4matic vs quattro

[Tom Nas]

OK, I perused the M-B press website and came up with this promo text. This
is for the C-, E- and S-Class, not the G or M. Anyway, if we take this any
further maybe it's stuff for the Torsen list?

Tom

The secret is the combination of 4MATIC with the Electronic Stability
Program ESP®, which on the four-wheel drive models incorporates the 4ETS
traction system.
Comfort and handling meanwhile conform to the customary high Mercedes
standards, thanks to extensively redeveloped front suspension and to the
AIRMATIC air suspension, which on the 4MATIC models too is fitted as
standard. Another advantage of 4MATIC is that it does without conventional
differential locks, which affect the steerability and handling of other
four-wheel drive cars.

Electronic Traction System 4ETS equivalent to up to three differential locks
Instead of differential locks, 4MATIC uses the electronically controlled
traction system 4ETS. If one or more wheels lose grip, 4ETS automatically
brakes them, thereby simultaneously increasing the amount of power sent to
the wheels with traction. These split-second braking impulses achieve the
same effect as up to three differential locks:

1. Rear: If one of the wheels starts to spin it is braked and
correspondingly more power is sent to the other rear wheel. In this way the
system acts like a rear differential lock.

2. Front: The same principle applies to the front wheels as to the rear
wheels, thus ESP®/4ETS also acts like a front differential lock.

3. Centre: If both rear wheels spin, both are braked simultaneously, while
at the same time the 4MATIC transfer case absorbs the speed difference
between the front and rear axle. Thus ESP®/4ETS also acts like a centre
differential lock.

The drive is split in a ratio of 40% to 60% between the front and rear
axles. This is the best possible split for safe handling and optimal traction.

Perfect teamwork: stability control and traction control
As an integral part of the Electronic Stability Program (ESP®) the 4ETS
traction control system is supplied with a wide range of sensor-derived
information about wheel speed, steering angle, the rotational movement of
the vehicle and lateral acceleration. A microprocessor uses this
information to automatically brake the appropriate wheel or wheels as
required, thereby improving traction during take-off on slippery surfaces,
or increasing stability during critical manoeuvres.
At low speeds, 4ETS brakes up to three wheels, thus replicating the effect
of three differential locks and maximising traction. As speed increases,
the system gradually reduces the automatic braking pulses in order not to
impair stability.

This perfect teamwork of ESP® and 4ETS with the full-time four-wheel drive
system means that the new S-Class 4MATIC models are not only very safe
cars, they are also very dynamic to drive.
Like all active safety systems from Mercedes-Benz, 4MATIC immediately
alerts the driver when he is approaching the vehicle's dynamic limits. A
flashing yellow warning light in the instrument panel unmistakably signals
him to adapt his driving style to the road conditions.

The heart of the 4MATIC system is a single-stage transfer case with open
centre differential, which absorbs the speed difference between the axles.
The transfer case is directly connected to the automatic transmission and
forms a complete power train with the engine, torque converter and front
differential. The front differential is designed as a "hang-on" unit and is
space-savingly mounted to the redesigned engine oil sump. A universal-joint
propshaft provides a good connection between the transfer case and the
front differential. Power is transferred to the front axle by low-noise
spur gears which also act as an oil pump, providing lubrication for the
transfer case. The rear differential is connected to the power train via a
shortened drive shaft.