Re: the question about different LSd's. I have recent experience with the
Quaife
in both a TR8 road race car and an MGB solo car. Quaife is really nice if your
suspension is properly set so that you do not pick a rear wheel off the ground.
If you pick up a wheel the Quaife will let the airborne wheel spin. You never
feel it. It does not upset the car like a locker, doesn't make the car push,
and
you car still push it around in the pits. A locker can be effective in some
situations, but will upset the car when it locks and will make it push. i hear
bad things about the Auburn cone types that are in the late Mustangs, mostly
from
Mustang racers. John
Barney Gaylord wrote:
> 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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