BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > M3 (E90 / E92 / E93) > M3 vs....
 
GetBMWParts
Post Reply
 
Thread Tools Search this Thread
      12-01-2007, 05:29 PM   #155
swamp2
Lieutenant General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 10,057
iTrader: (1)

Quote:
Originally Posted by footie View Post
swamp2,

I think your estimates for all cars are a little low, especially at higher speeds. On at least 3 tests the M3 has better 25.6s to 150mph yet in your figures it's a full second slower that that, the same applies to the Lexus. We already have tests showing the Lexus better your times and those of the M3 so why sugar coat it in the M3's favour.

I do believe that the M3 with DCT will be a little quicker but I doubt BMW will optimise the gears purely for acceleration, best guess would estimate the first 6 gears staying basically the same with 7th just increasing it's top end and long distance economy. I reckon the only real improvement between manual and DCT will come from the shift times which I reckon your figures are ever so slightly optimistic as the car will have only changed gears 4 times not 5.
Look it may be semantics but these are not "MY" estimates. These are physics based simulations using a commericial software program. When you say these numbers are low you should specify, low compared to what - the worst times, the best times, an average time. In general CarTest figures correlate well with the better times from mags but less often the best times. The thing about a deterministic simulation is that you get the same physics, same launch and same outcome every time. Isn't that in many ways better than the huge variation you get from magazines? I know gbb357 will never uderstand this, but it is a valid and valuable part of simulation.

Furthermore I am not sugar coating anyhting. How is showing the IS-F faster than the M3 MT (which is consistent with test data BTW) sugar coating anything?? You are simply wrong here! Also, for the millionth time simulation is BETTER at comparing relative times rather than absolute times.

I definitely disagree with you about the gear ratios BMW will choose for the 7 M-DCT, why make the car get better mileage thorugh gearing with the DCT itself will do that. Why not use closer ratios as well when you have 7 instead of 6 to cover the same total speed range. Do you think they need to make the high revving engine product faster speeds at very low engine rpm ala a Z06 You OPINIONS simply make no sense here.

Last I have no idea what you mean about 4 vs. 5 shifts. The software shifts all car in simulation at the optimum shift point to maximize acceleration, red line or below redline. I have used .25 s for MT shift speeds, .1 s for IS-F and .03 s for M-DCT. If you can find better data than that and want to run some simulations youself go for it.
swamp2 is online now   United_States
0
Reply With Quote
      12-01-2007, 05:36 PM   #156
swamp2
Lieutenant General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 10,057
iTrader: (1)

Quote:
Originally Posted by gbb357 View Post
I've been saying this from the begining. No software out there can really replicate "launch techniques" because it's a human factor. Reaction times makes a huge difference. Like the example that i've posted in the "regression thread", when i took my car in a track the best 1/4 mile that i got was 15.9 & 16.0. But when my friend drove my car who is much more experience than i am, he was able to do 15.4 and 15.5. The same applies to a track course, the driver factor will significantly have a huge difference on how fast or slow a car will perform.
Wrong.

If you want a deterministic simulation (do you know what that even means...?) to be a stochastic one, then no, this particular software does not do this auotmatically. However, putting a human into the "equation" is all you are asking for, and this can easily be done by computer. Next 0-X speed times are completely independent from reaction time, the clock only starts ticking once the car starts moving. Reaction time is simply irrelevant here. It only becomes relevant for the human at the drag strip, never for a simulation.

You just keep missing the poing, which is what about half of the earlier part of the thread was about. Multiple people pointed this out to you and you earlier and you are still oblivious to it and KEEP MISSING THE MAIN POINTS.
swamp2 is online now   United_States
0
Reply With Quote
      12-01-2007, 06:53 PM   #157
gbb357
Captain
 
Drives: IS300
Join Date: Oct 2007
Location: New York

Posts: 707
iTrader: (0)

Quote:
Originally Posted by swamp2 View Post
Wrong.

If you want a deterministic simulation (do you know what that even means...?) to be a stochastic one, then no, this particular software does not do this auotmatically. However, putting a human into the "equation" is all you are asking for, and this can easily be done by computer. Next 0-X speed times are completely independent from reaction time, the clock only starts ticking once the car starts moving. Reaction time is simply irrelevant here. It only becomes relevant for the human at the drag strip, never for a simulation.

You just keep missing the poing, which is what about half of the earlier part of the thread was about. Multiple people pointed this out to you and you earlier and you are still oblivious to it and KEEP MISSING THE MAIN POINTS.
As usual, blah-blah-blah-blah-blah. You are correct for once, i did miss the "poing". WTF is a "poing"! Reaction time is irrelevent when your trying to get the best acceleration time? LOL!!!!!!!!!! You are killing me. Have you run a car at all in a 1/4 mile track, oh wait you don't need to. You can just use your formula and calculate your time and speed. Reaction time is always relevent if you're trying to get the best possible acceleration just as wheel spin is relevent as well. It does not matter if your doing 1/4 mile or not. It will affect your time to get to 60 or the 1/4 mile. Just like if you do a 5-60mph is usually slower from 0-60mph if done correctly. You're right again, it does not matter in a simulation and that's why your numbers are way off and does not prove anything even though you where so adamant about it being more accurate than the numbers that the magazines where getting, especially C&D. It's just a freaking simulation, get over it!
gbb357 is offline  
0
Reply With Quote
      12-01-2007, 10:56 PM   #158
swamp2
Lieutenant General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 10,057
iTrader: (1)

Quote:
Originally Posted by gbb357 View Post
As usual, blah-blah-blah-blah-blah. You are correct for once, i did miss the "poing". WTF is a "poing"! Reaction time is irrelevent when your trying to get the best acceleration time? LOL!!!!!!!!!! You are killing me. Have you run a car at all in a 1/4 mile track, oh wait you don't need to. You can just use your formula and calculate your time and speed. Reaction time is always relevent if you're trying to get the best possible acceleration just as wheel spin is relevent as well. It does not matter if your doing 1/4 mile or not. It will affect your time to get to 60 or the 1/4 mile. Just like if you do a 5-60mph is usually slower from 0-60mph if done correctly. You're right again, it does not matter in a simulation and that's why your numbers are way off and does not prove anything even though you where so adamant about it being more accurate than the numbers that the magazines where getting, especially C&D. It's just a freaking simulation, get over it!
An appropriately mature and elegant response, "blah-blah-blah...". You really must learn what it means to discuss, debate and simply to write.

And "poing", OMG so sorry to upset your delicate sense of language, spelling and grammar. Notice the context using the word "point" in the immediately preceeding sentence? And that the "G" key is right next to the "T" key, probably not - a bit too subtle for you. On that point I will glady bet that I have many fewer grammar and spelling errors as a percentage in my posts than yours. No one here will be very confused as to who has a drastically superior mastery of language, both English and Science (which is a language you so tremendously misunderstand). P.S your "where" above should be "were" you little hypocrite .

You are so fantastic at missing key points I'm going to have to think of a clever little nick name for you. Like I said above....REACTION TIME IS IRRELEVANT TO TIMED SPEED CONTESTS OF 0-ANY mph, WHEN THE CLOCK STARTS WHEN THE MOVEMENT DOES. Of course reaction time is key when the bloody clock starts when the light turns green. A simulation of a 1/4 mi time uses 0.0 second reaction time. If you wanted to alter that and choose a reaction time you could, but trying to match the best a human can do, it seems best to leave that parameter as default. BTW, just to clarify, I have run at the 1/4 mi strip, but it is far from my favorite motorsport activity. Nonetheless I'd be happy to meet you at the strip in my beat on, 200k+ mi, 10+ year old car and teach you a thing or two.

You'll have to get over cars if you want to get over simulation because simulation is used so amazing broadly and deeply to design every modern car these days. It is used for just about everything: strength, durability, suspension kinematics and dynamics, engine, exhaust, brakes, comfort, safety, electrical, thermal, aerodynamics, acoustics, ergonomics, you name it. Maybe you might wonder why simulation is used so extensively (well you probably never actually pondered this...)? Let me tell you why - SIMPLY BECAUSE IT WORKS AND IS ACCURATE. Continue to live in your small isolated world of denial.

In fact you will have to get over yourself if you want to get over science or physics, they govern every little detail of your annoying self as well.
swamp2 is online now   United_States
0
Reply With Quote
      12-02-2007, 12:21 AM   #159
swamp2
Lieutenant General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 10,057
iTrader: (1)

gbb357: This is all that is left.

swamp2 is online now   United_States
0
Reply With Quote
      12-02-2007, 02:33 AM   #160
footie
Major General
 
footie's Avatar
 
Drives: ????????????
Join Date: Oct 2007
Location: BMW M3 will get a V6TT

Posts: 7,507
iTrader: (0)

Garage List
2008 E92 M3  [0.00]
Quote:
Originally Posted by swamp2 View Post
I definitely disagree with you about the gear ratios BMW will choose for the 7 M-DCT, why make the car get better mileage thorugh gearing with the DCT itself will do that. Why not use closer ratios as well when you have 7 instead of 6 to cover the same total speed range. Do you think they need to make the high revving engine product faster speeds at very low engine rpm ala a Z06 You OPINIONS simply make no sense here.

Last I have no idea what you mean about 4 vs. 5 shifts. The software shifts all car in simulation at the optimum shift point to maximize acceleration, red line or below redline. I have used .25 s for MT shift speeds, .1 s for IS-F and .03 s for M-DCT. If you can find better data than that and want to run some simulations youself go for it.
swamp2,

DSG style gearboxes are something I know a little about as I have had some experience with them.

Number one mistake is that they do not improve economy, they offer the same economy as a manual but better that of an automatic which is the biggest sales pitch by marketing. Number two, the M5/6 both are limited to 155mph but their true topspeed is about 205mph and 6th gear is good for about 186mph so where is the logic in that if the thing is limited on 95% of it's sales markets.

I just think you are jumping to conclusions that the gearbox will be set up for acceleration by on what you personally are looking for. If we were talking about the CSL then I would wholeheartedly agree with this opinion but we aren't.

As for simulators, I think the problem with them is people read too much into them. Think of it this way, if you pull up to the lights in your car (X) and along side pull up car (Y) which according to the simulator will beat car (Y), what would you excuse be to your girlfriend when you lost.

See me point, it all well and good to use them as a tool but that is all they are.
footie is offline   No_Country
0
Reply With Quote
      12-02-2007, 05:29 AM   #161
swamp2
Lieutenant General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 10,057
iTrader: (1)

Quote:
Originally Posted by footie View Post
DSG style gearboxes are something I know a little about as I have had some experience with them.
Which car with a DSG box have you owned? If it is the M5 you are referring to that absolutely is not DSG. SMG, DSG and DCT are all AMTs but SMG is absolutely not a dual clutch system as DSG and DCT are.

Quote:
Originally Posted by footie View Post
Number one mistake is that they do not improve economy, they offer the same economy as a manual but better that of an automatic which is the biggest sales pitch by marketing. Number two, the M5/6 both are limited to 155mph but their true topspeed is about 205mph and 6th gear is good for about 186mph so where is the logic in that if the thing is limited on 95% of it's sales markets.
WRONG. The data point I refer to is the GTI mpg for the DSG. It offers a 9% better city mpg than the MT. I'd bet the Audi with the DSG box offers similar benefit. The reason for this is quite simple and it is something SMGs do not offer: almost uninterrupted delivery of power to the ground. No letting off the gas, clutching, shifting, getting back on the gas, ALL WHILE DECLERATING from air and rolling resistance, not only wasting fuel in the process but slowing down which then requires wasting more fuel to get back up the speed you were going just when you started the shift. It is really quite wasteful. You can see it clearly on simulation charts of speed vs. time and it looks exactly the same with real world data

Quote:
Originally Posted by footie View Post
I just think you are jumping to conclusions that the gearbox will be set up for acceleration by on what you personally are looking for. If we were talking about the CSL then I would wholeheartedly agree with this opinion but we aren't.
Yeah, you're right no one buys an M3 because it if fast, no one cares about the acceleration. "What I personally want"??? WTF do you want - a slow sports car ? Give me a break.

Quote:
Originally Posted by footie View Post
As for simulators, I think the problem with them is people read too much into them. Think of it this way, if you pull up to the lights in your car (X) and along side pull up car (Y) which according to the simulator will beat car (Y), what would you excuse be to your girlfriend when you lost.

See me point, it all well and good to use them as a tool but that is all they are.
Since the time I started posting simulations (or commenting on performance numbers for that matter), I have always said that when things are within a couple tenths or so that it will always be a drivers race. As it will with these cars as well (like I have said repeatedly...).

As for your example, I'd say, "damn I know my car is faster and I can beat that fellow but he out drove me" (or "he has a heavily modded sleeper", that will always give you wiggle room as well...).
swamp2 is online now   United_States
0
Reply With Quote
      12-02-2007, 06:39 AM   #162
footie
Major General
 
footie's Avatar
 
Drives: ????????????
Join Date: Oct 2007
Location: BMW M3 will get a V6TT

Posts: 7,507
iTrader: (0)

Garage List
2008 E92 M3  [0.00]
Quote:
Originally Posted by swamp2 View Post
Which car with a DSG box have you owned? If it is the M5 you are referring to that absolutely is not DSG. SMG, DSG and DCT are all AMTs but SMG is absolutely not a dual clutch system as DSG and DCT are.
swamp2, I know the difference between DSG and SMG give me a break. The DSG I own is a Mk5 GTi (funny enough) though I have also owned an Mk5 GTi manual (both the wife's cars). When I was referring to the M5/6 (SMG) I was stating a fact that the gearbox was setup for maximum speed not acceleration though in fairness it copes bloody well with this as well.


Quote:
Originally Posted by swamp2 View Post
WRONG. The data point I refer to is the GTI mpg for the DSG. It offers a 9% better city mpg than the MT. I'd bet the Audi with the DSG box offers similar benefit. The reason for this is quite simple and it is something SMGs do not offer: almost uninterrupted delivery of power to the ground. No letting off the gas, clutching, shifting, getting back on the gas, ALL WHILE DECLERATING from air and rolling resistance, not only wasting fuel in the process but slowing down which then requires wasting more fuel to get back up the speed you were going just when you started the shift. It is really quite wasteful. You can see it clearly on simulation charts of speed vs. time and it looks exactly the same with real world data
I am not arguing with your data, I am just saying that the facts are there is no improvement in economy between the DSG and Manual. Maybe this will not be the case with the M-DCT as it has more gears, remember the DSG from VAG is 6 gears not 7.


Quote:
Originally Posted by swamp2 View Post
Yeah, you're right no one buys an M3 because it if fast, no one cares about the acceleration. "What I personally want"??? WTF do you want - a slow sports car ? Give me a break.
Sorry but I am a bit lost as to these above comments, as you are well aware Green issues are in the headline all the time now and I doubt even BMW won't be trying to improve the M3's economy further with the intro of this M-DCT gearbox. What happens if it's not got 7gears but 8, will you still believe that the 8 gears are setup for the sole purpose of acceleration. GIVE ME THE BREAK. PLEASE!!!!!

Quote:
Originally Posted by swamp2 View Post
Since the time I started posting simulations (or commenting on performance numbers for that matter), I have always said that when things are within a couple tenths or so that it will always be a drivers race. As it will with these cars as well (like I have said repeatedly...).

As for your example, I'd say, "damn I know my car is faster and I can beat that fellow but he out drove me" (or "he has a heavily modded sleeper", that will always give you wiggle room as well...).
I reckon driver's abilities play a much bigger role in acceleration times than almost anything. I have personally beat an old M5 with my S5 and I know that the odd of winning were well and truly stacked against me on that one.

All I am saying about simulators are they are a good estimate of a car's capabilities, nothing more.
footie is offline   No_Country
0
Reply With Quote
      12-02-2007, 10:33 AM   #163
gbb357
Captain
 
Drives: IS300
Join Date: Oct 2007
Location: New York

Posts: 707
iTrader: (0)

Swampass, you're a Moron.

Quote:
Originally Posted by swamp2 View Post
An appropriately mature and elegant response, "blah-blah-blah...". You really must learn what it means to discuss, debate and simply to write.

And "poing", OMG so sorry to upset your delicate sense of language, spelling and grammar. Notice the context using the word "point" in the immediately preceeding sentence? And that the "G" key is right next to the "T" key, probably not - a bit too subtle for you. On that point I will glady bet that I have many fewer grammar and spelling errors as a percentage in my posts than yours. No one here will be very confused as to who has a drastically superior mastery of language, both English and Science (which is a language you so tremendously misunderstand). P.S your "where" above should be "were" you little hypocrite .

You are so fantastic at missing key points I'm going to have to think of a clever little nick name for you. Like I said above....REACTION TIME IS IRRELEVANT TO TIMED SPEED CONTESTS OF 0-ANY mph, WHEN THE CLOCK STARTS WHEN THE MOVEMENT DOES. Of course reaction time is key when the bloody clock starts when the light turns green. A simulation of a 1/4 mi time uses 0.0 second reaction time. If you wanted to alter that and choose a reaction time you could, but trying to match the best a human can do, it seems best to leave that parameter as default. BTW, just to clarify, I have run at the 1/4 mi strip, but it is far from my favorite motorsport activity. Nonetheless I'd be happy to meet you at the strip in my beat on, 200k+ mi, 10+ year old car and teach you a thing or two.

You'll have to get over cars if you want to get over simulation because simulation is used so amazing broadly and deeply to design every modern car these days. It is used for just about everything: strength, durability, suspension kinematics and dynamics, engine, exhaust, brakes, comfort, safety, electrical, thermal, aerodynamics, acoustics, ergonomics, you name it. Maybe you might wonder why simulation is used so extensively (well you probably never actually pondered this...)? Let me tell you why - SIMPLY BECAUSE IT WORKS AND IS ACCURATE. Continue to live in your small isolated world of denial.

In fact you will have to get over yourself if you want to get over science or physics, they govern every little detail of your annoying self as well.
Blah-blah-blah-blah. I actually get the "poing". The "poing" is that you're a MORON! The fact that you had to explain yourself about the "poing" which was obviously a typo, shows how arrogant and self centered you are. You just don't like to admit that you where wrong and you are the type of person that is never wrong and is always right. Back on topic, again you MORON, reaction time is very relevent. If you start rolling the car and the clock starts as opposed to getting a good jump, don't you think that would make a difference you MORON. I'm all for simulation for estimating a car's performance capabilities, but again that is all that is, a freaking simulation! All it is for is to give you an estimation of what performance you should be able to get. IT IS NOT AN EXACT SCIENCE! That's why it's called an estimation you MORON. We already have covered how many variables that a simulation cannot equate. Tires, road surface, driver, just to mention a couple. Don't bring up desings you MORON, that is a completely different subject entirely.

Last edited by gbb357; 12-02-2007 at 03:16 PM.
gbb357 is offline  
0
Reply With Quote
      12-02-2007, 04:10 PM   #164
swamp2
Lieutenant General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 10,057
iTrader: (1)

swamp2 is online now   United_States
0
Reply With Quote
      12-02-2007, 06:12 PM   #165
gbb357
Captain
 
Drives: IS300
Join Date: Oct 2007
Location: New York

Posts: 707
iTrader: (0)

This movie was sooo funny Swampass and you're still a moron!

Quote:
Originally Posted by swamp2 View Post
This guy probably looks just like you.
gbb357 is offline  
0
Reply With Quote
      12-02-2007, 09:06 PM   #166
swamp2
Lieutenant General
 
swamp2's Avatar
 
Drives: E92 M3
Join Date: Sep 2006
Location: San Diego, CA USA

Posts: 10,057
iTrader: (1)


swamp2 is online now   United_States
0
Reply With Quote
      12-02-2007, 09:19 PM   #167
gbb357
Captain
 
Drives: IS300
Join Date: Oct 2007
Location: New York

Posts: 707
iTrader: (0)

Twice as funny and you're still a MORON!

Quote:
Originally Posted by swamp2 View Post

LOL!!!
gbb357 is offline  
0
Reply With Quote
      12-02-2007, 10:30 PM   #168
enigma
Captain
 
Drives: E92 M3 and Elise
Join Date: Oct 2006
Location: Land of the Microchip

Posts: 689
iTrader: (0)

The IQ of this board seems to be going down with every post these days.
enigma is offline  
0
Reply With Quote
      12-02-2007, 10:55 PM   #169
Keto
Major
 
Keto's Avatar
 
Drives: 550i M-sport AW
Join Date: Jul 2007
Location: N'awlins

Posts: 1,425
iTrader: (1)

It's more likely dementia, as he drives an IS300, and Lexus sells most of its cars to retirees.
Keto is offline   United_States
0
Reply With Quote
      12-02-2007, 11:09 PM   #170
OzStriker
Captain
 
OzStriker's Avatar
 
Drives: Ford Falcon Ute, Ducati 1198S
Join Date: Sep 2007
Location: Melbourne

Posts: 923
iTrader: (1)

Garage List
Send a message via MSN to OzStriker
OzStriker is offline   Australia
0
Reply With Quote
      12-03-2007, 08:53 AM   #171
gbb357
Captain
 
Drives: IS300
Join Date: Oct 2007
Location: New York

Posts: 707
iTrader: (0)

Quote:
Originally Posted by Keto View Post
It's more likely dementia, as he drives an IS300, and Lexus sells most of its cars to retirees.

Very nice, another moron. Do you even know what we're talking about, it's not about Lexus vs BMW you moron. I've been a fan of BMW since 86'.

Last edited by gbb357; 12-03-2007 at 09:33 AM.
gbb357 is offline  
0
Reply With Quote
      12-03-2007, 09:16 AM   #172
gbb357
Captain
 
Drives: IS300
Join Date: Oct 2007
Location: New York

Posts: 707
iTrader: (0)

Quote:
Originally Posted by Keto View Post
It's more likely dementia, as he drives an IS300, and Lexus sells most of its cars to retirees.
Just so you know, there are many members here that don't drive a BMW and you just diss Celsius who drives a LS430, Epacy drives a Maxima and ChitownM3 drives a Camaro SS just to name a few. Are you gonna be a typical badge whore fan boy and diss them all too?

Last edited by gbb357; 12-03-2007 at 02:33 PM.
gbb357 is offline  
0
Reply With Quote
      12-06-2007, 12:22 PM   #173
bruce.augenstein@comcast.
Lieutenant Colonel
 
Drives: Legacy GT - 13.704@99.39
Join Date: Jul 2007
Location: Manheim, PA

Posts: 1,867
iTrader: (0)

Pilot error? GIGO? Lousy software? Poor instructions?

Quote:
Originally Posted by swamp2 View Post
OK since you asked, I will humor you. There is no reason not to share the capabilities or validation of a software tool I like and call accurate.

Using the exact figures in your post and making only the following minor changes to the default CarTest parameters: weight - to match the measured curb weight (software includes options and defaults for driver weight and gas weight and they did not match the number you posted for this particular car), shift times - default is .5 s a more realistic figure for a good driver in a MT is .3 s. Conclusions:

-0-60: right on the money or within 3/10th however you like to call it
-0-100: within 7/10th or 1/10th
-1/4mi: within 1/10th to 4/10ths on ET
-1/4mi: trap within 1.5 - 3.5 mph

I think this is very typical of what one car get with CarTest. Do you notice how much closer this is comparing simulation to one actual test than the case we argued about for pages. I suspect that some tests do show better numbers and others worse for the E46 M3. My conclusion from this exercise is that both the reported figures for the car, the inputs to CarTest, the actual test itself and the simulation outputs are "consistent". There is no glaring/obvious problem with any of the pieces of the puzzle.

My C63 AMG results today were just as good!

Enjoy.

P.S. One big reason the E46 M3 is fairly fast given its peak hp/weight ratio (not all that hot) is it's high redline and short gear ratios i.e. torque multiplication, just like the new car (I mean wrt gearing not a moderate hp/weight ratio).
OK, now that the smoke has cleared and everyone has cooled off a bit, I thought I'd address these simulations.

Swamp, the thing is, useful tool or not, the simulation results seem to be fairly poor - notwithstanding your feeling that the results are just fine.

Using the above E46 M3 results as an example, the simulator seems to show a power shortfall of around 10% compared with C & D's "new car" results - and C & D's results are not atypical of what one might expect of such a vehicle, corrected to approximate SAE "gross" Standard Day meteorological conditions. Our car went a best of 13.12 at 107 and change, if memory serves.

A simulation that represents an approximate 10% power loss is seriously deficient.

Doing some minor analysis, the ET-to-speed relationship (ET times speed) is about right, with the simulation coming in at a 1396 compared to C & D's 1402. (What one should look for is a number of about 1400 or better, with very powerful street cars struggling to reach this number. Anything much over 1400 means you've got a significant traction or gearing problem - or a pilot unfamilair with basic starting line procedures. Much under 1400 shows traction and torque.)

One thing that does in fact stand out a bit is that the simulator shows a pickup of less than 20 miles per hour (19.81, to be exact) between the 660 and 1320 foot markers. Not to put too fine a point on it, but this car-made-of-electrons is a flat pig on the top end, which is just where you'd expect a power-laden, torque-challenged car to really be coming on strong, particularly with the relatively close gear-spacing BMW uses after second gear. Our E46 picked up an average of nearly 24 mph as a comparison, and other cars we've documented also have done comparitively well on the top end, as well.

Examples:

'85 Vette, 230 HP, 3230 pounds. Average 13.77 @ 101.36 MPH, picked up an average of 21.24 MPH in the last 660 feet over 20 runs.

'91 Saleen, unknown power and weight. Average 13.67 @ 102.11 MPH, picked up 20.71 MPH over a dozen runs.

'93 Vette, 300 HP, 3340 pounds. Average 13.13 @ 107.04 MPH, picked up 22.59 MPH over 31 runs.

'95 M3, 240 HP, 3220 pounds. Average 14.11 @ 98.42 MPH, picked up 20.15 MPH over 30 runs.

'04 M3, 333 HP, 3410 pounds. Only made three runs and didn't save the slips, but I checked while at the scene, and the car averaged around 13.2 @ about 107, with a 660 foot speed in the 83 range.

Now (and finally getting on point), your simulation in note #89 shows that the Lexus is also a pig on the top end, doing only around a 20 MPH pickup in the last 1/8th mile. A car with this power to weight will just flat do better than that, especially compared with the examples already given in this note.

I mean no disrespect, but to me, this is symptomatic of a general problem with these particular simulation results. I don't know the solution to the problem, but I do know there is a definite problem which makes these results pretty much without significant value, and by inference, other simulations you generate with this tool without a serious re-evaluation.

Bruce

PS - A high redline and short gear ratios have very little to do with actual quarter-mile results. Gearing essentially only matters a damn in the first 60 feet or so, and on a traction-challenged car, it won't make a significant difference even in that range. It's power and weight that mostly matter with cars in this performance range.
bruce.augenstein@comcast. is offline  
0
Reply With Quote
      12-06-2007, 12:58 PM   #174
lucid
Major General
 
lucid's Avatar
 
Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

Posts: 8,034
iTrader: (0)

Quote:
Originally Posted by bruce.augenstein@comcast. View Post
PS - A high redline and short gear ratios have very little to do with actual quarter-mile results. Gearing essentially only matters a damn in the first 60 feet or so, and on a traction-challenged car, it won't make a significant difference even in that range. It's power and weight that mostly matter with cars in this performance range.
Bruce, not sure what to make of this statement. What makes you say gearing matters during the initial 60 ft and doesn't matter after that? The car is accelerating both before and after 60ft, so how can torque at the wheel and a high redline not matter after 60 ft?
lucid is offline   United_States
0
Reply With Quote
      12-06-2007, 01:12 PM   #175
enigma
Captain
 
Drives: E92 M3 and Elise
Join Date: Oct 2006
Location: Land of the Microchip

Posts: 689
iTrader: (0)

Quote:
Originally Posted by lucid View Post
Bruce, not sure what to make of this statement. What makes you say gearing matters during the initial 60 ft and doesn't matter after that? The car is accelerating both before and after 60ft, so how can torque at the wheel and a high redline not matter after 60 ft?
He is right which is why I always say engine torque is overrated.

After the car is moving the engine should stay in its powerband. At that point the engine HP becomes a very good measure of TQ at the rear wheels since the engine RPM will be modified by whatever gears are needed at the speed the car is moving.

Its all about rear wheel torque but thats more a product of engine HP than engine TQ.

I suspect the flaw in the simulation may involve aerodynamic drag.
enigma is offline  
0
Reply With Quote
      12-06-2007, 07:15 PM   #176
lucid
Major General
 
lucid's Avatar
 
Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

Posts: 8,034
iTrader: (0)

Quote:
Originally Posted by enigma View Post
He is right which is why I always say engine torque is overrated.

After the car is moving the engine should stay in its powerband. At that point the engine HP becomes a very good measure of TQ at the rear wheels since the engine RPM will be modified by whatever gears are needed at the speed the car is moving.

Its all about rear wheel torque but thats more a product of engine HP than engine TQ.

I suspect the flaw in the simulation may involve aerodynamic drag.
You do realize hp and tq are directly coupled, and that hp is a measure of torque applied per unit time?
lucid is offline   United_States
0
Reply With Quote
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 05:58 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST