Thanks to the ingenius exhaust port routing from the regular S63 (for details see) the F10 M5 doesn't sound like a normal, burbly, cross-plane-crankshaft V-8. The exhaust note is similar to that of a flat-plane V-8, or a four-cylinder. That means no lope, but a lot of boom at very low (2000 and fewer) revs, and a staggering bark under load. It sounds incredible, especially at startup or at full throttle.
Inside the car, it's a different matter. The engine is quiet and refined, especially when you're off the gas and the exhaust noise subsides. Under full throttle, you're treated to some of the V-8's staccato intake music. Strange music, that is -- it almost sounds like the last M5's V-10.
Which is really, really strange.
Here's something you'll be shocked to learn: when I unplugged the factory stereo amplifier, the engine's note inside the car changed considerably. It was all but inaudible over two grand, becoming more audible but distant as the revs increased. Somebody call the "Ultimate Driving Machine" police: BMW is actually using the car stereo speakers to pipe in engine music? Hmm.
Eh, whatever, so what, the M5 sounds awesome inside or out. The steering is probably the best of any M5 yet (overall, the E60 M5 left us cold, and as much as we loved the E39, that M5's steering used a recirculating ball setup. It was good, but the F10 M5's rack and pinion system is more communicative.)
The biggest disappointment with the M5 is turbo lag. Yeah, yeah, how typical that I'm complaining about a turbocharged M5. Actually, I'm not complaining about the fact that the M5 wears turbos: I'm complaining that the S63TU engine has so much more lag than the non-Valvetronic S63 did. In that silly X6M (and the slightly less silly X5M), the turbos were among the most responsive I've ever experienced. Not so in the M5 - the lag is significant enough that you have to drive around it.
And it seems that M's engineers aren't fully using their arsenal of tools (Valvetronic, Double VANOS, direct injection) to mitigate lag. Case in point, drive at highway speeds, and the transmission is in seventh gear. Floor the throttle and you get a fairly quick downshift into third: revs in the top half of the tach, all is well. The problem is that there's no boost, so you get a clutch engagement, followed by no power for a second, followed by massive thrust. Boost should have been built by the time the downshift was done. VW does it and has been doing so for years. What gives?
Oh, and remember: a full second of lag is one thing in a slow car, but think of the opportunity cost in a car like this! A second of lag is means you've missed out on probably some 15 extra mph. Seems like a small problem, but it got old very quickly when trying to pass slower traffic on country roads.
The M5 has a standard start/stop system, and it works flawlessly. The engine is vocal enough that you really notice it turning off, but it starts immediately the second you start pulling your foot off the brake pedal. We've seen some claims from BMW that the new car is a full thirty percent more efficient than its predecessor, but later documents tone that down a bit. EPA numbers probably won't be out until this summer. It's safe to say the 4.4-liter V-8 will use less fuel overall than the outgoing 5.0-liter V-10, but how much of a savings will certainly depend on how hard you drive it.
For the record, I got 10.8 mpg, which is not bad at all considering how I drove. Which was like a jerk, obviously. Don't look at me like that you would have done the same!
Speaking of that kind of driving, I'll be on track tomorrow, and will be able to report more about what the M5 does on grippy surfaces. I can say that once you hit moderate speeds, this M5 is delightfully neutral, and will happily exit any corner butt-first should you ask it to. The long wheelbase makes drifts slow and controlled, and the brilliant steering reduces your stress factor to zero.
(OMG one minute left.)
There's a bit of lost isolation in the rear of the M5 compared to the regular 5-series: the subframes are rigidly attached to the body, which means you hear the differential working, and the ride is a bit more gritty. Bad thing? Not to me. This is an M5, if you want super refinement you can buy a 550i. And the whole point of an M5 is skirting along the compromise of packing sports car moves into a luxury sedan body.
And in that sense, this M5 is a far better M5 than the last one (which was always a bit too high-strung and sterile for its own good.) It's got almost all of the refinement of the current 5-series, all of the tech features, gorgeous styling, and elegant interior. And then it's got razor-sharp handling and the best steering we've seen in a 5-series in a long time, if not ever. And then it'll rip that smile off your face with outrageous acceleration. And if you're in Germany, and you buy the driver's pack, you'll be able to test out the raised 190-mph limiter. 190! In a sedan.