[200q20v] RE: Coil overs - some btdt

QSHIPQ at aol.com QSHIPQ at aol.com
Mon Nov 20 07:19:33 EST 2000

I'm not going to comment on the vendor you guys are having problems with 
(btdt on an S6), but will come forth with some observations, a lot of coil 
over setups have gone thru my shop.

-  stiffer front or stiffer rear.  I tend to use stiffer rear, but only about 
25in/lbs more in back than the front on the 4k/80/90/urq.  My experience is 
that the stiffer fronts makes for more understeer, something quattros don't 
need.  I also find that stiffer rears tends to allow a better oversteer 
attitude entering the corner (key for driving a torsen car quick)

-  Duct tape on the collars (Chandlers old girlfriend"Oh - my - God!").  NO.  
A couple of spot welds at the bottom of the collar will hold it in place (or 
even a seam weld).  Remember too that if there is play in the spring 
(extension makes spring totally unload), you either have to go up in spring 
length, or use a tether that prevents total extension (this is what race cars 
use - basically a couple eyebolts and a cable).  Easy to do on the rear of a 
quattro, really tough to do on the front.

-  Clunking and grinding/groaning during turns.  Ck out the swaybar extension 
links, they make these noises.  If a torrington bearing is crudded up, it 
will grind as you turn the wheel.

-  Spring rates.  2B is *very* agressive on spring rate applications.  IF you 
are making a track car, then use the higher rates (300+ on a 4k chassis is 
getting really stiff).  If you must live with it daily go lower, the linear 
rate spring is what is really helping you. If you find that a wheel is 
lifting during hard turns, you've gone too far.  A lifted wheel on a quattro 
is a no-no in terms of power to the ground (there is less or none, depending 
on your diff configuration)

-  Consider rear only conversions, front stock.  I've done several dozen of 
these setups, and it is a great compromise, and usually gets SO approval.  
Put in a good shock (koni or bilstein), get the correct f/r rake angle, and 
you will find that the cars handle really well.  If the front still isn't 
stiff enough, go eurethane on the SB bushings where they attach to the 
subframe.  Be careful on the triagulated swaybars (type 44 chassis) end 
bushings.  They are meant to have rubber slop in them.  A couple of instances 
of bars actually breaking, needs no further comment.

-  More on spring rates.  IME, the spring rate guildlines one should use 
comes from the published eibach and H&R rates.  (The urs4 site has them all 
listed for the S4/6, a great tool).  Don't start any stiffer than their 
stiffest rate, they spend more time testing, don't waste your dollars.  I 
usually start somewhere between the street and track setups they publish, 
since most coil overs are linear in rate, you don't need to be as firm as the 
progressive springs.


Scott Justusson
'87 5ktqw - Rear coil overs, ABT front Swaybar, Bilstein HDx4
'84 Urq - New stock springs, Bilstein HD x4
'83 Urq -  Front Bilstein/stock spring, Rear BogeTG/5ktqw rear spring (a 
cheap ass motorsports thing, hey it works well)

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