I did, spent about two days fiddling with software that didn't belong to
me. I started out by doing all the measurements required--that takes a lot
of work because you need to get it all very accurate. Then I ran the
software and was so shocked at the results that I went back and measured
everything again. Basically it told me that TR3's shouldn't be able to
turn a corner at walking speed without flipping on their side. A slight
exaggeration, but the numbers look really bad. The roll center for the
front end is about 4 feet underground, bump steer input is huge, there's
hardly any caster, camber varies greatly as the arm travels. I don't
remember specifics, I think I wrote a long email to the list that detailed
them, but I don't have a copy. I did find that many of the worst faults
can be corrected, and I did so--my cheater TR3 handles wonderfully. But if
you are planning to vintage race, you need to be very careful. I built an
adjustable upper arm (heim joints on front and back so the overall length
as well as the caster can be adjusted) and moved the upper arm pivot point
about one inch inboard. Raised the steering box about a half inch. Short,
stiff springs to lower the car and reduce front end travel (no way to
completely eliminate the varying camber) and lots of rebound damping. and
of course the usual sway bar, super-soft rear springs, etc, etc. Most of
the standard stuff that people do to make TR3/4 handle is in the right
direction.
So now I have a TR3 that corners as flat as a formula ford, does lovely
controlled drifts without understeer, and is not welcome at any vintage
event except SCCA, where the only thing they require to be authentic is
your entry fee.
-----Original Message-----
From: David & Krystal Wingett [mailto:elkhorn@megsinet.net]
Sent: Monday, February 04, 2002 2:21 PM
To: Dave Brackin
Cc: Friend Of Triumph
Subject: Re: Lower A arms & geometry
Has anyone run any of the new computer suspension diagnostic
soft wear, using our TR"x" as a model? I know most racers have lowered
there cars. I'm just wondering if anyone has actually done the engineering
design work to do it right. I have an older dos based program ... I
just
don't have a clue how to collect the data to fill in the prompts.
DW
Subject: RE: Lower A-Arm Studs
>
> Bill, I've got a new set of springs that should lower the car about 1
1/2".
> All other components are tr6 (minus the lower wishbone to frame mounting
> brackets of course).
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