Max oversteer- BMW M Roadster [review]


Although BMW intended the Z-3 to be an upmarket MX-5 contender, the scenario quickly changed when Porsche and Mercedes Benz decided to unleash their Boxter and SLK roadsters. Suddenly the 1.9-litre engine was not enough and the 2.8-litre straight six was rushed to the rescue. Not contented, the M department of BMW also made suggestions to the board for consideration.

Somehow during the gestation stage the M-engineers had managed to convince the designers to allow just enough space for their future M-Power engine. The designers were obviously convinced as the M-Roadster found its way into last year’s Geneva Motorshow as a teaser. Less than a year later we were driving the M-Roadster in Spain around the country roads surrounding Jerez and Spain’s F-1 circuit.

Now the M-Roadster claims the throne with the 321 Bhp M-Power engine that also powers the famed M-3. Remarkably, the 5-speed manual gearbox also fits snugly under the Z-3 bodyshell without alteration, albeit by the width of a toothpick. Unfortunately the enthusiasts’ 6-speed box would not fit and fortunately neither would an automatic. Frankly the 5-speed box is more than enough as the M-Roadster is overwhelmed by the massive power developed by this high tech dual VANOS, 24 valved, twin cammed straight six. Besides, the 6th ratio is a tall overdriven cog to reduce engine speed at high speeds and the roadster being naturally noisy at speed was not in dire need of this extra gear.

According to the development engineers who were on hand, the M-Roadster has been tuned for road use and its sheer ability on the race track just happens to be a part of its incredible capabilities. From the moment the car was started, it is clear that this is no ordinary roadster. The deep gruff exhaust and the metallic rasp on the overrun could only mean a high capacity, free flow exhaust system that is necessary to cope with the exhaust of a 300 plus Bhp motor.

However sitting in the M-Roadster, is nothing special, like any current state-of-the-art roadster, it asks nothing much of the driver. Everything falls to hand neatly and operates with deceptive ease and precision. Snicking the gear into 1st is so very easy, aided by the light clutch action. The slight stiffness of the accelerator pedal hardly gave a fitting prelude to what was about to be unleashed. The M-Roadster moves off really effortlessly with just a touch of the accelerator but punch open the throttle in 1st gear and one better have empty road not just in front but beside you as well. The traction of the 245/45 ZR 17 Michelin SX’s behind is completely overwhelmed. Traveling sideways seems like the order of the day as the rear end snakes around , tortured by the massive 350 Nm of torque the engine dishes from as low as 3250 rpm. The torture stays as the engine will spin up to a heady 8000 rpm, passing the power peak at 7400 rpm.

Even swapping to 2nd does not relieve the wheelspin as there is still enough torque to overcome the rear traction. Part of the reason is the cars light weight. The roadster weighs in at a lithe 1350 kg and less than 50% of it helps plant the rear end to planet earth while the 321 Bhp M-Power engine attempts to launch it. To help traction, there is a limited slip differential at the rear axle which has a 25% locking action. This of course helps but even the combined traction of both rear tyres cannot hold back the fury of 321 horses. But two gears is all it takes to get to 100 kph from standstill, all accomplished in a scant 5.4 seconds, still limited by available traction. When turned in for any corner in second gear , it is advisable to use less than two-thirds of throttle or be prepared for power oversteer. On the other hand, back off in mid corner and the tail will attempt to move out, tightening the line with a tendency to oversteer.

There is no traction control device, the M-engineers were quick to point out that this is a pure roadster and as the M-Philosophy goes, all the judgment is left to the driver and his right foot. Drive gently and the M-Roadster feels little different from the Z-3, but drive it the way it looks and suggests, one will need absolute concentration as we found out during the test route which snaked through the mountains. The corridor between oversteer and understeer is relatively narrow considering the performance potential wrought by the M-Power engine so judicious application is always the order of the day.

Thankfully the steering is quick and direct if lacking in tactility. Its assistance level disguises the performance vehicle that it really is. It asks and suggests nothing of its hidden potential. Remarkably, the Z-3’s chassis did not need any reinforcement as it was designed to be sturdy enough and there was just a hint of scuttle shake. Considering its weight is just 1350 kg, the BMW designers have done very well indeed. The only changes are a slight lengthening of the wheelbase, a widening of the rear track and fenders to accommodate the huge tyres, all done at BMW’s Spartanburg facility in the USA, including the fitting of the M-Power engine. The rear suspension comes from the previous 3 Series, a semi-trailing arm system known for its exciting tail-wagging antics. Of course it is well tied down now, but the newer Z-suspension would have been preferred but the M-Roadster was not entirely based on the latest 3-Series.

Yet, having said that, the M-Roadster handles rather well as our drive around the Jerez Formula One race track demonstrated. There was enough power to steer the M-Roadster by throttle around the track and just enough grip to drift around all the sweepers and hang on around the hairpins. For the consummate driver, this roadster does all this and more. In good hands it provides a blistering pace, but it is no pussycat, the M-Roadster commands total respect for it will punish those lame of foot or judgment.

In one swoop BMW have knocked the opposition for a six. There are no comparable roadsters currently available that can take on the M-Roadster, the Boxter even in the proposed 3-litre guise will probably produce 250 Bhp as their current 911Carerra S has 285 Bhp. The SLK was designed to have 4-cylinder powerplants and the 2.3-litre Kompressor is good for 193 Bhp and even the proposed 3-litre V6 will end up with around 210 Bhp. It will certainly take a lot more development on the part of the competitors to catch up with the current King of the Hill, the BMW M-Roadster.

Fast Facts

BODY: 2-Door Cabriolet, 2-Seater

ENGINE: 3.2-litre, Straight Six, Dual VANOS, 24 Valves, DOHC, Max Power: 321 Bhp @ 7400 rpm, Max Torque: 350 Nm @ 3250 rpm.

TRANSMISSION: 5-Speed Manual Gearbox.

STEERING: Power Assisted Rack and Pinion Steering

BRAKES: Ventilated Discs front and rear, Servo Assisted, Aluminum-Steel Composite Discs

SUSPENSION: front: MacPherson Strut, rear: Semi-Trailing Arms and unitary spring-damper units.

ACCELERATION: 0-100 kph: 5.4 seconds. 0-160 kph: 12.1 seconds

TOP SPEED: 250 kph, Electronically limited by BMW

FUEL CONSUMPTION: Urban Cycle: 16.6 L/100 km, Highway: 7.9 L/100 km



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