There’s a power struggle in Germany. Mercedes began the strife with its Cosworth 190 model. Now BMW has struck back with its own race bred M3 – but who holds the advantage? – What Car
Never mind the recent peace overtures between East and West Germany, have a look inside the Federal Republic where there’s a battle royal raging between the cities of Stuttgart and Munich – respectively, home bases for Daimer-Benz and the Bayerische Motoren Werke.
Although the fight is contested with an air of dignity, it is interesting to note how Mercedes is reacting to the new assault upon its supremacy by BMW, which is now putting a keen edge to its sporting image with cars like the new Z1 two-seater and a string of real performance variants of its saloons. The men from Munich have also recently launched a brand new V12 powerplant for the flagship 7-Series model – a move that has been responsible for some midnight oil burning in Stuttgart.
While Mercedes was still confident of retaining its hold in the very upper classes of car ownership. It was just a little concerned that BMW was chipping away into a new market sector catering for buyers who were looking for a combination of class and performance. To meet the challenge, Mercedes decided to add a lot of spice to its new ‘small’ saloon, the 190, which had proved to be competent but singularly unexciting – many of them ending up as taxis in Germany.
To make it all work, Mercedes broke with tradition and went to an outside agency. Cosworth Engineering of Britain, for help in applying new techniques for aluminum alloy casting in order to produce the complex four valves per cylinder head that is the essential ingredient of the 2.3-16.
Cosworth had done it before of course. The company’s vast experience in producing the Ford DFV V8 motors that dominated Formula One racing for so long transferred fairly easily to the road car application.
The result of the work by Cosworth and another British company, combustion chamber design experts Ricardo, is a compact and tough powerplant producing 180bhp at a high 6200rpm.
Not that there’s anyu obvious mention or the debt to Cosworth on the car itself – a little too much for the proud German to swallow perhaps – but there is a mildly aggressive touch to the outward appearance, with the add-on rear wing, deeper front spoiler, side sill extensions, and wheel arch lips.
Inside, though, it’s a different matter. The same, unmistakable Mercedes elegance is apparent, despite the presence of sport-like seats, and a gearbox with a dog-leg first gear. Otherwise, it’s as you would expect an executive Mercedes to be: big, leather covered steering wheel, electric windows, sunroof, remote mirror, wash wipe, and central locking, all for the princely sum of £25,540; that’s nearly £7000 more than the next 190 model, the recently introduced 2.6 which we tested in September What Car?
The Mercedes-Cosworth became available late in 1985, and has proved extremely popular, also proving its mettle on the race tracks of Europe where it received no full works blessing, but undoubtedly found help from Stuttgart when required. This year, the car has been rather outclassed – not only by the Ford Sierras boasting Bosworth heads with turbocharger, but, more importantly, by the adversary from Munich: BMW and its M3 model.
The M3 shares much in common with the Mercedes – and not only the German parentage. For example, the 2.3litre motor; a four cylinder unit like the Mercedes, but fitted with BMW’s own 24-valve head. Then there’s the five speed gearbox with dog leg first, and the general air of executive grace within the two-door bodyshell.
But, while the Mercedes is essentially a saloon given the sporting treatment, the BMW M3 is a race car, detuned for the road.
Under the present regulations governing Touring Car racing, a manufacturer has to build 5000 examples of a particular model in order to homologate it under the Group A regulations – the rules to which Touring Cars run in the present World Championship. So this is no ordinary 3-Series BMW, although nominally badged as such. It was designed for the race track by BMW’s Motorsport arm, but produced for the road by BMW AG.
And the M3 was designed with but one aim: outright motorsport success. In this respect, the M3 has proved its worth already, humbling the more powerful Ford Sierra RS Cosworths with contemptuous ease in the World Touring Car Championship, and despite the introduction of the far more powerful Ford RS500 ‘evolution’ model is still managing to win race outright.
Part of the reasons for the car’s success on the track is its impeccable design, pedigree, for the changes allowed under Group A regulations are significant but limited, so the original product has to be good in the first place.
Thus, back in 1981, the men from Munich decided on a successor to the mid-engined M1 sports car to be based on the new 3-Series due for launch in 1982. A four-cylinder engine was chosen rather than a straight six, mainly from racing experience where there’s less crankshaft vibration at sustained high revs.
The head itself is a multivalve design developed from the larger capacity M1 M635CSi and M5 units, with BMW’s Motronic system managing ignition and fuel demands.
The engine produces its peak power of 200bhp – that’s 20 more than the Mercedes Cosworth – at 6750rpm – again slightly higher than the Mercedes. The BMW unit also produces slightly more torque higher up the rev band than the Mercedes, with a figure of 174lbs ft at 4750rpm.
But if the Mercedes plays down its sporting element, with only subtle body modifications, the BMW goes the whole way, with bulging wheel arches, enclosing 15 inch alloy wheels, deep front spoiler and side sills, a rear apron with twin tail pipes, plus that unmistakable bootlid wing reminiscent of the ‘Batmobile’ CSL of the early seventies, the M3’s true spiritual heir.
But all of these appendages do have a specific job to do on the M3. They are not shoddy looking, go-faster add-ons, but functional and integral parts of the car that flow with the 3-Series’ lines and are made from high quality composite materials in the interests of light weight and strength.
For example, those bulging wheel arches are there so that much wider racing tyres can be fitted (no slick racing tyre must extend beyond the car’s external dimensions according to the Group A rules), while the front and rear air dams not only improve directional control of air flow at high speed but help in the car’s streamlining. BMW quoting a low Cd factor of 0.33.
However, it’s actually at the back of the car that most aerodynamic work has been carried out by the BMW Motorsport engineers. There the angle of the rear screen has been changed to direct all the better air flow over the rear mounted wing to give the car increased downward force on the rear driven wheels. This was no simple matter. The rear of the 3-Series had to be chopped away and completely redesigned, the height of the boot also being increased, too, by over 1 ½ inches. The top of the boot lid, and the wing are both made of plastic for lighter weight, too, while both front and rear windscreens are bonded in to improve bodyshell rigidity.
All this has an important bearing on motorsport use, where the M3 needs to be as aerodynamically slippery as possible to provide good straightline speed, while also getting plenty of downforce – and thus traction – for the rear wheels when trying to put the power of the race car’s 300-plus brake horsepower on the road.
Obviously, changes have been made to the suspension settings to cater for the increased power of the M3. Brakes, too, are bigger and thicker with uprated brake callipers. Suspension is independent with semi-trailing arms at the rear in common with other 3-Series cars. Anti-lock braking is standard.
Pricing of the M3 is similar to that of the Mercedes Cosworth, at £23,550, which is some £5000 more than the next car in the range, the four-wheel drive BMW 255iX, the M3 is available in left-hand drive only.
We tested the Mercedes-Cosworth back in September 1986, when it went head-to-head with Ford’s Sierra which had just been given the Cosworth treatment, too. Unfortunately, though, the Mercedes-Benz no longer had a car on its test fleet in Britain, but fortunately for us, Alan Minshaw stepped in to loan his car. To those who follow motor racing, Minshaw will need little introduction. Known as Mr ‘Demon Tweeks’ after the motor racing and rallying accessory mail order firm he runs in Tattenhall, near Chester, he is also a fine racing driver, too, presently racing a Volkswagen Golf GTi 16-valve in Britain’s own Group A Touring Car series.
So how do these two fine examples of German engineering compare?
In terms of sheer outright speed, then it’s the Mercedes that’s ultimately just quicker. When we tested the car back in September of last year, we managed a 145mph maximum.
That’s one mph down on the BMW claim for its M3 racer, yet round Millbrook’s high speed bowl, we could manage only 143mph, but it’s enough by an practical standard.
However, where the BMW does surge ahead is in the 0-60mph dash where we achieved a rubber-burning 6.8secs, the Mercedes over a second in arrears at 8.0secs dead. Up to 100mph the BMW streaks ahead in the autobahn dash, pulverising the Mercedes with 18.4secs time, the 190E 2.3-16 left breathless at 21.8secs.
So the newer car is certainly quicker under full throttle accelerator although not quite able to match the Mercedes’ top speed, but both can deliver their dynamic qualities in the very distinct ways.
Driving the Mercedes for the first time, it’s often a case that the prime sensation isn’t one of speed at all. The Cosworth head treatment gives the engine a peaky quality. Below about 5000rpm the unit feels rather mundane, as if its potent reputation has been overstated. Take it up about 5000rpm, though, and suddenly you have a different car on your hands.
What had seemed a quick, but rather, innocuous build-up of speed in this suddenly becomes an eye-widening experience as the Mercedes surge forward. Your foot hovers over the clutch pedal ready for a quick up change, but, incredibly, the tacho-meter is nowhere near the red line yet. When it does get there, a snatched change into fourth sees further fantastic forward progress.
Such characteristics are fine for the autobahn, but in country lanes, the lack of real low-down torque becomes something of a handicap. But keep the revs high by using the gearbox and the Mercedes will zing along.
The BMW behaves rather differently. Its close-ratio sports gearbox transforms the multivalve four cylinder’s output into a glorious and fluid crescendo of power. Despite the peaky nature of the multivalve unit’s surprising how much low-down torque is available, providing valuable flexibility on cross-country routes, away from the motorways.
In the handling department, the M3 feels the nervous thoroughbred that it is. Blip the throttle and the exhaust snarls, ready for action. But although the M3 displays high levels of grip, and sure-footed handling, you know the car is only working at 75 per cent. A higher degree of driver skill and finesse is required to extract maximum performance from the chassis.
No such problem with the Mercedes, though. Here is a fine chassis that could surely take extra power, progressive but finely controllable oversteer being the order of the day.
Who wins this battle of the Germans? It depends on your requirements if you wish to spend £25,000 on a small saloon. Certainly, the M3 looks the part, ensuring that you will receive admiring backwards glances wherever you go, And, on British road, it has better low down pull, but the disadvantage of left-hand drive.
The Mercedes is not so overly sporting but then many buyers prefer their cars to look innocuous, yet to perform well, and this the Mercedes certainly does, although the ‘Q-car’ disguise is pretty thin. It also has the benefit of four doors. On the minus side, all the Mercedes’ performance is restricted to a fairly narrow power band, rather more useful for the high possible speeds on roads in Germany than speed-restricted Britain.
Certainly, Alan Minshaw thinks his Mercedes is the best car he’s driven, but can’t decide on a replacement – unless it was another one. And this is perhaps where the strength of Stuttgart lies: customer loyalty. BMW may have stolen the limelight at present with its M3 and recently announced V12 7-Series car, but while Mercedes is responding, the battle continues. Waiting in the wings is a 2.5 litre 190 Cosworth, which could steal a flanker on upstart Munich and move the battle onto a new, higher plane. But for now, the M3 just holds the edge.
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March 3, 2008
1986 - 1989, Articles