Re: Voltage and suspension questions

[paul.heneghan@bbc.co.uk (Paul Heneghan)]

From: "J. Smethers" <smethers@fast.net>

>Am I correct in thinking
>that there should be no change in the voltage (as measured by the center
>console volt. meter) when the car is under a heavy electrical load.  I
>notice it especially when the engine fan kicks on.  I'm worried that the
>alternator may be dying.

I'm just guessing here (as I don't have a voltmeter in the car and I don't 
know where the voltmeter gets its signal from), but I would expect a small 
change in the indicated voltage when components such as engine fans, rear 
screen demisters and electric windows are switched on.  Audi (like all car 
manufacturers) use the smallest gauge cable they can get away with and 
therefore voltage drops are inevitable.  Also the internal impedance of the 
battery needs to be taken into consideration - I would only expect it to 
give out 6-9 volts during cold starting.

>Also, had the rear CABs replaced yesterday.  The car toes right now so I
>know an alignment is in order.  But I also notice that the car does not 
feel
>as solid as it did before.  Last night, I drove the car on a wet
>snow-covered highway and I could not get it to stick.  It felt real loose 
in
>the back, like never before.  I am only two months new to the quattro
>experience, so maybe this is common with this road condition.  Would the
>center diff. lock help here, and if so how fast and far can I drive with 
the
>center diff. locked.  Even this morning, I shimmied on wet train tracks.
>The car feels real loose - HELP.

Get an alignment ASAP. If the toe of any of the wheels is not right, then 
the car will suffer changes of direction dependant on the load on the 
wrongly toed wheel.

The centre diff helps traction under slippery conditions.  You can drive 
with it on as far and as long as you like (don't tow it though).  If you are 
making small radius turns with the centre diff locked on dry tarmac, then 
you will scrub some rubber off the tyres.  I often leave it locked when 
driving at speed along winding country roads.  The benefits are:
improved road holding - it corners as if it's on rails
rear brakes can do more work as they will now have an effect on the front 
wheels (I've read about this rather than noticing it myself)
if under acceleration or decelleration, one axle loses traction, then rather 
than spinning the wheels on that axle, power is fed to the other axle

The only disadvantage that I've noticed is that (appart from tyre wear in 
the dry) in snowy conditions, braking can easily lock up both axles at once 
which makes you lose lateral control and you can slide off the road.

Other diff lockers opinions welcome!

Paul
paul.heneghan@bbc.co.uk
1984 Audi 80 quattro
1983 Audi 100 Avant