Mercedes-Benz 450SEL 6.9
Overview
Manufacturer	Daimler-Benz
Also called	Mercedes-Benz 6.9 (North America)
Production	1975–1980 7,380 built
Model years	1977–1981 (North America)
Assembly	West Germany:Stuttgart
Body and chassis
Class	Full-sizeluxury car (F)
Platform	Mercedes-Benz W116
Powertrain
Engine	6834 ccM100V8
Transmission	4-speedautomatic
Dimensions
Wheelbase	2,960 mm (116.5 in)
Length	5,060 mm (199.2 in) 5,335 mm (210.0 in) (US and Canada)
Width	1,870 mm (73.6 in)
Height	1,430 mm (56.3 in)
Curb weight	1,985 kg (4,376 lb)
Chronology
Predecessor	Mercedes-Benz 300SEL 6.3

TheMercedes-Benz 450SEL 6.9 (marketed in North America as simply theMercedes-Benz 6.9) is the high-performance version of theW116S-Class saloon. It was based on the extended-wheelbase version of the W116 S-Class platform, introduced in 1972, but equipped with anM100 V8 engine from their flagshipMercedes-Benz 600, uprated to 6.8 litre engine, and featuring fullhydropneumatic suspension, licensed fromCitroën.

The 450SEL 6.9 was presented to the public at theGeneva Auto Show in 1974 as the successor to the original high-performance saloon from Mercedes-Benz, the300SEL 6.3 (1968–1972). Like the 300SEL 6.3 before it, the special displacement number (6.9) was affixed to the trunk lid to differentiate itself from the regular 450SEL. The 450SEL 6.9 was produced in very limited numbers from 1975 to 1980.

The 450SEL 6.9 had the first full four-wheel hydropneumatic suspension system from Mercedes-Benz and was the world’s first passenger car to be fitted with a modern form ofABS, an electronic four-wheel multi-channel anti-lock braking system fromBosch, in 1978.^[1][2]

For several years, the 450SEL 6.9 was the quickest-accelerating and fastest saloon in the world, reaching 100 km/h (62 mph) in 7.4 seconds and 225 km/h (140 mph) top speed.^[3]

The total production from 1975 to 1980 was 7,380 units, with 1,816 exported to the North American markets (United States and Canada) from 1977 to 1981.

The 6.3-litre M100 V8 engine, originally fitted to 600 and 300 SEL 6.3, was enlarged to 6.8 litres (6,834 cc; 417.0 cu in) by boring it out to 107 mm (4.21 in). Each hand-built unit was bench-tested for 265 minutes, 40 of which were under full load. The stricter emission regulations in the mid-1970s necessitated the larger displacement as to compensate for the lowered output. The fuel injection system was upgraded to the third-generation mechanically controlled, continuous-injection system Bosch K-Jetronic.^[4]

Due to its sheer size, the engineers fitted the dry sump oil lubrication system as to lower the engine height and preserve the low hood line.^[5] The dry sump system had larger capacity at 12 litres rather than 5 litres for the wet sump system fitted to the smaller M116 and M117 V8 engines. The dipstick was moved from the engine block to the oil tank’s filler cap. The larger oil capacity extended the oil change interval to 20,000 km (12,500 miles).

For the European and international markets, the M100 engine produced 210 kW (286 PS; 282 bhp) at 4,250 rpm and 550 N⋅m (406 lb⋅ft) at 3,000 rpm. The 450 SEL 6.9 for the North American markets had the reduced output and compression ratio (8.0:1 instead of 8.8:1) and was fitted with catalysator that requiredlead-free petrol: 250 hp (186 kW; 253 PS) at 4,000 rpm and 360 lb⋅ft (488 N⋅m) at 2,500 rpm. The 450 SEL 6.9 sold in Australia had slightly reduced output due to Australia's new 1977 emission regulations: 198 kW (269 PS; 266 bhp) at 4,200 rpm and 510 N⋅m (376 lb⋅ft) at 2,800 rpm.^[6]

During its entire production run, the engine displacement of 6.8 litres was the largest V8 engine ever built by Mercedes-Benz and by any European manufacturer since the Second World War.

The fullhydropneumaticself-levelling suspension system from Mercedes-Benz was first introduced in 450SEL 6.9 as a standard equipment. The other W116 models used the hydropneumatic system for the rear suspension only as level control under heavy load (Option No. 48/0, "Niveauregulierung").^[7] The full system was exclusive to 450SEL 6.9 until 1981 when the next generation, HPF II, was offered as an extra-cost option forW126 380SEL and 500SEL. The600 andW109 used theair suspension for self-levelling.

The Mercedes-Benz system differentiated fromCitroën system, introduced in 1954, in some ways. Mercedes-Benz used the timing chain to drive the hydraulic pump instead of rubber belt in Citroën system. Citroën system used a single pump to send the vegetable oil (and later mineral oil) to the brake boost, power steering, power clutch (when equipped with semi-automatic transmission), and hydropneumatic suspension system. Mercedes-Benz system had the separate pumps for brake boost, power steering, and hydropneumatic suspension, citing the better failsafe measures than Citroën in the event of a hydraulic failure. The Mercedes-Benz system contained the hard rubber dampers that served as temporary springs and allowed the car to be driven if the hydraulic pump or components failed. Both manufacturers had different approaches when the cars were parked and switched off. Citroën lowered themselves closer to the ground while Mercedes-Benz did not. Mercedes-Benz suspension system has the feature that maintains body level without squatting at the rear or diving in the front during the acceleration and braking respectively.

Initially, Mercedes-Benz did not plan on selling the 450SEL 6.9 in the United States given the oil crisis that hit the Americans very hard and increasingly tightening emission regulations. Mercedes-Benz had difficulties in meeting the European demand. However, the strong requests from the customers and dealers reversed the decision.^[3]

In the North American market, the 450SEL 6.9 was called simply the6.9 and featured the model name on the right side of the trunk lid. The retail price was more than $38,230 ($193,291.51 adjusted for 2024) for the 1977 model year and increased to $52,995 ($196,213.19 adjusted for 2024) at the end of production in 1980.^[3]

The 6.9 was fitted with foursealed beam 5.75" round capsule headlights with bezels and larger impact absorbing bumpers that lengthened the car by 11 inches. Due to theUS FMVSS bumper standard, thevariable height suspension was disabled, and the height adjustment knob was removed.^[8] To differentiate the 6.9 from other W116 models, the bumpers had a thick black rubber strip covering their entire width, and did not feature rubber bumper guards.

The engine output was reduced to 250 hp (186 kW; 253 PS) and 360 lb⋅ft (488 N⋅m) due to the stricter emission standards.^[9]

The retail price of 450SEL 6.9 wasDM 69,930^[7] at its launch in 1975 and was DM 81,247^[10] at the end of its production in 1980. The 450SEL 6.9 had a premium of DM 25,000 to 30,000 over the 450SEL.

While the 450SEL 6.9 was visually indistinguishable from the other W116 models, it had wider wheels and tires along with6.9 on the right side of trunk lid. The 6.9 had more standard features that were extra cost options in other W116 models: automatic HVAC system, power windows, power rear seats, headrests for the rear passengers, central locking system, headlamp washer and wiper system, heat-insulating glass, and a few other equipments.^[11]

Despite the higher retail price, the interior of the 450SEL 6.9 was indistinguishable from the other W116 models except for the different type of wood trims, height adjustment knob, and two extra warning lamps in the instrument cluster for the low suspension pressure warning and height adjustment indicator. Heated seats for driver and front and rear passengers as well as electric sunroof were extra cost options. No power-assisted external rear view mirrors and seat adjustments, commonly fitted to luxury cars such asCadillac andRolls-Royce during the 1970s, were ever offered in the 450SEL 6.9.

The first-ever automaticHVAC system from Mercedes-Benz was introduced in the 450SEL 6.9 as a standard equipment and as optional extra-cost equipment in other W116 models. The automatic HVAC system was adapted fromChrysler Corporation and had a compressor from Harrison division ofGeneral Motors.

The 450SEL 6.9 had exclusive wood trim finished in burledwalnut veneer on the dash and console instead of striatedzebrano veneer as found in other W116 models.

• After the persistent rumours, the French directorClaude Lelouche revealed the car he used to drive throughParis at a very high speed to the rendezvous point atMontmartre in his eight-minute film,C'était un rendez-vous. He used a 1976 450SEL 6.9 with the camera mounted under the front bumper. He used the sound track from theFerrari 275 GTB, giving the impression that he drove a Ferrari.
• The 450SEL 6.9 was driven by Vincent, one of the protagonists inRonin, and was involved in several of the film's car chase scenes.
• InDavid Lynch's 1996 film,Lost Highway, a 450SEL 6.9 was used as a major plot device, connecting all three main male characters in the film. In one scene, the hood was lifted up to reveal the 1,400-horsepower engine modification. In another scene, the car was used to push aFord Thunderbird off the road despite the latter applying the brakes.^[12]
• The Mercedes-Benz 450SEL 6.9 is referenced in George Harrison's 1976 song "It's What You Value" from his albumThirty Three & 1/3. The lyrics mention "Someone's driving a 450," alluding to the 450SEL 6.9 as a symbol of personal values and status. Harrison later confirmed in interviews that he had paid drummer Jim Keltner for his session work not with money, but with a 450SEL 6.9.^[13]

• International M-100 Group — Factory-authorized site with information on all M-100-powered Mercedes-Benz automobiles, (including technical forums and maintenance information). The Brock Yates article can be found here as well
• A Mercedes for the '70s: The W116 Series S-Class — A site mixing the history of the full-scale W116 with that of its many miniature replicas.
• Classic Car driver review
• Golden Brown: Four Days in a Mercedes-Benz 450SEL 6.9 - Feature (Car and Driver)
• Curbside Classic: 1977 Mercedes 450 SEL 6.9 – Deutsches Heavy Metal – a retrospective of the 450SEL 6.9
• Petrolicious: Mercedes-Benz 450SEL 6.9 Was All About Engineering – another retrospective of the 450SEL 6.9
• Youtube clip of Ronin high-speed chase featuring a 6.9

• Mercedes-Benz vehicles
• Rear-wheel-drive vehicles
• Cars introduced in 1975
• Cars discontinued in 1981

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