Aston Martin V8 vs. Mercedes-Benz 500 SEC C126 – 1982 road test

2015 / 2016 Drive-My

Clash of the Titans. 1982 Aston Martin V8 vs. 1982 Mercedes-Benz 500 SEC C126 (W126 based coupe). Big British horsepower, bred in (he old-fashioned way, meets the power of Germany’s new technology in this drawn-out, knuckles-bared battle for £30.000 of your money and more…

The best car in the world, men in the streets will tell you, is either a 190mph mid-engined Italian exotic or a gargantuan luxury limousine – a Boxer or a Bentley. The choice never strays outside those categories. Yet it should. The best in the world clearly cannot be last and mid-engined; cars of that kind are too limited in the range of their abilities. They have too little room and too much din: offer too little visibility and require too much of their drivers to be comfortable or effortless, paramount properties in most folks’ best car in the world.

Aston Martin V8 vs. Mercedes-Benz 500 SEC C126 - 1982 road test

The limousine is. admittedly, on the right track. It inevitably has a large, smooth, quiet, strong engine with silky transmission; construction standards that are of the finest – and spreading room for five bodies at least. But to remove it from the ‘best’ contenders you need only realise that the usual number of occupants for a car journey is something less than two. Thus, the number of times you will use your saloon’s five seats is low. That’s inefficient. Why not concede some unused space to make a shorter, lighter, more nimble car with less frontal area (plus a higher top speed and more frugality) because it has a lower roof line. Your best car in the world, then, would be a big, fast, luxurious two-door coupe with a refined, front-mounted engine (like the limousine’s) driving its rear wheels. It could be a car like the Jaguar XJS or Porsche 928 or, a price class up, our cover cars: Mercedes-Benz 500SEC C126 and Aston Martin V8.

In layout, these are classic coupes of the old school. They have big V8 engines (the Mercedes 5.0-litres; the Aston 5.3-litres) which propel them beyond 140mph. They have far too much torque for new-fangled front-wheel-drive systems, beloved of designers of cars of half their engine size. Their bodies have big car weights, wheelbases and tracks, but their all-indepcnder.t suspensions and extremely powerful all-disc braking systems – plus low- centred mass and big fat tyres – are clues that they are made to go very fast indeed. Faster than limousines. Both are built to very high standards – the Aston by hand: the Mercedes using the finest mechanical means, backed by bands of inspectors who apply their authority ruthlessly.

But there are vast distinctions between these cars: the first is price. The Mercedes-Benz 500SEC C126 1982 costs £28,700 (around £3000 more than the smaller-engined 380SEC C126 which misses out on standard ABS anti-lock brakes) – but the Aston weighs in at a whopping £39,999 (£2500 less than the latest price for the ultra-hot Vantage version, CAR Jan). Yet a price gap of £11.299 is not enough to eliminate the cars’ competitiveness, when the least you’ll pay is £30.000, according to two expensive car dealers we contacted. ‘You’d never get the Mercedes-Benz buyer’s money until he’d checked out the Aston.’ one central London trader told us. ‘When they’re spending this sort of money, they like to survey all contenders. The total’s not a problem if the car’s the right one. It’s on the company, anyway.’

Another Belgravia-based operator reckons Aston Martin owe Rolls-Royce for being able to ask their high prices. ‘Beside the £50,000 plus of a Silver Spirit, an Aston practically looks good value – especially since Astons’ people claim to equal Crewe’s finish standards. If anything. Mercedes have a problem with their price being a bit low.’ he adds. “It’s barely enough for the world’s best car. You’ll notice they charge more than £3000 more for the 5.0-Iitre coupe than the long wheelbase 5.0-litre saloon: that’s not because the coupe costs that much more to build. It’s to price the SEC C126 like a flagship should be priced.’

Aston Martin V8 vs. Mercedes-Benz 500 SEC C126 - 1982 road test

The second big distinction between the cars is their history and philosophy. Nobody, certainly Aston Martin, would pretend that the British coupe is modern. It’s a traditional, big-engined rich man’s coupe, first shaped the way it stands in the late ’60s, and even then related to the DB5 and DB6 models that went earlier. It has coped fairly well with the onrush of governmental ‘design rules’, but there have been difficulties. The Mercedes (unlike the Aston) springs from a line of saloons. It was new from the ground up the year before last. It has the very best of modern technology implicit in its design and production methods, it’s full of modern materials, and it is built to comply with legislation that has bothered Astons.

In short, the Mercedes was made for the ’80s and ’90s where efficiency is all: the Aston is from an era when the comment: ‘if you can’t afford the fuel, you can’t afford the car’ first became a cliche.

For the moment, let’s note the similarities. Both cars are front-engined coupes with single overhead cam V8 engines of alloy, driving the rear wheels through automatic gearboxes (only in the Aston can you have a manual). The Mercedes’s engine, made in the 5.0-Iitre capacity for only a couple of years, has even more recently benefitted from ‘Economy Concept’ modifications which have enhanced its torque at low revs without making much of its power. As a consequence, it punches out a mediocre 231bhp at 4750rpm. rather less than the 300bhp norm for other performance 5.0-litres like the Porsche 928S and Jaguar XJS.

The Aston-Martin V8, itself a recent beneficiary of economy-building mods (softer cam, valve changes, slight compression increase to 9.3 to one, ignition refinements) produces 306bhp at 5000rpm.

But torque is the name of the big coupe game. The Benz has a peak of 299lb ft at 3000rpm and offers around 90percent of its best output from 1000rpm so that an extremely tall, and frugal, gearing can be used. The Aston’s beautifully built and tuned (but decidedly ’old school’) engine has 318lb ft at 4000rpm. In the assembly, each engine is a work of art. The Mercedes’s is crafted mostly mechanically, while the Aston’s V8 (proved tough at Le Mans) is hand-built and signed – by one of four specialists in an office-sized room at Newport Pagnell. The Mercedes’s aspiration is by Bosch K-Jetronic mechanical fuel injection; the Aston breathes through four twin throat Webers.

The Mercedes economy concept has also been applied to the four-speed automatic transmission so that – broadly speaking – the car always pulls the tallest gear it can comfortably use. In normal starts, for instance, the car goes away in its second ratio (maximum 80mph) and picks up first (good for 35mph) only when it is selected or kickdown is used from standstill. At the same time, the box’s workings have been arranged so that downchanges are quick and easy to induce (by lever or loud pedal) so that the driver is never marooned in too high a gear without power.

The Mercedes-Benz overall gearing is exceptionally tall – 33mph/1000rpm in top – but its fourth ratio is very much a cruising ratio, not selected until the car is going quickly. Third (23mph/1000) has a maximum of around 130mph anyway. The upshot of this is that around town the big Benz rarely seems to pull more than 1800rpm and even when cruising at the 85 which seems to satisfy British policemen (that’s about 90 on the speedo) the tachometer is hardly registering 3000rpm. It’s difficult to see how this engine could be worn out by deliberate hard use, however prolonged. Its gearing and its thoughtful’ transmission I protect it too well.

The Aston’s engine/transmission team is much more conventional. The gearbox is a Chrysler Torqueflite unit, a three-speeder, but a far cry from the ’slushmatic’ one used to associate with US self-changes.

It even has a refinement that the Mercedes lacks, a lock-up mechanism for its 26.5mph/1000rpm top gear which prevents torque converter slippage (and consequent fuel usage). This acts from as low as 50mph on small throttle openings, and engages almost imperceptibly. First, if held to the engine’s 6250rpm redline, will show 65mph otherwise the change occurs at about 50mph. Second will run up to 110mph (that’s about 115 on the fairly-faithful speedo) but left to its own devices it changes at 80mph. a lower speed than in previous models we’ve driven. Likewise, kickdown into second is available only below about 65mph it used to be around 80mph. Below 35mph, kickdown gives you first gear and power.

Both cars have massive independent front suspensions by double wishbones and coil springs, and each has an anti-roll bar to contain sway on bends.

The Aston’s wheels are directed by powered rack and pinion steering which requires a little less than 3.0turns from lock to lock. It’s a direct gearing, though it must be borne in mind that the Aston’s turning circle is close enough to 40ft. By contrast, the Mercedes’s servo-assisted recirculating ball system, which also needs 3.0-turns, offers a 33ft turning circle.

At the rear, the Aston sticks to its tough, time-honoured de Dion suspension system while the SEC has the S-class saloon’s semi-training arms which incorporate an anti-squat system (as the front has anti-dive geometry). No fripperies like that on the Aston, just rather firm springs and dampers and a low centre of gravity. Both cars have powered disc brakes, but the Mercedes has that conclusive ABS advantage. The Mercedes whole weighs a hefty 3600lb at the kerb, which rather belies its image as a light car. The Aston, a heavyweight, weighs 300lb (or an unspectacular 8.3 percent) more.

It must be borne in mind, however, that the Mercedes C126 is the longer by 10in at 193in (its wheelbase of 112in compares with the Aston’s 105) and it is the taller car by 2.0in at 55in.

Forget the dimensions, start the engines, point the cars down the road and press hard on the pedal at right. The Aston leaps away, delivering instant power in its brutish way so that the driver soon enough knows that a big push in the back is available; any revs, any speed below 120-130. The Mercedes’s low first (you’ve activated the kickdown with that heavy right toot) gives it a very brisk step-off but the power delivery alter 25mph is smooth, elastic and constant rather than inspiring.

The 500SEC C126 drive train (eels rather like a Jaguar XJS’s, with less power. It has that same Coventry feeling of being pulled along at the end of a mammoth piece of elastic, rather than being propelled by a 5.0-litre procurer-of-explosions ahead of the occupants’ feet.

The Aston has decisively the more performace. It blasts to 60mph in 6.9 sec (8.0 for the Mercedes C126) and opens up a big lead by the time it reaches 100mph in 17.5 sec (22.0 sec). By the time it’s doing 120mph in 27.5 sec, it has left the German coupe a full 10 sec behind. For all that, there’s little to choose between the cars in top speed. Mercedes claim 140mph for the SEC and their British test car can do a whisker better than that, allowed a long enough run. Aston Martin will tell you the V8 cracks 150mph, but it won’t. The best we could return in an hour of trying – was 146mph.

It is the Mercedes’s aerodynamics and lightness that take it to that excellent top speed (achieved at a little more than 4000rpm and theoretically maintainable all day!) but its relative lack of high crank speed horsepower holds its acceleration back against the Aston. The British car scores handsomely in a kickdown sprint from 60mph to 100mph (a prime overtaking range) by recording 9.3 sec (13.5) and it flashes across the standing quarter mile in a rousing 15 sec (speedo flicking the late 120s) whereas the Mercedes manages a brisk 16.3 sec.

Were it not for the Aston’s decisive sprinting advantage, the economy difference between the cars would be hard to tolerate. At the pumps the Mercedes-Benz has very much the advantage handing in figures worthy of many a 3.0-lifre. The ‘government figures’ read most impressively of all (urban cycle 18.6mpg; constant 56mph 31mpg; constant 75mpg 18.6mpg) but our own experience shows that average consumption stays remarkably stable at around 17.5mpg. On country touring runs 19mpg is possible: in town the figures can fall to the 16s.

An Aston Martin V8 used to be an 11-14mpg car. Now, apparently thanks to its tune changes and its lock’-up top gear, it’s a 13-16mpg car. Average, we found, was nearly always a little below I5mpg; but as low as 13mpg when driven to deliver that portion of its performance that was not within the Mercedes’ capability.

The stress laid on economy by Mercedes-Benz shows some sign of backfiring as a result of the Aston’s improvement. It encourages the question: Does the buyer of such expensive cars care whether he’s getting a 17.5mpg car or a 14.5mpg car? Further, does he think an Aston, so much faster accelerating than a competitive Mercedes, justifies its extra thirst? We think he might do.

The issues here are extremely complex. On one hand we, the car users, need people like Mercedes- Benz to persist with the pursuit of economy; someday a 5.0-Iitre car will deliver 25mpg. Or 31mpg. Equally, we cannot over-value a benefit which – at current prices over a typically British annual mileage saves the Mercedes driver a mere fiver a week in fuel. After all, that same man has just paid £30.000 for his four wheels. And anyway, a 17.5mpg car is still an expensive car to fuel.

The questions raised here burned away in the CAR offices for the time the cars were with us (they may flare again in Sir!) but one of the older guard, a man not usually with us, put a bottom line on it when he said: ‘I think the Aston’s performance rather makes all that Mercedes-Benz work seem like a humble detuning job. which is a shame. But I’ll bet a 300bhp Mercedes, which ran to 100mph 4.5 sec faster, would return 14.5mpg – just like the AMV8.’

As far as chassis behaviour is confirmed, the cars are products of their backgrounds. The Aston, a sports car from a long line of them, is firmly set up so that its body movements are minimised and its tyres are little disturbed on the road’s surface. It corners with little roll even when taken to its limit- and it understeers gently always. Only deliberate provoking will loosen its de Dion grip at the rear, and you can snap it back into line with the quick, firm steering, as surely as you shut a door. The steering is beautifully weighted – firm at all speeds yet of benefit when parking. The straight-ahead precision (perhaps helped by the fact that the wheel is small) is just as well though: on uneven surfaces our test car had a tendency to ‘walk’ about on the road’s surface and needed constant tiny corrections to maintain its heading accurately.

The ride isn’t especially quiet at low speeds but it gets better higher in the range (whore patter from the big 235/70 tyres is reduced). There’s a comforting stability about the car at all times, and the firmness of its damping gives it a businesslike gait. The suspension can be caught out on big irregularities – holes rather than ridges – and the bump- through can sound like an explosion. That and the ‘walking’ apart, the Aston holds up well. It has stacks of grip, great stability and a ride that’s good enough.

What Mercedes-Benz do best is to make refined saloon cars: we expected the coupe to have a cossetting, quiet ride. We were surprised, therefore, that it generated so much patter and bump-thump at lower speeds – more than we remember of the various 500 and 380SELs W126/V126 we’ve driven. A Jaguar, below 50mph, would do decisively better.

As the speeds rise, however, the coupe comes into its own. The suspension soaks up bumps and road unevenness with eerie ability; it has the capacity to level the car which is the best we know this side of a Citroen – or another S-class. It happens quietly, too; the tyre noise evaporates in open-road cruising. There’s a slightly ponderous quality in the combination of Mercedes-Benz recirculating ball steering and over-large steering wheel. The car suffers in comparison with an Aston (whose steering is an example to all who design cars) but there are those who like a Mercedes’ dignified’ way of changing direction. It doesn’t snap onto a new heading, it eases onto it. This Mercedes is an understeerer, too, but it will break its tail near the limit. Correction is a reliable yet rather less open-and-shut manoeuvre than in the Aston. That’s on account of softer suspension, more body roll and that ever-so-slightly woolly steering. Make no mistake, though, the Mercedes has a fine chassis, disappointing for the noise it generates at low speed, but probably as good as the best in the world for soaking up hours of miles at three-figure speeds. The Aston, for all its precision, is in need of More Work.

To list all the luxury addenda of these cars would be to take up space we, frankly, do not have. The main difference between the equipment of these cars is ABS anti-lock braking, which the Mercedes has as standard equipment. More and more people – especially Benz buyers who are starting to option the system in large numbers on lower models – are aware of the life-saving potential of the system in conditions where the finest of driving technique can have little effect. The system (along with BMW’s and Audi’s) is simply the best. It deserves to be on all cars; some day it will be. The Aston makes up a little of the leeway it concedes in the braking department by offering a firmer, more progressive pedal than the Mercedes (ABS cars do seem to have built-in sponge which makes modulation more difficult) and it can be brought to short, precise halts even on wet roads. The large footprint (which might be thought to allow slippage on wet roads) doesn’t seem a handicap.

The properties of the cars which money can’t fix (as it can pack in the options) are comfort, decor and interior room. The Aston has plainly the smaller cabin and it is the rear passengers who notice it most. Whether that means rear passengers need more room in the Aston or that the Mercedes-Benz could afford to be seven or eight inches shorter is a moot point. You can carry four adults by Aston but it’s a makeshift operation; their shins and knees suffer and there isn’t much headroom. In the Mercedes, you do it in perfect comfort.

Mercedes are commonly called spartan but this SEC C126 is quite sumptuous with its wooden facia decoration and door capping, its tasteful carpeting, its big-cushioned bucket seats and its gadgetry (like the seat belt ‘hand’ which induced every passenger we carried to bolt up). Yet the Aston with its wall-to-wall hide and walnut and its finest quality carpet, has a commanding edge. Perhaps the smell of Connolly hides does It; maybe you can somehow sense the hand assembly. Whatever it is, the Aston’s cockpit seems the more luxurious place to be. (So comfortable is either car that to make a choice at all feels faintly ridiculous.)

The driving positions of the cars back up their characters. In the Benz you sit supremely high – especially if you use the umpteen- way electric adjustment on the door which can eventually attach your scalp to the rooflining (and change every other scat angle as well). The inevitable three-dial Mercedes dash is part of a facia which bristles with air vents and rocker switches, so sensibly placed. The system of ram air, separate ducts for driver and passengers, thermostatic controls for the air conditioning plus instant demisting, puts the Aston’s cumbersome ’Coolaire’ system to shame. We imagine that somewhere on the Newport Pagnell estate there’s a Nissen hut full of these systems, over-ordered in 1965…

The rest of the Aston dash is nice; white-on-black dials that seem peculiarly British in style, Jaguar push-push switches that work precisely, sensible Chrysler- inherited auto quadrant (which allows the driver to pull the lever back to 2 from D, but no further) – and all that walnut. The seating position is sensibly low for good body location, the seat bolsters firm. There’s no attempt at the Mercedes-up-high position.

The upshot of all this? The cars are far closer than they might have seemed at first. The price differential – huge to most of us can evidently be justified by those in the market. The Aston’s combination of improved fuel consumption and a handsome sprinting advantage threaten the Mercedes’ economy-with-smoothness solution far more than any of us thought it would.

(intervals, the better resale value, the bigger cabin, the lower running costs, the better cruising ability, the better parking protection, the quieter engine and ride, the lower price. It promises the most reliability; longest life.

It is the car you’d better buy. But the venerable Brit, the Aston Martin V8, still with more roadholding and lots more performance, deserves to be taken very, very seriously.

Aston interior is a luxurious place to be because of walnut on doors and facia, leather and wilton carpet all about. Front compartment is roomy; seats firm and generous but rear room is rather restricted for big passengers. Still, car qualifies as four-seater. Cornering is tenacious; roll is minimal and tendency to understeer is postponed to a high level. Ride is firm and there’s a good deal of low-speed patter, but it all becomes much smoother as speeds rise. Dash is comprehensively laid out but old-fashioned in both appearance and ergonomics Engine is gruff 5.3-litre V8.

Mercedes cabin is more decorative than most of the marque: wooden door cappings, deep carpet and seats point to fact that this is most expensive car of range.

Rear space is especially good; there’s plenty of room for four adults in this car – and for their luggage too.

Handling/cornering is of the highest standard; perhaps it’s a bit on the soft side for Aston buyers but excellence of suspension geometry Is borne out as car corners over bumps.

ABS anti-lock brakes are a fine feature but pedal is rather spongy.

Mighty 5.0-litre V8 delivers fuel economy of a well-tuned 3.0-litre.

Dash is familiar three-dial Mercedes.

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 CAR Mercedes-Benz 500 SEC C126 Aston-Martin V8
0-40 4.5 sec 4.0 sec
0-50 6.2 5.1
0-60 8.0 6.9
0-70 10.4 8.7
0-80 13.3 11.3
0-90 17.1 13.5
0-100 22.0 17.5
0-120 37.2 27.5
Standing 1/4 mile 16.2 15.0

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