BMW’s Nordschleife Star Ready for Track Day Heroes

Paul Myles

TU-Editor

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23rd May 2022

BMW has unveiled its fastest ever production road car to lap the iconic Nordschleife in Germany, the track focused BMW M4 CSL.

This tarmac-tearer lapped the infamous ‘Green Hell’ circuit at just 7:15.677 on the 12.8-mile track, with an official notarized time for the 12.943-mile circuit (the complete lap) of 7:20.207 – the best figures ever for a series-produced BMW car. Using a chassis based on the racing BMW M4 GT3, it enjoys a power hike of 40hp over the current BMW M4 Competition Coupé to 550hp and a host of meticulous weight-saving measures.

That power boost  is coupled to an extensive light-weighting exercise including carbon-fiber-reinforced plastic (CFRP) for body panel, chassis and interior components. The result is the special edition’s curb weight restricted to 1,625kg (3,575lbs) in standard specification in the German market, some 100kg (220lbs) lighter than the BMW M4 Competition Coupé. Overall performance is a sprint from 0 to 62mph in 3.7 seconds and 124mph in just 10.7 seconds – 1.8 seconds quicker than the BMW M4 Competition Coupé. Top speed is an electronically limited 190mph, begging the question that the car’s aerodynamic package is the chief reason for such a bizarrely high speed limitation.

Engine

Power was boosted by increasing charge pressure at the same time as making model-specific tweaks to the engine management. Yet this potent version of the 3.0-liter engine claims improved efficiency with WLTP-calculated fuel consumption of up to 28.8mpg (23.9mpg US) and CO2 emissions as low as 222g/km.

The straight-six engine has been adapted from racing car machinery and is focused squarely on high rev speeds and maximum power delivery. The crankcase’s sleeve-free, closed-deck construction helps to make it extremely rigid, paving the way for very high combustion pressures that boost power output. The free-revving performance is aided by a twin-wire-arc-sprayed iron coating for the cylinder bores and the forged lightweight crankshaft, while its torsional resistance enables it to handle extremely high levels of torque.

The M-specific components also include the cylinder head with 3D-printed core. This additive manufacturing process enables geometric forms to be created that are beyond the capability of conventional metal casting techniques. As a result, the coolant duct routing could be improved while also reducing weight.

Two mono-scroll turbochargers supply compressed air to cylinders 1 – 3 and 4 – 6 respectively while an indirect intercooler is supplied by a low-temperature circuit and specially-designed compressors. The system operates at a maximum charge pressure upped from 1.7 to 2.1 bar. Engine management has been modified accordingly to guarantee the constant power delivery up to the top end of the rev range.

Operating at a maximum pressure of 350 bar, the High Precision Injection system ensures efficient mixture preparation and clean combustion. VALVETRONIC variable valve timing and Double-VANOS fully variable camshaft timing likewise form part of the M TwinPower Turbo technology. The engine is also fitted with a particulate filter to improve emissions.

The cooling system comprises a high-temperature and a low-temperature circuit. The indirect intercooler works using an electric coolant pump in the low-temperature system. The main module in the high-temperature circuit and two remote coolers in the wheel arches supply coolant to the engine block and turbochargers with the help of a mechanical water pump. An electric water pump and an electric fan can also cut in when required. The large openings in the front apron additionally channel the oncoming air to an engine oil cooler and transmission oil cooler.

The oil sump has two separate chambers and an integrated suction channel. An extra suction stage allows the map-controlled oil pump to draw lubricant from the smaller chamber, which steps in when extra capacity is needed. This ensures a consistent supply of oil at all times, even under extreme lateral and longitudinal acceleration on the track. A firmer engine and transmission mounting aids driver chassis feedback. The powertrain is coupled to an 8-speed M Steptronic gearbox.

Production will begin at BMW Group Plant Dingolfing in July 2022 and is strictly limited to 1,000 units globally, priced in the UK from £128,820 ($160,965).

— Paul Myles is a seasoned automotive journalist based in Europe. Follow him on Twitter @Paulmyles_