Five things about the BMW X5: the second-generation SAV--as in "sport activity vehicle"--is bigger, more powerful, and better handling. Of course.

1. Sizable. The '07 X5 is bigger than its predecessor. The wheelbase is 115.5 in., which is a 4.5-in. increase. The length is 191.1 in., or 7.4-in. longer. The X5 is now 2.3-in. wider, at 76.1 in., and 2-in. higher, at 69.5 in. One consequence of all this is increased interior volume (e.g., overall passenger volume is 102.4-[ft.sup.3], which is an increase of 4.8-[ft.sup.3]), which facilitates the offering of a third row (albeit one that's essentially sized for children).

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2. Not a V for the 6. While most six-cylinder engines built by other manufacturers have the cylinder banks in a V-configuration, not the engine in the X5 3.0si. BMW engineers think the inline configuration is superior. The numbers for this new 3-liter engine are impressive: 260 hp (@ 6,600 rpm), or 86.8 hp/liter. 225 lb-ft of torque at 2,750 rpm. 0 to 60 in 7.8 seconds--for a vehicle with a curb weight of 4,982. While many contemporary engines are all-aluminum, this engine is a composite: aluminum/magnesium. There is a magnesium-aluminum alloy block assembly into which a silicon-aluminum (Alusil) insert is fitted. It contains the actual cylinder bores. Finally, there is a magnesium-aluminum upper crank case. In addition to which, there are hydroformed hollow camshafts, a plastic camshaft cover, thinner exhaust header flanges, an aluminum cam-chain tensioner, all contributing to lighter weight under the hood. The previous-generation X5 six weighs 22 lb. more than the new engine, and the new engine provides additional performance. It's calculated that in order to achieve the performance that the new six delivers without taking a new approach, the previous-generation six would have 30 lb. added to its mass. An electric water pump, variable-volume oil pump, and oil/coolant heat exchanger are other factors that are said to contribute to fuel efficiency (17/23 mpg). Yes, there is an eight, too, a 32-valve 4.8-liter V8 with an aluminum block and head. It produces 350 hp@ 6,300 rpm, and 350 lb.-ft of torque @ 3,400 to 3,800 rpm. Both have Valvetronic, which controls air induction through valve lift rather than using the throttle, consequently, for example, essentially eliminating pumping losses at low speeds, thereby contributing to a more efficient engine. Both engines are mated to a new automatic six-speed transmission. (Essentially the same: the 3.0si has a ZF 6 HP 19 TU and the 4.0 has a ZF 6 HP 26 TU; there is a variation in the final drive ratio, with 4.44:1 for the former and 3.91:1 for the latter.) There is no longer a manual. However, there is a sport-shift feature (e.g., there are paddles on the steering wheel). This transmission uses an electric/electronic shifter rather than a traditional mechanical lever, which makes the shifter seem more like a joystick in a video game than what one may be used to. This system is said to have been beneficial in a way that has nothing to do with the powertrain: It facilitates larger cup holders than would otherwise be possible thanks to its smaller packaging requirements.

3. So long, struts. Whereas the first-generation X5 has struts as part of the front suspension configuration, that's not the case with the '07 model. Rather there is a new suspension system with a double-wishbone multilink front suspension that uses upper lateral A-arms rather than struts, which is apparently the first time struts haven't been used in a BMW setup since 1961. There are still the double-pivot lower arms like those in the previous model. So this time there are three links on either side. The objective of the new design is to improve handling and riding comfort. For example, the shocks are isolated from lateral forces, thereby reducing friction, thereby contributing to a smoother ride. (In the rear? Essentially the same multi-link rear, though modified to accommodate the new platform's characteristics including the run-flat tires on standard 18-in.wheels.) Generally, this AWD vehicle has a torque split of 60:40 (rear-front), but it is possible through the xDrive system for 100% of the torque to go to a single axle.

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4. Built in the U.S.A. The X5 is exclusively built at the BMW Manufacturing Co. facility in Greer, SC. The first X5 rolled off the line on September 1, 1999. The last of the first generation was produced September 22, 2006. In between, 616,867 units were manufactured in the 4-million ft2 facility. The first '07 X5 was built September 28, 2006. There are two body shops in the plant, one for the X5 and one for the Z4 (roadster and coupe models and M versions of same). Then the two shops ship to the same paint shop and trim and final lines. There is full mixed-lot production at the plant.

5. Light but strong. The X5 has extensive use of ultrahigh strength steel throughout its structure. This helps contribute to a torsional stiffness of 27,000 Nm, up 15% from the previous generation model. Because this is a bigger vehicle than its predecessor, and because there was an effort to reduce mass as much as possible even with the additional size, light weight components are used throughout. For example, there are: an aluminum hood, plastic fenders, magnesium IP carrier, and cast aluminum front strut towers. The upper and lower lateral arms and wheel carriers are aluminum.

Gary S. Vasilash

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by Gary S. Vasilash

EDITOR-IN-CHIEF

There aren't too many factories that have a car museum attached to them. But BMW Manufacturing does. Check out the BMW Zentrum here: www.bmwzentrum.com