I suspect that this may come as a shock to some — at least those who worship the spinning propeller unabashedly — but BMW’s M badge, as iconic and colourful as it may be, is no guarantee of race-track prowess. Oh, it pretty much promises a plenty sporty ride, but the company’s M240i, for instance, is no track weapon. Its 382-horsepower turbocharged 3.0-litre is (sort of) willing, and its steering precise enough for parking-lot autocrossing. But, around a big, bad race track — and tracks don’t get bigger or badder than the 3.957 kilometres formerly known as “Mosport” — its brakes are, in the words of my favourite Scottish comic, Kevin Bridges, “complete shite.” They’re barely good for a lap and a half — and that, unfortunately, includes the warm-up.
An X3 M Competition, on the other hand, might have decent brakes, but an SUV, despite the “Competition” badging, is never going to be a sports car. Even an M4 Competition xDrive, seemingly the ultimate in road-going BMW coupes, gets a little twitchy flinging into Canadian Tire Motorsport Park’s (CTMP’s) notorious blend, downhill, off-camber double-apex Corner Two. Sure, it more than gets the job done, but you’re always reminded that it is, despite that “Competition” affectation, really a street car.
Not the M4 CSL, whose only purpose it would seem, is to drive at Ron-Fellows-like speeds around the circuit where Canada’s most successful NASCAR racer made his bones. Oh, there is a pretense to street-worthiness, but, in reality, there are no seats in the back, and the stock tires are short-lived Michelin Sport Cup Rs. In all regards, the M4 CSL is a track weapon, its 7:20.2 the fastest any production BMW has ever circumnavigated the famed Nordschleife.
2023 BMW M4 CSL Photo by BMW Canada
Part of the reason for that, as you might imagine, is that the M division has breathed pretty seriously on BMW’s ubiquitous 3.0L inline-six. Already twice-turbocharged in stock form, the CSL takes thing up a notch — or three! — by raising its maximum boost to an incredible 30.5 psi. That’s double the 15 or so psi typical of family-sedan turbos, a 25-per-cent increase over the 24.7 psi boasted by the M4 Competition, and, not so long ago, would have been typical of some form of outrageous drag-racing monster that grenaded its oil-soaked innards every quarter-mile or two. Besides being a technical marvel, the CSL’s 3.0L pumps out an inspiring 543 horsepower, 40 hp more than the Competition and a whopping 161 hp more than a garden-variety M440i.
And, Lordy, does she motor. CTMP’s unending back straight and high-speed corners just eat horsepower, making normally speedy sportsters feel, well, sorta slow. Not the CSL. Its 3.7-second sprint to 100 kilometres doesn’t begin to describe the drama of hammering out of tight-as-a-traffic-circle Turn Five and then pulling all the way to the far end of the kilometre-long back straight. Fast enough — though not quite at its 307-kilometre-an-hour electronically-limited top speed — that, like a really good motorcycle, things get a little light over the second of the Andretti Straight’s two humps. Throw in the wail of an inline-six — the most sonorous of piston combinations — screaming through a titanium exhaust into a cabin all but devoid of sound insulation, as well as a quick-shifting dual-clutch eight-speed, and you have internal-combustion at its finest.
Now, here’s the thing; all that spark-ignited sturm und drang is actually the CSL’s least impressive trait. Much more impressive — especially if you’re an experienced track warrior — are BMW’s latest carbon-ceramic brakes, the best binders I’ve tested this side of a McLaren Senna. Compared with the M4 Competition, for instance, the CSL arrives at corners only marginally faster, but you can brake so much deeper into the corners, it’s mystifying. As much as the engine kinda, sorta does pin you back in your seat, the 400-mm carbon-ceramics — squeezed by some ginormous six-piston front calipers, really do threaten to pop your eyes out of their sockets.
In fact, my favourite part of the whole day was not flying down the back straight at breakneck speeds, or squirming through off-camber Turn Two as Michelins and tarmac competed in a variable-traction tango. A lot more fun was holding on to the brakes as long as I dared into CTMP’s diabolical Turn Four — whose pavement is so stressed that it is Mosport’s most-replaced surface — only to use those tarmac-chewing ceramics to guide me round to the apex. Every mash of the brake pedal was a giggle, every slither of tires a miracle of car over squid. You’ll buy the CSL for its 543 horsepower; you’ll love it for its eye-popping brakes.
2023 BMW M4 CSL Photo by BMW Canada
2023 BMW M4 CSL Photo by BMW Canada
2023 BMW M4 CSL Photo by BMW Canada
2023 BMW M4 CSL Photo by BMW Canada
2023 BMW M4 CSL Photo by BMW Canada
2023 BMW M4 CSL Photo by BMW Canada
2023 BMW M4 CSL Photo by BMW Canada
2023 BMW M4 CSL Photo by BMW Canada
But, you say, BMW offers the same brakes (as an option) in the M4 Competition. Too true. On the other hand, the CSL — which stands for “Competition, Sport, Lightweight,” by the way — is a whopping 108 kilograms (240 pounds) lighter than the M4 Competition. The seats alone – rigid carbon-fibre racing buckets that grip your lower lumbars like they were designed by Spanx — are responsible for 24 of those kilos (53 pounds) all by their lonesome. Tossing the rear seats saves another 20 kg. Throw in a carbon-fibre hood (“M” badge molded into its underside, natch) and roof for another 10.8 kilograms, the loss of the aforementioned sound-deadening materials (worth another 15 kilograms) and another 20.8 kilos for the carbon brakes and lighter wheels, and you have severely reduced the load on both brakes and engine.
It also taxes the chassis less. Here again, everything is about track-worthiness, little attention paid to creature comfort. Not only has the M4 Competition’s xDrive AWD system been jettisoned in favour of sharper-turning rear-wheel-drive, but a multiplicity of suspension attachments have been stiffened and normally-squishy rubber replaced by rigid steel bushings. Just the thing for direct feedback on how the tires are feeling through the tricky Corner Five; not so much at absorbing the annoying little cracks in the road that set your steering wheel a-wiggle.
2023 BMW M4 CSL Photo by BMW Canada
But they don’t compare to what BMW has done to the suspension. More rigid all around, in Sport+, the CSL dampers render the ride princess-and-the-pea sensitive. Or in the words of the immortal Georg Karcher, they’re “devoted wholly to shock, not absorption.”
In fact, because the track was so cold — CTMP’s 6-deg-C well below the optimum operating temperature of the Michelin Cup 2s — BMW “recommended” that we not stress the Pilot Sports with the full Sport+ stiffness. Something about the damping fluid already being too thick from the cold temps.
Enthusiasm always victorious over common sense, I soon touch-screened the dampers into (almost) full hydraulic lock. And never has a BMW cornered so flatly or steered so directly. Long famed for judicious steering, this is the Ultimate Driving Machine’s, well, ultimate driving machine. The back end may wiggle under power — and when clamping on the those big front binders — but the front tires just stick like glue. I can’t remember an easier time hitting all of Mosport’s apex markers. No matter how late I left my braking or how injudiciously I yawed at the steering wheel, the big 275/35ZR-19 front Michelins — even if they, again, weren’t the full-zoot Cup 2s — didn’t budge an inch.
2023 BMW M4 CSL Photo by BMW Canada
But, that’s not all a result of stiff suspension and sticky tires. It may be a sign of my geekiness — one never really gets rid of the ‘pocket protectors’ one acquires with an engineering degree — but the CSL boasts the mother of shock-tower bracing. A multi-beamed structure connecting the top of both shocks, the CSL’s brace is seemingly so robust that it easily could serve as the frame for a small motocross bike when the M4 eventually gets recycled. And, when it comes to precise steering, shock-tower stiffness is next to Godliness. Perhaps more importantly, now that BMW hides all its engines under layers of featureless plastic and scrupulously-bundled wiring, the shock brace is probably the most visually impressive thing under the CSL’s carbon-fibre hood.
Having read all these accolade and superlatives, maybe you’re wondering if I’m saying the new M4 CSL is the perfect BMW.
Not quite. As a daily driver, I suspect that all the things that make the CSL so fantabulous on a high-speed track are going to make it less than desirable over city streets. Rigid suspension bushings and creased tarmac do not get along. “Wholly shocking, not absorbing” dampers bring little joy over moon-crater-like potholes. And the steering so light and precise on CTMP esses might get a little nervous on a rutted Canadian highway.
And sadly, that’s where, I suspect, most CSLs will end up. Priced at $166,500 and with only 40 or so coming to Canada, this ultimate in BMW track-weaponry will probably remain the purview of old money, folks more likely to compete in the Grand Prix de Yorkville — three times round Toronto’s toney Yorkville and Cumberland Avenues and then into Sassafraz to collect admiring glances — rather than pull off any full-blooded screeching of tire. And, with CTMP but a 45-minute scoot away, that’s truly a shame.
Keyword: Track Test: 2023 BMW M4 CSL