Overdamped, Underdamped (was WTB parts for 87 1/2 Coupe)

[larry C leung]

Underdamped means the springs will overwhelm the shocks on rebound, so on
rebound, instead of the car settling and going on it's merry way the
spring "overbounces" and the bump continues in the opposite direction,
over, and over and over again. The driver/passenger percieves this as a
bouncy ride.

And overdamped suspension (such as my rules mandated SCCA Stock Class
(ES) GTi with Stock springs and Tokico Illumina5's) acts differently. The
shock overwhelms the springs, so in effect, the springs don't get to work
to well. Here the suspension is actually rather "stiff-kneed", so the
ride is perceived as "harsh" or unyielding.

In the case of the GTi, I put up with it (that's why the externally
adjustables, at least you can dial out SOME of the harshness on the road
to and from events) because that's whats needed to be competitive at
beyond the local levels of SCCA Solo 2 competition. The reality is the
stock ride (OEM shocks) really didn't wallow much at all (A2, not the
piggish A3 and A4 GTi's) and is most definitely preferable.

As for underdamped cars, you can easily experience it when driving a
stock car with worn shocks. In the case of stock springs, it bounces
rather slowly and it wallows as the springs are allowed to use much of
their travel. For lowering springs, the car bounce rate is rather high
and very annoying. The wallow is gone only because the springs are stiff
enough that the forces that would be required to compress the springs
much is comparatively higher. If you payed careful attention, you'd
actually notice that there would be a very rapid side to side rocking,
but most people miss it, thinking it's an up an down or fore and aft
bounce.

Of the two improper extremes, I prefer overdamped. But if you do have
stiffer springs on your car, it may surprize you to put appropriately
stiffer shocks on to properly match the springs. The ride will actually
become smoother, even on our pockmarked, broken edge, rutted northeast
roads.

LL - NY

On Sun, 06 Jan 2002 22:12:31 -0500 Huw Powell <audi at mediaone.net> writes:
>I was gonna chime in (well, I guess I am), when I put the lowering
>springs on my Coupe (eibach?) it got or had a new set of fairly
>generic
>aftermarket struts/shocks, I *think* they were boge... but might have
>even been less ostentatious than that.  All I know is the ride is not
>too soft, or underdamped, or any of that.  I guess a set of dampers
>designed for lowered cars might make it even stiffer - not sure I
>would
>even want that!
>
>> Not in my experience...
>> I've used Eibach's and H&R's with Boges on my 4kqs...
>> not underdampened at all..
>
>> At 07:57 PM 1/5/02, you wrote:
>> >If you are planning to use H&R or Eibach (or any other lowering
>springs),
>> >Boges would be seriously underdamped, resulting in a bouncy ride. I
>would
>> >personally go with Bilstein, Koni or Tokico Illuma5.
>
>--
>Huw Powell
>
>http://www.humanspeakers.com/audi/
>
>http://www.humanthoughts.org/