5-series Straight-line Performance Discussion
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Originally Posted by Znod' post='246312' date='Feb 26 2006, 02:52 PM
Thanks for the ndw101 info. I can't tell if I am faster since I never did 1/4's using the other meter or altitude/weather corrections (which I couldn't have anyway without doing 1/4's). I have not equaled my earlier raw scores of three 8.71's for the 1/8. I have almost tied my previous best raw score 0 to 60--two 5.07's. But, faster, who knows?????
Incidentally, I misunderstood before. I'll put the corrections factors on the other thread right away. Sorry I misunderstood. But, let me know if you want me to do the corrections and post your new data above. If so, then should I correct your old data also?
I won't post any more data for you until you let me know for sure what you want me to do or to post. Sorry again that I misunderstood.
Incidentally, I misunderstood before. I'll put the corrections factors on the other thread right away. Sorry I misunderstood. But, let me know if you want me to do the corrections and post your new data above. If so, then should I correct your old data also?
I won't post any more data for you until you let me know for sure what you want me to do or to post. Sorry again that I misunderstood.
Thank you very much for the corrected numbers.I got them from the other thread.Just as I thought,my latest run was not my best due to a poor start.I really feel that the cold weather is a disadvantage for me because of my tires.I will do some tests in May when the conditions are close to "standard".
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Addendum to Post #1:
I decided to add a bit of additional information concerning the effects of altitude and weather adjustments. One main point to be made is that weather adjustments can affect unadjusted data positively or negatively. The same can be the case for altitude adjustments assuming that tests are made below sea level. Another main point is that a run that appears to be better (worse) on an unadjusted basis may not be better (worse) after adjustment. So, consider the unadjusted data for my tests 26 and 31.
................................Unadjusted Data
........................2/25--Test 26....2/26--Test 31
1/4 Mile Speed.....104.050.............103.660
1/4 Mile Time.........13.564..............13.657
Next, observe the following results of altitude adjustment alone.
............................Adjusted for Altitude Alone
.........................2/25--Test 26....2/26--Test 31
1/4 Mile Speed......105.902...........105.505
1/4 Mile Time..........13.331............13.423
These data show that altitude adjustment alone can never reverse the speed or time rankings of tests inferred via unadjusted data. That is, test 26 started out better on both dimensions and remains that way after altitude adjustment.
Now, observe what happens when both altitude and weather adjustments are made.
......................Adjusted for Altitude and Weather
........................2/25--Test 26......2/26--Test 31
1/4 Mile Speed.....104.862..............105.323
1/4 Mile Time.........13.461...............13.445
First, notice that neither set of data are as favorable as they were after altitude adjustment alone. This result occurs because the weather condition for both runs were more favorable than the agreed upon "standard" weather conditions. And, second, note that test 26 yields more favorable results when considering either the unadjusted or adjusted-for-altitude-alone data, but that this situation is reversed when both altitude and weather adjustments are made. This reversal occurs because the weather conditions were more favorable on 2/26 than on 2/25.
From the above data, we can infer the implicit weather-alone adjusmented values. They are
..........................Adjusted for Weather Alone
........................2/25--Test 26......2/26--Test 31
1/4 Mile Speed.....103.010..............103.478
1/4 Mile Time.........13.694...............13.679
These values show clearly that weather-alone adjustments can provide worse looking results than unadjusted data because of favorable weather conditions. They also show that weather adjustments can reverse the speed and time rankings suggested by unadjusted data.
Ultimately, the above analysis shows why it is important to make unadjusted data comparable before trying to draw performance inferences. It also shows why it is important to make both altitude and weather adjustments. Many of the effects described above can be seen to apply in the context of the various test results provided in post #1.
I decided to add a bit of additional information concerning the effects of altitude and weather adjustments. One main point to be made is that weather adjustments can affect unadjusted data positively or negatively. The same can be the case for altitude adjustments assuming that tests are made below sea level. Another main point is that a run that appears to be better (worse) on an unadjusted basis may not be better (worse) after adjustment. So, consider the unadjusted data for my tests 26 and 31.
................................Unadjusted Data
........................2/25--Test 26....2/26--Test 31
1/4 Mile Speed.....104.050.............103.660
1/4 Mile Time.........13.564..............13.657
Next, observe the following results of altitude adjustment alone.
............................Adjusted for Altitude Alone
.........................2/25--Test 26....2/26--Test 31
1/4 Mile Speed......105.902...........105.505
1/4 Mile Time..........13.331............13.423
These data show that altitude adjustment alone can never reverse the speed or time rankings of tests inferred via unadjusted data. That is, test 26 started out better on both dimensions and remains that way after altitude adjustment.
Now, observe what happens when both altitude and weather adjustments are made.
......................Adjusted for Altitude and Weather
........................2/25--Test 26......2/26--Test 31
1/4 Mile Speed.....104.862..............105.323
1/4 Mile Time.........13.461...............13.445
First, notice that neither set of data are as favorable as they were after altitude adjustment alone. This result occurs because the weather condition for both runs were more favorable than the agreed upon "standard" weather conditions. And, second, note that test 26 yields more favorable results when considering either the unadjusted or adjusted-for-altitude-alone data, but that this situation is reversed when both altitude and weather adjustments are made. This reversal occurs because the weather conditions were more favorable on 2/26 than on 2/25.
From the above data, we can infer the implicit weather-alone adjusmented values. They are
..........................Adjusted for Weather Alone
........................2/25--Test 26......2/26--Test 31
1/4 Mile Speed.....103.010..............103.478
1/4 Mile Time.........13.694...............13.679
These values show clearly that weather-alone adjustments can provide worse looking results than unadjusted data because of favorable weather conditions. They also show that weather adjustments can reverse the speed and time rankings suggested by unadjusted data.
Ultimately, the above analysis shows why it is important to make unadjusted data comparable before trying to draw performance inferences. It also shows why it is important to make both altitude and weather adjustments. Many of the effects described above can be seen to apply in the context of the various test results provided in post #1.
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Thanks much Eric. I am hoping the tread will be informative and enjoyable. Yes, definitely; gearing, of course, is highly pertinent to straight-line performance as you know.
And, yes, the Step's gearing is superior for straight-line performance--all other things equal. For example, just multiply corresponding single (e.g., first) gear ratios and rear-end ratios for the trannys being compared. When doing so for the Step versus the SMG/manual, one finds that the calculations for the Step imply, from an overall perspective, that the Step is better at producing rear-wheel torque for straight-line performance at least through the 1/4--other things equal.
However, a counteracting force is that the Step should, because of the inherent inefficiencies of autos, produce a greater loss in rear-wheel torque than the other trannys--about 5% more. So, considering matters for only first gear,
Step--4.17 X 3.38 = 14.1 (big advantage to the Step to this point)
SMG--4.05 X 2.93 = 11.87
14.1 - 11.87 = 2.23; 2.23 / 11.87 = 18.79% more rear-wheel torque for the Step other things equal.
Additionally, for example, .1879(330 ft lbs) > .05(330); thus, even after factoring in torque losses from incremental auto tranny inefficiency, the Step comes out ahead, in theory, in rear-wheel torque and, thus, in straight-line performance in first gear. This sort of analysis holds, from an overall perspective, through at least the 1/4 mile.
And, yes, the Step's gearing is superior for straight-line performance--all other things equal. For example, just multiply corresponding single (e.g., first) gear ratios and rear-end ratios for the trannys being compared. When doing so for the Step versus the SMG/manual, one finds that the calculations for the Step imply, from an overall perspective, that the Step is better at producing rear-wheel torque for straight-line performance at least through the 1/4--other things equal.
However, a counteracting force is that the Step should, because of the inherent inefficiencies of autos, produce a greater loss in rear-wheel torque than the other trannys--about 5% more. So, considering matters for only first gear,
Step--4.17 X 3.38 = 14.1 (big advantage to the Step to this point)
SMG--4.05 X 2.93 = 11.87
14.1 - 11.87 = 2.23; 2.23 / 11.87 = 18.79% more rear-wheel torque for the Step other things equal.
Additionally, for example, .1879(330 ft lbs) > .05(330); thus, even after factoring in torque losses from incremental auto tranny inefficiency, the Step comes out ahead, in theory, in rear-wheel torque and, thus, in straight-line performance in first gear. This sort of analysis holds, from an overall perspective, through at least the 1/4 mile.
Oops I accidentally multiplied by 4.17 for the SMG/Manual--having made a copy/paste error. I am correcting what I said above. Then I'll think about the rest of what you say below. Given the correction my analysis and point still hold, but even more emphatically.
Originally Posted by cobradav' post='246367' date='Feb 26 2006, 04:47 PM
Total ratio:
1st in SMG/Manual = 11.87
1st in Step = 14.09
2nd in SMG/Manual = 7.03
2nd in Step = 7.91
Each will get to 60 MPH in 2nd gear but you are getting into the power band quicker in the case of the Step. So there is an offset (tradeoff) to the slower shift in the Step and torque converter losses.
The Step gains in the economy area as both 5th (0.87) and 6th (0.69) are OD ratios while only 6th (0.87) in the SMG/Manual is an OD ratio.
1st in SMG/Manual = 11.87
1st in Step = 14.09
2nd in SMG/Manual = 7.03
2nd in Step = 7.91
Each will get to 60 MPH in 2nd gear but you are getting into the power band quicker in the case of the Step. So there is an offset (tradeoff) to the slower shift in the Step and torque converter losses.
The Step gains in the economy area as both 5th (0.87) and 6th (0.69) are OD ratios while only 6th (0.87) in the SMG/Manual is an OD ratio.
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Originally Posted by grogan545' post='246212' date='Feb 26 2006, 12:35 PM
1-The gear ratios in the step may be better suited to acceleration.
this is what i have been able to finf out regarding the gear ratios
Info as follows:
1st one is manual , the second is automatic
classification of emissions
catalogue number identifying the part number of the gearbox
gear ratios 1/2/3
gear ratios 4/5/6
reverse gear ratio
final drive ratio
please see attachment. Not being an expert in gear ratios, do you see anything in the attachement below that would support your hypothesis
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GUYS PLEASE DONT QUOTE PREVIOUS POSTS FULLY AS THIS REALLY ADDS A LOT OF LENGTH TO THE THREAD
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Originally Posted by 700700' post='246581' date='Feb 27 2006, 06:06 AM
please see attachment. Not being an expert in gear ratios, do you see anything in the attachement below that would support your hypothesis ![Thumbsup](https://5series.net/forums/images/smilies/imported/thumbsup.gif)
GUYS PLEASE DONT QUOTE PREVIOUS POSTS FULLY AS THIS REALLY ADDS A LOT OF LENGTH TO THE THREAD
![Thumbsup](https://5series.net/forums/images/smilies/imported/thumbsup.gif)
GUYS PLEASE DONT QUOTE PREVIOUS POSTS FULLY AS THIS REALLY ADDS A LOT OF LENGTH TO THE THREAD
And, you are right. Let's do our best to not quote large passages unnecessarily. I am going to go back and eliminate any excess I have quoted, and I would appreciate it if we all did so.
Update: OK, it's done; I left quoted material only when I think it is context relevant. Sometimes my quotes still are a bit long though.
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Here's my take on the SMG.
I'd suspect in a 0-60 sprint and most likely a 1/4 mile run the SMG will be slowest of the 3. On a road course however, the SMG would do better.
Main reason is the launch.
With the SMG you only have two launch options:
1. Mash the gas from a dead stop and hope for the best. (You can't torque-brake like you can in an automatic and you can't determine the optimum launch RPM like in a traditional manual).
or
2. Use Accelleration Assist (AA). Great if you are on a smooth and sticky surface that is consistent and you have good tread. Otherwise you'll roast the right rear tire which does not aid in going anywhere quickly. Once you hook up the remaining shifts are very fast but will by no means make up the lost time sitting-and-spinning.
Every now and then you'll get the right combination and all is well, but I've never been able to get consistent results.
I'd suspect in a 0-60 sprint and most likely a 1/4 mile run the SMG will be slowest of the 3. On a road course however, the SMG would do better.
Main reason is the launch.
With the SMG you only have two launch options:
1. Mash the gas from a dead stop and hope for the best. (You can't torque-brake like you can in an automatic and you can't determine the optimum launch RPM like in a traditional manual).
or
2. Use Accelleration Assist (AA). Great if you are on a smooth and sticky surface that is consistent and you have good tread. Otherwise you'll roast the right rear tire which does not aid in going anywhere quickly. Once you hook up the remaining shifts are very fast but will by no means make up the lost time sitting-and-spinning.
Every now and then you'll get the right combination and all is well, but I've never been able to get consistent results.
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Originally Posted by realtyman' post='246726' date='Feb 27 2006, 02:00 PM
Here's my take on the SMG.
Can you add anything to my listing for you above--weather, altitude, rollout, etc.? Here is what I show for you above.
Realtyman (SMG):
Unadjusted for Altitude and Weather:
0 to 60?5.35
(B&B exhaust; K&N filter; not using AA; GT2 meter; rollout?; altitude and weather?).
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Hey Znod.
I'll need a few more months before the weather cooperates.
Temps are still cold and it is impossible to hook up with the cold asphalt and all of the sand & salt on the roads (not to mention the skinnier and far less sticky snow tires).
The cool intake charge is nice but at the expense of a ton of wheel spin (why can't the V-8's get a limited slip
)
Altitude: around 350 ft.
Temp: So freakin' long ago I can't remember (although probably low to mid 70 degree).
Rollout: I'll have to find the G-timer, plug it in and see what I had.
I remember making some adjustment to something when I went from my chipped A6 2.7T to the 545i for roll resistance or something but I know that's not what you are talking about. Most likely it is the standard rollout that it comes programed with.
I'll need a few more months before the weather cooperates.
Temps are still cold and it is impossible to hook up with the cold asphalt and all of the sand & salt on the roads (not to mention the skinnier and far less sticky snow tires).
The cool intake charge is nice but at the expense of a ton of wheel spin (why can't the V-8's get a limited slip
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Altitude: around 350 ft.
Temp: So freakin' long ago I can't remember (although probably low to mid 70 degree).
Rollout: I'll have to find the G-timer, plug it in and see what I had.
I remember making some adjustment to something when I went from my chipped A6 2.7T to the 545i for roll resistance or something but I know that's not what you are talking about. Most likely it is the standard rollout that it comes programed with.
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Originally Posted by realtyman' post='246990' date='Feb 27 2006, 08:47 PM
Altitude: around 350 ft.
Temp: So freakin' long ago I can't remember (although probably low to mid 70 degree).
Rollout: I'll have to find the G-timer, plug it in and see what I had.
Temp: So freakin' long ago I can't remember (although probably low to mid 70 degree).
Rollout: I'll have to find the G-timer, plug it in and see what I had.
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Cant wait for your data realtyman!
Didnt you mention that you got better times w/out AA? If so what mode were you in?
Didnt you mention that you got better times w/out AA? If so what mode were you in?