If you are old enough..... you remember the days of the first cruise control systems and, if you were looking to obtain best mileage on the open highway, the advice was: "set your cruise and leave it alone!" It worked....

Now... Distronic Plus..... this system works hard to maintain two objectives: set speed and specified distance between you and the car ahead.....having experimented with the system during the last couple of trips have noted the following: unlike the old systems, this one will apply the brakes to maintain the set speed as you go downhill, also ( obviously ) during its attempt to slow you down and maintain the set distance between you and the car in front.... The result is that you will NOT see the mpg increase that was seen on the old systems, in fact... you may see a DECREASE as the system slows the vehicle and then accelerates.....the big difference is in the long downhill runs on an interstate......as it applies the brake to maintain the specified speed. I actually killed the Distronic going down a couple long downslopes.... I dont want increased brake wear and it was not really necessary to precisely maintain the speed. That being said I love it on the long level straight shots!

 

That makes sense that it could hurt brake wear. I haven't had any big hills but wondered if it used the brakes or did an engine braking.

 

Not a much of an issue with me..... because I know the system is doing a fantastic job and I am impressed with the technology..... i just prefer to let her roll on the down hills and let me determine if I need to slow it down.

 

I have a question on the Distronic. Several years ago I had the radar operated cruise on a Cadillac XLR. It was a new system at the time and I was not happy with it. When the road cleared in front of you, it had a tendency to then downshift and rapidly accelerate to regain the set speed. This resulted in rather a "jerky" experience.

Do the newer generation systems cure this problem or do you still experience hard acceleration when trying to catch up?

 

As soon as the Distronic recognizes there are no vehicles within the defined distance, it acclerlates the vehicle....because of the 7 speed programming which is biased to the "save fuel" side, it does not down shift unless you REALLY have allowed the vehicle to slow way down..... in other words, in a normal freeway driving situation you see that you are coming up on a slower vehicle ( maybe the system senses it before you do ) and you move to the left to pass...........very little action on the part of Distronic. if you keep on the tail of the slower car, the Distronic will keep the minimum distance until you move to the left and then it will accelerate smoothly ...... i would not call it a "hard" acceleration.