5-series Straight-line Performance Discussion
#131
Contributors
Thread Starter
Join Date: Aug 2005
Location: Austin TX
Posts: 6,554
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2014 X5 xDrive 5.0 M Package Carbon Black Metallic/2008 M Roadster Imola Red
![Default](https://5series.net/forums/images/icons/icon1.gif)
Originally Posted by grogan545' post='318952' date='Aug 4 2006, 11:52 AM
Hi Zman .Just now read your post.I will need some time to digest all that you are saying.Sounds like you are back to your very analytical normal self.After I digest this post I will try to give an intelligent reply.
![](http://thevistaforums.com/style_emoticons/default/wave.gif)
#132
Senior Members
Join Date: Jun 2005
Location: southestern pa
Posts: 458
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2008 550I,manufactured 2-27-08,delivered 4-2-08.Platinum bronze,natural brown interior,light poplar trim,cold weather package,heated rear seats,HD radio
![Default](https://5series.net/forums/images/icons/icon1.gif)
Originally Posted by Znod' post='318733' date='Aug 3 2006, 07:03 PM
Hi All:
An issue that comes up from time to time is "magazine racing"--using, for example, the test data provided by the "Big 3" auto magazines--the USbig3). The apparent problem in trying to use such results to assess the relative performance abilities of different cars is the formidable numbers of both intra-magazine and inter-magazine uncontrolled factors. I have done some work that suggests that averages can be used to do some pretty effective mag racing.![](http://thevistaforums.com/style_emoticons/default/yes.gif)
I have the following data for 31 different "fast cars" (fcs) from tests based on each of the USbig3: 0-60, 1/4 ET, and 1/4 TV. I won't provide the detail of my matching criteria, but I think they are pretty good.
Using these data, I performed matched pairs t tests for: (1) the mean difference in 0-60 for the 31 fcs for CD vs MT, CD vs RT, and MT vs RT. I did the same thing for 1/4 ET and 1/4 TV. One need not be concerned about my parametric test choice. The central limit theorem implies that the pertinent sampling distriblution of the mean is approximately normal given a sample size of approximately 30 or more. Thus, the results from my matched pairs t tests should be robust.![](http://thevistaforums.com/style_emoticons/default/iiam-busted.gif)
My results are:
.................................................. .......CD vs MT..........CD vs RT..........MT vs RT
One-tailed probability value: 0 to 60:
.................................................. .............23....................42............. .......28
One-tailed probability value: 1/4 ET:
.................................................. .............02....................09............. .......37
One-tailed probability value: 1/4 TV:
.................................................. .............36....................29............. .......42
So, the point to this point is that the mean differences for paired USbig3's usually are insignificant. In this regard, using standard statistical reasoning, the one significant difference is .02. Thus, it looks like there is a significant difference in the average 1/4 ET reported for the 31 fcs for CD and MT.
These finding suggest to me that the effects of the formidable uncontrolled for factors tend to cancel out across the USbig3. Thus, at the extreme, it often may not be too bad to decide tentatively that the IS350 is faster in the 1/4 than the 545i on the basis of only two tests--with one appearing in one USbig3 mag and the other appearing in another USbig3 mag. However, I would apply this approach with great skepticism if the two mags involved are CD and MT. Additionally, since .09 is consistent with less frequently used rejection level of .10, I also would be extra skeptical if mags involved are CD and RT. I'll emphasize the obvious caveat that the two-test approach to mag racing will result in, I think, significantly mores erroneous conculusions than if averages are used.
But, the main point, following from the large number of insignificant differences, is that mag racing is likely to be highly valid once USbig3 averages for the various fsc's begin to be used. So, for example, I would be very confident in deciding that the C6 Z06 is "faster" in the 1/4 than the 911 Turbo (480 hp) if the USbig3 average ET of the former is less than that of the latter. And, putting the two ideas together, the less and less I rely on averages the more I woul doubt the implications. Also, for example, I would be especially skeptical of the implications of 1/4 ET averages where, for example one average of 2 included CD and the other included MT (similarly with CD and RT).
Now, from an overall perspective, I have done nothing but provide something of an analytical foundation for the ways most of us would use mag tests in doing mag racing intuitively--use averages when possible. Two of my real contributions are finding that (1) we should be extra skeptical of the apparent implications of 1/4 ET comparisons if the mags involved are CD and MT or CD and RT and (2) mag racing is likely to be highly valid once USbig3 averages for the various fsc's begin to be used--especially if "problems" with CD vs MT and CD vs RT are avoided in the 1/4 ET arena. Another contribution not yet mentioned is the implication that USbig3 averages may come closer to "truth" than might have been expected since most of the differences tested are insignificant. I'll be doing at least one follow up "study" on the above ideas.
![](http://thevistaforums.com/style_emoticons/default/showoff.gif)
Any thoughts anyone or am I
?
Come on some one. At least make a comment that leads me to think that your read what I wrote.![](http://forums.e60.net/uploads/post-344-1154458767.gif)
An issue that comes up from time to time is "magazine racing"--using, for example, the test data provided by the "Big 3" auto magazines--the USbig3). The apparent problem in trying to use such results to assess the relative performance abilities of different cars is the formidable numbers of both intra-magazine and inter-magazine uncontrolled factors. I have done some work that suggests that averages can be used to do some pretty effective mag racing.
![](http://thevistaforums.com/style_emoticons/default/yes.gif)
I have the following data for 31 different "fast cars" (fcs) from tests based on each of the USbig3: 0-60, 1/4 ET, and 1/4 TV. I won't provide the detail of my matching criteria, but I think they are pretty good.
Using these data, I performed matched pairs t tests for: (1) the mean difference in 0-60 for the 31 fcs for CD vs MT, CD vs RT, and MT vs RT. I did the same thing for 1/4 ET and 1/4 TV. One need not be concerned about my parametric test choice. The central limit theorem implies that the pertinent sampling distriblution of the mean is approximately normal given a sample size of approximately 30 or more. Thus, the results from my matched pairs t tests should be robust.
![](http://thevistaforums.com/style_emoticons/default/iiam-busted.gif)
My results are:
.................................................. .......CD vs MT..........CD vs RT..........MT vs RT
One-tailed probability value: 0 to 60:
.................................................. .............23....................42............. .......28
One-tailed probability value: 1/4 ET:
.................................................. .............02....................09............. .......37
One-tailed probability value: 1/4 TV:
.................................................. .............36....................29............. .......42
So, the point to this point is that the mean differences for paired USbig3's usually are insignificant. In this regard, using standard statistical reasoning, the one significant difference is .02. Thus, it looks like there is a significant difference in the average 1/4 ET reported for the 31 fcs for CD and MT.
These finding suggest to me that the effects of the formidable uncontrolled for factors tend to cancel out across the USbig3. Thus, at the extreme, it often may not be too bad to decide tentatively that the IS350 is faster in the 1/4 than the 545i on the basis of only two tests--with one appearing in one USbig3 mag and the other appearing in another USbig3 mag. However, I would apply this approach with great skepticism if the two mags involved are CD and MT. Additionally, since .09 is consistent with less frequently used rejection level of .10, I also would be extra skeptical if mags involved are CD and RT. I'll emphasize the obvious caveat that the two-test approach to mag racing will result in, I think, significantly mores erroneous conculusions than if averages are used.
But, the main point, following from the large number of insignificant differences, is that mag racing is likely to be highly valid once USbig3 averages for the various fsc's begin to be used. So, for example, I would be very confident in deciding that the C6 Z06 is "faster" in the 1/4 than the 911 Turbo (480 hp) if the USbig3 average ET of the former is less than that of the latter. And, putting the two ideas together, the less and less I rely on averages the more I woul doubt the implications. Also, for example, I would be especially skeptical of the implications of 1/4 ET averages where, for example one average of 2 included CD and the other included MT (similarly with CD and RT).
Now, from an overall perspective, I have done nothing but provide something of an analytical foundation for the ways most of us would use mag tests in doing mag racing intuitively--use averages when possible. Two of my real contributions are finding that (1) we should be extra skeptical of the apparent implications of 1/4 ET comparisons if the mags involved are CD and MT or CD and RT and (2) mag racing is likely to be highly valid once USbig3 averages for the various fsc's begin to be used--especially if "problems" with CD vs MT and CD vs RT are avoided in the 1/4 ET arena. Another contribution not yet mentioned is the implication that USbig3 averages may come closer to "truth" than might have been expected since most of the differences tested are insignificant. I'll be doing at least one follow up "study" on the above ideas.
![](http://thevistaforums.com/style_emoticons/default/jump.gif)
![](http://thevistaforums.com/style_emoticons/default/showoff.gif)
Any thoughts anyone or am I
![](http://thevistaforums.com/style_emoticons/default/ball.gif)
Come on some one. At least make a comment that leads me to think that your read what I wrote.
![](http://forums.e60.net/uploads/post-344-1154458767.gif)
I guess what I am saying is that I always analize test figures on cars that I am interested in to see if they make sense.Most of the time they do but I would not want to use data that doesn't make sense in my averaging.
#133
Contributors
Join Date: Jun 2004
Location: FLA - East Coast, USA
Posts: 3,618
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: (USA) 645Ci, Silver Gray, Chateau, Cold Weather PKG, Premium Sound PKG, Sport PKG, Step, NAV [Std Equip in 645], HUD, Satellite (SIRIUS) Radio, Aux Input, Bluetooth enabled using iPhone 3GS w/ adapter cradle - Build date - 01/05, Baby delivered 2/24/05
![Default](https://5series.net/forums/images/icons/icon1.gif)
Ah, the recovery process has begun. Low and slow with lots of time to THINK and ANALYZE. Good work Znod. I kinda like 5th order polynomials myself
![Big Grin](https://5series.net/forums/images/smilies/imported/biggrin.gif)
#134
Contributors
Thread Starter
Join Date: Aug 2005
Location: Austin TX
Posts: 6,554
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2014 X5 xDrive 5.0 M Package Carbon Black Metallic/2008 M Roadster Imola Red
![Default](https://5series.net/forums/images/icons/icon1.gif)
Originally Posted by cobradav' post='319016' date='Aug 4 2006, 02:26 PM
Ah, the recovery process has begun. Low and slow with lots of time to THINK and ANALYZE. Good work Znod. I kinda like 5th order polynomials myself ![Big Grin](https://5series.net/forums/images/smilies/imported/biggrin.gif)
![Big Grin](https://5series.net/forums/images/smilies/imported/biggrin.gif)
![](http://thevistaforums.com/style_emoticons/default/pc.gif)
![](http://www.vistababble.com/forums/images/smilies/scared.gif)
#135
Senior Members
Join Date: Jun 2005
Location: southestern pa
Posts: 458
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2008 550I,manufactured 2-27-08,delivered 4-2-08.Platinum bronze,natural brown interior,light poplar trim,cold weather package,heated rear seats,HD radio
![Default](https://5series.net/forums/images/icons/icon1.gif)
Zman have you read the post on Dinan Engineering yet.He gives a very in depth analysis of computer engine controls.He doubts that performance can be improved with software.The on board computer will eventually adjust to any changes and equalize any changes.The most interesting statement to me was his statment about weather corrections.He indicated that the software actually "DETUNES" the engine to compensate for higher temps and humididty.It uses less timing and changes the fuel/air mixture to adjust for the conditions.My theory on this is that it is a step change rather than a gradual change.This would explain my sudden performance drop at about 75F.I see very little performance loss until the temp and humidity reach a certain point,then it drops suddenly.
#136
Contributors
Thread Starter
Join Date: Aug 2005
Location: Austin TX
Posts: 6,554
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2014 X5 xDrive 5.0 M Package Carbon Black Metallic/2008 M Roadster Imola Red
![Default](https://5series.net/forums/images/icons/icon1.gif)
That's really interesting g. What he says agrees exactly with your experience. We were backwards in thinking that engine mangement would compensate in a good way for bad weather. It apparently compensates to protect the equipment. And, our above, say 75F passes probably are better than they look after weather and altitude adjustment because of the retarded tuning. I will read the post and post back if I have more to add.
Edit: I see now that you replied to my long post. I'll read it later and will get back to you. I am working on my follow up post.
Edit: I see now that you replied to my long post. I'll read it later and will get back to you. I am working on my follow up post.
#137
Contributors
Thread Starter
Join Date: Aug 2005
Location: Austin TX
Posts: 6,554
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2014 X5 xDrive 5.0 M Package Carbon Black Metallic/2008 M Roadster Imola Red
![Default](https://5series.net/forums/images/icons/icon1.gif)
Originally Posted by grogan545' post='319244' date='Aug 5 2006, 07:13 AM
Zman have you read the post on Dinan Engineering yet.He gives a very in depth analysis of computer engine ...
#138
Contributors
Join Date: Apr 2005
Location: San Diego, CA
Posts: 7,363
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2007 E63 AMG | Obsidian Black | Schwarzes Nappa | Black BirdEye Maple | Premium II Package | Electronic Trunk Closer | Parktronic
Engine: RPi/Powerchips custom ECU tune, RPi Ram Air Kit (BMC filter, scoops), RennTech Sport exhaust, secondary cats, charcoal and resonator delete, custom AAA x-pipe
Exterior: 50% side windows / 35% rear window Formula One Pinnacle Series | Flat AMG hood emblem
Suspension: Renntech Lowering Module
Wheels/Tires: Radenergie R10, Falken FK452 245/30/20, Yokohama ADVAN Sport 285/25/20
-----------------------------------------
2005 545i Sport SMG | Ti Grau | Schwarzes Dakota | Anthracite Maple | Logic 7 | Nav
Engine: Custom AFE CAI, Superchips ECU remap, Sprint Booster, RDSport Dual Exhaust Conversion with Quad Pipes and X-pipe, 3 resonators deleted, 90mm tips!
Exterior: M-Tech Aero kit | M5 Mirrors | M5 Rear Bumper | Trunk Lid Finisher | Vorsteiner decklid spoiler | 50% Formula One Pinnacle Tint
Suspension and Brakes: Bilstein PSS9 coilovers, JBT BBK: 16" cross-drilled rotors, 8 piston and 15" cross-drilled rotors, 4 piston
Wheels: VIP Modular VR 02 20x9F, 20x10R | Toyo T1R 245/30/20F, 285/25/20R
Lights: PIAA 4150K Xtreme White Plus fog lights, AIB v3
MOST IMPORTANT: Hardwired V1; =)
ED Date: 4/7/05, Re-delivery date: 5/21/05
![Default](https://5series.net/forums/images/icons/icon1.gif)
Originally Posted by Znod' post='319281' date='Aug 5 2006, 08:00 AM
Where did you see the post more specifically? I haven't been able to bump into it.
http://forums.e60.net/index.php?showtopic=28871.
#139
Contributors
Thread Starter
Join Date: Aug 2005
Location: Austin TX
Posts: 6,554
Likes: 0
Received 0 Likes
on
0 Posts
My Ride: 2014 X5 xDrive 5.0 M Package Carbon Black Metallic/2008 M Roadster Imola Red
![Default](https://5series.net/forums/images/icons/icon1.gif)
Originally Posted by jiio' post='319282' date='Aug 5 2006, 10:07 AM
Here you go Znod,
http://forums.e60.net/index.php?showtopic=28871.
http://forums.e60.net/index.php?showtopic=28871.
#140
Contributors
Join Date: May 2005
Location: Chicago, IL
Posts: 1,986
Likes: 0
Received 0 Likes
on
0 Posts
![Default](https://5series.net/forums/images/icons/icon1.gif)
Originally Posted by Znod' post='274952' date='Apr 27 2006, 05:23 PM
Four types of loss are possible, drive train (including rolling resistance), aerodynamic drag, altitude, and weather.
I've just been reading up on these 2 long discussions about horsepower losses and such. As near as I can follow, one thing you are trying to solve is where the power losses come from when considering the nameplate rated 325 horsepower of your 545i and the 250HP seen at the rear wheel. There are only two internal forces at play here:
1) Thermal
2) Mechanical
Other external forces, such as aerodynamic drag or rolling resistance have no impact on how much HP is produced at the rear wheels. They certainly do have an influence on how fast you go. For example, you will produce 250HP at the rear wheels whether you are driving into a 30 MPH headwind or have a 10 MPH tailwind. But your speeds will certainly be different in these 2 cases.
Yes, you have properly calculated the aerodynamic drag of 35HP at 90MPH. But this is an external force on the E60 and does not mean you are producing only 190HP at the rear wheel: there still are 250HP there.
The internal thermal forces in play here include the altitude and weather differences you mention, because these conditions dictate how well the engine can approach maximum thermal efficiency . But internal thermal forces would also include the chemical variations of gasoline. Gasoline with 10% ethanol will yield a different power level compared to gasoline with 0% ethanol. The same applies to 91 octane versus 93.
Mechanical forces are the losses of the drivetrain and other parasitic losses, just as you have explained.
That's all. There are no other forces in play in a closed system that includes everything from the engine to the rear wheels.
I'm sorry to say this because of all the work you've put into all of this, but you should drop the aerodynamic "losses" from your calculations. Hopefully this will help simplify your formulas.