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Had to use the Cayenne to pull a pickup out of some snow today. The snow was crusty and about a foot deep with ice underneath so didn't take much to get stuck. We first tried to pull without shoveling the snow around the pickup wheels. Put the cayenne in off-road and locked the front diff, no PTV so unable to lock rear. Cayenne was on a thin layer of hard crust snow with ice underneath. Proceeded to spin both front and 1 rear wheel. Decided we had to shovel the snow from around the pickup. Once cleared I wanted to move the cayenne for better traction. The 3 wheels just spun due to the ice and small holes from previous spinning. Switched to normal on-road mode and was able to move the car with ease. Repositioned and tried pulling on the pickup again in off-road. No go so switched to on-road and was able to gain much better traction pulling the pickup out. So this tells me that in normal mode the electronics are better at finding traction than with diffs locked. How does this really system work? What have others experienced? I haven't played around with the all wheel drive system in the past so still learning about it. The Touareg had a similar system but didn't lock anything in off-road mode.
Your best pickup-rescue device is a 30', 1" yellow rope with bowlines tied in the ends. On ice one uses the tow vehicle's momentum to jerk the other vehicle, relying upon the elasticity of the rope to cushion the blow while imparting considerable energy to the towed vehicle, even while on a slippery surface. Common sense and practice are indicated in this operation, though, as excessive forces will eventually snap the rope with unpleasant effects. Over a long career ice fishing I have snapped a few. Generally the rope ends up lying under the tow vehicle, but the snapping motion is such that you definitely don't want any bystanders during the rescue.
Pretty sure your Cayenne does not have locking differentials, none of them ever came with a front locker and the rear locker was extremely rare on the 955/957 series. I do not think it was offered at all on the 958s. The only diff you can lock is the center one, after that you are relying on the brakes to transfer power to the wheels with traction. The differences you feel are the different traction thresholds programmed into the traction control system. Some settings offer more or less wheel spin before intervention.
Pretty sure your Cayenne does not have locking differentials, none of them ever came with a front locker and the rear locker was extremely rare on the 955/957 series. I do not think it was offered at all on the 958s. The only diff you can lock is the center one, after that you are relying on the brakes to transfer power to the wheels with traction. The differences you feel are the different traction thresholds programmed into the traction control system. Some settings offer more or less wheel spin before intervention.
Just going by what the manual states and stand corrected on the front diff locking. Both front where spinning along with one rear. I read in another place to lock the rear PTV is needed.
Edit: I think the confusion I had on the front diff is the lights. One would think the middle light is the center diff, top light is front and bottom light is rear. I originally read the operation several months ago but never used the off road mode since.
Just going by what the manual states and stand corrected on the front diff locking. Both front where spinning along with one rear. I read in another place to lock the rear PTV is needed.
Edit: I think the confusion I had on the front diff is the lights. One would think the middle light is the center diff, top light is front and bottom light is rear. I originally read the operation several months ago but never used the off road mode since.
So what you have are open differentials front and rear and a lockable center differential. The off road traction control programming on my 957 was super impressive off road in low range. It is speed sensor monitoring, selective wheel braking and probably throttle manipulation. I have had a LOT of 4wd vehicles and use them. I used to swear by the lockers in my Gwagens and Unimog. The Porsche system works extremely well, you can tell they spent lots of time developing it. I can usually flush out the flaws pushing off road but the Porsche system again, I found to be excellent.
Interesting that they fit lockers to 958s that don't even offer a low range. Seems like having the cart in front of the horse, but that may be a bit of Porsche tradition.
The rear locker is there today as part of the PTV option. Probably not a high priority option for me. I have driven Quattro based all wheel drive systems since 2002. They are great systems to which Porsche has really advanced nicely. In this one example it seems normal on road was better traction. The system is superior from what I have seen so from to the gen 2 Touareg I had. The early Audi's were split 50 50 so performance driving was interesting. Still I took the allroad to the track in the summer and on the ice for winter rallies. I got a chuckle at the last event a few years ago that the old guy in a station wagon had the fastest nonstudded tire time.
The 958 diesel only has a locking center differential. We were told that the torque the diesel puts out was to much for the front and rear lockers. Most of our driving is off-road - Overlanding and rally. That said the only time we have been stuck with ours is when we high centered in snow. As none of the tires were touching the little German inside the ECU went berserk trying to figure out what was going on. Our skid plates are functional, with a little momentum they also make a great toboggan on snow! With Maxtrax and the winch we were home free. Did not get stuck on this trip, in fact helped recover a stuck Tundra.
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03-22-2018, 12:33 AM
Off-road mode vs on-road
