Pan58

Okay the 1996 993 that I am in the process of purchasing has a Automatic Braking Differental / Limited Slip Differental. I have checked my books I have on the 993 and it does not really explain what the Automatic Braking Differental Does. Can some one explain this Feature?

ed devinney

ABD is a low-speed traction control that selectively applies individual rear brakes to minimize wheelspin. I haven't found it to be terribly useful but the upside is that you get 4 channel ABS as a byproduct.

Pan58

thanks for the explaination

ZombiePorsche44

"The Bosche 5 ABS/ABD system provides an anti-blocking (ABS) function as well as rear wheel traction control.

The ABD (Automatic Brake Differential) complements the ABS system and is used as a traction control aid at speeds up to 72kph (45mph).

For this purpose, an active input into the brake system is made if one driven wheel starts to spin. Since ABD control has to trigger the driven wheels individually the ABS/ABD system is designed as a 4 channel system."

Quote from Porsche 993, The Essential Companion (King of Porsche) by Adrian Streather

ZP44

RallyJon

It is very useful when starting off in slippery conditions. Especially uphill or turning from a stop. And mine is a C4, so I imagine it would be even more helpful on a C2 in those conditions.

Paul902

RallyJon,

do you see the green ABD dash light coming on? I've never seen mine coming on during normal driving, although I have seen in a few times doing "abnormal" things.

Paul

RallyJon

Not sure about the light--I'm usually looking at the road in those situations. Most obvious is the clicking whine from the corner that's slipping as the ABS cycles the caliper.

Pan58

You guys are great , this is my first Porsche , being and aerospace engineer I am kind **** about spec's and details and you folks have come thru in flying colors A+ is given for the help and response to this new owner. thanks alot.

TomF

I actually is pretty cool technology, however primitive by todays standards. I drive my car in the snow once in a while for fun and it is interesting to see when the ABD engages. It only does it occasionally in the regular Seattle rain. I also think that it senses throttle position because when I get the car to "drift" with a lot of throttle, it doesn't engage as long as the revs are up.

Pan58

Tom you are in the Seattle area , well I am located down by Puyallup go figure

ed devinney

If that's the case you really need Adrian Streather's 993 book: http://www.amazon.com/Porsche-993-Es...2214544&sr=8-1

Pan58

I have that book and have read it cover to cover twice very good book I might add.