregard for gearing, as that would be far too complicated to get into here.

anyway, the fact of the matter is, in the real world, 0-100kph times are a useful comparison of accelleration performance. a car that has a better 0-100kph time will always be in front of a car with a slower 0-100kph time in the real world.

For what you're saying to actually hold true in the real world instead of just on badly modelled physics and poorly applied mathematics, you would have to find a statistically significant sample of dissimilar cars, where one has a clear launch advantage over the other, but do the same 0-100 time, and where the one with the start line advantage does a much faster 0-400m time. because according to your theory, it will have covered many more metres by the time it reached 100kph than the other car. In your above example the V8 is already 0.48 seconds ahead by the time they have both hit 100kph.

it will have to be more than just one comparison though because if what you're saying is true it will happen wherever a car has a launch advantage and similar 0-100kph time. If you just find one out of all the awd performance cars out there, the result is much more likely to have been skewed by gearing which will be a much more significant factor in the real world. ie if one car had to pull another gear just before 100kph and the other pulls 3rd just after 100kph. That is a much more likely scenario to skew 0-100kph results inthe real world.

Anyway, the issue you raised really doesn't happen in the real world. go and find an old PCOTY or BFYB test. I'm sure they will show that an AWD turbo car with a very similar 0-100kph time as a front engine rwd taxi will not have a substantially better 0-400m time. I see your point, but its a theoretical problem not a real world issue. 0-100kph is a good indicator of performance 99% of the time in the real world.

[Big Rizza]

I can't agree with you Big Rizza. Too much theory poorly applied that doesn't even come close to modelling the real world.

one quick example of how poorly applied you estimations are from your last example...

the V8 wasn't doing 20kph for one second - that was its instantaneous velocity at the end of that second. A much more reasonable estimation (though still terribly innacurate) would be to average the speed for that second. ie the diffference between the speed at the beginning of that time period and the end of it. in this case 10kph. So the V8 would have travelled much closer to 2.7m instead of 5.5m as you state. And the innacuracies just keep on compounding from there with each subsequent time period.

I'll Leave aside the completely unrealistic modelling of the cars' accellerations and complete disregard for gearing, as that would be far too complicated to get into here.

anyway, the fact of the matter is, in the real world, 0-100kph times are a useful comparison of accelleration performance. a car that has a better 0-100kph time will always be in front of a car with a slower 0-100kph time in the real world.

For what you're saying to actually hold true in the real world instead of just on badly modelled physics and poorly applied mathematics, you would have to find a statistically significant sample of dissimilar cars, where one has a clear launch advantage over the other, but do the same 0-100 time, and where the one with the start line advantage does a much faster 0-400m time. because according to your theory, it will have covered many more metres by the time it reached 100kph than the other car. In your above example the V8 is already 0.48 seconds ahead by the time they have both hit 100kph.

it will have to be more than just one comparison though because if what you're saying is true it will happen wherever a car has a launch advantage and similar 0-100kph time. If you just find one out of all the awd performance cars out there, the result is much more likely to have been skewed by gearing which will be a much more significant factor in the real world. ie if one car had to pull another gear just before 100kph and the other pulls 3rd just after 100kph. That is a much more likely scenario to skew 0-100kph results inthe real world.

Anyway, the issue you raised really doesn't happen in the real world. go and find an old PCOTY or BFYB test. I'm sure they will show that an AWD turbo car with a very similar 0-100kph time as a front engine rwd taxi will not have a substantially better 0-400m time. I see your point, but its a theoretical problem not a real world issue. 0-100kph is a good indicator of performance 99% of the time in the real world.

From your comments it is immediately obvious that you have entirely missed the point of my post.

Firstly, I am 100% aware of the inaccuracies in modelling the distances travelled in my example. You don’t need to point them out to me. A better approximation for distance would have involved curve fitting and integrating under the curve to find the distance travelled. But nevertherless the point of the example was to show that the V8 would have been in front, despite identical 0-100km/h times, and if you don’t get too hung up on the over-simplification of the model it would be plain to see that.

As for the models themselves, they are over simplified and no vehicle in the real world would accelerate with the characteristics shown, and I am happy to admit that. But the models I have used were not supposed to be 100% reflective of what will happen in the real world. Don’t get hung up on them - they were merely examples literally made up on the spot to demonstrate my point.

And my point is that 0-100km/h times do not reflect the distance travelled over that interval. Without knowing the distance travelled, there is no way to tell which car will be in front. And that is indisputable, I'm sorry to say.

If you had understood this point, you would have realised that your point about gearshifts skewing 0-100km/h times actually gives credit to my argument rather than debunking it. In fact, the more variables you add, the more credit my arguement has. Yes it makes the model less representitive, but the model isn't the point of my arguement. More variables create more and more differences in the characteristics of the way a vehicle accelerates - therefore there will be more difference in the distance travelled from one vehicle to another over the same speed interval. Picking one point in time and measuring speed will not give an accurate indication of which vehicle will be in front, unless both vehicles have similar acceleration characteristics.

Obviously the 0-100km/h time has some merit – my saying it to be “completely useless” is obviously an exaggeration. A vehicle that does 0-100km/h in 24 seconds will obviously be beaten by a vehicle a vehicle with a 0-100km/h time of 3 seconds. Fair enough you can make an educated guess of which car will be victorious in a race based purely on the 0-100km/h time, but what I am saying is that this absolutely should not be the difinitive measure of performance that so many people consider it to be.

Personally, I don’t know how anyone who has understood my argument can disagree with it – 0-100km/h times just don’t give indication of the distance travelled, and therefore don’t show which vehicle has travelled further, and therefore don’t show which vehicle is in front. It’s not rocket science.

And now you want me to go and collect vast amounts of data to try and prove this point? Well, I have had quite a few people agree with me so far, so maybe you should be going to get vast amounts of data to counter my point? Perhaps when I get home tonight I will put out an old motor or wheels and make up a comparison…

The quarter mile time vs. 0-100km/h time isn't really what I am trying to say - Really I would need a 0-100km/h distance compared to 0-100km/h time comparison to give the definitive answer - but since you asked I grabbed a couple of comparisons from www.supercars.net, (although i'm not going to rely on this for my point as I don't trust a lot of these figures...).

mazda rx8 (2002) - 6.1 to 100 and 15 to the quarter

volkswagen golf Gti (2005) 6.5 / 15

Mazerati Bora (1979) 7.1 / 15

Three vehicles which travel 400m in an identical period of time, but reach 100km/h up to a second apart.

Lotus Carlton (1989) 5.4 / 13.5

Honda S2000 (2000) 5.5 / 14.8

The Honda S2000 is only 0.1 of a second slower to 100km/h, yet the gap is 1.3 seconds over a distance of 400m.

VW Golf R32 (2002) 6.1 / 14.1

mazda rx8 (2002) 6.1 / 15

Identical times to reach 100km/h, but the golf travels 400m in signifficantly less time

Ferrari 360 Modena (2000) 4.3 / 13

Dodge Charger SRT-8 (2006) 5 / 13

360 Modena reaches 100km/h in short order, but they cover 400m in equal time.

I don't really like supercars.net's figures, so I won't continue until I am home with numbers from motor or wheels.

Don't get me wrong, it's just as easy to pull out comparisons of similar vehicles:

Toyota Supra RZ (1993) 5 / 13.5

Jaguar XKR (2004) 5 / 13.5

But nevertherless that doesn't disprove my point - having some examples go one way and some the other just compounds my theory that 0-100km/h doesn't indicate who will win.

Anyways...

[hrd-hr30]

From your comments it is immediately obvious that you have entirely missed the point of my post.

I though tth epoint of your post was that 0-100kph times are useless. I mean that's what you said. sorry if I misinterpreted that. All you argument revolved around the difference between cars that get off the line faster and those that don't launch but come on strong in the top end. So again, if i misunderstood what your problem with 0-100kph was, its only because of your explanation. i can only go on what you're saying, not what you're thinking.

Personally, I don’t know how anyone who has understood my argument can disagree with it – 0-100km/h times just don’t give indication of the distance travelled, and therefore don’t show which vehicle has travelled further, and therefore don’t show which vehicle is in front. It’s not rocket science

I think its you who's missed the point. 0-100kph times are not designed to show who covers distance quicker. 0-400m times do that. 0-100kph times are designed to show which car accellerates to 100kph the quickest. you're right, it's not rocket science.

what you're saying here is like saying 0-400m times are useless, because a car might loose a race but be faster (in trap speed). so the slower car won. their both moot points.

[Big Rizza]

I will just re-iterate again that comparing 0-100km/h times and 0-400m times doesn't necessarily proove or disprove what I am saying. Taking my V8 vs turbo example again, the V8 was ahead by about 2-3 carlengths at 100km/h, but the turbo was accelerating harder - therefore above 100km/h the gap would be closing. What if that gap continued closing and became zero at 400m? The two cars would have identical 0-100km/h times AND 0-400m times.

One would assume they would be neck and neck the whole way, based on these figures, where in fact the V8 lead the entire race (other than the instant in time at the start and end).

(Just fuelling the fire people )

[Big Rizza]

0-100kph times are not designed to show who covers distance quicker. 0-400m times do that. 0-100kph times are designed to show which car accellerates to 100kph the quickest. you're right, it's not rocket science.

You are exactly right - but my point is that people use this figure as a definitive measure of performance i.e. the car with the lower 0-100km/h time will be faster. My point is that this is not true!

A reminder of THE VERY FIRST THING I SAID, and the essence of what I am saying:

There seems to be a lot of people who seem to be using the 0-100km/h time as a bench mark for vehicle performance. However, in my experience the 0-100km/h time is not a great reflection.

That is what this discussion is about.

Edited June 16, 2006 by Big Rizza

[hrd-hr30]

I will just re-iterate again that comparing 0-100km/h times and 0-400m times doesn't necessarily proove or disprove what I am saying.

no worries. I didn't compare 0-100kph to 0-400m times after you pointed that out before. I simply said you're misinterpreting what they are each about.

Taking my V8 vs turbo example again, the V8 was ahead by about 2-3 carlengths at 100km/h, but the turbo was accelerating harder - therefore above 100km/h the gap would be closing.

and again, real world cars don't behave like that.

What if that gap continued closing and became zero at 400m? The two cars would have identical 0-100km/h times AND 0-400m times.

so they are very closely matched, as the figures suggest. How many real life drag races have you seen where a 2 cars that run the same times, pull 3 carlengths to 200ft and then cross the line together? it just doesn't happen in the real world. that's my point. The lead only keeps changing in drag races in bad car movies!

[Big Rizza]

no worries. I didn't compare 0-100kph to 0-400m times after you pointed that out before. I simply said you're misinterpreting what they are each about.

Your post hadn't appeared yet when I wrote that, so it wasn't in response to your post immediately prior.

and again, real world cars don't behave like that.

What? It's impossible for one car to get off to a good start, and have a more powerful car then run it down?

So they are very closely matched, as the figures suggest. How many real life drag races have you seen where a 2 cars that run the same times, pull 3 carlengths to 200ft and then cross the line together? it just doesn't happen in the real world. that's my point. The lead only keeps changing in drag races in bad car movies!

I already said the numbers themselves weren't an accurate model of real life - and that point was very much an aside. Just merely pointing out that two cars with identical 0-100km/h and 0-400m times might not be neck and neck the whole way.

But the core of the arguement is that 0-100km/h times are not the best representation of a vehicles performance.

And at what point does the lead change multiple times? One car gets a better start, the other chases it down. One change in leader. One.

And tF&tF is a fantastic movie .

Edited June 16, 2006 by Big Rizza

[Big Rizza]

Anyways, this seems to be going around in circles a little. I can't help but read in a level of frustration on your side of the information super highway, which absolutely wasn't my intention. I'm not trying to piss people off! I admit to a smidgeon of frustration - I think I took it a little personally when you trashed my physics and maths skills . But seriously, I'm just trying to have a friendly discussion!

I don't think 0-100km/h is the best measure of performance - I have made that pretty clear. And I also think that people give this figure too much bearing when measuring performance. It's not completely "useless" as I said in exaggeration at the start, but I think that a distance, a speed and a time are all required to get a decent idea of performance. For example, a 0-400m time plus terminal velocity. Or a 0-100km/h time plus distance travelled.

It is similar to measuring a vehicles performance purely on the peak power number (or even power to weight ratio). It doesn't give the full picture!

Edited June 16, 2006 by Big Rizza

[TurboX]

Irrespective of what the crux of this discusion is, I have enjoyed the content and now at least dont go blindly on the 0-100 time as a definative measure of performance that I must admit I once did.

Thanks to Big Rizza and others that contributed to this thread.

[Big Rizza]

Irrespective of what the crux of this discusion is, I have enjoyed the content and now at least dont go blindly on the 0-100 time as a definative measure of performance that I must admit I once did.

Thanks to Big Rizza and others that contributed to this thread.

Glad you enjoyed the discussion

[scathing]

Anyways, this seems to be going around in circles a little. I can't help but read in a level of frustration on your side of the information super highway, which absolutely wasn't my intention.

It's always cool to see fellow car enthusiasts acknowledge each other and wave when they see each other on the information super highway.

[Dash]

I think hrd-h30 was merely pointing out the exaggerated figures you were using as an example,very similar to 0-100 and 0-400m times you just posted.

You should maybe include the decimal places and correct times(a mazda rx8 does 0-100 in 6.99 not 6.1)

Not having a go at you mate,its just saying that there useless is wrong and it does give an indication of what a performance car is like.

They are by no means 100% as the results can vary from test to test and saying a car that does 5.3 compared to 5.8 is going to be quicker at 160kph or 200kph is not always the case.

And before someone jumps in some old or obscure(super) car with wildly differing results to another,go grab a wheels/motor and flick through the back.Its all within a few tenths either way not seconds..

As for 0-160kph times or standing km times they would be good if everyone published them but I prefer 0-400m. I mean how long do you want to race for?Where are you going to race another car to top speed?

Thanks for the thread though, I've never actually thought about 0-100 in regards to distance travelled.