Automatic Speed Control - Porsche 928S 1983 Driver Manual

1 Set/accelerate
2 Reset
3 Cancel
Tempostat

(Automatic speed control)

The Tempostat will maintain any desired
speed with the range 50-200 km/h (30 to
120 mph) without your foot being on the ac-
celerator. Independent of this, you can
brake, change gear and accelerate as nor-
mal.
30
The operation of the Tempostat is controll-
ed by the antenna lever behind the wiper
antenna.
The speed being travelled at any point in
time can be fed into the electronic control
unit by moving the lever forewards (position
1).
You can then take your foot off of the acce-
lerator and this speed will be maintained.
By braking or stopping, the unit cuts itself
out, but the last speed fed into the unit re-
mains registered. This registered speed can
be recalled by moving the lever downwards
(position 2). However, should the ignition be
turned off, the registered speed is cancell-
ed from the unit.
If the registered speed is too low, you can
increase speed with the accelerator or by
moving the lever forewards to position 1 and
holding until the desired speed is attained,
and then letting the lever free. This speed is
now fed in to the unit and registered.
If the registered speed is too high, pull the
control lever towards the steering wheel
(position 3) or brake; this interrupts the Tem-
postat control, until the required lower
speed is attained, and then move the lever
forewards to position 1. Again this new
speed is registered and maintained.
Note: When you depress the clutch, the
speed control is interrupted, but when the
clutch is released, the speed control takes
over again.
To avoid accidentally overrevving the engi-
ne, do not move the gearshift lever into neu-
tral at road speed above 50 km/h (30 mph)
while the cruise controle is engaged.
If you exceed the speed registered in the
control unit, e.g. during overtaking by using
the accelerator, as soon as you come off of
the accelerator, the registered speed will be
automatically resumed. On a steep incline
either up or down, it is possible that the ve-
hicle will not maintain the registered speed
in a high gear, then you must change down,
to avoid labouring the engine by uphill, or to
ensure sufficient engine retardation by
down hill driving.
We do not recommend use of the tempostat
in heavy traffic or when road conditions are
unsuitable (eg. winding or slippery roads).