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Quattro vs. BMW iX (long)
Ok people, I just received from Julius a copy of a sales brochure from
BMW of Spain about the then new 325iX which contains about 15 pages of
information that I found interesting, so I'm sharing it.
I begins by explaining why BMW was creating an AWD car: for those people
who live in areas with extreme climate (lots of snow and ice) or bad
roads who don't want to give up the high levels of active safety,
control and confort that they are used to enjoying in ther cars. The
other target was those people who see AWD as the most efficient way of
transfering all the power of a highly capable engine safely to the road.
It goes on to state that AUDI had already demonstrated decicedly the
concept of AWD and although BMW had developed the RWD comcept to high
levels of refinement, there was demand for an AWD 3-series car.
The literature then goes on to explain how the system works. The car
still has the I-6 2.5l "baby six" engine. There is a transfer case
behind the transmission which splits the power 37% to the front and 67%
to the rear wheels trough a planetary gear center differential. It
mentions that this results in car that handles more like a RWD with just
a tad of overteer at the limit so that those people that alreary own a
BMW won't have to change their driving style, plus there is minimal
torque steer.
There is a driveshaft going to the rear differential, which is a "self
locking unit" in the sense that it uses the viscous coupling principle
to lock the differential instead of using the traditional clutch discs
of conventional LSDs. A viscous coupler connects the front driveshaft
to the center differential using a chain (it really is more like a
toothed metal belt - like the timing belt). This front driveshaft runs
alongside the transmision into the traditional front diferential. It is
noted that a locking differential in the front won't improve traction
and woudl hurt the directional control of the car. They make a big
point that all the differential locking is done automatically and that
the driver is left to concentrate on driving, which could be crucial in
emergency situations, unlike the AUDIs with manual locking.
The front differential itseft is housed in the aluminum oil pan and
seems to be smaller than the rear units. The diff. casing is an
integral part of the oil pan which has a driveshaft coming out each
side. The front suspension was redesigned to achieve a "negative pivot
radius esential for front wheel drive" isntead of the positive used in
RWD applications. The whole car was raised 30 mm. (I think this was
partially done to give it back some ground clearance taken away by the
additional hardware.)
Next they go over the ABS system. They say that it is an integral part
of the AWD system and that it works all the time, unlike AUDIs, where
the ABS is useless whenever the differentials are locked. It also makes
a big point about how hard it is to recover traction once you have lost
it on an AUDI with locked differentials. It says that if the 325iX
looses traction while braking, the wheels will start rotating again much
sooner than the Quattro. The ABS system also makes use of an
accelerometer to find out if the wheels are locked or if the car is
stopped. It also opens the ISV when you are downshifting without
matching RPMs to reduce the tendency of the engine to break the car and
loose traction on icy roads. Finaly, it detects any moment that could
be induced by accelerating in a surface where the left wheels have more
tractions than the right ones and vice versa and applies the brake on
the aprppriate corner to stop the spin.
Finally, it goes on to pricing information and a comparison between the
BMW 325iX, Audi 90 quattro, the Audi Coupe quatrro, and the Ford Sierra
XR 4x4 (Merkur XR4Ti). The cheapest was the Ford. This was explained
as sales tactics employed by ford to take market share from Audi due to
the excesive price of the Quattro option. The price of the 325 and the
Coupe are almost identical, and the 90 was a little cheaper. Apparetly,
BMW was selling a "much more sofisticated and safe" (and a little
faster) package for the same price as Audi.
I have sumarised a comparison table they showed:
325iX 90 Quattro Coupe Quattro Sierra XR 4x4
----------------------------------------------------------------------
Displacement (l) 2.5 2.2 2.2 2.8
Engine I-6 I-5 I-5 V-6
Power (KW/HP) 126/171 100/136 100/136 110/150
at (RPM) 5,800 5,700 5,700 5,700
Torque (Nm) 226 186 186 216
at (RPM) 4,000 3,500 3,500 3,800
Top Speed (MPH/KPH) 132/212 126/200 126/200 131/210
0-100KPH (0-62MPH) 9.0 9.0 9.0 9.0
AWD System Permanent Permanent Permanent Permanent
with viscous with viscous
engagement engagement
Empty weight(Kg) 1,215 1,200 1,200 1,250
Price(Pesetas) 3,480,000 3,250,000 3,475,000 2,625,000
Perhaps somebody else will know what was the equivalent price in U.S.$
back around 1988-1989.
They finish the sales pitch saying that although many manufacturers are
begining to offer AWD cars, only the 325iX with its "very special AWD
system" offers much more to the experienced driver:
- Superior capabilities due to its sophisticated AWD system.
- More refined I-6 engine.
- More advanced chasis and suspension with superior stability.
- Special ABS system that works efectively in all situations.
- All the comfort and individualized options only availabe from
BMW in this class.
Well, that was it. I don't intend to force any opinions on anyone but
it seems that BMW was agresively persuing potential Audi customers. It
does seem to be a great system for everyday driving in all but the most
extreme conditions with the feel of a RWD car. Perhaps its complexity
was its downfall.
---------------------
Luis Marques
'87 4kcsq