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      10-25-2016, 05:47 AM   #67
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Originally Posted by brad850csi View Post
I'm aware of all of this, it was the A5 and 2008 A4 I think that changed the location of the front diff iirc.

I understand that there is the equal length setup now with the fixed intermediate shaft running through the middle of the gearbox, but that still means that from the diff, one side just has the weight of a shaft and the other side has a both that weight as well as the weight of the intermediate shaft. Perhaps I shouldn't have worded my post quite that way, but in my mind the front diff isn't in the centre line, so there is still an effective difference in inertia between left and right.

It is 100% noticable in the lower gears and makes for a crap driving experience. As per my sig I have a C63 as my daily driver and the owner of the company I work for has had a number of quick Audis including the previous 3.0 Supercharged S4 and two of the current gen RS6, one prefacelift and one facelift. I've driven all of the cars quite a bit and I really enjoyed the DSG in the S4 as well as the lighter weight. The steering was a bit weird in regards to weight and consistent feel, but perhaps the 440nm wasn't enough to really show off the torque steer.

The first time I drove the RS6 however I remember when I floored it in 2nd gear at about 60kmh on the Auckland Harbour Bridge and it pulled the car noticeably to the left, then when I lifted off the throttle the car jumped back across to the right. It probably feels a lot more than it actually is, but it makes for hard precise driving on the narrow country roads that we have over here.

As soon as I experienced this again on a tight road where you don't get above 100kmh at all and still manage to use 40l/100km (6mpg) I thought to myself no, I'm never having one of these, even if it is a free hand me down from the owner when my C63 needs to go back, I'd prefer my C63 thank you!

I've driven an X5M and X6M on the BMW xdrive alpine experience but it wasn't clear on the snow if they had the same issue as all 4 wheels were spinning the entire time and depending on what previous tracks you were running over the cars could move massively all over the place (was so much fun) so I can't say if the BMW solution of having the front diff hanging off the side of the block will be an issue. What it will do however is give the M5 a very similar weight distribution to the current RS6/7 and I'm afraid it will feel quite nose heavy like the RS6 does.
Thanks for more details on how you experienced the RS6. I'm not certain if what you are experiencing is normal torque steer due to road surface or down to the very minimal difference in inertia between the drivetrain to the two front wheels. I often find that torque steer changes from pulling to the left or the right based on road surface. Ie if you placed the car differently relative to the grooves in the tarmac, caused by normal wear on the road, I usually find that while it pulls to the left if I'm on the left hand part of my lane, the car pulls to the right if I'm on the right hand side of my lane.

So while I do not question the RS6 having torque steer as you mention, I'm not certain it's caused by the diff being placed on one side, but suspect it's just as much highlighted because of uneven road surface (if the car changes the direction the front wheels pull, then that is caused by how the tires and surface are relative to each other).

The BMW solution of having the diff Attached to the side of the engine and not to the side of the transmission as per Audi, means that the engine still is positioned just as far back as in a RWD BMW. So while X-drive adds weight to the front axle, the weight distribution isn't as bad as on an Audi...

In this test of the S6 vs 550i X-drive AMuS weighed the cars and got the following weight distribution:

http://www.auto-motor-und-sport.de/v...hnische-daten/

Audi S6 Q: 56,5 / 43,5 %
550i X-drive: 53,5 / 46,5 %

A modern day 5-series With RWD is usually somewhere around 51-52 / 48-49 %

The 335i goes from 50,8 to 52,1 % front bias according to this article:

http://www.caranddriver.com/comparis...-bimmer-page-4

So while the X-drive obviously makes the car more nose heavy, it's not as dramatic as an Audi's weight distribution.
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      10-25-2016, 01:30 PM   #68
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Quote:
Originally Posted by Boss330 View Post
Thanks for more details on how you experienced the RS6. I'm not certain if what you are experiencing is normal torque steer due to road surface or down to the very minimal difference in inertia between the drivetrain to the two front wheels. I often find that torque steer changes from pulling to the left or the right based on road surface. Ie if you placed the car differently relative to the grooves in the tarmac, caused by normal wear on the road, I usually find that while it pulls to the left if I'm on the left hand part of my lane, the car pulls to the right if I'm on the right hand side of my lane.

So while I do not question the RS6 having torque steer as you mention, I'm not certain it's caused by the diff being placed on one side, but suspect it's just as much highlighted because of uneven road surface (if the car changes the direction the front wheels pull, then that is caused by how the tires and surface are relative to each other).

The BMW solution of having the diff Attached to the side of the engine and not to the side of the transmission as per Audi, means that the engine still is positioned just as far back as in a RWD BMW. So while X-drive adds weight to the front axle, the weight distribution isn't as bad as on an Audi...

In this test of the S6 vs 550i X-drive AMuS weighed the cars and got the following weight distribution:

http://www.auto-motor-und-sport.de/v...hnische-daten/

Audi S6 Q: 56,5 / 43,5 %
550i X-drive: 53,5 / 46,5 %

A modern day 5-series With RWD is usually somewhere around 51-52 / 48-49 %

The 335i goes from 50,8 to 52,1 % front bias according to this article:

http://www.caranddriver.com/comparis...-bimmer-page-4

So while the X-drive obviously makes the car more nose heavy, it's not as dramatic as an Audi's weight distribution.

The RS6 definitely always pulls the same way when getting onto the throttle and comes back again when you lift off. I've done this on a wide variety of surfaces and ones that are cambered both ways.

BMWUSA lists weights and weight distribution of almost all of the cars. I've picked the 5 below as well as the G12 7 as there are only LWB 7's in the US now. Note their site doesn't discuss the specs of the specific car weighed, so of course it isn't possible to be perfectly accurate on the differences.

F10
528i 3814 49.4/50.6
528i x 4001 50.1/49.9
535i 3957 49.6/50.4
535i x 4156 51.7/48.3
550i 4277 51.5/48.5
550i x 4431 53.0/47.0

G30
530i 3746 51.5/48.5
530i x 3878 52.5/47.5
540i 3847 52.2/47.8
540i x 4019 53.8/46.2


G12
740il 4195 51.4/48.6
740il x 4361 52.4/47.6
750il 4502 53.4/46.6
750il x 4623 54.4/45.6

x drive adds from 121lbs to 166lbs in the G12 and 154lbs to 199lbs in the F10. In the G30 it adds 132lbs to 172lbs.

It adds around 1 to 1.6% of weight at the front, ignoring the outliers of the 528i and 535i which add the most weight and are only 0.7% and 2.1% which are quite different to the other models.

I suspect that as the G30 while losing 68-137lbs also adds on 2.1% to 2.6% forward weight that a G30 V8 will be very front heavy and that is why there is a need for 4WD in the V8 powered cars, both M550i and M5.

I suspect the G30 M5 will be 54-55% front heavy in RWD and 55.5-56.5% front heavy in 4WD. And still 4250-4300lbs or 4350-4400lbs with 4WD.

Of course you'll basically need 4WD to get any power down due to a lack of rear weight, but adding 4WD will make it even more front heavy.

I've laid this out too in my other thread on here too.
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      10-25-2016, 03:03 PM   #69
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Quote:
Originally Posted by brad850csi
Quote:
Originally Posted by Boss330 View Post
Thanks for more details on how you experienced the RS6. I'm not certain if what you are experiencing is normal torque steer due to road surface or down to the very minimal difference in inertia between the drivetrain to the two front wheels. I often find that torque steer changes from pulling to the left or the right based on road surface. Ie if you placed the car differently relative to the grooves in the tarmac, caused by normal wear on the road, I usually find that while it pulls to the left if I'm on the left hand part of my lane, the car pulls to the right if I'm on the right hand side of my lane.

So while I do not question the RS6 having torque steer as you mention, I'm not certain it's caused by the diff being placed on one side, but suspect it's just as much highlighted because of uneven road surface (if the car changes the direction the front wheels pull, then that is caused by how the tires and surface are relative to each other).

The BMW solution of having the diff Attached to the side of the engine and not to the side of the transmission as per Audi, means that the engine still is positioned just as far back as in a RWD BMW. So while X-drive adds weight to the front axle, the weight distribution isn't as bad as on an Audi...

In this test of the S6 vs 550i X-drive AMuS weighed the cars and got the following weight distribution:

http://www.auto-motor-und-sport.de/v...hnische-daten/

Audi S6 Q: 56,5 / 43,5 %
550i X-drive: 53,5 / 46,5 %

A modern day 5-series With RWD is usually somewhere around 51-52 / 48-49 %

The 335i goes from 50,8 to 52,1 % front bias according to this article:

http://www.caranddriver.com/comparis...-bimmer-page-4

So while the X-drive obviously makes the car more nose heavy, it's not as dramatic as an Audi's weight distribution.

The RS6 definitely always pulls the same way when getting onto the throttle and comes back again when you lift off. I've done this on a wide variety of surfaces and ones that are cambered both ways.

BMWUSA lists weights and weight distribution of almost all of the cars. I've picked the 5 below as well as the G12 7 as there are only LWB 7's in the US now. Note their site doesn't discuss the specs of the specific car weighed, so of course it isn't possible to be perfectly accurate on the differences.

F10
528i 3814 49.4/50.6
528i x 4001 50.1/49.9
535i 3957 49.6/50.4
535i x 4156 51.7/48.3
550i 4277 51.5/48.5
550i x 4431 53.0/47.0

G30
530i 3746 51.5/48.5
530i x 3878 52.5/47.5
540i 3847 52.2/47.8
540i x 4019 53.8/46.2


G12
740il 4195 51.4/48.6
740il x 4361 52.4/47.6
750il 4502 53.4/46.6
750il x 4623 54.4/45.6

x drive adds from 121lbs to 166lbs in the G12 and 154lbs to 199lbs in the F10. In the G30 it adds 132lbs to 172lbs.

It adds around 1 to 1.6% of weight at the front, ignoring the outliers of the 528i and 535i which add the most weight and are only 0.7% and 2.1% which are quite different to the other models.

I suspect that as the G30 while losing 68-137lbs also adds on 2.1% to 2.6% forward weight that a G30 V8 will be very front heavy and that is why there is a need for 4WD in the V8 powered cars, both M550i and M5.

I suspect the G30 M5 will be 54-55% front heavy in RWD and 55.5-56.5% front heavy in 4WD. And still 4250-4300lbs or 4350-4400lbs with 4WD.

Of course you'll basically need 4WD to get any power down due to a lack of rear weight, but adding 4WD will make it even more front heavy.

I've laid this out too in my other thread on here too.
I wouldn't over think this right now. I've worked with Van Meel and promise it won't feel like a longitudinal Audi.

I don't think I've asked this specifically, but the RS6 you've been driving isn't by chance equipped with Air Suspension and Dunlop tires is it?
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      10-25-2016, 11:55 PM   #70
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Quote:
Originally Posted by lemetier View Post
I wouldn't over think this right now. I've worked with Van Meel and promise it won't feel like a longitudinal Audi.

I don't think I've asked this specifically, but the RS6 you've been driving isn't by chance equipped with Air Suspension and Dunlop tires is it?
Actually two different ones, both with air suspension. The first one was an early 2014 car with Pirelli P Zero originally, then Dunlop (but I can't remember what model exactly) I drove it with both tyres. The new one is a 2016 facelift and has Continentals on it.
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      10-26-2016, 12:00 AM   #71
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Quote:
Originally Posted by brad850csi
Quote:
Originally Posted by lemetier View Post
I wouldn't over think this right now. I've worked with Van Meel and promise it won't feel like a longitudinal Audi.

I don't think I've asked this specifically, but the RS6 you've been driving isn't by chance equipped with Air Suspension and Dunlop tires is it?
Actually two different ones, both with air suspension. The first one was an early 2014 car with Pirelli P Zero originally, then Dunlop (but I can't remember what model exactly) I drove it with both tyres. The new one is a 2016 facelift and has Continentals on it.
It's the alignment. Air Suspension goes out of Spec very easy and for whatever reason the Dunlops make it the worst.
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      10-26-2016, 12:33 AM   #72
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Quote:
Originally Posted by lemetier View Post
It's the alignment. Air Suspension goes out of Spec very easy and for whatever reason the Dunlops make it the worst.
Interesting info. Anything specific that should be checked by Audi, ie Toe in causes the issue specifically? Feel free to email me to further this conversation

Coming slightly back on topic, should the extra length of the intermediate shaft still create a small amount of torque steer that is detectable? In my experience it was very noticeable, and there are plenty of people discussing it in powerful front wheel drive cars which now use that same overall concept of offset front diff and various alignment or suspension tricks to try and get around it.

My overall point though is that I'd prefer the front wheels feeling to be the same at all times, ie to have no dilution in consistency from the power delivery.
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      10-27-2016, 12:40 AM   #73
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That front lip is really low, but pretty fierce looking.
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      11-06-2016, 05:57 AM   #74
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Quote:
Originally Posted by brad850csi View Post
Quote:
Originally Posted by lemetier View Post
It's the alignment. Air Suspension goes out of Spec very easy and for whatever reason the Dunlops make it the worst.
Interesting info. Anything specific that should be checked by Audi, ie Toe in causes the issue specifically? Feel free to email me to further this conversation

Coming slightly back on topic, should the extra length of the intermediate shaft still create a small amount of torque steer that is detectable? In my experience it was very noticeable, and there are plenty of people discussing it in powerful front wheel drive cars which now use that same overall concept of offset front diff and various alignment or suspension tricks to try and get around it.

My overall point though is that I'd prefer the front wheels feeling to be the same at all times, ie to have no dilution in consistency from the power delivery.
I'm not aware of any powerful fwd, or front biased awd, car that doesn't suffer some level of torque steer. An uneven road surface causes this to happen when the outside of the tire grips the tarmac. This creates a twisting force on the steering and makes the car want to steer in that direction. It's similar to what happens when you have to wide front tires and the car wants to follow the camber on the road surface.

So torque steer also happens on cars with equal length drive shafts.

Have there been many reviews on the RS6 that mentions torque steer BTW?
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