Hi everyone,

I just received my 2011 V6 Cayenne and enjoying it very much.

This is my first time experience with tiptronic transmission. While I was driving on automatic mode, I found out that the gear shifts up even though I keep my speed and rpm constant (this seem to make rpm go way too low). Also, the gear tends to shift down instead of up when I try to speed up by pushing the gas. Is this normal in tiptronic?

Thanks!

 

I'm not on super firm ground here but think that the tranny is shifting up seeking a lower rpm for the best gas mileage possible. Second, when you depress the accelerator the tranny knows you want power so it seeks a lower gear at higher rpm to give you the thrust you want. Perhaps this is too simple?

 

You are the first person to reply on my post in 6speed!
Thank you so much for the reply ronl!

 

I agree.

When cruising at set speeds, the transmission will choose the most economical gear thereby lowering fuel consumption. Higher gears mean lower revs, so the car will shift up to safe fuel, and make the driving smoother.

However when you press on the accelerator pedal, the system assumes you want to accelerate. As the car accelerates best in lower gears (or with higher revs) it will shift down to provide this. If you use kick-down (i.e press your foot all the way to the floor) then the car will likely drop several gears to give you maximum acceleration.

If driving in Sport mode the car will be more sensitive to throttle inputs, and so will be more likely to select lower gears to keeps the engine revs high.

I don't get my Cayenne until the end of this month, but it is my understanding that most automatic gear systems in "sportier" vehicles work this way

 

Now everything makes sense!

Thanks Conan for detailed answer!

 

We haven't touched on "throttle mapping" which, I believe in the Cayenne, is part of the PASM feature. Most modern sport vehicles such and Porsche and BMW, when so equipped, provide for driver selectable modes which run the gamut from luxury cruiser to tightly sprung roadster.

In sports mode, the tranny "knows" what you are looking for and delivers higher revs as you run the gears or on downshifts. Feels much more like a sports car than a cruiser. In comfort mode, driven like Lincoln Town Car, gears change at lower revs when accelerating.

Also, in sport mode, the electronic dampers dramatically "tighten up" the suspension (shocks, sway bars, etc.). This is the reason why, I think, that the Cayenne gets "smaller" the harder you push it. Really though, no matter what mode you are in, the vehicle senses your driving style and adjusts accordingly. (I think). Even the engine may come into play here as in steplessly adjustable vario valve timing which delivers a vastly sportier drive.


I believe that the steering is also mapped to tighten in sports mode and relax in comfort.

I have asked on a number of forums if folks understand the diff between Porsche electro hydraulic steering by ZF Zemoke and the bad press BMW steering in the new 5 and x3, also so named and also by same company. Did not get any replies but what I am beginning to piece together, and perhaps just a guess, is that the true difference comes from the fact that some of the newer electronic steering systems are demand driven, meaning that some of the steering motor features only kick in when "requested" by the driver. I think these awful, uncomfortable steering systems ( and I have driven 5 series, x3, and Sonata) are akin to the new auto stop/start functions. All this BTW is to lower the fleet average miles per gallon per government mandate- Booh!

Sorry I hijacked this thread on Tiptronic to dump some thinking on all these modern dodads and would appreciate hearing from some car know how gurus who really understand this stuff- mine is just from reading and guessing.