It was on the second day that the temptation became irresistible. Oh certainly, we’d spent a day tearing up and down Welsh mountainsides for the benefit of lensman Tim Andrew’s pictures. And perhaps there had occasionally been a touch of oversteer here and there on tighter corners to remind me that I was driving a BMW.

But the grip generated by those huge MXX Michelins was becoming disconcerting. No embarrassing tail-slides pulling away from road junctions in a hurry, no red-faces following rushed zig-zags through quiet, backwater intersections. In the end it took a dumped clutch at a secluded country cross-roads near to home. That did it.

A touch with the right foot to pick up the revs, then a sidestep with the left. Two large patches of French rubber on the road or not, the result was wickedly satisfying. The tenor howl rose from beneath the hood, the tail drifted slightly to the right, and those back wheels spun at last.

Well yes, it was uncalled for and, yes, they are expensive tires and, yes, they do belong to somebody other than myself.

You see, it isn’t often that people get away with shoe-horning very big, very powerful engines into small, thoroughbred, sports sedans better suited to high-revving, piccolo power units and get away with it. Usually such experiments are ill-conceived, sometimes poorly executed, and more often than not best quickly forgotten.

And in truth it’s not generally the Alpina way, either. Alpina usually sticks to “sensible” modifications like straightforward engine and chassis tuning. Usually, but not always. The Alpina B63.55 isn’t till-conceived, though. Oh, no, not that.

Sometimes, just occasionally, a car comes along that’s so fundamentally correct, so well thought out, that it can happily withstand quite drastic modifications. Less often can they withstand such changes without allowing the finer points of the originals to be compromised.

M3 Ancestry

The B6 hails from a racing success story, like most good hybrids. It is basically an 3 whose four cylinder engine has been replaced by a tune 3.5 litre six, although that’s nto the whole story. The M3 was the BMW that shook the European high performance scene in 1986 and arrived stateside a year later. There hadn’t been a BMW like it for many years – the company had grown conservative and the idea of using four cylinders to make one of their cars go quickly just wasn’t acceptable.

But the M3 wasn’t designed like the other BMWs, to woo executive customers away from Daimler-Benz. This little fellow was designed to win races. Thomas Ammerschlager, an ex-Ford Motorsport man, was in charge of the team at BMW Motorsport. And he, like the rest of the team at BMW’s highly specialized motorsport department, understands the basic elements of speed.

The first journalists to drive the new racer scarcely knew what to think. With those wide, boxy wheel arches and rear spoiler, the car barely looked like a 3-Series. On the sweeping circuit at Mugello in Italy where the M3 made its summer debut, it didn’t feel like any other 3-Series BMW.

And that engine. The 2.3 litre four cylinder engine Ammerschlager created had a 16-valve head and developed 200bhp at 6750rpm with 176lbs. ft of torque at 4750rpm. Nothing happened below 4500rpm; once over that barrier, however, everything happened. It carried on happening until 7000rpm and made sure everyone knew about it. In Group A racing trim, the little four produces nearer to 300bhp (the rank is strong enough to withstand 10,000rpm). More people now know about the little Motorsports engine that could.

Group A is Europe’s sedan racing category. To be eligible or “homologated” for it, manufacturers have to build at least 5000 cars for public consumption, cars which earn the nickname “homologation special.”

The M3’s success since 1986 has been enormous, with many international championship wins to its credit. But despite its appeal, the power unit is uncompromisingly noisy and needs to be worked very hard indeed to get any satisfaction, either in street or race form.

Enter Alpina

Burkard Bovensiepen knows a bit about racing BMWs, too. He did a lot of it before and after he created Alpina Burkard Bovensiepen GmbH in 1965. Alpina is an unusual company. It isn’t owned by BMW, yet BMW gives its blessing to Alpina’s work. It is a curious relationship. One company’s desire for excellence feeds off another’s similar desire.

Alpina is also an autocracy – Bovensiepen is the boss – big enough to turn out 600 cars a year and is recognized by the VDA in Germany as a manufacturer, not merely a tuning firm.

When a small group of journalists went to the Alpina base at Buchloe (say Book-low-ay) in 1988 just outside Munich, they expected to be shown only the new 5-Series based Alpina B10, and the B12, based on the 750i V12. To be honest, the performance levels of the standard cars are so high that the attention of Alpina produces a much lesser margin of improvement than Alpina has achieved with earlier BMW models. But the B6, held out as a surprise for our visit, is different from its stablemates, and it quickly became the center of attention.

B6 Engine

The B6 is equipped not with the standard 3.5 litre six cylinder BMW engine (you’d be forgiven for thinking that would suffice), but the Alpina-tuned version as fitted to the B10 sedan. These engines, like all Alpina engines, are hand-built in Bovensiepen’s engine shops, which are immaculate, the mechanics working in a squeaky clean environment on the shining, lightly oiled steel and alloy that forms the heart of every Alpina.

The modifications are mostly straightforward. The stock camshaft is swapped for an Alpina one, the valves are changed, and cylinder head porting is modified. In the B6, shorter forged Mahle pistons are used in conjuction with longer connecting rods to make the engine smoother. Chips for the Bosch Motronic engine management system are developed and modified by Alpina, too.

The engine is impressive. The non-catalytic converter cars for Europe deliver 260bhp at 6000rpm and 235lbs.ft of torque at 4000rpm. Catalytic converter-equipped cars for the rest of the world develop 254bhp, but Alpina uses EMITEC three-way catalysts rather than the ceramic type, to minimize power loss.

Once the big six is shoe-horned into the M3’s engine bay, there’s little room left fore and aft – millimetres, in fact. The firewall needs surgery to make things fit, and there is a special exhaust manifold and exhaust system fitted. The Getrag 5-speed gearbox is the same, with the same internal ratios.

The rear axle has a limited slip differential set at 25 percent, and the axle ratio is longer, up to 2.79:1 from 3.25:1. That’s enough to push the B6 to 152mph. The taller final drive also means long legged cruising capabilities. First gear catapults you to 45mph, second gear to 70mph, and by 6600rpm on the rev-limiter in third, you’ll hit a cool 93mph. At that speed you’re already in trouble with the law on most public roads throughout the world except some of the unrestricted autobahns in Germany. Fourth gear compounds the problem at a rev-limited 127mph. Officers of the law may not like it, but the chassis swallows up all that power with aplomb.

Suspension Bits

The M3 retains the basic suspension of other 3-Series cars, with MacPherson struts up front and semi-trailing arms out back. But an M3 handles like no other 3-Series. The steering rack is much faster, with a 19:1 ratio, front wheel caster is increased three-fold, semi-trailing arms are set at 15 degrees, and both front and rear anti-roll bars are repositioned. The spring and shock rates are stiffer and the ride heights lower. There are twin-tube gas shocks at the front and single tube at the rear.

The resulting M3 bears little resemblance to its 3-Series brothers. One hundred percent feel replaces the not-quite-sure sensation the 325i gives its driver when entering a corner fast in the wet. And should you push your luck just that little bit too far, the M3 compensates for your enthusiasm. Instead of snapping, ferociously into a power-on broadslide, the M3 will at first understeer – quite a lot, in fact. Like a mid-engined single-seater, more power in a high speed drift will push the tail out, but progressively so. The basic M3 is a beautifully balanced, well mannered car that responds to your touch as only a thoroughbred can.

Replacing that relatively delicate four cylinder racing engine with the massive six out to cause all sorts of problems, but it doesn’t. BMW has tried it, and they too know just how graciously the little M3 bows to the task. They too know that far from destroying the characteristics of the car, the big engine actually improves them. The B6 is so simple, so perfect in its conception, it’s a wonder that BMW doesn’t produce their own version.

The only chassis modification carried out in the creation of the B6 is the addition of front springs taken from the A/C equipped M3. They’re stiffer, and tough enough to handle the extra weight of the engine which, surprisingly, isn’t that great. The final touch is a set of Alpina wheels, which are an inch wider and taller than standard.

Salzburgring

Being part of that first group of journalists to visit Buchloe last year also provided me the opportunity of testing the B6 briefly on the Salzburgring in Austria. There, after miles of frustrating holiday traffic, the B6 could stretch it legs. And rather than plowing off in understeer, the B6 proved sharp as a tack. The merest touch on the thick leather Momo rim would have the B6 diving for the nearest apex. Follow through with the throttle and the nose would tuck-in further, cosily nuzzling the inner red-and-white striped curb of a turn. Ease-on still more power and the oversteer would increase gently, the big tires howling in protest, the lightweight BMW flying out towards the exit point of the bend in a satisfyingly controlled four-wheel drift.

On English and Welsh roads a year later, little had changed. The only difference between the car at Buchloe and the one loaned to us by BMW Great Britain is the full Alpina interior of the British car. This car has the multi-adjustable, Alpina-trimmed front seats in blue and green. The doors are trimmed in the same cloth and the dash now has walnut veneer. The BMW black gearshift knob is replaced by a wooden Alpina one and in front of that is the exclusive Alpina plate, telling the occupants that this is car number -35.

Because of the B6’s low seating position, even folks with long legs can get close behind the wheel with arms comfortably bent, yet still achieve heel-and-toe shifts without catching a knee on the wheel-rim or the steering column. Rear-seat passengers suffer from the usual lack of knee room you get in any of the 3-Series cars.

It’s very smooth, no doubt about it. If you wanted to split hairs, you could argue that there’s too much luxury. Somehow the elegant finish is too great an addition to the attractive but slightly flashy interior of the standard car. You might feel that the lily is glided, or that the sporting nature of this car is compromised by the trappings of wealth.

You might think that, until you strap in and turn the key. The bodyshell kicks nervously. The engine fires, but instead of the four’s raucous whinny, there’s the deep, basso rumble of a six that doesn’t sound quite ordinary. The exhaust note steadies to tickover. It’s uneven and a little rough for a BMW. Blip the throttle and the response is instant. The bodyshell jerks with the torque, like a stallion touched by the whip.

The Getrag gearbox is notchy as always. The clutch is reasonably weighted and at least smooth. Rolling away, the slight transmission whine is familiar, too. But flooring the throttle pedal brings a response that isn’t. The reaction at first is reasonable; then the revs climb and there’s an MX missile under your right foot. The power is immense and linear in it’s delivery, but even with this big engine the real action starts at around 4000rpm and carries on to the rev-limiter at 6600rpm.

Shifting all Getrag-equipped 3.5 litre BMWs, whatever the model, requires the same technique; full-power shifts will always be jerky until you’ve got the rhythm. The shifting is slow, heavy, and a little vague, the inertia of the flywheel in the big engine huge, and the injection cut-off sharp. Clumsy shifting just won’t work; the B6 will frustrate your progress, chew you up, and spit you out. Deliberation, firmly controlled clutch action, and a feathered throttle to prevent the revs dropping right off is what it takes, and lots of practice. With the shifting mastered, that MX under your right foot will take you skywards.

Performance

The standard M3 accelerates from zero to 60 in 6.9seconds and zero to 100 in 20.5seconds. It will cover the fourth gear 60-80mph increment in 7.3seconds and 70-90 in 7.9 seconds – good by most standards.

But at the GM Millbrook test facility, the B6 scorched its way to 60mph in just 6.0seconds (as fast as a Testarossa) and thundered on to 100mph in 15.8 seconds. The increments between 60-80mph in fourth took only 5.7seconds and 70-90mph exactly the same.

On the high speed circuit at Millbrook, the B6’s average of 152mph on a windy day, allowing for scrubbed-off speed on the banked circuit, is consistent with Alpina’s claimed figured of 156mph on the flat.

Round town though, the B6 is a pussycat. Owners can expect to drive around at crawling speed in fifth hear if they really want to. Driving normally, without tapping the enormous reserves of power, requires much less technique at the controls to get a satisfying result. The B6 putters easily about town and won’t show its brute strength unless asked.

Stopping is no problem. Standard M3 four-pot callipers (ABS is standard, too) on the 11.0inch ventilated front discs are designed to slow 300bhp lightweight racing cars. Suffice to say they are up to snuff.

The B6 is no ballet dancer when it comes to weight, but at 2,904 pounds it’s a full 254 pounds lighter than the standard M3. It also has 60bhp more under the hood and more importantly another 60lbs.ft of torque to go with it. Where the M3 has a power-to-weight ratio of 169.5bhp per ton, the B6 has a muscle-bound 200bhp per ton.

On the road you’d never think the B6 was that heavy. The highly geared steering and taught chassis give it nimbleness and the razor-sharp turn-in that the BMW M6 is famous for. The ride is pretty hard, but then that’s what you would expect. It’s not tiresome though, and doesn’t jostle the occupants too badly. On smooth roads, feel through the springs seems quite mellow; at high speed the B6 rides with arrow-like stability.

Overall the sensation is still very luxurious, but tempered with a degree of menace emphasized by the firmness and response of the chassis, which rises to the surface every time the throttle is opened. What makes the B6 such a superlative high performance car is the compatibility of chassis and power unit. There’s nothing clever about over-the-top sedans or sports cars that have masses of power and a lousy temperament. Anybody can put something like that together. The B6 is even fun and safe in the wet, and that’s saying something.

Fine Vintage

Bovensiepen is also a lover of fine wines. In fact, Alpina makes 10 percent of its income from trading in them. The folks in Buchloe like to think that their cars and wines are closely linked: both appeal to people who want the finer things in life and can afford to pay the price.

The B6 isn’t cheap. The expense of the engine transplant alone sees to that. The price in Germany is DM85, 000 which on current exchange rates is about $43,000 (not including US taxes). The B6 is more or less built to order, so you can’t get much more exclusive than that. But like some of the virtually priceless Bordeaux wines lying quietly in Bovensiepen’s cellars, there’s always a premium to pay for the very best.

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An M3? Come on, guys, that’s ancient history, isn’t it? Well, in some ways you’d be correct in saying that about BMW’s little sedan race. But when we started testing tuner M3s – cars supposedly capable of outperforming that factory offering – we discovered something interesting. Mechanically, the tuner cars were no improvement over the stock M3; in fact, not only did they prove less drivable, but they couldn’t match the standard Bavarian’s performance at the track, either. Which made us think the M3 deserves a place in our rapidly growing “Track Test” data base. The M3, old news or not, is so well balanced that it is a benchmark by which other performance cars must be measured.

When BMW set out to compete in the international touring car championships of 1987, they needed a special car. The rules for Group A racers required that manufacturers build within any given 12 month period 5000 cars essentially similar to the racers. To gain a bit of “unfair advantage,” Munich started with the body of their 3-series and created a special production model incorporating a good number of tweaks and subtle modifications useful for racing. In the time-honoured tradition that has prompted carmakers to produce such customer cars as the Plymouth Roadrunner Super Bird, Ford Mustang Boss 429, and Porsche Carrera RS, BMW created a roadgoing “funny car” to allow putting the same tweaks on their racers. The result is the M3, a race car for the road.

The exterior is extensively modified from stock. The fender flares are tastefully done, and look designed in, not just added on afterward to clear wider tires (the rules allow up to 10.0 inch wheels in touring car racing, with no body changes allowed). The entire rear window area has been altered for better aerodynamics on the race track. The bottom edge of the rear glass has been moved back several inches, giving it a steep rake. A composite cap fairs in the glass to the existing body. The trunk lid has been raised by another composite cap which carries the spoiler. Fit and finish are excellent.

In contrast to the rest of the 3-series BMWs sold in the US, which use the inline six, the M3 uses BMW’s venerable iron block four. The iron four has been around for more than two decades. The old block is fitted with a double overhead cam 16-valve head which benefits from the many years BMW has spent in tuning and racing this engine. This is a natural choice for racing, as the newer aluminum engines from Munich are perfectly good for civilian use but were never intended to put out as much as the racers need to be competitive, and are not as structurally rigid. As evidence of the four’s ultimate ability, recall that this humble block was also the basis for BMW’s successful Formula One effort of the early eighties. At nearly 200 horsepower, the M3 engine is probably at the very limit of what a 2.3 litre normally aspirated engine can develop for street use. The tuner cars we tested proved this point emphatically.

While the outside changes are obvious, the changes under the skin are even more extensive. The front suspension pickup points have been subtly altered from those of the stock 3-series. The front hub carriers are also different, for more caster, lending greater stability and better road feel. The ratio of the power steering has been quickened. Lower A-arms are of aluminum rather than steel. Springs, shocks, and bushing have been altered from stock, with rising-rate springs added at the rear. The M3 carries the bigger brakes of BMW’s 635 and 7-series. Power reaches the ground through a 25percent limited slip differential.

Inside, the M3 has excellent, multi-adjustable, highly supportive leather seats with high, firm side bolsters. Along with the Corvette and Porsche 911, these are among the best sports car seats anywhere. The steering wheel is set high, at a steep angle. It offers good grip, with perfectly placed thumb hooks. The instrument panel and controls have that characteristic no-nonsense BMW look and feel that says “this is a driver’s machine.” Instruments, controls, and pedals are all ideally placed. The dead pedal and the placement of gas and brake for heel-and-toe downshifting tell you that this is a car with sporting intentions. The heating/AC controls and the trip computer are clearly, logically labelled. The large glass areas allow good vision to all sides. Rear seating and headroom are adequate. The carpeting and trim pieces fit perfectly.

On the drag strip, the M3 launches best at 4300 to 4500rpm. We measured 0-60mph in 7.38 seconds, and the quarter mile in 15.65 seconds at 90.8 mph. The M3 has very short gearing, as one would expect in a race car. Second gear only reaches to 53mph. It’s tempting to say that car would be quicker with taller gearing, but the shifter feels so good that there probably isn’t much time lost in the extra shift before 60.

We measured a top speed of 139mph (the factory claims 142; close enough). Revs at top speed were 6900rpm, just 100 shy of redline. At that speed, the M3 felt securely planted, no doubt in part due to its racing modifications. The steering conveys a solid, well connected feel at speed. The M3 also retains that typical BMW ability to absorb big bumps while still delivering sharp handling characteristics. On the skidpad, the M3 exhibits very benign handling. We played around with tire pressures. Reducing pressure at the rear (to 38 psi cold all around) reduced understeer and made the car easier to steer with the throttle (it tucked in a little more on lift off) but didn’t affect ultimate cornering levels. The car could be kept on the line with the steering wheel held steady, and steered with just the gas pedal. At the limit, the car understeers gently. We measured average lateral acceleration at 0.81g. This car would do considerably better on the skidpad with more aggressive tires; the Uniroyal Ralleye is not today’s hot set-up. The narrow general-purpose tires may also account for the good but not stellar braking distances; this sort of car with ABS is capable of shorter stops. A sticky 255/50 tire would fit nicely, requiring no changes to the car.

The engine feels rough below 1500 or even 2000rpm, but smooths out above that, although it never approaches the levels of smoothness of BMW’s other engines. It has a growly sound and character, in the best tradition of four cylinder sports cars of a bygone era.

On the road, the car gives a false impression of sluggishness if driven conservatively. If the revs are kept too low, the four cylinder engine and deficit in low-end torque make themselves felt. If never taken out on an empty, twisty road, many drivers would overlook this car’s outstanding sporting character. The engine doesn’t have that strong bottom-end character of an American muscle car; it’s tuned for top end performance. When driven as intended, on a twisting road with the engine never dropping below 4000rpm, everything suddenly falls into place. The engine rockets the car from corner to corner, and the hard pedal of the ABS-assisted brakes lets the driver go into turns deep than he had thought possible.

Many cars feel fine when driven moderately hard, but lose their composure when going above eight or nine-tenths; not the M3. The feeling is one of being in total control even at ten-tenths. In short, the BMW M3 feels like a racing sedan. Which is exactly what it is.

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