2008 BMW M5

Could this high-tech road jet be any more perfect?

Let's get the expected impressions out of the way so we can tackle the technology smorgasbord that separates this Teutonic road jet from other 5-Series Bimmers and everything else on the road. With apologies to Clint Eastwood, these include much good, some bad and an element of ugly.

The good: this fourth-generation M5 may be the fastest, most muscular, most precise, and glued-to-the-road four-door most of us will ever experience. It rockets from rest to 60 mph in 4.5 seconds, corners like a front-engine race car and can brake so hard it can bounce your eyeballs off the windshield.

The bad: it appears aimed as much for techno-geeks as for serious drivers. The overly complex, user-unfriendly and often frustrating iDrive multifunction controller alone requires an evening of manual study to comprehend, after which owners will keep their manuals handy for on-the-fly reference. Add to that a mind-boggling plethora of driver-programmable powertrain and chassis settings that offer 279 combinations through an MDrive menu that can be linked to an MDrive button on the steering wheel.

Ugly, as always, is in the eye of the beholder. A lot of folks, ourselves included, have been non-fans of BMW's current 5- and 7-Series styling. That said, it's either growing on us or these updated '08 5s are improved enough to look much better to our eyes, or both. But we did thoroughly dislike our test car's optional Madeira Walnut trim, a reddish-brown wood with horizontal graining that looks painted on with a course brush. Your taste may differ, but we much prefer the standard brushed aluminum trim, or the other optional wood, Olive Ash burl.

Engine tech

Click here to find out more! Nothing quite like a 500-hp V-10 muscle motor stuffed into a mid-size sedan! This is the modern German big-bucks version of the mid-'60s Detroit muscle car, which works quite nicely for Audi's awesome V-10-powered S6 as well. Why a V-10? Elmar Schulte, BMW's engine development manager, says, "We wanted five liters. The ideal cylinder displacement is 0.5 liter. To get five liters, we needed ten cylinders." Uh, Okay.

One key credo of BMW M is high-rpm, so this V-10 is engineered to rev eagerly to its somewhat astounding 8250-rpm redline with some small sacrifice in low-end torque&which, trust me, won't be missed. Lightweight reciprocating components are used throughout, which also helps reduce total vehicle weight and balance front/rear weight distribution to near 50/50. There are three power and throttle-response settings: the P400 default mode (for valets and your son's prom night) caps the engine's horsepower at a mere 400 and gives normal throttle response; P500 unleashes all 500 horses with quicker response; P500 Sport (for track work and New York parking garage attendants) provides full power with even quicker response.

BMW's Valvetronic system, which controls fuel/air intake via valve actuation without a throttle, is not (yet) developed for high-revving engines, but this M V-10 does use double-VANOS variable camshaft control on both chain-driven intake and gear-driven exhaust cams. And, like all M engines, each cylinder has its own electronically controlled throttle. Its ultra-high 12:1 compression ratio is enabled by an ultra-quick ionic-current system that senses knock at each spark plug and retards ignition timing of individual cylinders to prevent it.

The "semi-dry sump" oiling system uses two reservoirs, a small one ahead of and a larger one behind the front frame crossmember, separated by a baffle. A mechanically driven variable-volume oil pump delivers sufficient pressure, but never excess volume, at all times for all operating conditions. Two electrically driven scavenger pumps recover it from pickup points determined by the Dynamic Stability Control system's lateral-g sensor (to account for cornering loads), and a recirculating pump moves it from the front to the rear main reservoir. Cooled by a coolant-to-oil heat exchanger, its temperature and level are monitored by sensors that drive an oil temperature gauge (in the bottom of the tachometer) and a low oil level warning lamp. (Curiously, BMW has decided that coolant temperature gauges are not useful and has eliminated them from most models, including this one. We strongly disagree.)