[s-cars] Xi, 4Motion, 4matic

[Mike Sylvester]

Thanks.
Ok.  Now it makes sense.
All the sites are marketing fluff, but at least the Torsen site has some
diagrams.

Mike

----- Original Message ----- 
From: "Keith Maddock" <keith.maddock at gmail.com>
To: "Mike Sylvester" <msylvester at verizon.net>
Cc: <s-car-list at audifans.com>
Sent: Tuesday, November 30, 2004 5:52 PM
Subject: Re: [s-cars] Xi, 4Motion, 4matic


> Mike Sylvester <msylvester at verizon.net> wrote:
> > An open diff has a fixed torque split of 50/50 and a locked diff has a
> > variable torque split based upon wheel traction and drivetrain friction.
> >
> > How do you get a fixed torque split of anything but 50/50 on an open
diff?
> >
> > Mike Sylvester
> > '95 S6 avant
>
> Good question! :)  For an axle open differential, I don't know of any
> open differentials that have a torque split of anythign other than
> 50/50.
>
> But for the center position, an open differential can be created using
> a planetary gearset that allows a fixed static torque distribution
> other than 50/50.
> http://www.bmwusa.com/vehicles/3/330xiSedan
> and
> http://tinyurl.com/5yol3  (Caddy STS)
>
>
> Further on that, the latest generation of Torsen center diffs are
> based on such a planetary gearset, allowing the center Torsen to have
> a static torque distribution of, say 40/60, then further bias is +/-
> or -/+ from that split   This is used in at least one truck
> application that I know of, and I beleive Audi has also toyed with
> this if it isn't already in production for them.
> (one way to reduce power-on understeer....)
> http://www.torsen.com/products/T-3.htm
>
> Cheers,
> Keith