BMW M4 CS 2017 Review - International

BMW’s M4 forced us to ask uncomfortable questions about M. The most uncomfortable of them was whether it still knew how to make light, lithe, nimble sporty cars.

The M4 was, intrinsically, a very good fast car, but it wasn’t the custodian of the E30 M3 mantra of using corners to make up for any straight-line losses and delivering fun in front of anything else people might expect of an M3.

The M4 felt more like a junior M6, more like a baby grand tourer than a two-door M3. There’s a big, strong, sweet-spinning engine, for sure, and a secure, fast chassis. And, it must be said, a luxurious interior and a comfortable ride. Maybe too comfortable.

M developed the hard-core M4 GTS presumably just to show us that its chassis was capable of giggles and hoots, but it was microscopically limited in scope.

But, now there’s this, the M4 CS. And it’s really very good, addressing most of the M4’s headaches as M tries its best to make a GT car a sports car.

While the engine isn’t at the core of the issues that rob the M4 of its E30 M3 lineage, M has still given the M4 CS more of it. The 3.0-litre inline six eschews twin-scroll turbochargers for a pair of variable-geometry units and they’ve now been amped up to punch out 338kW of power and 600Nm of torque.

Those numbers add 7kW and 50Nm to the M4 Competition Package’s output figures and M claims the rear-wheel drive coupe punches to 100km/h in a claimed 3.9 seconds, on its way to a 280km/h top speed.

Those numbers aren’t far short of the M4 GTS, which offers 368kW and 600Nm, hits 100km/h in a claimed 3.8sec and has a 305km/h top speed.

But the standard M4 has never lacked for straight-line gristle. It’s lacked an enthusiasm for changing direction quickly. That’s changed, as evidenced by a 7:38 Nordschleife lap time, despite the M4 CS being softened off to the point where it’s not a pure track car, but a road car that’s happy on the track, just like the E30 M3.

The rear wing is just a carbon-fibre Gurney flap on the bootlid and there’s a fixed front splitter. And for all its not-a-track-special status, our test car had the optional bolt-in half roll cage.

At 1580kg – more than 100kg up on the race-ready, rear seatless M4 GTS -- it undercuts the stock M4 dual-clutch by 32kg, with M using a carbon-fibre roof (which saves 6kg alone), bonnet (25 per cent lighter than a steel one) and boot to pull weight down.

But it’s the work on the suspension tuning, the geometry and the stiffness of the rear-end that have made the difference. Where the standard M4 manages corners nicely, the M4 CS hunts them down and attacks them, with glee.

Firmer than the M4 Competition Package and softer than the GTS, the CS delivers the same Comfort, Sport and Sport+ steps as the standard car, but its feet land on different rungs when you push the button.

The differences are noticeable as soon as the car starts rolling, but unavoidable when it starts yawing towards an apex. The steering wheel is still too fat, settling blobbily in your hands and failing to invite initial intimacy in the way an Audi RS wheel does, but the improvements in the electric power steering’s set-up put that to rest.

There’s more feedback and more directness in the steering now, and the calmer back-end means you get more accuracy at the front-end with a reduction in nervousness on direction changes at the back. Talk about goal conflicts.

It invites confidence and joy, where the M4 invites respect and progress. The (optional) carbon-ceramic brakes are unstoppable, capable of absorbing ferocious punishment while retaining a high, strong, stable pedal position.

While they have genuine, imposing strength from speed, the six-piston callipers also allow for fine, nuanced mid-corner adjustments, largely because the high pedal is so firm, all the time.

There is no more waiting for the odd moment after turn-in with the standard M4, the one where you’re waiting for the body to move across on the rear springs. That doesn’t happen, because the body control is astonishingly good.

You still feel as though you sit too high, above the roll centre of the car in the heavily bolstered, strongly supportive driver’s seat, but that no longer feels disconcerting in any way, under any circumstances.

There’s a flatness to the car’s cornering stance that invokes reassurance, yet the thing still manages to absorb every bump and to punch out of any shape of bend without being tossed around.

It’s like it’s been tied down hard, yet softened when it needs to be without affecting it. The idea of that combination is odd, but in a good way, like a chocolate porter in winter.

It’s so good at every angle of corner and every bit of topography we found that we got out of it looking at the Michelin Pilot Sport Cup 2 265/35 R19 front and 285/30 R20 rear tyres with involuntary nodding respect, which seemed odd in hindsight. These are wrapped around custom forged wheels that are just 9kg and 10kg respectively.

The extra grip of the CS is matched by extra freedoms and accuracy from the skid-control system. You can hardly pick when the computer is intervening in its Sport and Sport+ modes and you don’t seem to lose any speed anyway, so you don’t bother ever turning it off.

All of these upgrades leave the M4 CS as a car that invites you to be aggressive with it, in the vain hope that you’ll make it lose its manners or find the point at which it stops being fast and fun. And you don’t find any of it, just more dollops of giggle factor.

It’s still more chuck-and-go than chuck-and-slide, but that doesn’t make it less fun. The way it punches out of second-gear corners on full throttle, over bumps when the cornering has already loaded up the suspension, is truly astonishing.

On any other car, the upgraded steering would star, but here it’s the back-end of the car that keeps climbing in your estimation, with an ability to ride well, tie down any float and to explode out of bends all at the same time.

BMW claims it gets a downforce boost from using the M4 GTS’s rear diffuser, but that’s clearly more decorative than useful, with the active differential doing much more of the work.

It’s a far better machine on winding slow corners, too, rotating around its axis either under brakes, under a bit of throttle or even just leaning on the front tyres.

It’s still more than 1500kg, but it feels 200kg lighter than that in the slow stuff, without losing the precision it always boasted at high speed. Lift off in a fourth-gear bend to change direction and it will calmly nudge its nose towards the apex, lean on both outside tyres simultaneously and push on through.

The engine is strong, but it’s not the highlight, even if it now crackles on every Sport and Sport+ mode lift-off like you’re running over bubble wrap.

Oddly, this is louder from outside the car than inside it. We had two cars running line astern and I could hear the lead car’s crackle even with my windows up, while I had to listen for my own.

There never seems to be an end to the engine’s mid-range strength, which is its glory and its curse at the same time.

It reaches its torque peak at 4000rpm and keeps grinding out 600Nm until 5380rpm and then it hits the power peak at 6250, but keeps revving to 7600rpm before you need to pull the right-side steering-wheel paddle back for another gear.

Pushing the inline six out to the rev limiter is a nice thing to do because it’s smooth, sweet and sounds deep down low and more metallic up high, but it doesn’t rise to a crescendo in the way the classic inline sixes do.

It’s far easier to pull out of corners in a higher gear, with the tacho needle waiting for you as low as 3500rpm, because the monster torque means it’s no slower that way and it’s also more stable. And one less shift on the way in to a corner and on the way out again gives you a lot less to do.

M also rated the engine’s oil-circulation system to keep operating at 1.4g of lateral acceleration, because that’s what the rest of the car is expected to put it through.

Then again, it’s even easier again just to leave the car in Drive and let its own brain do all the shifting, because it’s as fast at it as you are, and does it in just about all the same places you would have done.

It’s mightily fast, and the torque means it can be mightily fast all the time, but it’s not aurally thrilling in the way it does it, apart from the off-throttle theatrics, though it’s never bad or boring.

There are so few unwanted vibrations that it’s almost as refined as a limo, and the depth of the engine note is more Johnny Cash than the last CSL’s torn corrugated iron sheets.

The seven-speed dual-clutch has a flaw, though, and that’s in the middle mode of its three steps. The first is for comfort, gently slipping through changes, while the upper level is short and sharp, snapping out blistering shifts with barely a crack.

But the middle mode is altogether less convincing, with light-throttle shifts delivering unwelcome head-toss backwards and forwards.

The trick part of the entire package is that, while BMW insists it’s a firmer, more aggressive car than the M4 or the M4 Competition Package, the reality is that – unlike the rock-hard GTS -- the ride is just fine, thanks very much.

It doesn’t seem to lose anything significant in bump absorption for comfort (not to mention for power-down or turn-in), even with the damping rate in the middle setting.

The only drawback is a slight resonance in the cabin at about 3800rpm on light throttle. Other than that, it doesn’t lose much to its lesser cousins.

The cabin is dotted with Merino leather and Alcantara (the seats, the steering wheel), while it retains niceties like climate-controlled air conditioning, the brand’s top-level HiFi Professional sound system and its Professional sat-nav unit.

If you doubted its light-weight bona-fides, the door skins, made from compressed natural fibres, and the cloth pull loops that replace the door-handles will remind you every time you close the door.

M also hooks this all together with BMW’s Laptimer app, if racetracks are your thing.

2017 BMW M4 CS pricing and specifications:
On sale: October
Price: $180,000-$200,000 (estimated)
Engine: 3.0-litre, in-line six, twin variable-geometry turbochargers
Output: 338kW/600Nm
Transmission: seven-speed dual-clutch, rear-wheel drive
Fuel: 8.4L/100km
CO2: 197g/km
Safety rating: N/A