Re: coupe gt suspension

[Scott Fisher <sefisher@cisco.com>]

Dan asks, on behalf of his brother-in-law:

> Can anyone who has run the various setups on CGTs
> comment?  I think the TG with some stiffer springs will
> be plenty, and I can get the TGs prettty cheaply.

I'm currently running an '83 CGT with your option #3 -- stock springs
and reasonably fresh Bilsteins (less than a year old), courtesy the
previous owner.  Given the kind of driving I do with the car, I'm very
happy with this setup -- suspension travel is good, thumping over bad
pavement isn't too harsh, it's got a great freeway ride and that's where
75% or more of my driving is done.  And when I *do* get into the
twisties, it's stable, balanced, predictable, and very, very
controllable -- certainly one of the *easiest* cars to drive fast that
I've ever experienced.  

I'd say your BIL's decision depends largely on the condition of the
springs -- if they're still sound, I'd go with the Bilsteins and look
into stiffer anti-roll bars (there's currently none at the rear on my
'83, don't know about the '87) to reduce roll-induced camber change,
which is basically what I'm probably looking at next.  That way the car
will corner flatter than it does now and work the tires a little harder,
but I won't chip any more of my teeth on impact with those big iron
plates in the construction area on one of my alternate routes home (and
it's the one with a couple of nifty corners, too!).  

The rest of the decision-making factor would include asking your BIL
about road conditions and type of driving.  The Bilstein/stock spring
combo is reasonable on bad roads and yet still provides great response,
balance and stability when I hit the mountain roads.  If most of your
BIL's driving is done on winding roads with good surface condition and
only a little on uneven pavement, then he may get more bang (or would
that be less? :-) for his buck with the springs and Boge TGs.  

Two other data points about bars and Boges, not from an Audi but from a
car with four rings cast or stamped into most of the major components:
when I was autocrossing competitively, I did some tweaks to my own '84
GTI and also co-drove a friend's '83 GTI.  We were both in Stock class,
meaning you couldn't change the springs, you could use any shock you
wanted, and you could add, remove, or replace the front anti-roll bar
(but make no changes at the rear). 

I put Tokico Illuminas on my car, kept the bars stock, and dialed the
rear shocks 2 clicks (out of 5) stiffer to add in some initial oversteer
on corner entry.  Lisa ran Boge Turbo shocks and a stiffer front
anti-roll bar.  We both ran the most front negative camber we could dial
in, about 1.25 degrees, without going with (illegal in our class) offset
bushings or slotted strut mounts.

We both drove both cars, and no matter who was driving, Lisa's '83 ended
up being just a little quicker than mine.  The feared increased push
from going with a stiffer front bar never showed up, for the reasons I
hint at above: we figured we were reducing front-end roll enough that,
combined with the extra negative camber, we stayed in the good part of
the front camber curve (which on MacPherson cars is linear as an effect
of body roll, I'll remind anyone who may have forgotten).

Anyway, that's a vote of confidence for a) the inherent quality of the
Boge shocks, OR b) going with shocks and a stiffer front anti-roll bar
if he decides against changing springs.  Or... maybe it's just a vote in
favor of increasing the roll stiffness 25%. :-)

There's one thing I haven't looked into yet.  The subtle effect of
shorter front springs on any body-roll induced camber changes is
something I haven't yet worked out for the Coupe; just from eyeballing
the front suspension while I was doing the brakes a few weekends ago, it
*looks* like shorter springs would give me a hair more static negative
camber, which is what the FWD hotshoe wants; it would mean the front
tire would be more vertical under a comparable amount of body roll, AND
the stiffer spring would mean that you'd have to have higher cornering
loads (read: higher speed) to get to that amount of roll.  The net
effect should be to put off terminal understeer to a much higher speed
than that permitted by the stock settings.  But as I say, I haven't
measured things and could be wrong.  Anyone have experience with this?

--Scott Fisher
  Sunnyvale, California