Delrin bushes (was: Re: BTDT for front control arm bushings)

[Mark L. Chang]

Some background - 90q20v with 16" wheels and 205-45/16 tires. Eibach and
Bilstein shorties with Delrins up front and OEM out back. The Delrins
are sleeved and were turned by Todd Candey. All other bits from the
waist down were replaced at the same time - Hell, find out here:
http://www.audi-quattro.org/mycars/90q20v/suspension/

My beef is not with ride. Ride is great. Again, Seattle has nice roads
(IMHO) and it works out well here. The car is tight as a drum, no doubt.
The problem I have is definitely with NVH and harshness of imperfections
in the road. For instance. Crossing a bridge such as I-90 here you get
metal expansion joints. Those can be a real sharp and jarring feeling
with the delrins in there. They are definitely felt more, um,
"accurately, as Javad said.

Upside is that turn in is crisp. Very crisp. My 4kq with a similar setup
but without delrins was tight but not as crisp in turn in.

The complete package lends itself very nicely to carving the roads. I
don't know about on the track, because I've never taken the car out on a
track, but it's definitely fun to drive. I recommend the eibach/bilstein
setup. Very nice ride, IMHO, and the wife actually doesn't mind it as
long as the road is smooth enough to not give us the effects of delrins.
Now *that's* saying something.

The 45-series tire and the Delrins definitely add up to more harshness
over poor surfaces. If you live in Chicago, forget about them. Bob
Dupree had 'em in his car, and that was my advice to him as well.

Would I use them again? Maybe, maybe not. I thought I'd give them a
shot. I would never have considered them if the roads here weren't
amenable to them, for sure. As far as reliability, a buddy with a CQ and
2B delrins up front had an issue with them rounding out. His were not
sleeved, though, so the bolt was turning in solid delrin and not in a
metal sleeve. Different design that 2B went away from in later
revisions.

On Wed, Nov 06, 2002 at 09:49:22PM -0500 or thereabouts, JShadzi at aol.com wrote:
> Well, as has been pointed out, it could be an issue in areas where roads are
> really bad.  Here in Sunny California, the roads are pretty good,
> pothole-wise, but there are still plenty of cracks and bumps in some of the
> roads, which can be felt more "accurately" once you have the delrins in.
> Overall, though, bushings are not shock absorbing devices, and the end
> resulting ride should be determined by shock and spring/tire tuning.
>
> Busings will result in varied NVH (Noise, Vibration, and Harshness), but the
> ride is really determined by your shock/spring combo, and also the tire
> specifications such as side wall height which will greatly affect ride.  Mark
> may want to expand on his experience with Delrin bushings and how they
> affected his ride, but IME it was more harshness and not a ride issue.
>
> As far as reliability, Delirn bushings are as good as it gets when it comes
> to Audi control arm bushings.  I have used Delrin bushings in some race cars
> for 4 seasons and counting, on the street I don't think they will ever need
> replacing (specifically with 2Bennett bushins IME).  I'd like to hear
> anyone's reliability experience with Delrin bushings that wasn't excellent.

--
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