[BULL]

UPDATE: I'm not sure if everyone gets that there are Excel spreadsheets that can be downloads and played with, but there are.

Also, I'm updating the spreadsheets to be more eye-friendly (thank you to 762CAT for complaining, without him, you would all have headaches.) I've done the A8 comparison first because there are more of you and more of you change out your ass-ends...

Lastly, the calculations DO NOT account for where your power band is or is not, just because your gearing will get you there, does not mean your motor will...


(original post below)
==================================


I've posted a version of this up before, but I've always wanted to be able to compare the M6 / A8 gear change points by speed.

I use this for the Standing Mile event that I play in... You use it as you see fit...

Standard internet disclaimer goes along with this, the worksheet isn't warrantied to be free of error, use as a reference tool only. If you enter the wrong numbers, your screen will explode in your face, possibly making you prettier...

For those who are experts at Excel, I am NOT, don't biatch at me... If you don't like mine, go make your own...

Further, I acknowledge right up front that the formulas are a bit screwy, but there is (was?) logic behind the madness and it suits me, if not you, see above...

The big elephant in the room (worksheet) is the tire revs per mile***. I know this, don't biatch at me, and again, see above... Before you start biatching, we're likely talking about 1%, and I can live with that even though I don't like it. I also believe that the revs/mile CHANGES from low speed, highway speed, and REAL speed. This based on lots of direct testing... Think centripetal force on the tire belt...

Directions for use:

1. Make a copy and save it elsewhere if you're anything like me...
2. Spreadsheet is not locked, if you delete stuff, see #1
   
3. Have an understanding of what's going on...
4. Enter rearend gearset ratio
5. Enter tire revs/mile***
6. Enter RPMs for each gear that you want to see, delete RPMs
7. Eat lunch

EDIT: Added "Comparison" worksheets so you can directly compare the same transmissions with different differential gearsets.
EDIT2: Corrected a few minor issues in the M6 GS1/GS2 worksheet
EDIT3: Replaced A8 vs A8 worksheet with "compact" version, easier on the eyes and cleaner.
EDIT4: Replaced M6 vs M6 as in edit3
EDIT5: Replaced M6 vs A8 as above, that's it for now unless somebody finds something.

 

[blaze]

I've posted a version of this up before, but I've always wanted to be able to compare the M6 / A8 gear change points by speed.

I use this for the Standing Mile event that I play in... You use it as you see fit...

Standard internet disclaimer goes along with this, the worksheet isn't warrantied to be free of error, use as a reference tool only. If you enter the wrong numbers, your screen will explode in your face, possibly making you prettier...

For those who are experts at Excel, I am NOT, don't biatch at me... If you don't like mine, go make your own...

Further, I acknowledge right up front that the formulas are a bit screwy, but there is (was?) logic behind the madness and it suits me, if not you, see above...

The big elephant in the room (worksheet) is the tire revs per mile***. I know this, don't biatch at me, and again, see above... Before you start biatching, we're likely talking about 1%, and I can live with that even though I don't like it. I also believe that the revs/mile CHANGES from low speed, highway speed, and REAL speed. This based on lots of direct testing... Think centripetal force on the tire belt...

Directions for use:

1. Make a copy and save it elsewhere if you're anything like me...
2. Spreadsheet is not locked, if you delete stuff, see #1
   
3. Have an understanding of what's going on...
4. Enter rearend gearset ratio
5. Enter tire revs/mile***
6. Enter RPMs for each gear that you want to see, delete RPMs
7. Eat lunch

ahahahhahahahahahhahah

 

[BULL]

*From other thread...

With stock tires and a 3.90, 175 mph will put you at 6131 rpm, which is why you would need to shift.

I get just a touch over 6200, (close enough), and you're right, I either have to push 6400, which gets me ~180mph, or shift, and lose...

6400rpm isn't that bad, right....????

 

[BULL]

 

[BULL]

LaserDoc

Did you run the 3.90 before you changed over to the 9"?

 

[LaserDoc]

No, I knew the 9 was going in, so I left the 3.70 in.

LaserDoc



Did you run the 3.90 before you changed over to the 9"?

Now, at 7200, I can hit 215 mph with a .865 5th gear and a 3.25 rear.

 

[LaserDoc]

The modern Hemi record is 212.xxx, in the mile. Hmmmm,lol!

 

[BULL]

I added a couple of variations on the spreadsheets, now you can directly compare the same transmission with different gearsets (differential ratios)



And it's very apparent why you A8 owners all like the 3.09's so much, without them, 7th and 8th are kind of useless for anything other than highway mileage....

 

[BULL]

No, I knew the 9 was going in, so I left the 3.70 in.



Now, at 7200, I can hit 215 mph with a .865 5th gear and a 3.25 rear.

The modern Hemi record is 212.xxx, in the mile. Hmmmm,lol!

What's your 1st gear ratio going to be in that trans?

 

[blaze]

I added a couple of variations on the spreadsheets, now you can directly compare the same transmission with different gearsets (differential ratios)



And it's very apparent why you A8 owners all like the 3.09's so much, without them, 7th and 8th are kind of useless for anything other than highway mileage....

nice.

 

[LaserDoc]

What's your 1st gear ratio going to be in that trans?

2.42 6th gear is the same as the stock 5th, .77!

 

[BULL]

You versus me....



(I didn't change your gear ratios on 2nd, 3rd or 4th...)



It sure will scream, 'can't wait to hear about it...

 

[blaze]

thanks BULL nice work man

 

[DMNKILR]

thanks BULL nice work man

Thanks!! Makes for some really interesting reading for those of us changing a few things around in the driveline

 

[BULL]

I'm working on an acceleration based sheet that will tell you *WHEN (as in at what point in the mile...) you'll be shifting....


**You'll need accelerometer data to use this one... Feasibility yet to be validated...

 

[Blown7]

I'm working on an acceleration based sheet that will tell you *WHEN (as in at what point in the mile...) you'll be shifting....


**You'll need accelerometer data to use this one... Feasibility yet to be validated...

Use the accelerometer from the vehicle on the Can bus.

 

[BULL]

Use the accelerometer from the vehicle on the Can bus.

Yeah, that's a possibility, I've got data from an external accelerometer for the run I'm looking at, I don't know at this point if it's accurate enough or not to accomplish the goal, time will tell, maybe tonight...

 

[BULL]

So my other spreadsheet that I was going to post that used acceleration and time data ended up not working out...


blaze

So this ended up being non-viable... There is to much variability in the approach, a combination of inaccuracies in the g-load sensor and timing. I think in order for this approach to be viable, there needs to be another order of magnitude of accuracy and repeatability.

For example, if you watch the video, the g-load sensor bounces around quite a bit, even watching it many times and trying to average out the data ultimately results in a failed interpretation.

While I got the numbers to match (somewhat) my 173.7 standing mile time and speed, I had to "cheat" them to make it workout.

 

[blaze]

So my other spreadsheet that I was going to post that used acceleration and time data ended up not working out...


blaze

So this ended up being non-viable... There is to much variability in the approach, a combination of inaccuracies in the g-load sensor and timing. I think in order for this approach to be viable, there needs to be another order of magnitude of accuracy and repeatability.

For example, if you watch the video, the g-load sensor bounces around quite a bit, even watching it many times and trying to average out the data ultimately results in a failed interpretation.

While I got the numbers to match (somewhat) my 173.7 standing mile time and speed, I had to "cheat" them to make it workout.



View attachment 138689

ahem.. i rest my case.. BULL can calculate the crap out of ANYTHING.

nice work man. wish you lived closer.


edit: non-viable how? nevermind i answered my own question looking closer. you just need more runs and more data from others.

 

[BULL]

ahem.. i rest my case.. BULL can calculate the crap out of ANYTHING.

nice work man. wish you lived closer.


edit: non-viable how? nevermind i answered my own question looking closer. you just need more runs and more data from others.

Thank you, it really isn't high level physics to be honest, really 1st year stuff.

My goal was to be able to say at what point, down to say 10 or 20 feet within the mile, I was making that final shift into 5th gear. If I could do that accurately, then by substituting the other differential gearset in, I could then say how much longer in time I would have to accelerate and then therefor achieve what trap speed.

But with just a couple of iterations and experimentation, it became clear that the accelerometer data bounces and/or isn't repeatable to the precision level I need. Like I said, as it is, I really had to cheat to get even this first level to look anything like my actual run....