Cap / Rotor Question , CRUISE CONTROL !!

[treed2 at wsu.edu (T. Reed)]

On Wed, 11 Feb 2004, A J wrote:

> Hey whats up with your cruise control ? did you
> install that from another scirocco ? or is it
> aftermarket ? I want to know , Aaron -
>

Hey,

How'd you know I had cruise control ?! :)

(BTW: I'm fwding this reply to the list as well for informational
purposes..)

It's the same factory Hella cruise control system used on VWs, Audis,
Saabs, Volvos, etc. that has a vacuum pump and rubber diaphragm actuator,
along with a computer, vacuum-and-electric pedal switches and a speed
sensor.

I snagged it from an 1980 Audi 4000, but substituted the pedal switches
for later versions. It's quite modified, actually.. I had to fabricate the
linkage and weld up an actuator mounting bracket as the system never came
on the 16v Scirocco from the factory. The stalk switch is easy to come by
as it is the same one used in the Audi 4k, Cabriolets and Sciroccos, as
well as some early A2 Golfs. The speed sensor from the Audi didn't fit so
I wired up the cruise to a pin on my MFA gauge cluster that runs to the
speed sensor for the MFA.

My pedal cluster wasn't equipped with threads for the switches so I had to
hold them in place with a pair of nuts (M12x1.5, I think?) on each.

Most recently I installed an inline vacuum restrictor (made on a metal
lathe out of solid brass rod) for the throttle actuator to smooth out the
throttle response (adjust throttle position in smaller "bites") and it
helped immensely. With my 2.0l 16v, the speed adjustment was very
on-and-off before adding the restrictor. Now its difficult to tell
whether the throttle is being held by the cruise or the driver.

The system works great; it can be turned on and off (duh) with the switch,
disabled with either the clutch or brake pedal, and there is a resume
feature to get back to the speed it was previously set at. Additionally,
if you hold the SET switch down the car will accelerate and set the new
speed. Unfortunately the computer from the 1980 Audi is an early one and
does not have tap up/tap down or coast features. I'm researching whether
or not such a computer would be a direct swap or involve a different
switch and/or wiring.

The install was not too difficult - the hardest part was whipping up the
linkage. I had to buy piano wire, bend it in to shape and get it TIG
welded to make a linkage that could use factory plastic ball-joint ends
and freewheel properly when the throttle was being actuated by the pedal
and not the servo.

The bracket is just two 1/16" steel plates I welded together, drilled
mounting holes in, and carefully cut with a die grinder to accommodate
the cross section of the servo.

Because of the placement of the rubber servo over the hot exhaust
manifold, I made an aluminum heat shield that bolts to the upper intake
manifold support bolts and keeps the high temps from melting the rubber.

I looked in to aftermarket, but everything I found was quite expensive and
had some real drawbacks. The factory system can be had rather cheaply if
you go to a junkyard or pick up the parts on eBay. It works well, and it's
factory.. which is always a good thing! (unless we're talking cooling
systems .. grr!)

Any questions? :P

-Toby