Jackson is on the correct track, but you need to be
careful with the rear panhard bar or you will end up
with serious "binding" which will cause instant
oversteer. The basic problem is that the panhard bar
and the 1/4 ellip springs move on different arcs. The
panhard bar tries to push the spring sideways and
binds. You obviously don't have this problem with coil
overs. The springs were originally designed to provide
horizontal control, but are not up to the task for
sticky tires at race speeds. If you are still running
the four link rear binding is even more probable.
The solution is to arrange the 1/4 ellipticals to
provide the freedom to act like coil overs and use the
panhard bar for horizontal control as it should be.
There are a number of ways to do this, but the
simplest is to open up the mounts on the ends of the
springs to allow movement (space) on both sides. I
used 1/4" on both sides. I also ground the sides of
the springs flat. I also went to a three link sytem by
installing a third link on the top side of erthe rear
banjo. Jim Roberts mechanic (John Stamps) gave me this
advice.
I had Landrum Springs make up some custom 1/4 ellip
springs of slightly different thickness. Allowed
slight changes when scaling the car. I also had good
results from the aftermarket springs from MM.
BTW placing the spacers on the bottom of the springs
lowers the car. A quick way to lower and reduce spring
pressure at the track without spacers is to simply
move a spring to the other side of the stack.
The 540lb front springs are the absolute minimums for
road racing, especially if you have any elevation
changes such as Road Atlanta or Mid Ohio. My car
oversteered the most when the nose pointed down. The
above changes and seriously strong front springs
seemed to cure the problem. Prior to these changes I
had to tip toe through turn 12 at RA.
I have never driven a Sprite on public roads. I'm
chicken, so I can't comment on road spring rates.
Most groups will allow you to run tube shocks on the
rear of sprites, and they are a major improvement,
especially for adjustability.
Lastly unless you can unweight the rear inside wheel
like Dave J, Colby and Jim Roberts, locked (welded)
rear ends tend to cause a push-loose. The car
initially pushes, causing you to turn in more, thus
slowing the car (you may also slow because of the
push), as the car slows, the front end is able to
generate enoough grip to turn the car, when it does
the additional steering input becomes effective and
you think that you have a loose car. The solution is a
limited slip, I'll avoid the discussion on the
different merits of the different types of LS's.
I found that there are major improvements available
from changes in the supspensions of sprites.
Hope this diatribe is of some benefit.
Doug Wilson
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