Automatic Braking Differential

[Little Gator]

Does anyone know what a "automatic braking differential" is? It is listed as a standard feature on my car's window sticker. When I asked the service writer at the dealership, he didn't know. His 2 fellow service writers thought I was nuts, and that I must be mistaken about what I thought I read because they never heard of it. 2 salespeople didn't know either. I pointed out that the same feature is mentioned in the new 2013 911 handout that they gave me 2 days earlier, but it too did not explain what it is. Is is something mechanical, or is it a deceptive name for a software program within the PCM?

[Karrera4]

I think it brakes the inside rear wheel to keep it from spinning when accelerating out of a corner....which is typical on car with higher hp and no Torque biasing diff or limited slip diff.

A TBD will only lock up under load. A LSD will lock up under load as well as decel.

[Airdoc]

Seems like it is part of PSM but they dont say exactly what it is.


"As standard, the new 911 models are equipped with enhanced Porsche Stability Management (PSM), which maintains stability even at the limits of dynamic driving performance. Sensors continuously monitor the direction, speed, yaw velocity and lateral acceleration of the car. Using this information, PSM is able to calculate the actual direction of travel at any given moment. If the car begins to oversteer or understeer, PSM applies selective braking on individual wheels to restore stability.
Under acceleration on wet or low-grip road surfaces, PSM improves traction using the automatic brake differential (ABD) and anti-slip regulation (ASR). When the SPORT PLUS mode of the optional Sport Chrono Package is selected, the PSM threshold is raised to allow a sportier driving style."

[Airdoc]

Sorry, found it.

"If one of the wheels is about to lose traction, PTM uses the ABD function to apply the corresponding brake. As a result, more drive is automatically transferred to the opposite wheel. If both wheels on one axle are in danger of slipping, ASR immediately intervenes and modifies engine output to maintain drive. "

[Dr. Bill]

It's the electronic gizmo that makes sure you wear out the rear brake pads as fast as the front ones!