Review: Mercedes W163.I ML 55 AMG (2001)

Overview

Released in Australia in January 2001, the Mercedes-Benz W163 ML 55 AMG was a large SUV. Manufactured in Tuscaloosa, Alabama, the four-wheel drive W163 ML 55 AMG was powered by a 5.4-litre V8 petrol engine that was mated to a five-speed automatic transmission.

M113.981 V8 engine

Assembled by hand, the M113.981 V8 petrol engine had an alloy cylinder block with 97.0 mm bores and a 92.0 mm stroke for a capacity of 5439 cc, cast-in Silitec (Al-Si alloy) cylinder liners, fracture-split forged steel connecting rods, iron-coated aluminium pistons, an alloy cylinder head, a single overhead camshaft (SOHC) per cylinder bank driven by a double-roller chain, three valves per cylinder (two intake, one exhaust) actuated by roller rockers, two spark plugs per cylinder and a compression ratio of 10.5:1.

Compared to the 5.0-litre M113 V8 engine in the W163 ML 500, the M113.981 AMG engine had:

A reconfigured crank drive;
Forged aluminium pistons with oil-cooling via injection nozzles;
A twin-pipe intake system;
Unique ‘built’ camshafts;
A specially adapted variable intake manifold; and,
AMG exhaust system with larger pipes and modified mufflers to reduce back-pressure (and noise).

The ML 55 AMG could accelerate from rest to 100 km/h in 6.9 seconds and had a top speed of 235 km/h. Over the combined NEDC cycle, fuel consumption was 14.4 litres per 100 km.

Mercedes-Benz W163.I ML 55 AMG specifications
	Engine	Trans.	Peak power	Peak torque
ML 55 AMG	5.4-litre petrol V8 (M113)	5sp auto	255 kW at 5500 rpm	510 Nm at 2800-4500 rpm

Transmission

The Mercedes ML 55 AMG had a five-speed, electronically controlled automatic transmission. The gear ratios were 3.59 (1st), 2.19 (2nd), 1.41 (3rd) and 1.00 (5th), with a final drive ratio of 3.46 and low-range reduction ratio of 2.64.

ETS 4WD system

The Mercedes W163 ML 55 AMG had a permanent four-wheel drive in which power was distributed in a 48:52 front:rear distribution from the Borg-Warner 44-06 transfer case (which had an integral centre differential). Instead of differential locks, the ‘Electronic Traction System’ (ETS) of the W163 M-Class could detect wheel slip and would automatically apply brake pressure to the slipping wheel to transfer torque to the wheels with grip.

For low-speed operation, a 2.64:1 low-range ratio could be engaged at the touch of a button. In this mode, the transfer case provided a 50:50 front:rear torque split.

Dimensions and body

Compared to the Mercedes-Benz W163 ML 430 , the ML 55 AMG was 48 mm longer (at 4635 mm) and 2 mm taller (1804 mm), though width (1833 mm) and wheelbase length (2820 mm) were unchanged. Kerb weight, however, increased by 140 kg to 2230 kg.

The chassis of the W163 ML was based on a box-section, ladder-type frame that comprised two offset longitudinal members welded to three cross members. Damping to reduce transmission of road noise and bumps in the road surface was provided by the sub-frames for the front and rear suspension in combination with ten rubber bushings.

Visual cues for the ML 55 AMG included unique body-colour bumpers, twin power domes on the bonnet, chrome trim for the radiator grille and side skirts, painted wheel-arch flares and two chrome-finish exhaust pipes.

Suspension

The Mercedes W163 ML 55 AMG had double wishbone front suspension with the upper control arms and shock absorbers attached directly to the frame, while the front sub-frame carried the lower control arm and the steering gear. The front suspension also incorporated torsion bars that were supported by the centre cross member, in combination with an anti-roll bar on the lower wishbones.

The double wishbone rear suspension had a similar design, though torsion bars were replaced by a combination of coil springs and shock absorbers with progressive-rate springs. Similarly, the rear axle upper control arms and spring/damper assemblies were mounted directly to the chassis frame and the lower wishbones and anti-roll bar were carried by a sub-frame.

Both front and rear suspension utilised twin-tube gas-pressure shock absorbers.

Steering

The Mercedes ML 55 AMG had rack-and-pinion, power-assisted steering.

Safety equipment

Standard safety equipment for the Mercedes ML 55 AMG included dual front airbags, front and rear side airbags, ABS, electronic brake force distribution, brake assist, electronic stability control, traction control, and front and outer rear seatbelts with pre-tensioners and load limiters.

Brakes

The Mercedes ML 55 AMG had 345 mm by 32 mm internally vented front brake discs with four-piston callipers and 331 mm by 14 mm solid rear discs with two-piston callipers.

Features: Mercedes ML 55 AMG

Standard features for the Mercedes ML 55 AMG included 18-inch five-spoke AMG alloy wheels (9.0J) with 285/50 R18 109W tyres, Mercedes-Benz’s COMAND (Cockpit Management and Data System), ‘Audio 30’ sound system with seven speakers and a CD changer, air conditioning, cruise control with speed limiter (‘Speedtronic’), power adjustable and heated contoured front seats with memory settings, buffalo leather seat covers, xenon headlights with washers, front and rear fog lights, wood/leather sports steering wheel, 60/40 split and folding rear seats, remote central locking, power adjustable and heated mirrors, power windows, a height and reach adjustable steering wheel, power tilting/sliding sunroof, an anti-dazzle rear view mirror, tinted windows, a cargo cover, roof rails, dark-brown burr-walnut wood trim, velour carpets, a trip computer, an alarm and immobiliser.