where to get 4kq springs??????

[Jason Gray]

I measured the spring rates myself, they were same from two different 4KQs
that I checked.

The formula for spring stiffness is  =(1,500,000(#/in^2)*W^4)/(N*D^3)

where W is the wire diameter in inches (raised to the 4th power)
N is the number of free spring coils
D is the diameter of the overall coil spring (raised to the 3rd power),
measure across coil from middle of the wire
The 1,500,000(#/in^2) is a constant that comes from the inherent properties
for spring steel. (same equation could be used to calculate stiffness of
wooden springs (or whatever) if you had the right constant for the material.

For front springs,
W= .504"
N= 6
D = 5.28"

For Rear Springs
W= 0.528"
N= 5
D = 5.26"

The coil diameter (D) is a bit smaller at top and bottom of the springs,
making these sections of the spring slightly stiffer (progressive). This
would result in a slight error if you were comparing to truye linear springs
but since both front and rears are wound the same way, the difference is
negligile when compairing them to eachother. The major effect of the
stiffness here is the diameter of the wire (because it is raised to 4th
power in the equation for spring rate). The small increase of the wire
diameter for the rear springs really boost their stiffness. I confirmed the
calculated spring rate by compressing the springs (with my full body weight)
and measuring the resulting deflection. My notes show that the fronts were
even 10% softer than calulated.

Having only a front sway bar (stock) likely is greatly responsible for the
stock understeer, despite the stiffer rear springs.
Once I got the set of stiffer rear springs onto the front, it greatly helped
to control body roll, the stock fronts are way too soft for street
performance.

 Jason K  Gray
Anchorage Alaska


----- Original Message -----
From: "Michael Gough" <mdg3369 at newtsplace.com>
To: <jason510 at att.net>; <quattro at audifans.com>
Sent: Monday, June 30, 2003 8:09 PM
Subject: Re: where to get 4kq springs??????


> >> One problem here, the 4KQ front spring rate is around 110#/inch and the
> >>rears springs are around 160#/in. Moving the stock front springs to the
rear
> >>will dramaticly SOFTEN the rear spring rate. Combined with stiffer front
> >>springs, this would make the 4KQ understeer even worse than it already
does
> >>with stock springs. See my 4/22/03 post (below) describing my dabblings
with
> >>stock springs.
> >
> >
> > I don't want to start a war here but both my personal experience of
actually
> > running stock front springs in the rear of my 4kq and my knowledge of
> > engineering say this theory of lowered spring rates is highly doubtful.
> >
> > I will stick to the "experimental results" and point out that I am not
the
> only
> > one to run front springs in the rear of my car and neither I nor anyway
else I
> > have ever heard of has experienced degraded handling when doing so. To
the
> > contrary the handling improved with considerably less understeer and
body lean
> > even before I added the rear sway bar.
>
> Considering the fact that the majority of the weight on the 4kq is on the
> front suspension, coupled with the fact that cars for the general public
are
> designed to understeer when pushed hard, the alleged 110/160 F/R spring
rate
> is VERY hard to believe....
> How exactly did you come up with these numbers?
> Mike