LSD & The Grinch

[JHertzman <JHertzman@aol.com>]

In AD6-016 Scott Johnson answers "newigi@aol.com, who had a question about
LSDs (limited slips)", and wrote "Exactly when Alfa switched to LSDs is quite
unclear. Even John Hertzman, who has most if not all of the relevant parts
books, could find a clear answer. Some recommend checking the underside of the
diff... LSDs have chevron-patterned ribs as apposed to parallel."

While looking for my previous post on "when" (which I recall as their having
been optional on 105s as early as 1964) I found what I consider an
authoritative answer in AD5-228. Paul Tenney wrote:

"I have never personally seen a 2L 105 GTV or 115 Spider without a factory-
installed LSD.....EXCEPT for a couple of Spiders where some cannibalistic
previous owner has swapped out the entire rear axle unit for an earlier 105
version.  This was probably done to obtain the LSD unit for use on a 1600 or
1750 Spider or GTV.

"I was told about 25 years ago by "someone who should know" that ALL 2L USA
105 GTV's and Spiders and 115 Spiders had the LSD units as standard factory
equipment.  I don't know about the TI or Berlina versions except that the sole
Berlina I've owned had the LSD axle.  It is easy to check visually since the
alloy centersection reinforcement rib pattern is different between the non-LSD
and later LSD versions.  The ribs on the LSD versions just forward of the
removable sump plate form a sort of capital "A" letter; the others do not, as
I recall it now (perhaps
imperfectly)."

The "about 25 years ago" was 'about' 1973, and it is a very safe bet that the
"someone who should know" was someone who *did* (and does) know, at least for
USA cars.

Later in the same post, in response to the then-current question, he wrote
"Regarding handling changes, the use of a competition-prepared LSD will
definitely increase understeer just as will the use of a heavier front "anti-
roll" bar on any RWD car.  Indeed, it is almost impossible to roll a
competition-prepared car by hand with the steering wheel turned even a little
off-center;  the car wants to go in a straight line regardless of steering
input. The LSD has nothing to do with "roll-steer" or roll stiffness.  This is
a function of chassis tuning alone.  This is one of the reasons it is
imperative to do an extremely comprehensive - and complete - evaluation  of
ALL factors affecting handling to make sure any revisions are as well-informed
and effective as they are well-intentioned."

This seems worth tacking on in view of the recent discussion of mongrel and/or
bastard cars, in which some people got the impression that Tenney opposed any
changes. He didn't. He did feel, as he said there, that "it is imperative to
do an extremely comprehensive - and complete - evaluation  of ALL factors
affecting handling to make sure any revisions are as well-informed and
effective as they are well-intentioned". And he did have a high standard for
what constitutes "well-informed". 

Tenney tells me that he is gone. I hope he changes his mind, but I wouldn't
count on it. I'm glad he was here, while it lasted.  

John