Re:History of active diff at TTE(was: Haldex)

[Michael Zamikhovsky <MikeZ755@sprintmail.com>]

Matt Rooke wrote:

> >Anyway, I've no idea how hard it is to change the Haldex software, but I
> >would love for it to turn out to be easy as pie to pop in a temporary
> >program that is the equivalent of locking the center differential, for use
> >on the race track or in the snow, particularly if the program could be
> >selected from a dash switch.  (The unused FWD ASR switch comes to mind.)
>
> Your right, that would be a very trick setup!  The next question would
> be durability of the clutch running it locked, would it self-destruct?
> Probably not, being an Audi and all.  But the wires would corrode and
> fry, and the clutch would engage when you turn on the fog lights, or
> some such bizarre-ness.
>
> >Then one could have a TTq that works like a 4kq/urq.
>
> When the clutch isn't locked, think FWD 4k.  That a gorilla sat on.
>
> Good idea, and one for the tuning software guys to work!
>
> Matt Rooke
> '91cq

That has been used in rally for a while now. In Toyota Corolla WRC there was 5
different diff lock maps available to griver 3 years ago. These maps were
combined with main ECU maps to save components and optimise performance. In
past a diff called Hydrolock was used. It utilised pressurised hydrolic fluid
from oversised power steering pump to lock and unlock as instructed by its ECU.
X Track transmissions were developed that could accomodate variety of center
and front diffs. You could even interchange them.( Visco vs Active.) At Toyota
this started the year they were given off for cheating. They developed a new
trans for Celica together with XTrack and tried it out in various national
championships. than it went into Corolla.

Mike Z