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Tuesday 5th December 2006


BMW Z4 M COUPÉ

Ian Kuah investigates the brutal Beemer. We think he likes it

BMW Z4 M Coupe
BMW Z4 M Coupe

Our first impressions of BMW’s new Z4 Coupé bring to mind the proverbial enigma wrapped in a puzzle. Here is a car that aspires to greatness against luminaries such as Porsche’s amazing Cayman S. But as we quickly found out, while this pair may appear to be a direct rivals on paper, the reality is quite different.

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Spiky

The BMW is in some respects a sharper instrument than its rival from Stuttgart, but that same sharpness also makes it spiky, a trait that some hardcore drivers will welcome, and the rest of the population will feel uncomfortable with.

The heart of the Z4 M Coupé is the same 343bhp 3.2 litre straight-six M motor shared with the M3 as well as its roofless Z4 M Roadster sister. At 1,495kg, the Z4 M Coupé is an insignificant 10kg heavier than the ragtop, but a whopping 75kg lighter than the M3. Its 5.0 sec time to 62mph just edges out its four-seater cousin by 0.1sec and it is stopped at 156mph (250km/h) by the same electronic limiter.

None of that however, gives much of a clue to how the car drives in the real world.

Up in the hills near Estoril, with the snarl of the single-throttle-per-cylinder straight-six echoing off the rocks, we are busy finding out, and our first impressions are of a car with some very clear differences to the Z4 M Roadster we drove on Spanish roads two months before.

Ergonomically perfect

BMWs is known for its ergonomically perfect driving positions and the M Coupé is no exception. The pedals are nicely set up for heel and toe action and the stubby gearlever is just where you want it.

The fixed fastback roof makes the interior environment feel quite different though. Ensconced in this womb of a cabin, you feel snug, and larger people may even feel claustrophobic. But if you are sized like 95 percent of the population this car will fit around you like a glove.

Although the weight of its excellent power-steering seems no different from the Roadsters, the Coupé is more pointy, answering inputs to the helm by diving for the apex of a bend with a sharper response. On a smooth road, grip levels are huge, and on a sinuous road, you quickly start to think your way around corners.

As we get more familiar with its handling, exiting slower bends with the traction control light flashing becomes a regular occurrence.

Initially, we had the Sport mode for the e-gas throttle engaged, but now we disable it. With throttle response dialled back to normal, we make smoother and more relaxed progress on the road with other traffic around. The highly strung Sport mode can wait for the racetrack this afternoon.

Stiff car

Good structural stiffness makes a huge difference to the handling of any car. If a platform is highly resistant to tensional bending, the suspension geometry will remain accurate under load and work as its designers meant it to.

Scoring 14,500Nm/degree in BMW’s torsional stiffness test, the M Roadster is pretty stiff for an open car, and despite its wide 225/45 and 255/40 rubber on 8.0J and 9.0J x 18-inch alloys rubber, scuttle shake on poor roads in minimal. Even so, it does not come close to the Coupé’s impressive 32,000 Nm/degree, which is more than double the Roadster’s rigidity.

This extra structural strength means that the engineers have been able to dial in much more aggressive suspension settings knowing they will be maintained better even under high lateral loadings on a racetrack.

The springs and dampers are a completely new set-up. The front spring rates are increased by about five per cent, but because the rears are progressive rate it is hard to put a comparative number to them. It is easier to say that that the first half of their travel is similar in rating to the Roadsters, but once that point is reached, their rate rises faster. The characteristics of the Sachs/Boge dampers are calibrated to match.

What makes the Coupé more pointy however, is the combination of a quicker 12.8:1 steering ratio (Roadster 13.7:1) and a 1mm thicker rear anti-roll bar, which combine to mitigate some of the understeer you feel in the Roadster. “Because the Coupé shell is much stiffer, we can load the chassis more on initial turn-in and so improve overall handling response,” explained BMW M’s chassis guru, Gerhard Richter, who is also one red hot test driver.

That quicker steering is most welcome especially as it makes the car more responsive, yet never twitchy in the way that a Ferrari 360 Modena so uncomfortably is.

However, the stiffer suspension also makes the Z4 M Coupé a restless partner on less than smooth roads. Where the Cayman S flows from apex to apex, its PASM active damping riding out bumps with authority, the Z4 Coupe’s firmer ride, coupled to the hair-trigger replies from the motor in Sport mode, is a recipe for a car that makes your adrenal glands work overtime.

Playground

It all becomes clear on the racetrack though, and to make sure we got the message, BMW provided a playground in the form of the famous 4.36km long Estoril Circuit. Damon Hill set the lap record here in 1993, and three years later Jacques Villeneuve won the last Portuguese Grand Prix before the track had its F1 calendar slot revoked.

In the Z4 M Coupé, this relatively twisty track is a third gear effort for the high-revving M car, and you only take fourth in two places. Its chassis balance is exquisite and the car’s extreme rigidity, 50/50 weight distribution, quick steering and ample power make it a drift king’s dream car. That of course, is not the fastest way around a given bend, and so we stop larking around and concentrate on setting a fast lap.

With a couple of reservations, the Z4 M Coupé is in its element on the track. Quicker steering and thicker rear anti-roll bar not withstanding, initial turn-in is still nose led, so getting your entry speed to a slow bend right down to ensure the front tyres have maximum grip on the way in will pay dividends on the way out.

The high level of mechanical grip allows you to carry massive speed through the more open corners. There is one open bend leading onto a straight that you can approach flat in third, and snatch fourth just before turn-in, nailing the throttle all the way through as you drift past the apex, aimed at the exit kerb on the far left. That is immensely satisfying.

The final corner before the pit straight is a great one too. A long, almost constant right-hander, this is the bend where Villeneuve famously passed Schumacher on the outside. Best taken in fourth to reduce loading on the chassis and drivetrain, we tucked in tight to the right-hand kerbs, and balanced the car on the edge of adhesion with a steady 94mph showing on the clock all the way round.

Hard-core

In the final analysis, the Z4 M Coupé sits in a niche of a niche in the sports coupe marketplace, and will only appeal to a small segment of really dedicated hard-core drivers. BMW itself recognises this by admitting to a very low production volume.

But I think you'll like it.