The cov­ers don’t come off BMW’S lat­est su­per­sa­loon un­til Septem­ber, but we’ve al­ready sam­pled its power – and its new driv­e­train

Evo - - CONTENTS - Adam Towler (@Adamtowler)

COR­NER ONE: GET ON the throt­tle early at the apex, a few de­grees of slip-an­gle from the rear, an al­most un­de­tectable squirm from the nose, an eas­ing of the steer­ing an­gle but lit­tle more. Sling­shot ac­cel­er­a­tion. Smirk. Yeah, that’s quick. Tap the screen. Cor­ner two: on the throt­tle early again, the fab­u­lous sen­sa­tion of a gen­er­ously loaded su­per­mar­ket trol­ley arc­ing into a drift around the hair­pin of the condi­ments aisle; smok­ing Miche­lins. This is the same car. A clever car. They call it ‘ two cars in one’.

They also use the word ‘in­evitable’. ‘They’ be­ing BMW M boss Frank van Meel and vice pres­i­dent of en­gi­neer­ing Dirk Häcker, who are dis­cussing one key fact about the new M5: it’s four-wheel drive.

While it’s prob­a­bly true that BMW can no longer re­sist the call from cer­tain mar­kets to power both axles, it’s the on­go­ing power-race against ri­vals that means de­ploy­ing such prodi­gious per­for­mance through only the rear wheels has be­come in­creas­ingly un­re­al­is­tic. Yet BMW, much like AMG with its new E63 (Driven, evo 231), has gone all­wheels-driven in its own way.

The M5s that await us at BMW’S Mi­ra­mas test­ing fa­cil­ity, not far from Mar­seille, are scruffy pro­to­types dis­guised with camo-swirls. We will hence­forth know this car as the F90 (M-cars now get their own type num­ber), and while it doesn’t take much imag­i­na­tion to visu­alise the ap­pear­ance of the fin­ished ar­ti­cle, harder to see are de­tails such as the car­bon­fi­bre roof, the sunken cen­tre­sec­tion of which con­tin­ues the same styling mo­tif as the bon­net.

Un­der that bon­net lies a new gen­er­a­tion of the fa­mil­iar 4.4-litre twin-turbo V8, now with higher in­jec­tion pres­sure, re­designed tur­bos and new cool­ing and oil-sup­ply sys­tems. It’s con­nected to an eight­speed Step­tronic gear­box, not an M DCT twin-clutcher. A back­wards step? Not at all, ac­cord­ing to Häcker, who says the ul­ti­mate per­for­mance of the torque- con­verter is vir­tu­ally in­dis­tin­guish­able from the twin­clutcher. He says it also holds an ad­van­tage when you’re just am­bling around, do­ing what M5 driv­ers spend most of their time do­ing. For the same rea­son, the rear sub­frame is now at­tached to the body with bushes, not solidly mounted: M has tried to broaden this car’s ap­peal.

‘The car had to feel like a rear­wheel-drive car, but with a bit more trac­tion,’ is van Meel’s suc­cinct sum­mary of the project brief. To achieve that, the engineers have adopted and de­vel­oped ex­ist­ing com­po­nents – the Ac­tive M diff from the M3/M4 and the trans­fer case from the M760i, which al­lows the

power to be sent to both axles – and com­bined them with new soft­ware in a sin­gle, in­te­grated con­trol mod­ule.

The trans­fer case, sit­u­ated be­hind the M5’s gear­box, con­tains an elec­tron­i­cally con­trolled clutch that sends power via a drive­shaft to the dif­fer­en­tial at the rear. At that point, new car­bon­fi­bre clutch plates can dis­trib­ute torque from zero up to 100 per cent on ei­ther side. Mean­while, an­other drive­shaft runs up to the front axle where there’s an open diff. For the first time, one ECU looks at ev­ery in­put: steer­ing, throt­tle and brak­ing from the driver, plus yaw, lat­eral, lon­gi­tu­di­nal and wheel-slip data from the car. It knows what’s hap­pen­ing be­fore you do.

The clever­est part of the driv­e­train is the cen­tre diff, as its clutch can be any­thing from locked to­tally open, mak­ing the car rear-wheel drive, to com­pletely closed, for a 50:50 pow­er­split. M engineers don’t like to talk torque-split per­cent­ages be­cause the M5 deals in much more sub­tle, pre­cise metering to in­di­vid­ual wheels. So so­phis­ti­cated is the M5’s brain that the shuf­fling around of torque is said to be un­de­tectable.

The lat­est 5-se­ries (the G30) is use­fully lighter than the model it re­places, mak­ing it a good start­ing point for in­te­grat­ing around 60kg of ad­di­tional drive­shafts and dif­fer­en­tials. De­spite all that kit, the new F90 M5 is said to be lighter than its 1870kg F10 pre­de­ces­sor. Its wheels are 19 inch­ers as stan­dard, with ei­ther Con­ti­nen­tal or Yoko­hama rub­ber. A 20-inch wheel shod with Miche­lin Pi­lot Sport 4s (or a Pirelli equiv­a­lent) will be an op­tion.

All this means very lit­tle with­out an ap­pre­ci­a­tion of the driv­ing modes. As with so many mod­ern cars, so much of the end re­sult, and the labour spent dur­ing de­vel­op­ment, is at­trib­ut­able to the soft­ware. This new M5 has the usual Com­fort, Sport and Sport+ modes that are in­di­vid­u­ally se­lectable for the steer­ing, throt­tle and dampers, and there are also three stages of tun­ing for the Driv­el­ogic gear­box.

How­ever, it’s the Dy­namic Sta­bil­ity Con­trol (DSC) op­er­a­tion that re­ally mat­ters. With it fully on, the M5 is as four-wheel drive as it gets, although still with an em­pha­sis on rear- driven en­ter­tain­ment. Move to M Dy­namic mode and that be­comes ‘4WD Sport’. This, as you might ex­pect, favours an even more rear-bi­ased setup. Switch DSC off com­pletely and you have a choice of three modes: 4WD, 4WD Sport and 2WD, all shown on the idrive screen. The last of those is, you guessed it, en­tirely rear-wheel drive.

Thank­fully, you need not twid­dle away through these modes in idrive (or tap the hard keys on the cen­tre con­sole, which in­clude one for a new sports ex­haust) like a con­cert pian­ist, as they can be pre­set as ‘M1’ and ‘M2’ pro­grams, ac­ces­si­ble via but­tons on the steer­ing wheel.

Out on track, the new M5 feels as bru­tally rapid as you might ex­pect. BMW hints at a fi­nal out­put of around 610bhp, with in ex­cess of 516lb ft of torque (the pre­vi­ous M5 was good for 552bhp and 501lb ft), but if that’s the case then these are par­tic­u­larly well-fed Bavar­ian horses of noble parent­age.

This is also the first M5 to fea­ture

‘Ini­tial signs are that the new M5 is sur­pris­ingly ag­ile for a car of its size’

elec­tric power-as­sis­tance for the steer­ing, but it’s one of M’s bet­ter ef­forts and when lap­ping the wet, low-grip cir­cuit it’s pos­si­ble to get a real sense of the level of ad­he­sion avail­able. Mainly, though, it’s the car’s high-speed bal­ance that im­presses, and the ini­tial signs are that the new M5 is sur­pris­ingly ag­ile for a car of its size. Play with the throt­tle mid-cor­ner and the car’s at­ti­tude sub­tly shifts; change di­rec­tion through the fast S-bends and it locks onto its new line with dogged en­thu­si­asm and stays with you, re­sist­ing un­der­steer keenly.

How­ever, it’s when you get back on the power that the M5 is re­ally in­ter­est­ing. Even in 4WD mode it al­ways feels rear- driven, and if you’re greedy with the throt­tle on cor­ner exit it’ll adopt a very neu­tral at­ti­tude. It’s not in the least bit in­tim­i­dat­ing, even with the DSC off. 4WD Sport mode will al­low the rear to swing out given sim­i­lar provo­ca­tion but then pulls things straight with very lit­tle steer­ing in­put re­quired.

And 2WD? A riot. Or a hand­ful. It’s bril­liant fun on a test track with some­one else’s tyres, but if you just wanted to get home fast on a wet night in Novem­ber… Well, at least now you can go for 4WD mode.

Two cars in one, then, and a thor­ough re-imag­in­ing of the M5. We can’t wait to drive the fin­ished car.


Below: car­bon-ce­ramic brakes will be an op­tion on the new M5, and are iden­ti­fied by gold-painted brake calipers. Bot­tom: turn sta­bil­ity con­trol off and you’re given a choice of three modes, in­clud­ing one for rear-drive an­tics

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