On Sat, 10 May 2003 mocharand5@aol.com wrote:
> Just curious, how much has anyone lowered there car? Has anyone gone more
> then 2 inches?
This could be a trick question.
If you lower the car by changing the tire diameter, then the answer is
YES. To do this, you need a 23 inch diameter tire (something like
225/45-15) and you do have to lower the suspension via changes in spring
height an additional .5 inches (approx.)
If you want to do it be suspension changes only, then you need to do a lot
of work, because of a couple of reasons. First off, the front
suspension... by lowering a lot, you wind up with goofy geometry (and a
lot of bump steer). To compensate, you need to play with the length of the
upper a-arms (and ultimately with the location of the upper fulcrum pin).
In the rear, when you get beyond the point where the rear axle is level,
you wind up with a situation where there is dramatic toe change as you
compress the suspension. So, unless you change the pivot locations for the
trailing arms, there is a limited amount of "gain" to be had here.
That said, with lowering springs in the front and rear and with some minor
changes, you can lower the car quite a bit. I run my race car with the
front frame (measured where the axles is located) is about 2.25 inches
from the ground and the rear frame (measured where the main out frame rail
meets the trailing arm crossmember) is about 2.75 inches from the ground.
This is quite low and would be totally undrivable on the street.
The changes that you need are:
front: you can lower the car by putting in some TriumphTune "sprint"
springs. These are in the 420 pound range and are quite short. I forget
the lengthsm but I have them written down somewhere. I'll also point out
that the lengths are what they list in the catalog.
front: you can lower the front MORE by _either_ flipping the lower a-arms
upside down (this has the effect of lowering the spring pan) _OR_ adding
"spacers" between the spring pan and the lower a-arm to place the spring
pan lower toward the ground.
front: about 1/4" of spacer distance translates to almost .5" of
suspension lowering.
front: excessive lowering will increase the amount of negative camber in
the front. At some point, you will need to compensate. The best way to do
this without moving the upper fulcrum pin is to saw off the inner ends of
the upper a-arms and weld in some (internally) threaded rod to accomodate
some "rose joints" (aka Heims joints). This allows you to _lengthen_ the
upper a-arms to dial in some positive camber (and get back to reasonable
camber angles).
rear: use off the shelf lowering springs. If you try to go really low,
you'll have to get out the suspension geometry software to figure out how
to dial out the excessive toe-in angles. The big problem here is the
amount of toe change (e.g. bump steer) for a given amount of suspension
movement. To compensate you need really stiff springs. My rears are in the
600 pound range.
rear: with many of the lowering springs (like the TTune "sprint" springs),
you will need to run spacers. I run 3/4" in spacers to get to the 2.75"
(actually it might be 3") frame height. These spacers are stackable, so
you can get 1/4", 1/2", 3/4" and 1" height spacers.
rear: I have not done this, but it looks like once you get you camber
where you need it, you could modify the pivot point either by offset
bushings or be welding and redrilling the pivot brackets to move the pivot
point _UP_ so you can lower without getting the big toe changes.
c ya,
rml
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