-----Original Message-----
From: spitfires-owner@autox.team.net
[mailto:spitfires-owner@autox.team.net] On Behalf Of George P.
Sent: Thursday, April 15, 2004 11:51 AM
To: Spitfire List; Nass List
Subject: driver's side lean
I've been reading the "drivers side lean" thread and have some
comments/questions.
First, when I got my Spit ('78 US Fed 1500), it had a distinct "dsl" -
removed rear spring, re-arched, reinstalled, lean about 95% gone. 19
years and 40K or so miles later, it's still about 80% better than when I
bought the car.
Second, I've also heard of folks rebuilding their rear spring with one
or two longer leafs to provide more support. Comments??
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I added a parallel main leaf to the stack on my Race Spit but it has the
old style fixed spring. I can't say how it would work on the
swing-spring. I would think that if it were clamped along with the
lower leaf to the diff that it would tend to undo some of the
characteristics of the swing spring and exacerbate the wheel tuck
effect.
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Third, other racers may correct me here, but my understanding of chassis
set-up (from 8 years on Ferrari of Washington's Ferrari Challenge and
Grand-Am GT team) is that the effects of weight on the chassis is
diagonal. In other words, if the left rear sags from whatever cause,
the right front would lift. *NOT* that the left front would also sag.
Now, having said all that, I do recognize that Spits do tend to lean to
one side. So I'll admit to some confusion here. Maybe someone (Joe C,
Paul T, or Terry T) can put this into layman's terms that we can all
understand.
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I would tend to agree with your assessment, but since I don't have any
empirical data it is only an assumption.
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Fourth, Camber Compensator. With a '78 1500, is this "device" of any
use to me, or is it only useful to the older "swing axle" (if I'm even
using *that* term correctly) cars??
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This one is something I CAN talk about with some measure of authority.
The camber compensator would not do much good on a swing-spring car
since it's function is pretty much what the swing-spring does. However,
I am making a kit for later long axle cars that will work if the swing
spring is replaced with an original fixed spring. The kit is pretty
much the same as for early cars but the spring component and link kits
are longer to accommodate the longer axles. You might have to play with
the front sway bar to balance the car front to back after the change.
Most likely, you will need to go to the smaller front bar to get it to
turn without understeer. The price is the same as the original kit.
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Fifth, since I questioned whether or not I used the "swing axle" term
correctly, is there a site with a good description of the different rear
suspensions? Maybe on Paul T's site somewhere?
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On the Spit and GT6 there are only two basic types of rear suspension,
Swing axle and Rotoflex. The rotoflex uses a lower control arm and
needs the rotoflex coupler to account for variations in the axle length
as the wheel travels through the upper and lower limits. The swing axle
changes geometry as it travels through its limits. This change in
geometry is what leads to the dreaded "wheel tuck" when the unloaded
tire in a hard turn lifts and the axle falls. That is what spawned the
camber compensator and the swing-spring.
There are 2 variations of the swing axles, the early fixed spring
(through Mk3) and the later swing-spring.
Regards,
Joe
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