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F30 / F31 / F32 / F33 / F36 (2012 - current)
The sixth generation 3 series, chassis code F30. 2013 model year 328i and 335i sedans now in production. Read the F30 frequently asked question thread for all your basic question and dive into all the details in the ultimate F30 information thread.

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  #26  
Old 02-03-2013, 02:31 AM
Geekenstein Geekenstein is offline
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Sorry to dig up this old thread, but I found a press release from BMW that says the F30 does have a limited slip diff. http://cache.bmwusa.com/Pdf_8a2b5321...03ce9ea52.arox

From page 18: The DSC system incorporates
the following functions: Anti-lock Braking System (ABS), Automatic Stability
Control (ASC), Dynamic Traction Control (DTC), Dynamic Brake Control (DBC)
and Cornering Brake Control (CBC), along with start-off assist, brake drying and
an electronic limited slip function for the rear differential, which can be activated
using the "DSC Off" button.

There's also a Car and Driver article that describes it the same way.

Strange BMW doesn't advertise this feature much. I guess they're afraid of litigation if people hurt themselves by turning off DSC.
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  #27  
Old 02-03-2013, 06:40 AM
LegendsNeverDie LegendsNeverDie is offline
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Quote:
Originally Posted by Geekenstein View Post
Sorry to dig up this old thread, but I found a press release from BMW that says the F30 does have a limited slip diff. http://cache.bmwusa.com/Pdf_8a2b5321...03ce9ea52.arox

From page 18: The DSC system incorporates
the following functions: Anti-lock Braking System (ABS), Automatic Stability
Control (ASC), Dynamic Traction Control (DTC), Dynamic Brake Control (DBC)
and Cornering Brake Control (CBC), along with start-off assist, brake drying and
an electronic limited slip function for the rear differential, which can be activated
using the "DSC Off" button.

There's also a Car and Driver article that describes it the same way.

Strange BMW doesn't advertise this feature much. I guess they're afraid of litigation if people hurt themselves by turning off DSC.
The F30 does not have a true mechanical LSD. There are cars in this segment that offer it, like the Cadillac ATS for example.
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  #28  
Old 02-03-2013, 06:41 AM
LegendsNeverDie LegendsNeverDie is offline
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Quote:
Originally Posted by TEAShea View Post
Nope. Limited slip rear differentials are disappearing - except for dedicated track cars. They are substantially less valued than they used to be. The ability of modern cars like a BMW to use the DSC to control the geometry and dynamics is the reason. For example, most sophisticated new cars lightly apply the inside rear brake under hard cornering. Limited slip differentials have a number of disadvantages - including additional complexity and reliability issues. The new Mclaren MP4-12C does not have limited slip.
Quite the opposite actually.
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  #29  
Old 02-03-2013, 07:10 AM
Elk Elk is offline
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Quote:
Originally Posted by Geekenstein View Post
Strange BMW doesn't advertise this feature much.
Perhaps because it is not really an LSD.

Instead, the car has an open differential with a simple system which merely applies the brake to the rear wheel which is spinning, providing resistance which the open differential can use to transfer some of the force to the opposite wheel. It is somewhat akin to a tank turning by dragging one tread.

That said, it is useful in getting going in very slippery conditions such as snow.
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  #30  
Old 02-03-2013, 07:41 AM
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kpgray kpgray is offline
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Quote:
Originally Posted by Elk View Post
Perhaps because it is not really an LSD.

Instead, the car has an open differential with a simple system which merely applies the brake to the rear wheel which is spinning, providing resistance which the open differential can use to transfer some of the force to the opposite wheel. It is somewhat akin to a tank turning by dragging one tread.

That said, it is useful in getting going in very slippery conditions such as snow.
It is an amazing system under real world conditions! Gone are the days of one spinning rear wheel and throwing a shovel and couple bags sand in the trunk (shovel to dig the snow out from around the wheels and sand helps put weight on the rear end (attempting to achieve a 50/50 F/R balance?!) and the sand is used to sprinkle under the driving tire to help gain traction) However, BMW's LSD can create overconfidence when driving in very poor conditions like snow because you are masked from the actual condition! Just because you can accelerate well and corner without sliding sideways, you cannot stop any faster than any other vehicle! Turn off the DSC and get a more accurate picture of the road condition but be careful as your passenger may dig their finger nails in the dashboard. We are expecting snow 4 days this week in Michigan!
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  #31  
Old 02-03-2013, 08:55 AM
Geekenstein Geekenstein is offline
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Quote:
Originally Posted by Elk View Post
Perhaps because it is not really an LSD.

Instead, the car has an open differential with a simple system which merely applies the brake to the rear wheel which is spinning, providing resistance which the open differential can use to transfer some of the force to the opposite wheel. It is somewhat akin to a tank turning by dragging one tread.

That said, it is useful in getting going in very slippery conditions such as snow.
Isn't that what DSC does? The doc says you can activate limited slip by turning off DSC.
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  #32  
Old 02-03-2013, 09:17 AM
Elk Elk is offline
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One activates the above described rear wheel braking system by pushing the button once.
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  #33  
Old 02-03-2013, 09:44 AM
Geekenstein Geekenstein is offline
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Hmmm, do you have a good source for this information?

Nothing against you. It just bugs me that BMW doesn't seem to really have this documented anywhere.


What you seem to be saying is something like this:
  • First start up the car... full DSC enabled. (Does this include individual wheel braking? I believe so)
  • Press the "DSC off" button. DSC partially disabled. DTC enabled (brakes individual rear wheels for maximum traction, rather than maximum stability)
  • Hold down the "DSC off" button. No stability or traction control is provided, but individual brakes are still applied only to one rear wheel to prevent inside wheel spin. Seems like a great way to destroy your rear brakes at the race track.
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  #34  
Old 02-03-2013, 10:51 AM
Elk Elk is offline
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The documentation is poor and the terminology used by BMW perhaps even worse.
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