brianrheffron

Would it be possible to isolate all of the normal control inputs into the autobox of an S4 and activate it manually. I was thinking of some sort of electo-mechanical device worked by push buttons or paddles behind the steering wheel. My 928 is the first auto I have ever owned and they are a mystery to me so I'm looking for comments from some of the experts.

the flyin' scotsman

Before you go through all that work why not drive it using auto gear lever manually...........and push the loud pedal all the way.

SeanR

x~

IcemanG17

When running properly an autobox will perform quite well.....then shifting it yourself is the best of both worlds......about the only thing you loose is one gear...... Basically and auto is like driving the 5 speed with only 1-2-4-5 gears....

brianrheffron

OK. I have adjusted the cables to what I think are the correct tensions and play and I get good part throttle downshifts to third, etc and I also do shift manually some of the time. What I was hoping for was a more positive control over what gear I am in. I live in the West of Scotland where twisty roads are the rule and so is rain. Also we have loads of roundabouts at larger junctions and these tend to collect oil and diesel drips which makes the surface pretty slippery when wet. When pressing on my fear is that pushing the throttle hard in third and in mid corner might give me an unwanted downchange into second (with consequent jump in revs and power) which could unsettle and even spin out the car.
Most modern electronically controlled auto boxes on higher performance cars in Europe have a manual mode that lets you select gears sequentially, usually by flippers behind the steering wheel. Do you think that such a mod. would be possible on an old style auto box like the 928s ?

the flyin' scotsman

hi Brian..............where on the West coast? my parents live in Helmsdale north of Inverness.

I wouldn't worry too much about downshifting and spinning if your car wears good rubber of which you'll get many varied opinions as which is most suitable; I use Michelin Pilot Sport A/S. Not so much worried about rain but snow; as in right now!!!

dr bob

Brian--

A workable compromise might be a combination of a parallel kickdown switch with a loose TV cable.

A parallel kickdown switch (PKS) is an electrical switch that mimics the operation of the switch under the throttle pedal. If you look under the pedal you'll see the existing switch, which activates when the pedal is fully depressed. That switch activates a relay that activates a small solenoid valve on the transmission. That solenoid will artificially lower the control pressure in the transmission to make it shift down much more readily. A PKS is some switch or button that you'll add, wired in parallel with the switch under the pedal. Close the switch, and you have "sport mode".

The TV (throttle valve) cable runs from the trans to the throttle relay assembly on the side of the intake manifold. ON my car, it's the cable with the little wire retainer installed. Adjust that cable loose a few turns, causing the car to want to downshift late. That should take care of the 'unexpected downshift' issue when navigating slippery roundabouts at speed. When you do want the more aggressive performance you can engage the PKS and get a much more aggressive sport mode of shifting. Makes for the best of both worlds.

928ntslow

I'd do a search. There is a lot of ground covered on this topic.