BMW is thought to be readying a lightweight, range-topping version of the new M4 coupé, and reports suggest it could revive the hallowed CSL nameplate.
The CSL moniker – it stands for Coupé Sport Leichtbau (lightweight) – was first applied to the ultra-exclusive E9-generation 3.0 CSL sports saloon in 1972 and revived in 2004 for a lighter version of the E46-generation M3. Since then, the lightest and fastest versions of BMW's sports cars have been badged Competition, GTS or simply CS, according to their positioning.
An anonymous source on the Bimmer Post forum suggests the M4 CSL will enter production in July 2022. Taking the previous CSL cars as an indication, we would expect a run of around 1500 units.
Irrespective of the production car's official name, a similar treatment to the recently revealed M5 CS is likely, meaning it will prioritise weight loss and enhanced dynamic performance, with a more overt track focus than the standard M4 Competition.
Power from the M4's 3.0-litre twin-turbocharged straight six could be bumped up over its standard 503bhp output, cutting the 0-62mph time down from 3.9sec while nudging the 180mph top speed up slightly. But the model's track focus means it will almost certainly gain an overhauled suspension system and shed a significant amount of weight.
The M5 CS weighs around 70kg less than the standard Competition, rides 7mm lower on uprated dampers and wears hardcore Pirelli P Zero Corsa tyres. Carbon brakes are fitted as standard, and an aggressive, aero-focussed body kit differentiates the the model from the Competition version. New images of what is thought to be the M4 CSL suggest it will adopt a similar set-up.
It's unclear how BMW could reduce the M4 Competition's 1725kg kerb weight, given that it already uses carbonfibre for the roof panel (a carbonfibre roof was one of the E46 M3 CSL's headline features). Like the M5 CS, however, it stands to swap its bonnet, door mirrors and bumpers for carbonfibre items and will likely make liberal use of carbonfibre and Alcantara throughout the cabin, in line with its track billing.
More information on this prototype will likely emerge in the coming months, but an official unveiling by the end of the year is likely. Expect a significant premium over the M4 Competition when it launches in 2022.