Automatics and the system of car control

Discussion on Advanced and Defensive Driving.

Postby tonyh » Sun Apr 24, 2016 10:21 pm


I have a retest coming up for rospa and will be using an automatic. The vehicle is an old saab 900 with a 4 speed auto.
I have had the car two weeks, prev had a lexus gs300 auto.
I'm playing with it and am using the box in the same way I would use a manual. braking before the corner or hazard and then shifting to 2 or3. Starting in1 etc etc. Using the lower gear to balance the car round the corner and overtakes again shifting to a lower gear.
Any helpful hints would be greatly appreciated.
Regards
tonyh
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Postby waremark » Mon Apr 25, 2016 10:01 am


The most important thing is that you tell the examiner something about the characteristics of the gearbox and why you are using it the way you are. Try for a good balance of smoothness and control.

I suggest you should take some advantage of the auto operation where there is no benefit from overriding it. For example, I would leave it in D in towns and when following a string of slow cars. If changing down manually for hazards, you may get the best results by changing down during the braking phase, rather than waiting until after the end of it.
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Postby hir » Mon Apr 25, 2016 12:43 pm


tonyh wrote:I have a retest coming up for rospa and will be using an automatic. The vehicle is an old saab 900 with a 4 speed auto.

I'm playing with it and am using the box in the same way I would use a manual.


If the auto box is one of the really old mechanical boxes with no electronic manual/sequential mode incorporated within, I would not attempt to use it as a manual box. These auto boxes were never designed, nor intended, to be used as manual boxes. The only time you should be using a lower gear in "lock-down" mode is when (say) descending a steep incline. The old mechanical boxes were usually quite sensitive to accelerator pedal pressure with change down (not kick down) being effected with moderate accelerator pressure. This is the best way to effect change-down with these old style mechanical boxes.

However, if the Saab has an electronic auto box with a built-in manual/sequential mode, then carry on enjoying using it as you would a manual box. Just look upon it as a clutchless manual.

Good luck with the re-test.
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Postby waremark » Mon Apr 25, 2016 3:30 pm


hir wrote:If the auto box is one of the really old mechanical boxes with no electronic manual/sequential mode incorporated within, I would not attempt to use it as a manual box. These auto boxes were never designed, nor intended, to be used as manual boxes. The only time you should be using a lower gear in "lock-down" mode is when (say) descending a steep incline. The old mechanical boxes were usually quite sensitive to accelerator pedal pressure with change down (not kick down) being effected with moderate accelerator pressure. This is the best way to effect change-down with these old style mechanical boxes.

Maybe. This approach does not necessarily work well when accelerating out of a bend. As the limit point runs and you accelerate progressively, you want smooth acceleration. You do not want the gearbox to kick down as you accelerate. It may (repeat may) therefore work better if intending to use firm acceleration out of the bend to select a lower gear hold position before entering the bend.

I must admit it is a long time since I have driven a 4 gear auto. Ones in the household at the moment have 7 or 8 gears. I am failing to keep up - the latest have 9 gears.

Tony (the OP) refers to use of 1, 2, and 3. It would be unusual for an old style gearbox to have a 1 position - maybe Saabs were different, or maybe his gearbox is not that old-fashioned.
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Postby tonyh » Wed May 04, 2016 5:55 pm


Thanks to all who contributed to my original post.
I found them very helpful.
I played with the box which was a 4 speed electronic , the car is 20 years old! Holdingthe lower gears round bends etc. And starting in 2.

I managed a high silver and the comment by my examiner was that my use of the automatic was awesome.I FAILED a gold due to a (in his view) an unnecessary overtake and exceeding the speed limit on a dual carriageway during an overtake. Not the same one.. I await the official report.
I will do better next time , back with a manual!
:D
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Postby Horse » Thu May 12, 2016 10:38 pm


That's an interesting conundrum : if you're supposed to be demonstrating 'progress', how can an overtake be unnecessary? [But not unsafe?] 'Inappropriate ' - ie just before a 30 limit where you will more than likely obstruct the other driver, perhaps.
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