[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]
AWD Alfa 164 Q4 [was: 5 bangers galore]
>From: Eliot Lim <firstname.lastname@example.org>
>Date: Thu, 10 Nov 1994 11:31:36 -0800 (PST)
>yes, a magnificent piece of work. the vr6 is right up in that league
>(or should i say that the alfa V6 is in the vr6's league?)
Unfortunately, I haven't had a chance to drive the VR6 yet. After all
that's been said and written, it sure looks like a winner.
>you are slightly mistaken. the 959 is the first system to feature
>variable torque splits (under no-slip conditions, that is). the 4
>"fixed" modes that you are referring to are just initial torque split
>settings, which would then change under different conditions.
>e.g. the rain setting starts the car out with 50-50, while the dry
>starts it out with a more rear-biased split. the awd system takes
>input from here and there, including the turbo boost gauge. i.e. when
>the turbo is delivering full boost, up to 80% of the torque goes to
>the rear wheels, even with no wheelspin. at parking speeds drive
>to the front wheels is completely disconnected to make the steering
I'll have to take your word for it, since I don't have much info on 959.
I would actually very much appreciate if you, or anybody else, is
willing to share (point to) any good article written on the subject.
I guess I was confused with these four initial torque-split numbers.
How exactly is this "initial" defined by Porche; after all, as you said,
starting (parking lot) setting is 0-100 in all cases. With continuously
variable, microprocessor-controlled, torque-split with many input
parameters, it doesn't make sense to talk about specific differential
ratios (e.g. 50-50, 20-80, etc.) I suppose that if one chooses "rain"
button, a computer map with one set of weights controls the torquesplit,
while "dry" button down-loads a different map with weights giving a car
more rear bias. Does this make sense?
>the alfa does not have variable initial values.. it starts off with
>50-50 (i think?) and then varies it as the car moves.
I came across a couple of articles on the 164 Q4; one in Autoweek (Jan.
10, 94) and one in British Fast Lane mag. (Jan. 94). Both say that the
car has "most sophisticated (and complicated) 4wd system to ever appear
in a production road car."
Here are some excerpts from articles that can be used to update your
writeup ;) :
"Called Viscomatic, this system was developed by Alfa in conjunction
with 4wd specialist Steyr-Puch of Austria."
"... A huge amount of work (and money: $34 million) went into the Q4's
development, because of its radically innovative design and high level
of sophistication compared to similar permanent 4wd systems."
"...It utilises viscous couplings (in which the fluid density can now be
varied through a hydraulic pump to alter the slip), an epicyclic
differential (center, Ed.) and a Torsen rear diff. The system is
integrated with the ABS and the Motronic engine brain to offer what
seems like complete flexibility."
"...The amount of torque drive transmitted to the rear axle can be
adjusted frm zero (making it essentially front-drive) to 100 percent
(making it pure rear-drive). Both these extremes occur only when the
front or rear wheels loose their grip entirely."
"...The control unit actually processes information on running
conditions, such as the angle and speed of each wheel, the steering
angle, brake pedal pressure and whether or not the reverse gear is
"...In the case of light braking, a larger amount of torque is
transmitted to the front wheels. ...An interesting feature of the
Viscomatic system is the absence of stress on the steering wheel when
cornering. In fact the system recognizes cornering maneuver from the
steering angle, and adopts a specific drive torque split.
When grip is reduced by slippery roads. the system uses specific
computer maps that guarantee constant traction no matter the
"...What is the result for the driver of this boatload of technology?
...With no wheelspin, no torque oversteer, the system always delivers an
extremely responsive and neutral car. The Q4 truly handles like a
proverbial train on rails."
Add to this a short ratio six-speed Getrag gearbox, meaty tires
(205/55 16") and dash mounted dial for two suspension modes: sport and
automatic. Price: equivalent of $40K. Available in (continental) Europe
only. Sadly, because of Alfa's sales slump, it may never be sold here.
Oh, yes, the Autoweek concluded with: "Wringing all you can get out
of the Q4 comes at cost of getting just 11.4 mpg. It's a small price to
pay the piper for a great dance." Indeed! I guess they haven't completely
debbuged the software yet. "Toni, don't you think all 4 wheels should be
turning in the same direction?"
I hope I didn't upset too many quattro heads :)
Ljubisa Stevanovic (email@example.com)
87 5000 TQ