The combination of power, speed and agility BMW has struck for its 145mph M3 racer is impressive enough, but what really sets the car apart is refinement – Car
It takes a degree of willpower to hold an engine precisely at 4800rpm, when the gearlever is in neutral and the car is going nowhere. The din and vibration are obtrusive, even in a car such as a BMW 3-Series, which is supposed to be smooth and refined. It bears no relation to a car pulling 4800 as it swoops along a piece of open road.
But if you can hold the BMW M3’s engine revolutions precisely at four-eight, then snick the gearlever into its dog-leg first, then pop the short-throw clutch just right – neither slipping it nor dropping it – and flooring the accelerator, you will generate just the right amount of smooth, smoky, shrieking wheelspin and the car will bolt forward. You will be on your way to 60mph in 6.8sec, and 100mph in 18.5
If you keep your foot hard down and snap the last gearchange through at just about 127mph (131 on the clock) you discover very rapidly that the M3 – even one like ours which hadn’t done the 8000-10,000 miles cars need for optimum performance figures – is good for 145mph.
This is all contingent, of course, on your extracting what power there is to extract from the twin-cam, four-cylinder, 16valve, 2.3litre engine. The tachometer red sector suggests that you make your gear changes at 7000rpm. The ignition cutout insists that you go higher than 7300rpm. But it’s best for performance if you change at 7250rpm, because the power delivery is predictable enough and the rev-counter is accurate enough to allow you reliably to evade the rev-limiter by just 50rpm. You feel quite safe doing it, since the engine of this racing car has been built to tolerate 9000-10,000rpm when it’s used on the track.
It is quite a surprise, after your first half hour on the road in this quick but very refined little animal, to discover that BMW claims it is no less than the successor to the legendary M1 which is ‘destined for touring car racing in more or less standard form without too many modifications.’ After all, it hardly looks like a car to be compared with the M1, the 3.5litre 160mph supercar, built between 1978 and 1981, which established itself as the first well-built, properly developed and truly practical supercar in the Italian tradition.
It is practical no longer, of course. Only 450-odd M1s were built and many were destroyed in crash and bas races for grand prix drivers, called the ProCar series. So M1s now command the kind of prices that cause them all to be locked in climate controlled garages on the Riviera.
The M3, based as it is on the Bavarians’ cheapest, smallest and commonest saloon, does not look like a car of the M1’s eminence. Most will see it as the last word in yuppie-mobiles, with its slick combination of bulges, bumps and scoops – but nothing so garish as chrome.
Yet closer inspection shows a car whose body add-ons are far less artfully used than most. There is about the M3 the cheerful air of the race-special. It seems to have done without too much honing by designers. The bulbous steel wheel-arches are there because this car is allowed 10in wide wheels on the track. They could look better, but they work. The nose spoiler was optimised in the wind tunnel, not the studio. The raised rear deck, incorporating a bootlid of rather filmsy construction complete with rough edges, is there only because it will surely add speed on straights. The same goes for the odd-looking extra rake on the rear window. And the rear wing, OTT for the road, cuts lift to the low level one needs in a car which will usually be doing 160mph by the time it gets to the braking area.
There are side skirts, too; one suspects they are the only truly cosmetic part of this car’s extra décor, and present only to provide a bridge between the extra body bits front and rear. The whole would look funny without them. As it is, with all its dams and ducts, strakes and spoilers, this car manages to achieve a drag factor of only 0.33, which is pretty remarkable. The frontal area may be lower than a normal 3-series’, too, since the M3 sits half an inch lower than its cousins.
But this is a four-cylinder 3-series, not a six. BMW’s race engineers face up to the obvious questions – “Why?” – with a volubility that may not please some folk in marketing, whose job is to get on with selling ‘velvety sixes’ by the thousand.
Peter Flohr, chairman of BMW’s Motorsport division, says the four offers a relatively short crankshaft which keeps bending and torsional stresses to a minimum. A six would not reliably stand up to 9000rpm. Flohr also says the four offers better low-end torque.
A further advantage must be that the four is a substantially shorter engine than BMW’s equal capacity six, and locates its main engine mass further back in the chassis than a six’s would sit, to the benefit of the handling.
In any case, this four-cylinder has a superb pedigree, the kind which will appeal to those who care about cars (as opposed to caring about being seen in them). It has its roots in the old ‘60s BMW 1500 four, which subsequently became the basis for BMW’s championship-winning formula one turbo engine in 1983. It is also related to the unit which proved such a flier in formula two. Its head design is closely akin to the M1’s: with the M635CSi it shares valves, valve gear cam profiles, combustion chamber design, pistons and conrods.
The engine produces its 200bhp at 6750rpm (1958bhp with a catalyst fitted) and accommodates this with 174lb ft of torque at 4750rpm. Though such figures imply that the engine must be kept singing sweetly, its manners below 3000rpm are still near perfect. There are four valves/cylinder set in pent-roof combustion chambers whose spark plugs are centrally located. The valves are directly actuated by twin overhead camshafts which are driven by duplex chains (the formula one engine has gears). The forged crankshaft runs in five main bearings. Each crank is used as a balance weight, which would obviously enhance the engine’s smoothness.
The M3’s engine’s capacity of 2302cc – and the acknowledge relationship it has with the big BMW sixes (including its oversquare cylinder dimensions of 93.4mm bore, 84mm stroke) show how BMW has had a ‘modular’ engine set for years, without stressing the point.
The M3 is fed and controlled by an advanced Bosch Motronic engine management system which ‘tunes’ the engine’s gas delivery and ignition every time the crankshaft turns. The power is put through the Getrag close-ratio gearbox which BMW has been using for a decade. The main virtue is that its top gear allows the engine to pull almost to the top of its rev range; top gearing is close enough to 22.3mph/1000rpm. But the Getrag’s inclusion in any specification sheet these days leads to a suspicion, rightly, that the car will have a slow, probably awkward gearchange action.
The M3 chassis bristles with strategic modifications, yet the paper specification is as for any old 325i – MacPherson struts with an anti-roll bar in front, semi-trailing arms with an anti-roll bar behind. There are disc brakes all round, with ABS as standard, and the steering is by power assisted rack and pinion.
But within that general description of a 325i, almost everything is changed. The car wears 15in wheels with 205/55VR tyres on 7in wide rims. Its front stub axles are specially made to house bigger wheel bearings from the 528i. There are redesigned steering knuckles. Five-stud wheels (alloys as standard) replace the four-stud type. At the front, the suspension has specially calibrated gas shock absorbers and the steering castor angle is increased to three times the 325i’s. This, BMW says, gives the car more stability and ‘centre feel’ at high speed, but the price is an increase in self-centering inclination and a general increase in effort. The power steering, a rack and pinion system, has its gearing quickened so that the car now needs about 2.9 turns, lock to lock.
Body roll control has been a big pre-occupation of Thomas Ammerschlager, head of ‘exclusive products and high performance vehicles.’ So the front anti-roll bar has been redesigned for the M3; it has better pivots and is much thicker than the standard part. It now exerts twice as much effort against roll as a standard 325i bar. At the rear, the semi-trailing arms are untouched, except that they are accompanied by their own stiffened anti-roll bar and have high rate springs and gas shock absorbers. The whole car is set about 0.5in lower.
To cope with the extra go and stop, the car has a limit slip differential as standard, plus bigger diameter and thicker brake discs fitted with reinforced callipers. It is notable that in this car, where the emphasis is on sheer no-fills performance, there is no question of a four-wheel-drive system. Perhaps it would weigh too much. In any event, the M3 with all its body mods (most in steel) but lighter four-cylinder engine, still manages to add 90lb to the 325i’s 2475lb, and the group A regs under which the car will race this season (in the under 2.5litre class) will not allow much in the way of weight saving.
In any case, the M3 road car’s power/weight ratio of 12.8lb/bhp is an exceedingly lively one. It’s better than either the Audi Quattro’s (14.3) or the Porsche 944 Turbo’s (13.5) and it also beats its own rapid stablemate, the BMW M535i (14.1). It’s only a whisker behind the Lotus Turbo Esprit (12.5lb/bhp) and can even live with an Aston Martin V8 (12.5). The fastest hot hatchbacks – Golf GTI 16V and Escort Turbo – are up in the 15lb/bhp region and are out of the race.
At first, the car doesn’t even feel fast. It feels refined, especially if you’re familiar with the rather rumbling, truck-like gait and the mid-range boom periods of a Cosworth Sierra, still a redoubtable car. Compared with that, the M3 is simple, smooth and well-mannered. Its stiff front dampers can cause the nose to bob about a bit at low speeds, but all bumps are consumed with the low, well-muffled thumps familiar to BMW users and the engine will trundle at 2000rpm if you ask it to. The mailed list is well concealed.
But once you feed the engine 5000rpm or so, there’s real alacrity there. In fact, there’s an impressive response from as low as three. Once the engine’s sweet willingness makes its impression, you feel the same compulsion that comes to drivers of the Bavarian sixes. A need to feel the performance and use the revs. Some say the four’s buzz is no match for a six, but nevertheless above 4000rpm the engine sings. Beyond 5000rpm it stats a kind of polite howl, and then, for the last 1500rpm the engine’s sounds really bear out its formula two heritage. It is the sheer quality of those racing car sounds, delivered without ear-strain or shock value, that start to set this car apart. All the way, power is delivered with an ever-strengthening push, until the rev-limiter steps in to curb enthusiasm at 7300rpm. There is no evidence that power tails off before that.
So the sounds are marvellous; the power is intoxicating, but the true strength of this 2.3litre four is the immediate, sensitive, subtle nature of its throttle response. You meter the power minutely in corners. You deal out engine braking with rare precision. You blip the throttle to match engine revs exactly to a snap-selected lower ratio. You break off the power exactly at 7250rpm, knowing that the superb engine will respond without a perceptible pause.
The gearbox needs taming. Its dog-leg shift into second is slow, and all the slower because M3s are left-hand drive cars and British drivers always need to polish up their right-hand changing skills. But first is a long, strong ratio (maximum beyond 40mph, if you use full noise) and second (67mph maximum) is low enough to carry the progress strongly on, even though there’s a long pause for the gearchange. From second, it’s not just a backward snap into third; there is a speed beyond which the lever cannot be moved. But third carries you on just beyond 90mph.
There is quite a gap between third and fourth. If you change out of third at maximum, the engine is doing less than 5000rpm when it takes up in fourth. And if you change out of third at 70mph, something you might do if you were only half-heartedly hurrying, the engine will have to pull fourth from around 3600rpm, 1000rpm short of its strongest band. So it’s necessary to remember not to change out of fourth too soon.
Fourth to fifth is magnificent. The ratios are so close that the power can flow in one long, barely interrupted surge. More good news is the fact that the straight-line fourth-fifth change is the fastest in the box. Fifth will actually work from town speeds – 40mph or so – and it’s really strong from 80 or 90, right up to its maximum. On that score, we managed a best of 143mph true around the two-mile Millbrook banked loop, but since the top lane’s hands-off speed is only 100mph, the car was cornering quite hard all the way. We’d estimate that this car, running in neutral conditions on a straight road, could get close to 150mph, about 6750rpm.
The most enlightened people at BMW, Thomas Ammerschlager high among them, have been working for years to kill them, have been working for years to kill off the assertion that BMWs are tail-happy cars. The new 7-Series is evidence of it, the M3 provides more. This is not to say that it will never oversteer – but it is certainly true that the balance of the M3 is such that both ends are very near their adhesion limit before one or the other lets go.
One primary handling advantage the M3 has over rivals such as the Sierra Cosworth and the Merc 190 2.3-16 is its compactness. The car feels small. You can tuck it hard into the apexes of tight bends on narrow roads, and feel that there’s invariably road left for indiscretions. Body width plays the biggest part here (though the BMW is several inches shorter than both Mercedes and Ford). The M3 is three inches narrower than the Merc, and a striking nine inches less wide than the Cosworth Sierra, a fact that is certain to tell on the track in group A saloon races this season.
But the chassis characteristic are what matter to fast road drivers. This is a low, firmly suspended, beautifully balanced little car, which holds on very tightly at both ends, and goes where you point it. It hardly rolls at all in corners, as its stiff anti-roll bars would lead you to suspect. The steering is as sharp as you need, yet is still protected well from harshness and road shocks. It also resists – as the Cosworth Sierra and wide-tyred, stiffly suspended cars do not – a tendency to tramline under brakes. The M3 stoppers themselves wash speed effortlessly away time after time; their only requirement is a fairly hefty push on the pedal.
I have my suspicions that the M3, is a final oversteerer. But I know damn’ well that on any public road in the realm you’ll have to stick your neck out to discover whether that’s true or not. At brisk cornering speeds there’s enough of a front slip angle to allow precise throttling-off to add weight to, then tighten the nose into bends. In the wet, outright provocation with power in tight corners can make the car step a foot or so sideways. But you need a test track to investigate the power slides which the car will be reluctantly pushed into with lots of revs and power, sharply applied. Even then, it wants to stay straight. If oversteer happens, the tail can be snapped back into line with a flick of the wrists. The body does not rock or squat or buck; it just stays flat.
Because it is suspended very firmly, the BMW can be choppy at low speeds. The front, in particular, pitches a little on rough roads at low speeds. But when the car gets going, it becomes level and comfortable. A real and rare virtue is the subdued way the body treats bump-thump. It filters out annoying noises as well as many as luxury saloon. No racing car was ever like this.
The M3 is, in short, a car whose handling and roadholding are a lot better than most of us will ever need them to be. The person who truly uses the car hard on the road will need to learn it first. For that exceptional level of chassis ability, the M3 provides actual ride comfort. No rationalising will be needed on an owner’s part. It is sporty and firmly damped, but it is quiet, too, and the usual Bavarian body solidity is as heartening as ever.
Comfort is delivered in other ways, too. This car has a more or less routine upper 3-Series cockpit. It is trimmed with car and quality. There are sports seats and a thick-rimmed three-spoker for a steering wheel. The needles on the black and white instruments are red instead of white, though, and the speedo and tacho dials are recalibrated to take account of the car’s high top speed and revability. And instead of a fuel consumption indicator, the M3 has an oil temperature gauge – a much more useful gadget, even to road drivers.
On the fuel usage front, BMW quotes some remarkable statutory figures, the most improbably of which is that the M3 does 48.8mpg at a speedy 56mph. One of life’s useless facts, that, even if it’s repeatable. The important thing is that this car will return 20mph if you cane it severely, and up to 25mph if you treat it as though you own it. At, say, 23mpg, the enlarged 15.4gal tank gives a touring range of 350miles. At present, the 30 or 40 British buyers BMW expects to attract each year will be delivered non-catalyst cars, which run on 98 octane four-star fuel. The good news is that when the time comes, these machines will be able to be fitted with catalysts without problem, and will be capable of being tuned to run on lower-octane lead-free fuel.
There’s no pretending that this is a car for the masses. It isn’t even a car for the discerning few. It is a car for zealots, who can afford £23,000 and who by some fluke have avoided having it hijacked by men selling Sierra Cosworths, Mercedes 190 2.3-16s, or Alpina C2s. But the enthusiast who buys an M3 will be helping himself to the best-handling, and one of the fastest cars BMW has ever built for use on the road. The wonder is that it’s mannerly and refined, too.
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February 25, 2008
1986 - 1989, Articles