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RE: Lower A arms & geometry

To: "'Larry Young'" <cartravel@pobox.com>, fot@autox.team.net
Subject: RE: Lower A arms & geometry
From: Bill Babcock <BillB@bnj.com>
Date: Tue, 5 Feb 2002 10:21:29 -0800
The software I used was from one of the race car builders in England. I
don't remember which. As far as I know it was not for sale--I "borrowed" a
copy with the promise that I would erase it when I was done. It had a
primitive interface even though it ran in Windows. I did as promised, and
deleted it, though I sure would like a copy. 

-----Original Message-----
From: Larry Young [mailto:cartravel@pobox.com]
Sent: Tuesday, February 05, 2002 5:45 AM
To: fot@autox.team.net
Subject: Re: Lower A arms & geometry


Ok, I'll ask the stupid question.  What software are we talking about
here,
and where can it be found?  I messed a little with dyno software, but
haven't
ventured into suspension.
Larry Young

Bill Babcock wrote:

> 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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