Just for Fun: Is the Step Still King in the Realm of the
07-17-2006, 11:58 AM
#51
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Originally Posted by BetterMakeWay' post='311829' date='Jul 17 2006, 02:02 PM
Ahhh chill man. I was just joking. 
Me too.
About the rest of my thoughts well...i said this because i bealive it's innapropriate to measure 2 cars straight line abilities just by compraing numbers. And what numbers? Some from your own results and some from a mag. If you want to compare numbers find a similar 550i run the g meter on it and then compare numbers with your own runs in the 545i (runs made in the same day, in the same place, by the same driver, in similar if not identical cars). More appropriate is a drag race between the 2, done for more than once to get a conclusive result. Do that and then you'll see that you'll come to my words. The 550i wins every time. By how much....well that's a fact we need to see. Same was with the 545ivs535d discussion.
What you suggest does not "prove" anything in terms of whether, on average, 550i's or 545i's are the faster. I agree that a number of same place/same time races with a number of different 545i's and 550i's would be more credible than the implications of my data. But, a decent experiment has not yet been conducted. So, I'll stick with my arguments--remember, just for fun. Also, as more magazine data is revealed, I will change my arguments as the data are revealed. If, for example, each of the big three US mags show, say, 13.3 or less for the 550i in the 1/4, then I'll be arguing that the 550i is faster.
As it stands, the current US mag data clearly suggest that the 550i is faster. But, on the other hand, we have user-derived data that are contradictory--one set of which contradicts the magazine results (i.e., my data and grogan545i's data). And, remember, I never said that I believe my arguments. Evidence sometimes suggests things that are counter intuitive and beg for additional experimentation and data gathering to yield the "truth."
Me too.
About the rest of my thoughts well...i said this because i bealive it's innapropriate to measure 2 cars straight line abilities just by compraing numbers. And what numbers? Some from your own results and some from a mag. If you want to compare numbers find a similar 550i run the g meter on it and then compare numbers with your own runs in the 545i (runs made in the same day, in the same place, by the same driver, in similar if not identical cars). More appropriate is a drag race between the 2, done for more than once to get a conclusive result. Do that and then you'll see that you'll come to my words. The 550i wins every time. By how much....well that's a fact we need to see. Same was with the 545ivs535d discussion.
What you suggest does not "prove" anything in terms of whether, on average, 550i's or 545i's are the faster. I agree that a number of same place/same time races with a number of different 545i's and 550i's would be more credible than the implications of my data. But, a decent experiment has not yet been conducted. So, I'll stick with my arguments--remember, just for fun. Also, as more magazine data is revealed, I will change my arguments as the data are revealed. If, for example, each of the big three US mags show, say, 13.3 or less for the 550i in the 1/4, then I'll be arguing that the 550i is faster.
As it stands, the current US mag data clearly suggest that the 550i is faster. But, on the other hand, we have user-derived data that are contradictory--one set of which contradicts the magazine results (i.e., my data and grogan545i's data). And, remember, I never said that I believe my arguments. Evidence sometimes suggests things that are counter intuitive and beg for additional experimentation and data gathering to yield the "truth."
07-17-2006, 12:00 PM
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Originally Posted by BetterMakeWay' post='311829' date='Jul 17 2006, 02:02 PM
Ahhh chill man. I was just joking.
About the rest of my thoughts well...i said this because i bealive it's innapropriate to measure 2 cars straight line abilities just by compraing numbers. And what numbers? Some from your own results and some from a mag. If you want to compare numbers find a similar 550i run the g meter on it and then compare numbers with your own runs in the 545i (runs made in the same day, in the same place, by the same driver, in similar if not identical cars). More appropriate is a drag race between the 2, done for more than once to get a conclusive result. Do that and then you'll see that you'll come to my words. The 550i wins every time. By how much....well that's a fact we need to see. Same was with the 545ivs535d discussion.
About the rest of my thoughts well...i said this because i bealive it's innapropriate to measure 2 cars straight line abilities just by compraing numbers. And what numbers? Some from your own results and some from a mag. If you want to compare numbers find a similar 550i run the g meter on it and then compare numbers with your own runs in the 545i (runs made in the same day, in the same place, by the same driver, in similar if not identical cars). More appropriate is a drag race between the 2, done for more than once to get a conclusive result. Do that and then you'll see that you'll come to my words. The 550i wins every time. By how much....well that's a fact we need to see. Same was with the 545ivs535d discussion.
One thing is for sure; weight and power ratio are major factors in speed and acceleration (in this case). We have exact power difference, but we don't have exact weights difference; hence, we can't mathematically calculate the theoretical advantage of either car except for what as been tested in the real world. And that my friend, we have to take a face values.
On the theoretical front, a 545i needs to be about 400 lbs lighter than a 550i to beat the 550i by .2 mph at the 1/4 ET given all things constant except for weight and HP.
Don't believe me, do the math.
07-17-2006, 12:43 PM
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Originally Posted by BetterMakeWay' post='311873' date='Jul 17 2006, 03:39 PM
Is it that hard in US to find a brother 550i or 545i to do the freakin drag race?
07-17-2006, 01:07 PM
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Originally Posted by Bimmer32' post='311854' date='Jul 17 2006, 03:00 PM
On the theoretical front, a 545i needs to be about 400 lbs lighter than a 550i to beat the 550i by .2 mph at the 1/4 ET given all things constant except for weight and HP. Don't believe me, do the math.
Don't believe me, do the math.Porsche Cayman S MT 4/06...295 HP.....3098 lbs.....4.8.....13.3.....104.6.....10.5 lbs/HP
Porsche Cayman S RT 11/05..295 HP.....3098 lbs.....4.8.....13.3.....106.2.....10.5 lbs/HP
Average.................................295 HP.....3098 lbs.....4.8.....13.3.....105.4.....10.5 lbs/HP
BMW M Roadster RT 6/06......330 HP......3270 lbs......4.7....13.2.....107.9.....9.91 lbs/HP
BMW M Roadster CD 6/06.....330 HP......3277 lbs......4.6.....13.2.....107.0.....9.91 lbs/HP
Average................................330 HP......3274 lbs......4.65...13.2.....107.45....9.91 lbs/HP
Letting weight reduction compensate for HP, in effect, the BMW weighs 295 X 9.91 = 2,924 lbs--174 lbs less than the Porsche. Yet, the BMW beats the Porsche by about 2 MPH on average in the 1/4. By your calculations, shouldn't the BMW beat the Porsche by about 174/400 X .2 MPH = .087 MPH? Of course, I know that other things are not equal here, but aren't numbers fun. And, things can't be exactly equal in concept, even for the 545i and the 550i, since their engines have different HP/torque curves.
But, anyway, with respect to the 550i and 545i, my math implies that "things" are as though the 550i weighs about 369 lbs (3800 - 3431) less than the 545i (i.e., since approx. 3800 / 325 = 11.69, while 3431 / 325 = 3800 / 360 = 10.56)--assuming that the two cars' curb weights are the same. However, by some accounts, the 550i gained 100 lbs. If so, then the equivalent difference is 269 = 369 - 100. So, by your math, the 550i would beat the 545i by only .135 MPH in the 1/4 = 269/400 X .2 MPH--a difference that is insignificant.
But, on the other hand, the BMW/Porsche example contradicts your math, IMO. In the example, the Porsche lbs/HP ratio is .59 higher that that of the BMW. In contrast, the 545i lbs/HP ratio is 1.13 higher than that of the 550i. These data suggest that the 550i would beat the 545i by about 3.83 MPH in the 1/4 = (1.13 / .59) X 2 MPH. This prediction is not exactly borne out by the extant US mag data--i.e., 2.1 = 105 - 102.9 (average for 4 cars tested). However, if we throw out the seeming outlier from the US mag data (104 MPH), then the differnce is somewhat closer to 3.83--2.4 = 105 - 102.6 (average for 3 cars tested).
But, finally, if the 550i did gain 100 lbs, then its lbs/HP ratio is about 3900 / 360 = 10.83. And, [(11.69 - 10.83) / .59] X 2 MPH = 2.91. The importance of this value is that it is close to, what IMO, is the best estimate of the "true" average MPH difference in the 550i and the 545i based on the US mag data (2.4)--i.e., and, 2.91 is not much different than 2.4. So, maybe the 550i did gain 100 lbs and the "true" average MPH difference between the two cars will turn out to be in the area of 2.4 to 2.91 MPH.
But, anyway, based on calculations, what do you think the acutal difference in 1/4 MPH will be for the 550i versus the 545i on average?
07-17-2006, 01:17 PM
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I had understood the 550 was only around 60lbs heavier than the 545?
07-17-2006, 01:29 PM
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Re my earlier post I had thought that Znod posted that there was a 369 lb difference between the cars - I now see what he was getting at.
07-17-2006, 02:47 PM
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Originally Posted by swajames' post='311895' date='Jul 17 2006, 04:29 PM
Re my earlier post I had thought that Znod posted that there was a 369 lb difference between the cars - I now see what he was getting at.
[(11.69 - 10.83) / .59] X [13.3 (Porsche) - 13.2 (BMW) sec = (.86 / .59) X .1 = .15.
If so, then the "true" average ET for the 550i would turn out to be 13.73 - .15 = 13.58 (rather than 13.5 as suggested by the MT test)--where 13.73 is my best estimate of the "true" ET average for the 545i (average for three tests). Finally, note that the value of .15 does not come close to satisfying the standard heuristic that every 10 extra HP reduces ET by .1. In this regard, if the 550i really does have 35 additonal HP over the 545i, then we would expect to see an ET difference closer to .35. Maybe the increase in HP is composed only of small horses.
Honestly, I do think that the mags will end up implying that the 550i is faster than the 545i on average. But, I don't think the difference will be as great as many expect.
07-17-2006, 02:58 PM
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Originally Posted by BetterMakeWay' post='311873' date='Jul 17 2006, 01:39 PM
Is it that hard in US to find a brother 550i or 545i to do the freakin drag race?
07-17-2006, 03:58 PM
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Originally Posted by Znod' post='311881' date='Jul 17 2006, 04:07 PM
I was thinking about what you said. So, I decided to test your thoughts against some empirical data.
Porsche Cayman S MT 4/06...295 HP.....3098 lbs.....4.8.....13.3.....104.6.....10.5 lbs/HP
Porsche Cayman S RT 11/05..295 HP.....3098 lbs.....4.8.....13.3.....106.2.....10.5 lbs/HP
Average.................................295 HP.....3098 lbs.....4.8.....13.3.....105.4.....10.5 lbs/HP
BMW M Roadster RT 6/06......330 HP......3270 lbs......4.7....13.2.....107.9.....9.91 lbs/HP
BMW M Roadster CD 6/06.....330 HP......3277 lbs......4.6.....13.2.....107.0.....9.91 lbs/HP
Average................................330 HP......3274 lbs......4.65...13.2.....107.45....9.91 lbs/HP
Letting weight reduction compensate for HP, in effect, the BMW weighs 295 X 9.91 = 2,924 lbs--174 lbs less than the Porsche. Yet, the BMW beats the Porsche by about 2 MPH on average in the 1/4. By your calculations, shouldn't the BMW beat the Porsche by about 174/400 X .2 MPH = .087 MPH? Of course, I know that other things are not equal here, but aren't numbers fun. And, things can't be exactly equal in concept, even for the 545i and the 550i, since their engines have different HP/torque curves.
But, anyway, with respect to the 550i and 545i, my math implies that "things" are as though the 550i weighs about 369 lbs (3800 - 3431) less than the 545i (i.e., since approx. 3800 / 325 = 11.69, while 3431 / 325 = 3800 / 360 = 10.56)--assuming that the two cars' curb weights are the same. However, by some accounts, the 550i gained 100 lbs. If so, then the equivalent difference is 269 = 369 - 100. So, by your math, the 550i would beat the 545i by only .135 MPH in the 1/4 = 269/400 X .2 MPH--a difference that is insignificant.
How does your math imply that the 550i is 369 lbs less than the 545i? Are you violating the rules of mathematics when you are doing reverse calculations? Could you give me a set of assumed parameters for the 550i and 545i (include lbs and hp for each). Then I'll plug in my formulas and calculators and post my work.
But, on the other hand, the BMW/Porsche example contradicts your math, IMO. In the example, the Porsche lbs/HP ratio is .59 higher that that of the BMW. In contrast, the 545i lbs/HP ratio is 1.13 higher than that of the 550i. These data suggest that the 550i would beat the 545i by about 3.83 MPH in the 1/4 = (1.13 / .59) X 2 MPH. This prediction is not exactly borne out by the extant US mag data--i.e., 2.1 = 105 - 102.9 (average for 4 cars tested). However, if we throw out the seeming outlier from the US mag data (104 MPH), then the differnce is somewhat closer to 3.83--2.4 = 105 - 102.6 (average for 3 cars tested).
Znod, I'm a bit comfused by your calculations. But first off, you can't simply compare lbs/HP between a Porsche and a BMW because other factors such such as drivetrain gearing, and rear mount vs. front engines. There is much advantage to rear mount engines. So, when we compare lbs/HP, we can only compare BMW 545i to 550i since the only difference is lbs and HP (given that all others can be the same from factory). To use lbs/hp negates other factors not including weather such as drag, drivetrain gearing ratios, tire sizes, Everybody follow me so far?
But, finally, if the 550i did gain 100 lbs, then its lbs/HP ratio is about 3900 / 360 = 10.83. And, [(11.69 - 10.83) / .59] X 2 MPH = 2.91. The importance of this value is that it is close to, what IMO, is the best estimate of the "true" average MPH difference in the 550i and the 545i based on the US mag data (2.4)--i.e., and, 2.91 is not much different than 2.4. So, maybe the 550i did gain 100 lbs and the "true" average MPH difference between the two cars will turn out to be in the area of 2.4 to 2.91 MPH.
At this point, we can't assume the 100 lbs more for the 550i. We need some facts to narrow our theoretical calculations.
But, anyway, based on calculations, what do you think the acutal difference in 1/4 MPH will be for the 550i versus the 545i on average?
Give me some time later on so I can present my calculations for ET for both cars. The beautiful of this exercise is that all variables are constant except for lbs and HP; otherwise, I'd have to write a technical issue and everyone would be turned off.
Porsche Cayman S MT 4/06...295 HP.....3098 lbs.....4.8.....13.3.....104.6.....10.5 lbs/HP
Porsche Cayman S RT 11/05..295 HP.....3098 lbs.....4.8.....13.3.....106.2.....10.5 lbs/HP
Average.................................295 HP.....3098 lbs.....4.8.....13.3.....105.4.....10.5 lbs/HP
BMW M Roadster RT 6/06......330 HP......3270 lbs......4.7....13.2.....107.9.....9.91 lbs/HP
BMW M Roadster CD 6/06.....330 HP......3277 lbs......4.6.....13.2.....107.0.....9.91 lbs/HP
Average................................330 HP......3274 lbs......4.65...13.2.....107.45....9.91 lbs/HP
Letting weight reduction compensate for HP, in effect, the BMW weighs 295 X 9.91 = 2,924 lbs--174 lbs less than the Porsche. Yet, the BMW beats the Porsche by about 2 MPH on average in the 1/4. By your calculations, shouldn't the BMW beat the Porsche by about 174/400 X .2 MPH = .087 MPH? Of course, I know that other things are not equal here, but aren't numbers fun. And, things can't be exactly equal in concept, even for the 545i and the 550i, since their engines have different HP/torque curves.
But, anyway, with respect to the 550i and 545i, my math implies that "things" are as though the 550i weighs about 369 lbs (3800 - 3431) less than the 545i (i.e., since approx. 3800 / 325 = 11.69, while 3431 / 325 = 3800 / 360 = 10.56)--assuming that the two cars' curb weights are the same. However, by some accounts, the 550i gained 100 lbs. If so, then the equivalent difference is 269 = 369 - 100. So, by your math, the 550i would beat the 545i by only .135 MPH in the 1/4 = 269/400 X .2 MPH--a difference that is insignificant.
How does your math imply that the 550i is 369 lbs less than the 545i? Are you violating the rules of mathematics when you are doing reverse calculations? Could you give me a set of assumed parameters for the 550i and 545i (include lbs and hp for each). Then I'll plug in my formulas and calculators and post my work.
But, on the other hand, the BMW/Porsche example contradicts your math, IMO. In the example, the Porsche lbs/HP ratio is .59 higher that that of the BMW. In contrast, the 545i lbs/HP ratio is 1.13 higher than that of the 550i. These data suggest that the 550i would beat the 545i by about 3.83 MPH in the 1/4 = (1.13 / .59) X 2 MPH. This prediction is not exactly borne out by the extant US mag data--i.e., 2.1 = 105 - 102.9 (average for 4 cars tested). However, if we throw out the seeming outlier from the US mag data (104 MPH), then the differnce is somewhat closer to 3.83--2.4 = 105 - 102.6 (average for 3 cars tested).
Znod, I'm a bit comfused by your calculations. But first off, you can't simply compare lbs/HP between a Porsche and a BMW because other factors such such as drivetrain gearing, and rear mount vs. front engines. There is much advantage to rear mount engines. So, when we compare lbs/HP, we can only compare BMW 545i to 550i since the only difference is lbs and HP (given that all others can be the same from factory). To use lbs/hp negates other factors not including weather such as drag, drivetrain gearing ratios, tire sizes, Everybody follow me so far?
But, finally, if the 550i did gain 100 lbs, then its lbs/HP ratio is about 3900 / 360 = 10.83. And, [(11.69 - 10.83) / .59] X 2 MPH = 2.91. The importance of this value is that it is close to, what IMO, is the best estimate of the "true" average MPH difference in the 550i and the 545i based on the US mag data (2.4)--i.e., and, 2.91 is not much different than 2.4. So, maybe the 550i did gain 100 lbs and the "true" average MPH difference between the two cars will turn out to be in the area of 2.4 to 2.91 MPH.
At this point, we can't assume the 100 lbs more for the 550i. We need some facts to narrow our theoretical calculations.
But, anyway, based on calculations, what do you think the acutal difference in 1/4 MPH will be for the 550i versus the 545i on average?
Give me some time later on so I can present my calculations for ET for both cars. The beautiful of this exercise is that all variables are constant except for lbs and HP; otherwise, I'd have to write a technical issue and everyone would be turned off.