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Originally Posted by CarAndDriver
Building factory hot rods must be a good business.
Practically every automaker has an R or a GT or a V or an S or a Spec-Something-or-Other sexing up its catalog. But nobody commits to the job with the fervor of BMW’s M division GmbH. Granted, the gulf between track and street that opened up years ago means that BMW’s speed shop no longer puts motorsport specials on the road with detuned race engines. But that doesn’t mean new M’s are nothing more than Big Macs with barbecue sauce.
Okay, maybe the 1-series M sort of is.
But take the example of the new 560-hp “M TwinPower Turbo” M5—Bimmer-nerd code: F10—that goes on sale in the U.S. late next summer as a 2013 model.
In the F10 M5, you get: a unique engine [see sidebar]; a unique, reinforced and re-ratio’d, seven-speed dual-clutch transmission; and a unique, electronic limited-slip differential with a unique aluminum horse-collar mount for added rigidity. There’s a unique suspension with forged aluminum components and nary a part number shared with any other BMW; a unique variable-ratio steering gear with hydraulic instead of electric boost as in other 5s; unique, iron-and-aluminum brake rotors clamped by unique radial-mount, monoblock front calipers housing six asymmetrically sized pistons per wheel; and a unique front crossmember, stiffened and attached by two additional bolts because somebody thought that was important. A unique rear-suspension cradle is rigidly mounted to the unibody to eliminate the weight and flex of rubber bushings, unique stiffening rods and shear plates underneath serve as extra bracing, and the car runs enough special software to land it on an asteroid.
You may scoff upon learning the M5’s price, expected to fall near $92,000. To that prodigious sum we say: How can BMW possibly sell a couple thousand copies per year so cheaply? What does the dedicated tooling cost, anyway? How much is it to change 10 things about an engine, including the induction system and compression ratio, and then recertify it? It’s a lot of Big Macs. Maybe not as many Big Macs as creating a bespoke V-10, as in the previous E60, but a lot.
The new M5 will assuredly be profitable. But whether it is spectacular or merely great—many people would put a 4300-pound luxury sedan that hits 60 mph in 3.7 seconds firmly in the former category—it’s definitely no parts-bin badge job.
Speaking of acceleration numbers, we have them, stolen on a quiet side road in southern Spain while nobody was looking except some ducks and possibly a Chinese spy satellite. It took a while to master the new M5’s picayune order of button pushing and lever pulling to activate the launch control (example: Step on the brake but not too hard, hold the shift lever forward but not for too long).
Launch control automatically dumps the clutch at about 3000 rpm and upshifts for you. When we finally did it right, the quarter-mile went down in 12 seconds flat at 122 mph. In another 6.3 seconds, the car was passing 150 mph. It pulls nearly 1.0 g braking from 70 to 0 in 165 feet. A skidpad figure will have to wait until we can get a car to test in the U.S.
Compared with an E60 M5 equipped with an automated manual transmission, the F10 is a half-second quicker both to 60 mph and through the quarter-mile, and 2.4 seconds quicker to 150 mph. The braking distance is seven feet longer, but then, the F10 is about 200 pounds heavier. Will the larding up of our favorite vehicles ever stop?
Well, with the M5, one must remember that it remains unapologetically a heavyweight. It is an executive express, a velvet-wrapped hammer, a shark in whale’s clothes. It is not a four-door Lotus Elise. BMW figures M5 owners are richer than M3 owners and that they want commensurate levels of luxury and gizmology. Indeed, you cannot select a gear, push a pedal, or turn the wheel in the new M5 without assistance from the many watchful computers monitoring your every bodily twitch. Even the roar of the M TwinPower Turbo (we just like saying that name), muffled by the turbos and the cabin soundproofing, is partly ersatz, enhanced by a playback of engine noise through the stereo system to give passengers a heightened “acoustic experience.” (Two noises in the M5 that aren’t artificial are the tick-a-click of the dual-clutch automatic doing its business and, in our test car, a distinct hum from the differential.)
Experiential acoustics aside, BMW goes to lengths to make the electronic boundary layer between you and the machine transparent, or, at least, subject to an off button. And if you forget that nearly everything you’re feeling, hearing, and doing has been run through a microprocessor, the car, like the Matrix, is a nice place to be.
A sense of security pervades its every motion on the road, even when you’re busting through 100 mph on a riptide of—dare we say it?—profoundly diesel-like torque. The M5 flies through sweepers with a doctor’s note excusing it from Mr. Newton’s lecture, remaining flat and cool and seemingly impervious to the lateral forces that should roll it heavily to the outside given its relatively compliant suspension. You can starch up the shocks with the “Dynamic Damper Control” button, but even on “Sport Plus,” the car doesn’t tramp.
The M5 spurns the electric-assist steering in lesser 5-series models for a more natural-feeling hydraulic boost. And thanks to sharper camber and caster settings, the car’s commitment to the driver’s desired trajectory is firmer than in the wandering 5s and 7s we’ve driven lately.
When a hairpin comes up, the default stability-control mode is an intrusive buzzkill, cutting power and tapping the brakes even when the M5 seems well within its impressive cornering limits. Switch to the more playful M Dynamic Mode and you begin to see why; the rear just leaps sideways when kicked by the ol’ M TwinPower Turbo. To its credit, BMW avoided making the M5’s chassis too safe and dull by dousing it with understeer, even if increasing numbers of BMWs now sell in markets with, ahem, new drivers. In this department, the M5 is unquestionably an M. Stand down the stability control entirely and watch the M5 bonfire its tires drifting sideways, spitting smoke and chunks of expensive Michelin Pilot Super Sport rubber.
Yet, a slight fog of artificiality is there. The steering does everything you could desire—everything, that is, except talk back with those little organic tugs and sags that make lively cars feel, well, alive. What does tug and sag a bit is the power delivery as the M TwinPower Turbo’s boost crests and falls. We’re not talking lag here because there really isn’t any, just faint disturbances in the g-force that will bother some old Jedi knights who love long, linear windups to stratospheric redlines.
The previous V-10 had an 8250-rpm redline. With the M TwinPower Turbo, Elvis pretty much leaves the building at 6000, though the revs go to 7200 rpm, supposedly for track-day lappers who like to hold gears longer—and, we suspect, to uphold the M tradition of making spin-dizzy engines. The tall gearing of the seamlessly proficient seven-speed, with its two overdrive top gears handing off to a 3.15:1 axle ratio, is well matched to the M TwinPower Turbo’s torque curve, or lack of curve, as it were. The torque “peak” of 502 pound-feet is more of a mesa, arriving just off idle at 1500 rpm and not fading until 5750 rpm, *figures for a gasoline engine that would make even Herr Diesel envious.
If the M5 achieves its stated goal of a 30-percent gain in fuel economy, combined mpg could reach 20 when the EPA gets around to rating it. BMW is also strongly hinting that the U.S. market will again get a manual-transmission option.
Change, like cold gazpacho, always has its haters. Atavists will doubtlessly cry out that M has abandoned them with all this turbo madness. To paraphrase a recent comment on our website: When the M5 got a V-8 for 1998, people said they missed the inline-six. When it got a V-10 for 2004, people longed for the V-8. That is all true, as is the fact that the new M5 remains a delectably sweet reward for personal financial success. And if the next M5 is a diesel-electric hybrid that hits 60 mph in three seconds flat, will we say the same? Maybe, but only if BMW comes up with an even better name than M TwinPower Turbo.
The M TwinPower Turbo 4.4-liter V-8 is known internally as the “S63 TU,” (for “technical update”), a term that marks its evolution from the older S63 already installed in the X5 M and X6 M.
The basics remain unchanged: The 90-degree aluminum block is crowned by reverse-flow heads that draw induction air from the sides of the engine and exhaust it to the center, where the headers and twin Honeywell turbos lie in the block’s vee. A spider web of individual tubes supplies each twin-scroll turbo with the exhaust gas of four cylinders—two cylinders from the left bank and two from the right. For each turbo, the respective firing orders of the feed cylinders provide equally spaced spurts of exhaust energy.
The new M5 is the first M to adopt Valvetronic, a BMW technology that meters intake air by varying intake valve lift instead of with butterflies (a backup throttle plate remains for crisis scenarios). Because of the bulky valve hardware and the limitations it places on engine speed, the M division has until now spurned Valvetronic. But BMW has downsized and lightened the components and reshaped the contact surfaces to enable the S63 TU’s 7200-rpm redline, 200 rpm higher than the X5 M’s.
The turbo compressors grow by about 10 percent to generate additional volume and 21.8 psi of boost, a gain of 4.4 psi. The large boxes hanging off the front of the engine are the air-to-water intercoolers, closely coupled to the turbos to shorten lag time. They are twice the size of those in the X5 M to limit intake temps at a relatively chilly 131 degrees for higher air density and power.
Direct fuel injection reduces combustion temperatures, so the TU’s compression ratio was raised from 9.3:1 to 10.0:1 to maximize energy yield from the fuel.
The X5 M’s engine banks are run by a single Continental/Siemens computer on the fire wall, but tighter clearances under the M5’s hood required splitting the box in two and moving the computers onto the engine itself—right next to the catalytic converters, in fact—so water cooling is used to prevent meltdown of the now-Bosch-supplied brains. The exhaust pipes running down both sides of the flywheel housing are 3.1 inches in diameter, 0.4 inch bigger than the X5 M’s, with double-layer walls to help contain heat.
The 529-pound S63 TU (nine pounds lighter than the retired V-10) is about as photogenic as a box of eels, but, says the M divison’s lead engine man, Jürgen Poggel, “If it is not sexy, it is powerful, which is sexy.
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