2007 BMW X5 3.0si and 4.8i Review

When it arrived nearly seven years ago, BMW’s X5 could have simply added another respected premium nameplate to the ranks of sport-utility vehicles.  Instead, it redefined the class.  BMW’s description of that original X5 as a “Sports Activity Vehicle®“ represented a new approach to the concept of a traditional SUV—one that linked handling, performance and agility to the conventional attributes of practicality, versatility and off-road ability.

Before its launch, some skeptics raised serious doubts about “a BMW sport-utility vehicle.”  But with seven years of acclaim by owners and critics, and some 580,000 X5s produced in BMW’s Spartanburg, South Carolina factory, the X5 has become the very definition of sporting SUVs – or, as BMW prefers to categorize it, the iconic Sports Activity Vehicle® (SAV®).  And for 2007, BMW refines that definition with an all-new X5, one that includes an even higher level of achievement in each of those original concepts.

At the same time, specific goals were set to keep the X5 abreast of the competition.  These included optional 7-passenger seating, which would increase the X5’s practicality without compromising its established constellation of attributes.  In addition, enhanced variability and versatility, such as fold-flat rear seats, roomier cargo area and automatic tailgate, provide even greater flexibility of usage.  It is this cluster of key attributes that has made SUVs in general so popular.  Finally, the new X5 had to include an expanded offering of options to satisfy customers’ ever-growing expectations.  In addition to the all-important 3rd-row seating, new possibilities would include Active Steering, Active Roll Stabilization, Electronic Damping Control, rearview camera and variable 2nd-row seating.
In addition, all the attributes present in that original X5 have been thoroughly enhanced in this new model.  As in previous years, the X5 offers a choice of 6-cylinder or V-8 performance: the X5 3.0si and the 4.8i, both of them with better performance and excellent efficiency.  The flagship 4.8i boasts BMW’s all-aluminum Valvetronic V-8, boosted to 4.8 liters and 350 horsepower.  The 3.0si features BMW’s new 260-horsepower aluminum/magnesium inline-6.  Standard equipment on both models is a new 6-speed STEPTRONIC automatic; in a change from previous years a 6-speed manual is no longer available in the X5.  BMW’s outstanding xDrive all-wheel-drive system continues, enhanced via a closer link between the xDrive electronics and the X5’s Dynamic Stability Control to provide even quicker, more accurate response. 

The rising demands of the class also required a clean-sheet chassis, with modest increases in virtually all interior and exterior dimensions.  The result provides real advantages in terms of space, comfort and carrying capacity without turning the X5 into a “really big SUV.”  Despite the increase, the 2007 X5 remains within the mid-size class.  With an overall length of 191.1 inches, the X5 still tapes in well under such full-size competitors as the Lexus GX 470, Cadillac SRX and Range Rover HSE.

Another key part of that new chassis, the X5’s new front suspension represents a break with a 45-year-old BMW tradition: It’s a double wishbone multi-link design with upper
A-arms combined with double-pivot lower links—the first non-strut design since 1961.  The company’s departure from its traditional dual-pivot strut front suspension was dictated by customers’ increasing expectations for ride and handling.  Combined with a longer wheelbase, wider track and BMW’s revised 4-link Integral rear suspension, the new front design sets new standards for on-road ride and handling, as well as improved all-road ability.  In keeping with its original mission, the X5’s focus still places more emphasis on pavement performance, keeping it well abreast of the competition.

Even with all these changes, the 2007 X5 retains the basic character of the original, which was an additional primary design parameter.  As the benchmark vehicle in the class, the X5 needed enhancement, not replacement.  Maintaining the balance of its original attributes while raising the level of each was the primary goal, one that makes the X5 all-new, but still familiar.  And just like the original, still setting standards.

X5 3.0si: The latest edition of BMW’s trademark inline-6 makes the most accessible X5 even more appealing
BMW’s newest 6-cylinder engine makes its debut in the X5 3.0si.  This aluminum/magnesium composite inline-6 features the latest engine technology from the company whose middle name is “motor.”  Almost all vehicle manufacturers of 6-cylinder engines have adopted the V-6 format, whose compactness is advantageous in small or midsize cars with front-wheel drive.  By contrast, BMW’s inline 6-cylinder engines are brilliant for their smoothness and sound, and treasured for these attributes.  An increase in fuel efficiency and even tighter control of emissions were also set as goals for this BMW engine generation.

Compared to the previous X5 3.0i model’s engine, the new motor achieves notable progress on all fronts:
•           Greater power, 260 hp vs. 225 hp – a very impressive 86.8 hp/liter.
•           Greater torque, 225 lb-ft. vs. 214, and stronger torque characteristics across the broad range of engine speeds.  Appropriately for a substantial SAV®, the new engine attains its maximum torque at just 2750 rpm.
•           Higher revving ability.  The “redline” is 7000 rpm, vs. 6500 for the previous engine.  This allows the X5 driver to “wind out” the engine for maximum acceleration and exciting sound.
•           Superior fuel efficiency.  Even though performance is enhanced, EPA mileage ratings are significantly improved; the city value increases by 1 mpg, the highway by 2, compared to the ’06 X5 3.0i with automatic transmission.
•           Reduced weight – 22 lb. less.  Had BMW engineers developed the previous engine to meet their goals, it would have added about 30 lb. – and thus would have weighed fully 52 lb. more than the new engine actually does.
•           More compact – Because there is just one external drive belt, vs. the previous two, overall engine length is about an inch shorter.  This frees space for other vehicle attributes customers value, such as climate control, passenger’s-side airbag, a capacious glove compartment or impact-absorption capabilities.

The benefits are all part of a concerted effort to make across-the-board improvements in engine performance.  These are the result of an array of changes in the new design over the previous inline-6.  

Much of the weight saving, for instance, is the result of the new engine’s aluminum/magnesium architecture.  The engine consists of three major components, a magnesium-alloy bedplate, magnesium-alloy upper crankcase and a silicon-impregnated (Alusil) aluminum-alloy insert.  The first two magnesium castings create an extremely rigid, lightweight engine block.  The aluminum-alloy insert provides the actual cylinder bores, much like the Alusil crankcase in the X5 4.8i’s V-8 engine.  Other weight savings come from such items as new, hydro-formed hollow camshafts, plastic camshaft cover, thinner exhaust header flanges and an aluminum cam-chain tensioner.

Obviously, the adoption of the Valvetronic system plays an important part.  Valvetronic varies valve lift to control engine power, dispensing with a conventional throttle.  The
2nd-generation system includes a number of minor alterations from the original design, introduced in 2002 in BMW’s V-8 and V-12 engines.  More rigid reciprocating parts allow a 500-rpm increase in engine redline, while an increase in valve lift improves top-end performance.  The added rigidity also permits faster opening of the intake valves, so they are effectively open longer.  Phasing of the two intake valves—where one opens sooner than the other—improves low-load efficiency and cylinder filling.

Complementing these changes, a new intake system features 3-stage induction, which spreads the torque band across a wider rpm range.  Likewise, an altered combustion chamber shape and a wider range of variability in the double VANOS  valve-timing system also play a role in the power and efficiency improvements.  Further modifications, such as all-new engine electronics and higher fuel-injection pressures, increase the accuracy of ignition timing and fuel delivery.