More safety, more performance, more refinement now with much more style
AutoCar, 12 July 1973
AT-A-GLANCE: Very advanced new model with twin-cam straight six engine and four-speed automatic gearbox. Substantial, but heavy safety engineered body good performance, reasonable economy, much improved handling and excellent ride. Very expensive but unique in its class.
Fog lamps are built in alongside outboard of the headlamps and there is a stout rubber-mounted rubbing strip running right round the car.
MERCEDES-BENZ adhere religiously to a policy of long production runs and some of the security in buying a Mercedes comes from knowing it will not change for several years. When a new model does come along, it represents a radical and significant step forward, as well it should with so much concerted development and time at the engineers' disposal. The new S-class of large saloons introduced last September are therefore very advanced, thoroughly proved and built to even higher standards than before. Despite a very high price, which is justified when you examine the specification in. detail, the first allocation of cars destined for this country sold out very quickly and demand is still running at a very high level.
The concept of the new S-class was frozen some six years ago, before the previous 250 was increased to the 280 which preceded the latest model. Tooling for the body was ordered three years ago and some S-class prototypes formed the basis of the Mercedes experimental safety vehicle programme. While the structural engineers worked on crash protection, the emissions experts got to grips with exhaust pollution standards and the combined result is a car which more than meets all present and proposed European standards. In it too is the potential to go on to 1980 at least with any rear-end, side or roll-over resistance that might be written into the statutes over the next few years.
As a structure therefore the hull of the S- class body is immensely strong in the cabin area and designed to crush progressively at the ends. The thicker than usual front screen pillars hint at the integral nature of the whole shell and the much higher than average kerb weight is mostly accounted for by the safety features. This S-class 280SE is 225 Ib heavier than the previous model tested in June 1970, some of this being attributable to a slightly larger overall size but most of it being under the skin. Actual dimension comparisons show it to be 2in. longer, 2in. wider and 1 in. lower.
The elegant, slightly wedged shape of the S-class saloon appears to be more pronounced than this when you see the car on the road.
With the latest addition of a 4.5 litre vee-8 engine there are four power unit options in the S-class starting with two versions of the twin-cam straight six first introduced in the smaller "new generation" saloons just over a year ago. Although this unit retains almost the same 2.8-litre swept volume of the earlier single-cam 280 engine, it is much smoother at high revs, better on emissions and 10 per cent more powerful at the top end.
At first glance a 2.8-litre engine developing 185 bhp (DIN) in a large saloon weighing over 32 cwt at the kerb might seem to be underpowered. By tailoring a new automatic transmission very carefully to suit the model, Mercedes have managed to provide the 280SE with extremely brisk acceleration, a substantial top speed and very reasonable economy if required.
Tail lamps are fluted to keep the lenses free from road dirt. The main bumper and the smaller rubbing strip above it have rubber inserts.
To emphasise that the S-class Mercedes is intended to be very safety orientated, the 280SE has two very worthwhile extras, normally hidden out of sight.
The majority of Mercedes customers specify automatic transmission and the test car had this fitted. It is an expensive £280 extra but, in our opinion, an essential part of the very refined package. Power steering, which costs £134 extra on the smaller models is standard on all cars in the S-class range. The mechanical part of the four-speed epicyclic gearbox is the same as before, but there is now a proper torque convertor (with 2.2-to-1 magnification at stall) in place of the old fluid coupling. Part-throttle downshifting is provided and use of the manual selector resets the normal kickdown limits, as will be explained in detail later.
As before, the "E" part of the car's nomenclature stands for "Einspritzmotor" or fuel injection Bosch electronic as used by BMW, Porsche and Volvo. It works impeccably, automatically compensating for the various temperature requirements of cold starting, warming up and running in high ambient conditions. Starting takes much less churning than with the old mechanical Bosch system used previously on the 280SE, and the high idling speed which used to be an annoying feature of the mechanical system is no longer required.
On turning the key, the S-class 280SE is always an immediate starter and straight away there is eager engine response. Under; normal driving pattern the car moves off from rest in second, but the application of full throttle will select bottom if required for a much more lively step off. To prevent surging on a hill start or make sure no time is lost in a getaway, the driver can engage bottom manually at rest by moving the selector through the staggered gate to the lowest "L" position. The car will then move off and hold bottom to a rev limit of 5,400 rpm before changing automatically into second, further upward changes being inhibited.
Using the manual over-ride to the full we recorded a 0 to 60 mph acceleration time of 9.7 sec and a 0 to 100 mph time of just under 30 sec, these being 1.5 and 10 sec respectively quicker than the times for the old 280SE tested in 1970. In top the S- class car ran to just beyond its power peak with the help of a slight tail wind, and just short of the peak in the opposite direction. The mean of exactly 125 mph is therefore equal to the theoretical maximum of the car and shows how well production tolerances are maintained in Germany.
Back seat passengers have headrests, seat belts (extra on the test car) and a substantial centre armrest.
Most of the time on the road however the driver is content to leave the selector in D and let the clever gearbox make all his gear changing decisions for him. Progress then is in keeping with the car's appearance and image – smooth, almost gracious and efficient.
On a journey from London to the Midlands via Gloucestershire (which took in about equal shares of motorway and main road) we made good time, arrived relaxed and recorded an overall fuel consumption of 20.6 mpg over 180 miles. When we came back later the same day we pressed on a lot harder, shaved about 30 minutes off the traveling time but managed only 16.2 mpg.
Many owners, we suspect, will treat the car in the former manner all the time. Theirs will be the loss, for when a sporty driver takes over (or the owner feels a sporty urge) the 280SE suddenly shows a new side to its character which many may never discover. Above its normal and rather restrained automatic upshift points is a torquey peak to the power curve into which the engine leaps with a sudden growl from its induction and a surprising amount of verve. Unless the driver keeps a wary eye on the speedometer markings (there is no rev counter on this model), he will all too easily hit the ignition cut-out which operates at exactly 6,500 rpm. Given its head by means of the selector, the 280SE will run to 54 mph in second and nearly 90 mph in third. In the D position automatic upshifts occur at only 40 and 79 mph respectively, and it is impossible to kickdown from third to second above 29 mph. With the selector in S this limit is raised to 43 mph, so the whole of this top-end performance bonus has obviously been carefully planned by the engineers. Overall it endows the 280SE with a fascinating dual personality which is somehow immensely satisfying.
Heater controls are grouped in the centre of the car, above the radio console. The temperature for each side of the cockpit can be varied independently.
As we found with the same twin-cam engine in the 280 CE coupe we tested in January this year, top-end smoothness is remarkable and it is impossible to fault the power unit on any score. It is quiet and refined throughout the range, an example of sweetness to all other engine manufacturers.
Ride and Handling
The suspension of S-class cars is even more of a step forward than the structure and styling. Gone completely is the swing axle back end, this being the final step in a progressive history of improvements to it. The back end of the 280SE employs a conventional splayed trailing arm system, drive shafts being fitted with twin constant velocity joints each side, the plunge required by suspension movements being accommodated in the joints themselves. At the front there is a novel double wishbone layout using the anti-roll bar as a longitudinal locating link and incorporating progressive anti- dive in the geometry. The front sub-frame has been eliminated, road noise being designed out at source, rather than insulated from the structure.
The result of all this re-thinking is a truly remarkable improvement in both the ride and noise levels inside, coupled to much safer handling than on any Mercedes ever before. In our first appraisal of the S-class in Spain last year we suspect we might have been misled by tyre pressures raised for the rigors of circuit testing. Certainly here, on the surfaces and bumps we know so intimately, the 280SE is much more impressive and in the same class as those other standard-setters, the Jaguar XJ6 and BMW 520. Stability at high speed is excellent and the ride seems to improve the whole way up to maximum speed.
To take the effort out of the steering, reduce kick-back and improve stability, the S-class cars have no front wheel offset (i.e. the king-pin axis passes through the centre of the tyre's contact patch) and this has permitted with the aid of power assistance a very quick steering ratio giving less than three turns between locks. Steering response is therefore first class and now that the back end has been liberated from its swing-axle quirks the 280SE handles in a way that puts many so-called sports cars to shame. Adhesion at all times was excellent and the way the back end squats down and hugs the road on a tight turn is tremendously reassuring and almost uncanny. By pushing the cornering limits so far out of reach, Mercedes have made this an incredibly safe car with tremendous margins in reserve.
The spare wheel is fitted under the floor of the boot, with the jack clipped in beside it. Inside the boot lid a reflective warning tiangle is clipped where it can be seen from behind.
Brake pedal effort is exceptionally light, less than 40 Ib effort being sufficient to lock the wheels on a dry surface. We experienced no significant fade during 10 stops from 70 mph which is a remarkable achievement for a car weighing not far short of two tons as tested. The handbrake is applied by a big stirrup handle on the right of the facia and it lacked efficiency probably because it is a conversion from the pedal parking brake fitted with left-hand drive. The anti-dive geometry works well, keeping the large bonnet level under heavy braking and preventing the headlamp beams from diving into the road surface at night.
Fittings and Furniture
Trim materials are a mixture of cloth on the centre panels with more durable pvc on the sides and edges of the cushions. This combination was cool to sit on in humid weather and looked particularly luxurious on the test car which had a very "quiet" plaid pattern with nicely keyed colour tones. The driving seat has two sets of runners at different angles so that the height can be adjusted, and both front seats have reclining backrests. Although the angle and reach of the steering column are fixed, they were not criticised by any of our wide range of drivers. All seats have adjustable headrests.
Inertia reel seat belts are built in at the front so that the reels and the vertical webbing are invisible, the buckle end appearing con- veniently and very neatly from a slot in the pillar by the driver's shoulder. Our test car had equally neat automatic belts in the rear also, which we found very reassuring when trying the car in its chauffeur-driven executive role. There is a generous amount of legroom in the rear compartment and a broad central armrest which folds away when.carrying three abreast. Elasticated net pockets in the backs of the front seats take folders, books and all manner of bulkier reading material.
Essentially, although the 280SE is a comfortable car to be driven in, it is a driver's car above all else and the instruments and controls are well laid out. Seen through the upper part of a neatly-styled simulated leather steering wheel are a large speedometer with push-button trip reset, a clock and a combination dial containing fuel, water temperature and oil pressure gauges. The oil pressure gauge normally has its needle hard up against its maximum reading stop, in the traditional Mercedes fashion. We found the fuel gauge gave an unduly pessimistic indication of the contents in the very large 21-gal tank, so we were never able to take full advantage of the useful 300-mile range.
All the running controls, like the indicators, wipers, washers, headlamp flashers and lamps are worked by a right-hand stalk and an adjacent rotary knob. On the left in the central console are the heater controls, above the position for the radio. Four vertical slides regulate temperature, independently for each side of the car, and distribution with a multi- speed fan switch between each pair. Pushing all slides up automatically gives maximum demisting. Independent of the heater is a com- prehensive fresh-air system with four face level outlets, all adjustable for volume and angle. Special ducts pipe hot air to the inner skin of the door trim pads where it forms a thermal envelope and incidentally keeps the door cavities free from moisture. An electrically heated back- light is standard and the test car was fitted with the optional electric sunroof, rocker switches for both these accessories being just above the main heater slides, along with a roof lamp switch.
In a pocket sunk into the rear shelf behind the righthand headrest is a small, but comprehensive first-aid kit and clipped inside the boot lid there is a reflective warning triangle. This automatically shows whenever the lid is opened and it also comes out for standing in the road to give advanced warning: As well as the usual locking arrangements for steering, doors and boot, a centralised system causes all other locks to be operated by turning the key in the outside of the driver's door. This is a welcome time-saver when parking, but care should be taken to ensure that it is never done by pushing down the sill pip on the driver's door and leaving the car by another door with the key still inside. Slamming any other door after the centralised system has been set does not cancel the lock on that door, and we locked ourselves out with the key inside on one occasion. An additional lock allows the boot to be secured independently, like the glove locker.
Living with the 280SE
With a high basic price at the outset and several very expensive extras to be added on, the 280SE is quite a staggering £6,894 delivered on the road to the same specification as our test car. Whilst this is a very substantial increase on the £4,680 being asked for a 280SE only three years ago, the latest car is a completely new design which has largely been executed for safety and refinement regardless of cost. The standard of finish is better than ever before, and the quality of the interior mouldings as well as the exterior paintwork is very hard to fault and sets a new, very high standard for Mercedes. The combination of tasteful and discreetly modern styling is virtually unequalled anywhere.
Although the underbonnet looks complex, most components are easy to find and the essential top-up points are very accessible. The bonnet lid is self-supporting when lifted.
We seriously doubt if any Mercedes owner is the do-it-yourself type, but certain practical aspects of the car are important to everyone. The wheelchanging arrangements, for example, are straightforward after all luggage has been removed from the boot. A substantial geared jack is held securely in a spring clip along- side the spare and there are four easy-to-find jacking points. In case of any trouble on the road, a very reasonable tool-roll is provided with a good range of chrome-vanadium spanners, a screwdriver and two pairs of pliers.
Boot and bonnet lids are both strongly counterbalanced and although the layout of the engine bay appears complex, everything is tidily laid out and easy to get at. Battery and screenwasher bottle are right at the front by the offside wing and the spark plugs are very accessible between the two camshaft covers.
Plug-in provision for diagnostic checking is part of the standard wiring loom, so authorised Mercedes dealers should be able to trace any faults very quickly.
Prospective owners should study the table of maintenance costs closely. Small regular services are reasonably priced, but the bigger ones are expensive and at around £3.50 per hour for labour charges any additional work is liable to be very expensive. Although most of the spares costs are extraordinarily high (£36.33 for the main silencer alone; for example, and £63.70 for a new alternator outright), on a car like a Mercedes it is unlikely that these will give trouble in less than five years or 50,000 miles.
Once you look beneath the skin on this significant new model and start to analyse its features and engineering, it is easy to see where the money has been spent and if quality and safety engineering can ever be costed realistically, the price asked for the whole package does not seem so unreasonable. We would like to think that the strong demand for the S-class of new Mercedes comes from people with as much money as sense who have examined it as closely as we have, and not just those who want the latest Mercedes regardless. Whatever the reasons for its success, it is a very good car indeed, enjoyable to drive or ride in and in our carefully considered opinion worth its very high price.
© 12 July 1973 AutoCar, UK.