Re: Coil-over shocks

[QSHIPQ@aol.com]

In a message dated 97-05-30 00:34:59 EDT, you write:

<<  I still can't figure out why eveyone is obsessed with coil overs. Keep 
 the damper and spring separated for max control and performance .  
 Coilovers were only designed for packaging not for "superior" 
 performance, They tend to bind the stut shaft and make the low speed 
 damping erratic and generate excessive heat in high speed damping.  If 
 you want to see state of the art in dampers look to touring car, some of 
 the stuff being done there is wild.
 
 Later!
 
 
 Eric Fletcher S.O.C.
 '87 5KCSTQ WAY too many toys
 Trans-am/Sportscar Chassis Engineer
 St. Louis, MO
  >>
Interesting post.  Having done a couple coil over setups, I find the
conclusions drawn above somewhat misleading.  Coil-over is a packaging
concept, but that is NOT all.  They do tend to bind when one picks the wrong
effective spring length for the ride height chosen.  Low speed damping
control and high speed heat might apply to a race car with MASSIVE spring
rates and low relative travel, not so the case with a more reasonable street
car.  The main advantage of coil over design and application is the
flexibility you have without having to custom wind any springs, that can get
expensive, try buying just the springs from any of the "kits".  Eibach's ERS
springs are off the shelf, linear rate springs available in a universal 2.5in
dia, and you can spec the effective length in 2" increments and the spring
rate in 25lb increments, and relative to ANY kit available elsewhere, they
are price competitive for audis.  

Corner balancing a car for the track, changing ride height, linear rates, and
phenomenal handling make coil-overs a serious improvement for the audi cars.
 All you need to do is drive one, take a lap time, and one will realize that,
even with all the "kits" available, this setup will do donuts around most
others.  Not at the expense of ride control, height, or comfort or longevity
either.  The street ride is not choppy, hardly unacceptable for the
autobahners q's are known to be.  The long wheelbase and overhang, tame even
some of the wilder coil-overs installed in audis.  

Downside?  I find that most folks that have them on street cars, don't change
the height after the initial dial in.  Most have an idea on what and where
they want ride height, and once the suspension is dialed in there, few change
the height.  So adjustability isn't really the advantage for "most" folks.
 Getting the proper spring length and rates, especially with the 44 chassis
takes a lot of work, btdt.  The rewards are worth it, the decrease in the
tail wagging antics of the 44 chassis alone brings smiles.  

On a related subject, a cousin of mine I talked to last weekend has an
interesting job at Ford these days, that of suspension engineer.  We nerded
extensively, and his summation, "we have all the programs available to give
us an indication of suspension setups, but until we put it on a car and test
it, the results are just paper."    He was also most facinated by the
multilink rear of qship.  

Bottom line:  Don't write off a mod until you've btdt.  My experience, as
Audi Chassis Engineer Emeritus, is that coil-overs are a sensible and decent
alternative, in performance and price, to ANY "kit" currently on the market.
 Proper execution of the mod, any mod in fact, is what differentiates the
good from the bad.  Lots of books and reference material available to anyone
that wants it, several include workbooks that make you a post-graduate
quickly.  

Proper suspension setup is not rocket science.  Understand the physics, and
what you want the car to do, and the rest is straight forward.  Ride in a car
with a proper suspension, the comparo is really easy, you have more
evaluation in the seat of your pants than you might give yourself credit for.

Going wild in touring car?  Great for those with the bux or sponsors, given
the prices (gave a gander too - gasp), I don't see this coming to the
mainstream for quite some time.  The ultimate, as always, is only a wallet
away.  Given the level of performance B4B coil overs give, doubt many will
hand over the ckbook for "better".

Just a couple of pennies arbitraged thru the peso

Scott
'87 5ktqw
'84 Urq