PH Heroes: BMW E28 M5

David Vivian looks back to one of BMW's greatest hits

The Nordschleife: 40 right-handers, 33 left-handers and one very, very long learning curve. Rather depressingly, given the length of time I've been doing this job, I've somehow managed to avoid racking up a manly number of close encounters with the legendary 12.9-mile circuit that winds its way through the forested Eifel valleys 90km southwest of Cologne and Jackie Stewart once encouragingly described as The Green Hell.

Until a few months ago, my tally of laps was a desperately pathetic two, posted way back in the early '90s. Then, last October, I was lucky enough to be invited to the BMW M5's 25th birthday bash. Based at the M division's long-established Nurburgring test centre a five-minute walk from the Nordschleife's pit lane, the idea was we'd get to fire pristine examples of all four M5 generations down the throat of The Green Hell.

An illuminating exercise it was, too. I got to spin-up my 'Ring track time by 200 per cent and made one interesting, but perhaps not altogether surprising, discovery. The best M5 for extracting maximum value from a far-from-mastered Nordschleife - and by that I don't mean the fastest and most accomplished but the most intriguing, absorbing, rewarding, playful and plain addictive - wasn't the 500bhp V10 E60 or the 400bhp V8 E39. It was the 286bhp 6-cylinder E28. The original M5.

As the E60 and screaming V10 power exit stage left to make way for the new twin-turbo V8 M5 in a few months' time, it seems only right to revisit the car that started it all back in 1984. And the first thing that strikes you as you walk up to it is how old and simple its design is. There was a complete step change in the way cars looked between the boxy, angular E28 and the softer, more rounded forms of the E34 5 series that followed it four years later. Which isn't to say the older way of doing things wasn't better.

Just look at that low waistline and the slim pillars. Step inside and, quite apart from the brilliant 360-degree visibility, the glassy cabin feels light, airy and voluminous in a way that more modern saloons hardly ever do. There's a startling clarity and absence of clutter to the design of the cabin as well. Maybe it's a little austere but it's also superbly practical, and the instrumentation - anchored by a huge and effortlessly readable speedo and rev counter - has yet to be equalled in a Five. The simple, intuitive switchgear is similarly satisfying to use.

Less impressive are the lofty driving position and stiff, sharply bolstered seats which, along with the thin steering wheel rim and mushroom-shaped gearknob, are rather more forceful reminders that this beautifully preserved, almost as-new, example is actually a quarter of a century old. The amount and quality of engine noise that enters the cabin is another giveaway. You sense that soundproofing wasn't top of the priority list when they made this one. The tappety clicks of the twin-cam valvetrain and whining cogs of the five-speed transmission are audible components in the soundtrack. But oh my, what a motor.

Derived from a racing engine designed by Paul Rosche intended specifically for the Motorsport division's first road car - the brilliant, Giugiaro-styled, mid-engined M1 - the 3.5-litre, 24-valve M88 straight-six got its first 'post-M1' try out in the M635 CSi. BMW Motorsport's CEO at the time, Jochen Neerspasch, reckoned the combination of coupe body and mighty engine would give Porsche's 911 Carrera a hard time. It did.

Meanwhile, the E28 5-series was being groomed for a similar insertion of supercar pace with the 'warm-up act' M535i - essentially a 535i with fancy wheels and modest spoilers and 'M Technik' branding - though getting the BMW board to agree to the marriage of the sober, sensible 5-series executive saloon and the mad, savage M1 engine proved trickier. The green light was eventually granted, but only on the strict understanding that the whole project was kept on the down-low.

Which is why the fastest and most powerful car on BMW's 1984 Amsterdam show stand was also the stealthiest. The cognoscenti clocked the lattice-pattern alloy wheels, the front splitter and the discreet 'M' badges. But there were no fanfares, no ballyhoo, no thrusting marketing campaign. The first M5 slipped into the world through the side door, just the way BMW wanted it. But this understated saloon had supercar-rivalling performance: 0-60mph in six seconds and a 151mph top speed.

All right, that's not so hot by today's supercar standards (you need an E60 M5 for that), but here on the Nordschleife it feels fast enough. The razor-sharp throttle response - achieved by having a separate throttle butterfly for each cylinder - hasn't been surpassed by any subsequent M5 and gives the car an eager, alert edge that urges you to press on. In that respect it seems very modern. But almost immediately you're reminded that it isn't.

The gearchange has a positive enough action but requires slow, deliberate handling. Then there's the body roll and comparatively modest grip. The 16-inch rims with their tall tyres, combined with soft suspension, give the chassis a distinctly unhurried, almost languid, demeanour. Everything feels cushioned, linear and progressive - almost as if you're forever 'taking up the slack' but in a very precise, measured way. Far from being a damper on enjoyment, it just seems to give you more thinking time.

Later in the day I'll drive the E60 M5 and that will seem almost supernaturally enabled by comparison, carrying tens more mph into bends and seemingly able to put down nearly all of its 500 bhp way before it would be wise unbridle the E28's 286. Yet in the E28 I feel much more intimately involved in the action. Yes, the limits are lower, but the rewards are that much more accessible and exploitable. All right, when it goes sideways - and if you're having fun on the Nordschleife it most certainly will - big armfuls of correction are needed. But it all happens so benignly and progressively it just puts a big grin on your face. Ease the pace a tad and you can balance it nicely on the throttle in a neutral attitude, just within the tyres' limits.

That the next M5 will be a hugely impressive machine, I have no doubt. But it won't offer the root-level rewards of the first one, a PH hero through and through.