At 12:39 PM 8/12/98 -0700, Mike Gigante wrote:
>
>>>3) LSD
>>
>>.... Lysergic acid Diethylamide .... Somehow I suspect you are refering
to something else?
>
>Indeed, I am referring to a Limited Slip Diff.
Oh yeah! I would dearly love to install that LSD. I would also like to
use wider wheels and a larger engine, but alas, such luxuries are not
allowed in Stock class.
>If you are lifting the inside rear, .... Note that the common Quaife LSD
will not work in this situation.
You know, I hadn't thought about it in that light. But I suspect you're
right, that the all gear and no clutch Quaife LSD would just free wheel
with one tire off the ground. Hmmmmm. Brings up my next problem (question).
I am considering going into Street Prepared class with SCCA, where legal
mods would include LSD, wide wheels, lowered suspension, larger carbs,
exhaust headers and the like. I have been collecting parts for a while and
am currently looking for a LSD. I was real high on a Quaife unit until
this comment rang the bell. One of the quaint characteristics of a Quaife
LSD is that if you jack up car and turn one rear wheel it does indeed free
wheel, and you can't tell that the LSD unit is in there. (Just in case
someone wanted to sneak one in unnoticed.) It doesn't take a lot of
resistance at the tire to make it work, but it does take some, so you do
have to keep both rear wheels at least touching the pavement.
So now the question. Someone is offering me a couple of LSD's, one Spicer
and one Detroit Locker. The only LSD unit I have any hands on experience
with was a Ford Traction Lock unit in my 1974 Mustang, and I have certain
reservations about that one. I'd appreciate any info anyone can supply
about the workings of these LSD units. What works and what doesn't? Parts
and/or service environment? You get the idea. What does anyone know here?
>....
>Again, it may not be allowed (but it was a BMC catalogued item at least
for the spridget).
Alas, never a factory option for the MGA that I know of, only available as
an aftermarket part, so not allowed in Stock class. But I'm still
interrested in LSD for the future.
>BTW, you can also just weld up the spider gears in the diff to give
yourself a permanently locked diff. It is hard on the axles though and
causes understeer on turn-in.
Yeah, strictly dirt track stuff. Makes tight turns very difficult on hard
pavement.
>>>4) stiffer rear shocks (very stiff bump damping before 'blowoff')
>>
>>.... can continue to wheel around on three like that until it slows down
or completes the turn. ....
>
>Aaahh, but it does help. It helps a bit earlier in the process. By
increasing rear damper stiffness you will get less roll on the transients
at turn-in. .... As a result of reducing transient-induced roll (i.e. the
lurch on turn-in), you may find you no longer lift the rear wheel. This
works well for me.
Yeah, I know what you're getting at. But, with experience I have nearly
eliminated "lurch on turn in" by judicious use of soft feet, slow hands and
smooth driving. Even with a very gradual transition into a tight 180 at
less than 30 mph the rear wheel will still lift, like big time! If it was
just a couple inches of bounce followed by immediate touchdown, then
stiffer shocks might help a bit to surpress the lurch. What I'm talking
about here is enough body roll to affect a complete long term lift, not
just a lurch.
>Finally, as someone else noted, if you re-arch the new springs to be at
stock height, how can anyone complain?
They can't. That would be perfectly legal. One problem here is that no
one is likely to know what the correct ride height should be, as it is not
stated anywhere in the Factory Workshop Manual, and I haven't found any
other source for that information. Perhaps that spec never existed. Who's
to say what it should be? This could lead to some intentional hedging on
the extreme side of dimensional tolerance.
I fully expect that my new springs are too tall, because under normal load
conditions there's only a short downward travel available in the rear axel
before it hits the limit of the rebound straps. And I suspect that the old
springs are a bit too low, just because of the general appearance of the
height of the car compared to other similar models. But either of these
impressions could be wrong.
If there is indeed no spec for the ride height, who can say what "out of
spec" is? If the springs sag a little in normal use over the years, and
that is normal and expected and part of the original design of the vehicle,
then the current (lower) height of the old rear springs could be argued to
be perfectly normal, stock, within spec, and legal for Stock class. Or,
can anyone out there come up with a printed spec for the ride height of an
MGA with a definite stated +/- tolerance or a max/min dimension? This is
not just a rhetorical question. I really would like to know.
Barney Gaylord
1958 MGA with an attitude
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