BMW's Roadster Finally Hits Its Stride
Dan Edmunds
06-02-2009
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==========REVIEW SUMMARY========== What Works:
Stout 3.0-liter twin-turbo engine; refined ride and handling; cockpit space and layout; gracefully executed retractable hardtop; revamped iDrive.
What Needs Work:
Flatulent engine note; long, heavy clutch throw; price is getting up there.
There's this guy at work (let's call him Dan) who never warmed up to BMW's Z3 and Z4 roadsters. Something about them simply didn't ring true.
Bottom Line:
The BMW Z4 has finally crystallized into a truly desirable roadster by fully departing from its über-Miata roots.
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==========PERFORMANCE SUMMARY========== 0-60: 5.2s (4.9s w/ rollout)
1/4 Mile: 13.4s @ 103.7mph
Slalom: 68.9mph
Skidpad: 0.87g
60-0: 106ft
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"The original Z3 seemed like a reactionary car," says Dan, "a concept BMW didn't really believe in themselves. But everyone had to respond after the Mazda Miata reinvigorated the demand for small two-seat sports cars."
And the result seemed like an über-Miata, too — except the super-suit didn't fit well.
BMW must have felt the same way, because the redesigned car received significant changes and a new name: Z4. Attempts to tailor the suit included a wheelbase stretched by nearly 2 inches, a stiffer chassis and a much improved rear suspension.
But the magic still wasn't there and the Bangle-administration styling was polarizing, if not confrontational. Doubters like Dan remained unconvinced.
"I remained unconvinced," says Dan.
So the recent arrival of the new 2009 BMW Z4 sDrive35i roadster at our offices was met with considerable suspicion. Some approached it carrying a grudge, in fact, because its new power-retractable hardtop signals the end of dedicated fixed-roof versions like the M coupe, considered by some to be the best thing about previous Z roadsters.
Heart Transplant
What the Z4 really needed was a major infusion of horsepower. After all, the competing 2009 Mercedes-Benz SLK350 and 2009 Porsche Boxster S both meet or exceed the 300-horsepower barrier. The outgoing Z4 whimpers in the corner with but 255 horses.
The 2009 BMW Z4 sDrive35i has that problem handled, because it's now propelled by the same 300-hp 3.0-liter twin-turbo inline-6 that we covet in the 335i and 135i. And this impressive power plant goes the competition one better because it also delivers 300 pound-feet of torque — about 35 lb-ft more than either of its BMW siblings.
Press the go pedal on your favorite on-ramp and the Z4 sDrive35i exhibits effortless strength and delivers a sustained midrange punch that comes from a torque peak that arrives at just 1,300 rpm and stays put up to 5,000 rpm. This prodigious grunt also reduces the need to stir the six-speed gearbox as often — a handy trait because we're still not keen on the long-throw clutch action found on many BMWs, including this Z4.
Unleashed at the track, this adds up to a 5.2-second run to 60 mph from a standstill (4.9 seconds with 1 foot of rollout like on a drag strip) in the face of a slight headwind on the way to a 13.4-second quarter-mile run at 103.7 mph. That's about a tenth of a second quicker to 60 mph than the last Boxster S we tested, though the '09 Boxster might squeak ahead again once we test it with its new 310-hp engine. (It'll be close.)
Longer, Lower, Wider, Heavier
The new Z4 might have gone quicker still if it hadn't gained about 360 pounds. Some of the extra weight comes from the new hardtop, but the new Z4 is also 5 inches longer. The wheelbase is essentially unchanged at 98.3 inches, so the extra length resides in the front and rear overhangs.
This mass may have dulled the reflexes of the new Z4 through our slalom maneuver somewhat, and it posts a speed of 68.9 mph. We've put a 2007 Boxster S (a car that weighs about 400 pounds less) through the same cones, and it goes nearly 3 mph faster.
On real roads, however, the 2009 BMW Z4 delivers crisp turn-in, reliable grip and lots of confidence. There's an unflappable sophistication to the way the Z4 responds to driver commands. It feels more planted and less frenetic than before, and that makes it easy to build up speed and really push.
But the Z4 pushes back at the limit with mild but sometimes persistent understeer that doesn't readily respond to lift-throttle attitude adjustments. It's not particularly off-putting, but the similarity to the BMW 135i is worth noting.
Brakewise, our Z4 has garden-variety single-piston sliding calipers that really work. Stops from 60 mph eat up only 106 feet of our test track, and pedal feel remains firm and steady time after time. It makes us wonder why the 135i bothers with huge (and expensive) six-piston fixed front calipers.
As Ever, a Sport Package
Our 2009 BMW Z4 test car has $2,300 of Sport package, which means it sits 0.4 inch lower and comes with Adaptive M Sport suspension, consisting of computer-controlled adjustable dampers that constantly vary their firmness based on road surface inputs, steering angle and lateral acceleration data. The limits of adjustment are constrained by three driver-selectable maps (Normal, Sport, Sport+) accessed through the Dynamic Drive Control switch.
The Normal position turns out to work best 95 percent of the time, especially on winding back roads that have a less-than-pristine surface. And the normal setting settles the car nicely on city streets and freeways alike, making the new Z4 a composed daily driver.
The Sport and Sport+ settings prove most suitable for glass-smooth pavement, track use and those times when the stability control overlord might get in the way.
Life Begins at the Top
The new top is a big step forward for the 2009 BMW Z4, and not just because it looks stunning while it adds top-up serenity and security. The big get is the elimination of the claustrophobia and poor visibility associated with previous Z roadsters.
Its thinner metal roof sections have no bows, which contributes to a 1.8-inch increase in top-up headroom despite a 0.3-inch reduction in vehicle height. And there's nearly a full inch of additional shoulder room because this top's folding junk goes in the trunk instead of a space-robbing slot wrapped around the seats. Both are truly useful increases that don't escape the notice of our tallest testers.
There's more glass area, too. The rear window grows larger because it no longer needs to be shuffled into a folding fabric sandwich, and the top mechanism has no scissor hinge to hide, so slender C-pillars and small rear side windows adjoining the pillarless door glass can be used.
Late Appointments
The Z4's enhanced interior space has been made even more hospitable with upgraded equipment offerings and a striking design.
Handsome brushed aluminum panels add interest to the interior, but their matte sheen doesn't reflect sun back in our eyes. Likewise the interior leather surfaces utilize pigments that reduce heat buildup.
Amazingly, top-down direct sunlight doesn't wash out the 8.8-inch fold-up screen that's part of the $2,100 navigation system. It's controlled with the first-ever appearance of iDrive in a Z roadster, and the timing is perfect because the new generation of iDrive software finally works.
The interior is sprinkled with thoughtful storage compartments ranging from fold-down door pockets to a cockpit-width shelf behind the seats to an available pass-through to the trunk. This new Z4 roadster has more spread-out room than you'd think.
Summing Up
And that's just it. The improved top and the interior changes instantly make the 2009 BMW Z4 Roadster a credible choice for any extended cross-country journey we care to make. Add in the twin-turbo engine and the refined ride and handling and it's quite tempting.
The $52,475 base price for an sDrive35i represents a jump over last year, and at first we thought the $64,020 as-tested price of our test car was out of whack. But the sum total of the improvements to this car is substantial and transformative. The 2009 BMW Z4 sDrive35i is now more than able to rub shoulders with the Mercedes-Benz SLK roadster and the Porsche Boxster S, and on that basis the price is not out of line.
The new 2009 BMW Z4 sDrive35i made believers out of a lot of fence-sitters. No longer is this a two-seat BMW roadster with an identity crisis.
"Perhaps they should have renamed it Z5," says Dan.
Article source and
video here:
http://www.edmunds.com/insideline/do...topanel..1.*#2
