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BMW M3 and M4: which is best?

  1. They’re meant to be identical, the M3 and M4. You’re not meant to be able to tell them apart. Well, aside from the stunningly obvious fact that one is a coupe and the other a saloon. The suspension settings differ fractionally, but only to take account of the M3’s extra 23kg and make them feel more similar. They have identical track widths, too, even though the standard 4-Series is 40mm wider than the boggo 4dr. This means the saloon M is now 80mm wider than normal. Talk about stance. 

    We must talk about other things too. Chiefly turbos. The arrival of the new M3/M4 signals the death of the naturally aspirated M car. Yes, this does matter. M purists, the type who never saw eye to eye with the outgoing 4.0-litre V8 (too big), will not be appeased by the fact this fifth-generation car returns to the classic straight-six layout when it’s joined by a pair of high-speed spoolers. Turbos kill engine response and noise. 

    Pictures: Lee Brimble 

    This article first appeared in Top Gear magazine 

  2. Apart from that, we have a classic M. You can still have a six-speed manual gearbox (although 90 per cent won’t), the power makes its way out of the car along a carbon propshaft and through a clever differential to the rear wheels alone. It comes on 18-inch rims, although if you want the optional carbon-ceramic brakes (and you do), you also have to spec the 19-inchers. I’m not sure I’ve used a better set of ceramic stoppers. They’re a delight: precise, potent, one of the best things about a car that has a lot going for it anyway. 

    We’re on a road. The N2 to be precise. The idea is to get to grips with the M3’s habitability/drivability before switching to an M4 for the outer-limits stuff at Portimão race track. The trouble is, M3 on N2 is proving a winning combo. The road is, quite frankly, a joke. Roads like this shouldn’t be allowed. Far too tempting. It sweeps beautifully, elegantly, rhythmically northwards from Faro, maintaining height, delivering vistas – paradise for third gear. Well, it would have been third-with-occasional-flurries-of-second in the old car, and it could be third in the new one, but right now I’m in fourth. 

  3. Fourth works just fine. As long as you have 2,000rpm on the clock, the new M3 takes off. The mid-range is stellar, an effortless hurl, promptly delivered. Has BMW rewritten the rulebook for turbo engines? No, not quite. It has tricks, this engine, but the total eradication of lag isn’t one of them. Nor is a spine-tingling engine note. It makes noise, and a lot of it, but the tune is artificially amplified by the ECU and pumped in through the speakers. And you can tell. 

    But as a means of enjoying this road, I’m sold on the new M3. Sold on almost all of it. You can start with the basics. The seats are sculpted just so; you find everything exactly where and how you want it. There’s even a conventional handbrake. Our car has the double-clutch DCT gearbox. 

  4. I think the knob looks ‘meh’ and the low-speed manoeuvring is a bit tricksy, but apart from that it’s doing the job perfectly well. There are also buttons to alter the steering, engine, suspension, gearbox and stability. We’re leaving them alone right now. The traction control cuts in a bit, but, hey, we’re meant to be taking it easy, just cruisin’. 

    The M3 flows along the N2 so well I assume the road is flattering it – it is predictably well surfaced, after all. That’s until I see a hard-driven Punto yawing back and forth like a just-popped Jack-in-the-box. The BMW isn’t having to make much apparent effort. All the controls do as they’re told, when they’re told, and traction, suspension and composure are immaculate. I’m full of admiration for it, I feel warm towards it, it’s chuffing impressive, hard to criticise. I start thinking of its rivals. On this road, the C63 would be more exuberant, but its torque would get the better of its body control. An RS4 might be as fast, but it would be leaden in comparison. 

  5. The M3 has changed. The last-generation car’s pin-sharp, yowling V8 was so crisp and pure it gave the M3 a very distinct, almost edgy character. You had to drive it, to work with it, to know its strengths and frailties. It fired your soul. You don’t have to think about driving this one nearly so much. It’s a much more rounded proposition – its repertoire as broad and even as the torque curve that dominates the driving experience. To say that it’s M5-junior would be easy, but – mostly – inaccurate. There are similarities in the power delivery, of course, and it’s similarly quiet and placid on motorways, but the M3 is so much more agile and entertaining. I do have some reservations over the ride’s firmness on broken surfaces, but on the whole my concerns have been allayed. 

    It’s a tremendous road car: fast, poised, effortless. Does a turbo M3 work on the road? Yeah, it does. Time for the track. 

  6. What is it with this corner of Portugal? First the gorgeous N2, now the plunges and crests of the scintillating Portimão race track. The Yas Marina Blue four-door has been traded for an Austin Yellow two-door. The colours are better than those crass, clumsy names, but I can’t see either being a top choice in Britain. Out here, the harsh sunlight is pinging on the yellow paint, and the M4 seems to bathe in its own acidic halo. 

    But we need to venture beneath the skin again. For the first time on an M3, both front and rear subframes are solid-mounted to the central monocoque to increase stiffness. No bushings at all. Open the bonnet, and instead of a plain strut brace, a sinuous carbon-fibre construction artfully curves itself around the bay, strengthening the bonds between chassis, suspension turrets and engine carriers. I’m sure it’s not a coincidence that the carbon weave looks like snakeskin. 

  7. The suspension is completely bespoke, ditto much of the engine bar the capacity itself – M division has a lot of autonomy in the design and development of its cars. The driving ethos this time, besides how to enable the car to cope with an extra 110lb ft of torque, was to lower the weight. It comes in 80kg lighter than the old one. I bet you’re thinking the lion’s share of that comes from the smaller motor, but once you add in all the ancillaries (intercooler, turbos, pipework, etc), straight-six betters V8 by only 10kg. Instead, the weight savings are across the board: carbon propshaft saves 5kg, front seats are 7kg lighter (and, in a second snaky analogy, the seatback shape reminds me of a hooded cobra), rear bootlid saves about another 5kg, etc. And both are identical, don’t forget. Well, the saloon’s rear entrances mean it’s that bit heavier and has a fractionally more rear-biased weight distribution. 

  8. It’s clear the chassis is sharp. Not darty to the point of instability, just accurate and honed. Those are the hints we got from the M3 on the road – the faithful way it held a line, the positivity of the nose, the resistance to understeer. Has this been done to try to offset the bluntness of the turbo delivery? Because it is blunt. OK, so it revs surprisingly fast and the turbos don’t over-surge, giving you more than you ask for. They’re fast-reacting – you can meter out the power very precisely. 

    No, if I have a problem with this engine, it’s that there’s no reason to use high revs. BMW makes a great song and dance about the fact this turbo engine can rev to 7,600rpm, but when maximum torque is available at any point between 1,850rpm and 5,500rpm, there’s no pressing need to wait for the change-up lights to start flashing, no sense of anticipation to what awaits the driver beyond 7,000rpm. Not even better noise.

  9. In fact, there’s so much grunt on the exit of Portimão’s slow corners that second hits too hard, so you short-shift to third to smooth out the torque onslaught. Same goes for the top end of third. The M4’s ability to pile on speed and remain composed while loaded up with g-force is impressive. It’s only over the most abrupt crests that you get some squirm from the back axle. 

    The M4 really holds together on the track. The chassis is wonderfully predictable – there’s very little understeer, you can totally lean on the grip and if the torque surge does catch you out and the rear end starts to swing, everything is clearly telegraphed. The balance is fantastic and that clever electronic differential really knows its business. Tone down the traction control (MDM mode permits some lairiness), and you can string together clean, fast laps or exit each corner with some opposite lock. Makes you feel like a legend. 

  10. There are other buttons, too. Portimão is just about smooth enough to tolerate Sport Plus suspension (Sport is the sweet spot on Portugese roads). The steering is best in Sport wherever you are – it’s the Goldilocks mode, although the electro-mechanical system relies on weight and accuracy, not genuine transparency, to give you confidence. But we know the days of great steering are now past, don’t we? 

    But the Sport Plus engine mode is rather special. It has an anti-lag system. This, for me, is the M3’s party trick. If you lift off or brake, the ECU keeps the turbos spinning by managing the airflow and injecting a bit of extra fuel. And we mean spinning. The teeny turbos, each the diameter of a pill bottle top and driving three cylinders, don’t drop below 120,000rpm (they have a max speed of 190,000rpm), so when you get back on the power, they’re already there, forcing the induction. Look, it’s never going to have the almost shocking response and immediacy, let alone the yowling top end, that made the naturally aspirated M3s so utterly beguiling, but this might just be the best (and certainly most instantly responsive) turbocharged engine I’ve come across. 

  11. Weirdly, if the M4 has a weak point on the circuit, it’s the same ceramic brakes that I praised on the road. It’s nothing to do with their power, and they don’t fade, but the ABS is more active than it needs to be, the pedal travel longer. 

    Is there a detectable difference between coupe and saloon? At the risk of searching out pointlessly small differences in order to make myself look more chin-scratchingly knowledgeable, yes, I think there is. I drove the M3 on track too because, well, you would, wouldn’t you? It felt a bit more flighty over crests, and the merest fraction looser at the back. Put it down to the marginally higher centre of gravity, the tiny rearward weight shift. Or perhaps I’m searching for differentiation where none exists.

  12. Both are good cars. Exceptional cars, in fact. I’m dismayed that BMW has stepped away from natural aspiration, but I understand the reasons it’s had to, and if I’m honest the end result is better than I’d expected. And that’s not damning it with faint praise. Yes, some of the purity and thrill has inevitably been lost, but the M3 is still on the right path. 

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