Hardcore BMW M4 CSL brings 542bhp, sheds 100kg

BMW has revived the hallowed CSL name for the first time in nearly two decades for a highly strung and stripped-back new variant of the M4 coupé - arriving exactly 50 years since the legendary 3.0 CSL was launched. 

Priced from £128,820, the BMW M4 CSL will be limited to 1000 units – just 100 of which will come to the UK – and is more powerful than any BMW M3 or M4 variant yet produced, gaining a power boost of 40bhp over the current range-topping BMW M4 Competition.

It's said to be the fastest BMW road car to lap the Nürburgring, with a time of 7min 15.677sec. 

Power comes from the familiar B58 twin-turbocharged straight-six engine, which has been tuned to produce 542bhp at 6250rpm and 479lb ft of torque at 2750rpm, shaving the 0-62mph sprint time slightly to 3.7sec, and the 0-124mph time to 10.7sec.

As in the standard M4, power is managed by an eight-speed M Steptronic gearbox, which sends power to the rear wheels exclusively.

Shorn of its rear seats and with a raft of other weight-saving measures, the new M4 CSL drops around 100kg in weight from the standard M4 to tip the scales at 1625kg - just 40kg more than the hardcore GTS variant of the previous-generation M4.  

Around 21kg has been saved with modifications to the chassis, including the addition of lightweight ceramic brakes and bespoke lightened alloy wheels, springs and struts. The bonnet lid, meanwhile, is now made of carbonfibre-reinforced plastic. 

Inside, M carbonfibre bucket seats cut the overall weight by 24kg, while the removal of the rear seats and seatbelts saves a further 21kg.

With those adjustments in mind, the M4 CSL achieves a power-to-weight ratio of 334bhp per tonne - only slightly less than that of the Porsche 911 GT3.

Under the skin, the M4 CSL benefits from a number of changes for improved dynamic performance. Adaptive suspension is included as standard, while the ride height has been lowered by 8mm for improved aerodynamics. A pair of 19in wheels feature at the front and 20in wheels at the rear. 

The CSL also features a composition of cast aluminium front-end strut braces, with individually-tuned axle kinematics, dampers, auxiliary springs, anti-roll bars and bespoke tuned wheel cambers, and drivers can tailor the CSL’s grip levels with a ten-stage traction control system which caters to differing track surfaces and tyre temperatures. 

The most obvious design changes are at the front of the car, with a bespoke version of the M4’s kidney grille and more aggressive air curtains and front splitter. There is a bespoke rear wing boosting downforce, too. 

BMW M’s racing pedigree is also on show on the inside of the car. The bucket seats can be adjusted only in a workshop, while the backrest angle is fixed. A six-point harness can also be fitted to each seat and there's a dedicated cubby for two racing helmets in the rear. 

Despite its track focus, the M4 CSL largely matches the standard M4 for in-car technology. Sat-nav, BMW’s intelligent personal assistant, smartphone connectivity, wireless device charging and a head-up display with M-specific options are all standard, as is a raft of advanced safety aids. 

The history of BMW CSL

The CSL moniker has appeared on several BMWs in years gone by, but the last model to gain a standalone CSL variant was the E46-generation M3 in 2003. Also powered by a straight six, the M3 CSL produced 355bhp and 272lb ft at 4900rpm, with power managed by an oft-lambasted SMG robotised manual gearbox. 

The CSL badge stands for Coupé Sport Leichtbau (Coupé Sport Lightweight) and was first worn by the E9-generation 3.0 CSL 50 years ago, which was built as a homologation special to allow BMW to enter the European Touring Car Championship. 

The formula hasn’t changed much, though. The 1972 car received a host of lightweight changes, such as a slimmed-down steel body and aluminium alloy doors, bootlid and bonnet. European examples also featured Perspex side windows.