Actually, the input I am receiving from several accomplished tuners/racers
makes me think I have a spring problem (need to soften the front) and an
alignment adjustment need - - moreso than a problem resulting from the LSD.
The LSD helps me put the power down, and I can now literally hammer it, a
lot earlier in the apex.
G
----- Original Message -----
From: Dupin family <dupina@crisny.org>
To: <gears@azstarnet.com>
Cc: George Ryan <quad4fiero@webzone.net>; <autox@autox.team.net>;
FieroRacing List <fieroracinglist@fieroheaven.com>
Sent: Thursday, December 02, 1999 11:08 AM
Subject: Re: RACING Thorsen LSD in mid-engined cars
> Does this mean that you won't change the cam on the Cadero 4.9L?...You're
happy with
> it?
> Does it also mean that the LSD is good for you, bad for the Q-4 setup??
> Let us know what alignment you end up with when it's "right".
>
> Phil
>
> Tom Hill wrote:
>
> > Hey George,
> >
> > We finally got the chance to do some road racing with the '88 version of
the
> > Python. Saturday we were at Phoenix Int'l Raceway and managed to get
about 15
> > laps between Greg and myself before the car 'broke'. Turns out that we
have a
> > transmission vent problem that never presented itself in autox. We have
never
> > had the sustained high speeds like road racing. Consequently we blew an
axel
> > seal and were dumping trans oil on the exhaust. Not a pleasent thought.
> >
> > As far as handling at PIR, the car was super twitchy at high speeds. We
may not
> > have had enough toe in for the large tires. Also we did not check the
rear toe.
> > Duh! For whatever reason we did not think of that. I think the
suspension is too
> > soft at 300lb front and 350lb rear. I could really feel the suspension
> > compressing a lot on the oval. It was a lot more than the old chassis. I
think
> > another 50 to 75lbs would have been adequate. We had problems getting
the big
> > tires up to temp but is was pretty chilly out there. As a result, the
tires
> > seemed to do a lot of skating. Not so much that you could not compensate
but
> > just enough to be a bit disconcerning. The tires also felt like the
sidewalls
> > were a bit mushy. You could feel the tires 'wind up' and let go under
heavy
> > cornering. That might have accounted for some of the skating also. Any
way you
> > look at it, the suspension still needs some tuning. I can't really say
how much
> > of the handling problems were attributed to the Torsen.
> >
> > As far as power....that's a total different story. This thing is a total
animal.
> > We started the 'improvement' stage by installing an MSD ignition. What a
total
> > difference. We then put a different exhaust on it and woke it up even
more. The
> > improvement was just as much again as installing the MSD. I was mid-way
through
> > 5th gear on the front stretch before having to back off to brake for
turn one.
> > No one was running off and leaving me. Vipers, Porsches, etc. were just
inching
> > away from me on the front. I could even pull the Corvettes on the
straight
> > sections. However, one thing you have to remember when you are road
racing
> > verses autox, when you're down shifting from 5th, ya gotta remember
which 4th
> > gear you're putting it in. I accidently hit 2nd at about 90mph and the
back end
> > did everything but pass me. I realized right away what I had done but I
didn't
> > want to step on the clutch with the tail wagging all over the place. I
figured
> > the best thing to do was to ride it out and fight it until I could
control it.
> > Anyway, the 'Vette that was on my ass sure got a lot smaller in the rear
view.
> >
> > We managed to fix the car for an autox event the following day and set
top time
> > of day for door slammers by over two seconds. I even managed to beat
Greg by 1.3
> > seconds with a 69.4 run to his 70.7. Don't get the idea that Greg is a
bad
> > driver. He will routinely beat my butt on the tight technical courses.
This
> > course just happened to be a high speed course that flowed extremely
well. Just
> > the way I like them. The Python was at the upper RPM band for 3rd gear
which
> > puts us in the 70mph range.
> >
> > Sorry for the book but I though I'd let y'all know how our weekend was.
> >
> > Tom
> >
> > George Ryan wrote:
> >
> > > In true TLS fashion, I was able to almost get my car together (?) just
> > > before the end of last season. I had a fuel pump problem at the Pikes
Peak
> > > National Tour, was able to finish one lap. Lately, I have ALMOST been
able
> > > to run the entire day, all 8 laps.
> > >
> > > Anyway, WHEN the car is able to make it around the track (I have
accepted
> > > the humility of dialing in a Prepared car) it has terminal understeer.
I
> > > have worked with tire pressures, shock settings (12 way HAL's on the
front,
> > > modified Koni struts with adjustable perch in the rear) but with
little
> > > results.
> > > The Fiero simply does not want to turn. I have eliminated (almost) the
> > > alignment. What is left is two things - - too much front spring
(350lbs) in
> > > the front (the scales while weight jacking showed a total of 790lbs
in the
> > > front) - - or the diffy.
> > >
> > > Last year I ran cut stock springs on the stock Fiero front suspension,
this
> > > year I went to a coil-over suspension. The sway bars are the same ones
as I
> > > used previously. All the oversteer and snap-spin characteristics are
> > > gone - - the '88 Fiero rear cradle with adjustable links has tamed the
rear.
> > >
> > > I have a 3.94:1 ratio 5 spd Getrag with a Thorsen-Gleason LSD built in
the
> > > tranny. I know the LSD makes quite a difference, on a tight 180 degree
turn
> > > last event I struggled to get around the corner. If I lifted, the
turning
> > > ratio tightened appreciably, if I added throttle the car pushed, the
more
> > > throttle, the straighter it wanted to go. Constant throttle was the
only way
> > > to go!! Is this just a driving style I need to adapt, or should I
consider
> > > losing the LSD in spite of the performance (straight-line and
ProSolo/drag
> > > launches)?
> > >
> > > I thought I would tax the brains of you suspension guru's and seek
input.
> > > about both the springs and LSD.
> > >
> > > Thanx
> > >
> > > G
>
>
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