The famous badge is back, but is the stripped-out BMW M4 CSL worthy of continuing the bloodline? We get behind the wheel to find out
Words: James Fossdyke
Ironically, considering the ‘L’ stands for ‘lightweight’, BMW’s CSL badge carries with it a considerable burden. Not in terms of pounds and ounces, of course – the little logo on the boot lid barely tips the scales at all – but in terms of expectation. Despite seeing service on only a few occasions, the CSL’s history is long and illustrious. So the arrival of a new CSL model is not just a promise but also a rarity. And by happy coincidence, it’s also an ideal way to celebrate 50 years of BMW’s M division.
In the two decades that have almost passed since the M3 CSL was introduced, the BMW range has changed (by which we mean grown) significantly, and the obvious standard-bearer for the CSL moniker is the new M4. After all, the M8 would be too big and bulky for the name, and the Z4 is only available with a folding roof. So M4 it is, and the car has had to undergo some significant surgery as BMW bids to make it worthy of the badge.
Top of the agenda was weight reduction. The M4 Competition already had a CFRP roof, so BMW simply added a bonnet and boot lid made from the same material, shaving 1.2kg and 6.7kg, respectively, from the standard car’s kerb weight – even though the boot includes a more pronounced, M3 CSL-style spoiler. Then the back seats were ripped out, replaced with a massive parcel shelf and a luggage net to save 21kg, while carbon-fibre bucket seats were included as standard, saving a further 24kg. Add in lightweight alloy wheels, CFRP aerodynamic features and a carbon-fibre centre console, and you end up with a car that weighs 100kg less than a standard M4 Competition.
Unless, of course, you opt for the M Carbon bucket seats with enhanced comfort, which you should choose because you don’t want to spend £130,000 on a car with a fixed backrest and height adjustment that won’t work without the aid of a spanner. The enhanced comfort system gives you electric adjustment and easier access to the space where the rear seats would have been, but yes, they’re about 15kg heavier than the standard seats.
They do, however, improve comfort in a cabin that’s noticeably less comfortable than that of the standard M4 Competition. The new centre console means there’s no armrest – you get a pad against which you can rest your wrist while using the iDrive controller, but that’s it for touring comfort – and there’s much less leather on show. However, BMW has stopped short of stripping the M4 down completely. The navigation system, climate control and digital instrument cluster have all been retained, but there are some sporty additions.
Chief among these are the lashings of red trim and the Alcantara upholstery that’s liberally dotted around the place, as well as the light-up CSL logos in the seats. Hardly lightweight, we know, but a neat touch nevertheless. Despite the carbon fibre and sportiness, though, the quality remains impeccable. Every button feels just as well-engineered as it does in an M4 Competition, and the swathes of glossy carbon fibre are devoid of rough edges.
In fact, the M4 CSL feels better built than most supercars, and it’s considerably more practical. Yes, the back seats are gone, but they weren’t much use for grown-up passengers anyway, so losing them is no great hardship. Instead, you get a handy parcel shelf and the same 470-litre boot as the standard M4. That’s almost as much space as you get in the practical X1 SUV, albeit in a slightly less useful shape.
And BMW has tried to inject something of the supercar into the design. There’s lots of exposed CFRP on show, including the aerodynamic add-ons to the front apron. There’s red trim, too, accentuating the grille and the aero additions, while the lights illuminate in yellow to mimic GT racing cars.
But all this stuff is really superficial. Under the skin, BMW has worked hard on the mechanical components, squeezing an extra 40hp from the twin-turbo 3.0-litre straight-six and bringing the total to 550hp. That reduces the 0-62mph time by two-tenths to a mere 3.7 seconds, but the standard M4’s 155mph limiter is removed, freeing up the CSL to hit a top speed of 190mph – and an M4 Competition won’t manage that even with the M Driver’s Package.
BMW M’s engineers didn’t stop there. There’s a cast aluminium strut brace in the engine compartment to increase the body rigidity, and there’s a lightweight titanium exhaust that saves 4.3kg compared with the standard steel equivalent. M Carbon ceramic brakes have also been fitted, shaving another few kilos, while the gear ratio spacing is tuned specifically for the CSL. Perhaps more importantly, BMW has dropped the suspension by 8mm to lower the centre of gravity, tweaking the spring rates and damper response in the process, and the company has modified the traction control, which can be adjusted when the stability control is switched off. Settings 1 to 5 are the same as in the M4 Competition, but 6-10 are bespoke and are geared toward faster lap times.
Given that, it’s no surprise to find the CSL feels more focused than the standard M4, but the surprising thing is just how little difference the CSL package makes in day-to-day use. One of the beguiling things about the M3/M4 family is the subtle individualism of each body type, and the coupé is, predictably, the most hardcore of the three. Upgrading to the CSL turns things up to 10.5, rather than 11, but the standard M4 was already a brilliant sports car.
Nevertheless, the CSL has a greater air of intent, particularly with the active exhaust switched on. That gives the sound of the usually silky straight-six engine a bit more snap, which is matched by the slight increase in suspension stiffness. The M4 Competition is already firm, and the CSL can feel a bit too savage around town, but the ride settles down on faster roads, and it becomes the ideal sports car, feeding information into the back pocket of your jeans without shaking your teeth out.
Then there’s the steering, which in true BMW fashion, is sublime. There’s an immediacy to it, and the system manages to find a perfect balance between feel and smoothness. It’s as though it’s filtering data from the tyres, cancelling out the noise and allowing the important information through to your fingertips. And when you turn the steering wheel, the nose responds immediately, dragging the car into corners where it stubbornly remains, with tenacious grip from its Michelin Pilot Sport 4S tyres, even on greasy, autumnal roads.
Although the engine is rowdy when it starts, it’s deceptively smooth most of the time, offering progressive power delivery and sharp response. There’s an occasional sense that it’s straining at the leash a bit at low speeds, which adds to the excitement, but it doesn’t help the refinement very much. Not that the CSL is especially refined anyway. With soundproofing sacrificed to save weight, and wide tyres, quite a lot of noise seeps into the cabin, and you can clearly hear the sound of grit and mud smacking into the underbody. Within a few hundred yards, you can tell this is a more raw interpretation of the already raucous M4 Competition.
And that’s before you start fiddling with the M menu. As with the M4 Competition, you can tweak the behaviour of the engine, gearbox, steering and brakes, as well as deciding just how much slip you want from the rear differential. And you can configure each one individually to create your own presets, which are accessed via the little red “hot keys” on the steering wheel.
The suspension can be made firmer using the Sport and Sport Plus settings, and that impacts the already stiff ride slightly. There’s a little more jiggle and bounce over potholes and imperfections, which can make it intolerable on really rough roads, but the trade-off is an improvement in body control. While there’s still a small amount of sway in corners, the Sport and Sport Plus settings seem to make the body follow the wheels that little bit faster, particularly during rapid changes of direction.
Similarly, the sportier setting for the steering just increases the weight slightly, while the Sport setting for the brakes makes the pedal feel that bit more responsive. Both settings are an improvement on the already solid Comfort option, but, in truth, they don’t make all that much difference to the overall experience – we’re talking tweaks rather than wholesale changes. The settings for the engine and transmission, however, have a much more pronounced impact. With Sport mode engaged, the engine feels more eager, and it snarls a little louder, giving the car an even more menacing exhaust note, while Sport Plus turns the engine into a growling beast that jumps forward if you so much as breathe on the throttle pedal.
The gearbox comes with a choice of six settings, giving the driver a chance to choose between automatic and manual shifting, each of which has three settings to make it more or less aggressive. For us, the sweet spot is a combination of Sport mode for the engine, brakes and steering, with the suspension in Comfort mode and the gearbox operating as a manual unit with medium ferocity. That gives the car a lovely analogue feel as you snap through the ratios, the exhaust punctuating its increasingly noisy growl with flatulent pops, bangs and fizzes as you do so. The noise is key to the CSL experience, and the lightweight sound insulation helps to bring you closer to the action.
That action is pretty spectacular on the right road. BMW says the CSL is a more track-orientated model than the standard M4 Competition – it would undoubtedly be great fun on a track, as the Nürburgring lap time of 7:15.677 would suggest. But it’s still a fabulous road car, even though it’s difficult to explore its limits legally or even safely. But there’s so much grip, so much balance and such an addictive soundtrack and power delivery that every drive is an adventure.
Despite all this brilliance, the CSL has its problems and they aren’t insubstantial. For one, only 1000 are being made and just 100 are coming to the British Isles, each with a price tag of just under £130,000. And they’ve all been sold. So unless you’re among those 100 customers, you’re going to have to have the standard M4 Competition, which instantly saves you about £50,000. Sure, you get something less exclusive and less raucous, but otherwise, there’s no real downside. The M4 Competition is very nearly as capable and slightly more practical – you can put kids in the back, for starters – and while it might not be quite as brilliant on a racetrack or on a Sunday morning blast, it’s slightly better in the real world. You can even have it with an all-wheel drive for extra security in the wet.
Not that you’ll want to drive the CSL on anything other than the right road and the right day. Even the more upmarket seats are too tight and too hard to be comfortable in traffic or on long drives, and that, combined with the stiff ride, prevents the CSL from working on a road trip. Unless, of course, you’re prepared to stop every hour or so. So if you have great roads on your doorstep, the CSL is going to be a blast, but if you’re planning long drives to the Alps you’ll be better off with a standard M4 Competition.
The M4 CSL, therefore, is fabulous in and of itself, but it struggles to justify its price tag. And there’s worse to come because it doesn’t really deserve the CSL name, either. Yes, it was always going to be difficult to improve on the M4 Competition, and modern regulations make it tricky to build properly lightweight sports cars, but the CSL doesn’t really feel like a light car. It’s brilliant, but it isn’t especially light. Perhaps BMW really should have called this the CS. It’s a badge that carries far less weight and could be fitted to a car that really carries too much of that to properly justify the extra ‘L’.
