It's No "M", But This "is" Still Goes Like Stink
“Overboost.” We can’t shake the word out of our heads while sitting at the obligatory press conference outlining the 2011 BMW Z4 SDrive35is. The German engineers flown in for the occasion are doing an excellent job of describing the intriguing phenomena, but we need to feel it. To think that a self-induced adrenaline-like rush for an inanimate machine really exists is downright intriguing. It’s akin to a factory installed “NOS” button for rich people. We have to experience it.
About 30 minutes later, we’re heading onto the streets surrounding the New Jersey Motorsports Park in an sDrive35is, one of two models the automaker produces with this “overboost” function (the other being the 2011 335is Coupe). The yee-haw! feature is reserved for only the latest sport rides wearing the famed “is” badge. Our car burbles at idle, warmed up, prepped, and ready for action. It’s time to see what it’s all about…
To those uninitiated in BMW’s model parlance, “is” is the brand’s performance level set between regular models and those specifically tinkered by M GmbH, the creator of the brand’s most powerful speed hungry machines. The line was birthed in the 1980s when the E21 320is hit world markets and ever since, has served as a happy medium for buyers wanting a tad more speed for a smaller price premium.
Although it would be convenient for BMW to simply call the sDrive35is a “Z4 M,” it’s definitely no M. Here’s why: First, its exterior form is nearly a spitting image M Sport Package-equipped Z4s. Second, it’s no lighter than the common model on which it’s based and utilizes the standard model’s brakes and suspension, among other crucial get-quick parts. Lastly, the powertrain, though more powerful, hasn’t been fine tuned and bolstered using sturdier M division components.
Whereas M’s creations yell, “Look, I can go fast,” with their bulbous haunches, bigger wheels, massive binders, and motorsport stances, the 35is wears an M Sport Aerodynamic kit as standard (optional on all Z4s), uniquely designed 18-inch rollers (19-inch optional), and subtle touches like blacked-out exhaust tips with bolder surrounds, silver mirror encasings, and a matte aluminum bar in the lower front intake grille. Speed in an “is” is coyly understated.
Each sDrive35is packs an easier-breathing, direct-injected 3.0-liter straight-six paired with twin turbochargers churning at an increased boost pressure of 11.6 psi versus the usual 8.7 psi. Total output now stands at 335 horsepower at 5900 rpm and 332 pound-feet at 1500 rpm. It’s 35 horses more powerful and offers 32 more pound-feet of pulling grunt than the tamer sDrive35i, its next closest sibling.
Compared to the 35i’s N54 series engine, the sDrive35is’ engine achieves max power and torque 100 rpm later. It’s a hellion of a powerplant bent on hitting law-breaking speeds as hastily as it can.
Despite the power increase, the 35is is no thirstier for premium fuel than the regular 35i with DCT (17 mpg city/ 24 mpg highway), nor is it heftier at 3549 pounds. It’s somewhat green too, utilizing a mild regenerative braking system (think of it as a civilized F1-derived KERS) to power auxiliary components on-demand.
The whole is only mated to the brand’s tried and tested seven-speed dual-clutch transmission (DCT) providing millisecond shifts at the push/pull of awkward-looking wheel-mounted plastic toggles, or by way of the standard gearshift. Shifts are quickened for the 35is with a lighter weight dual-mass flywheel and revised DCT programming.
The major fault of the ‘box’s setup are the paddle shifters. Make no mistake, they’re no true positive upshift, negative downshift paddles. They’re confusing as hell, not to mention unnatural, cheap in hand, and look as if they’ve been pulled off an early 1990s Big Foot Power Wheels. Cool aluminum upshift/downshift paddles like those on all other DCT-equipped vehicles aren’t available on the 35is. According to BMW, they’re on their way.
Turning right onto flat straight line road known as County Route 555, we remember the last time we had a Z4 in our garage. It was a few months ago during our roadster comparo when it was joined by three of its closest competitors. We tirelessly flogged a six-speed manual sDrive35i on L.A. County’s quick-switching, off-cambered, decreasing radius roads.
The sDrive35i ended up placing third — nearly fourth — in the comparison, behind a second place Audi TTS and winner Boxster S. We were shockingly disappointed with the sDrive35i’s un-BMW-like chassis imbalance, harsh suspension, and it’s awkwardly matched engine/transmission setup.
We can tell you now that after a few fast paced miles on Route 555 and the empty curvy paths east of Route 676, the latter fault is nullified in the 35is — the combination is smooth, powerful, and quick to respond. As for a harsh suspension, it still rides rough, even with the adaptive suspension set in “Normal.” With respect to the “disconnected chassis,” we’ll have to wait to see how well it really contends with extra-tight twisties once we get a tester in L.A. But here on New Jersey’s glassy back roads encircled by dark green forest, the roadster is nothing less than enthralling.
Lunging from a standstill is as forceful and graceful as a thoroughbred racehorse taking off from its gate. Torque is so abrupt, and has as such a low rev introduction, that it can initially be shocking to unsuspecting drivers. It literally shoves you rearward as if to say “Go ahead, try me, punk.” We’re used to it — our Long Term M3 sedan dares us to unfurl the same mighty German slingshot every time we strap in. Just when you think all acceleration is said and done, Mr. Overboost comes in to play.
Stomp the long right pedal and a subtle “click” is felt beneath it. For a full seven seconds, the twin snails churn 14.5 psi of boost, shooting another 37 pound-feet of pure hard thrust to the sticky rear rubbers. Tach needle hurtling as if in high speed fast forward, it’s now pegged at the 7000 rpm limit, yearning for a few more digits to be illuminated in bright white. Something this addictive should be illegal. We wouldn’t believe BMW’s conservative 4.7 second 0-60 mph claim one bit. The sDrive35is feels quicker.
Each upshift is marked with a blazingly quick bark and backward shove. If a list of the most intoxicating, sexually-explicit automotive vocals ever existed, we’d add this one to the batch (engineers say it took them quite a while to tune a note befitting the pedigree). Successive revs translate into higher pitched rumbles and growling snarls from the twin-turbo six. Push away the same paddle and downshifts seamlessly rev-match, imparting increased engine control — and, of course, delicious tones — just before corner entry.
Hit a bend fast and the long muzzle digs harder than any Z4 drop top. Yet, it’s still less balanced than its other siblings and shows plenty of debilitating understeer. Even so, it’s an improvement over the dodgy sDrive35i.
Thank the standard Electric Power Steering (EPS) that is beefed up for “is” form. The faster the car moves, and the more aggressively it turns, the more feedback (or the more ratio) telegraphed to the driver. Honestly, we can’t stand overly electronic helms, but this one does its job impeccably, cultivating more confident entries and exits.
M division’s adaptive suspension also helps to boost the Z4’s road hold. It drops the roadster about 0.4-inches lower than a standard model and stiffens or softens depending on road condition and driving behavior. “SPORT” mode brings the setup to near DTM levels, jostling and jolting over slight street imperfections. Knock it into “SPORT+” and traction control is nixed, turning the roadster into a Formula D contender with enough throttle enticement.
Designers included all the usually optional M Sport Package pieces (M badged steering wheel, pedals, shift knob, instruments, sills) as standard equipment. Given its communicative suspension, we’d make sure to opt for the plush multi-way adjustable seats. Windows down, tin top tucked neatly in trunk, the 3.0-liter’s sound intensifies into an intoxicating aria.
Cruising through Millville we made every excuse to push/pull gears for the pleasant inundation of barks, burbles, and short lived overboost fixes. Cockpit appointments are as luxurious and comfortable as they come. Navigation and premium sound can be checked on the order sheet, or like our tester, can be left off entirely. In any configuration, it’s a technologically advanced environment that coddles passengers without annoying roadster din, top on or off.
Will BMW’s quickest, most potent seductive roadster win the hearts of a few new customers, specifically those seeking more speed and performance? We think so, but we only borrow the cars…
Base price for the seductive roadster you see here is a whopping $61,925, including a $875 destination and handling charge. It’s a $9150 premium over the lesser sDrive35i and compared to the range starting model, the sDrive30i, it’s $15,050 more.
Consider other Germanic offerings and the 35is is square in Porsche Boxster territory. A 2010 Boxster S with a six-speed manual wears a $58,950 sticker with a $950 destination and handling fee. A bare bones, badass 2011 Boxster Spyder rings in at $61,200, no fees attached.
There’s no denying, though, that the sDrive35is is an enticing drive. All you have to do is downshift, lean on hard on the right pedal until it “clicks,” hold on, and prepare to be titillated. To really find out if it’s worth the price of admission, we’ll have to gather its competitive set and head out on one long drive.
|2011 BMW Z4 sDrive35is|
|Vehicle layout||Front-engine, RWD, 2-pass, 2-door, convertible|
|Engine||3.0L/335-hp/332-lb-ft twin-turbo DOHC 24-valve I-6|
|Transmission||7-speed twin-clutch auto|
|Curb weight||3549 lb (mfr)|
|Length x width x height||167.0 x 70.5 x 50.6 in|
|0-60 mph||4.7 sec (mfr est)|
|EPA city/hwy fuel econ||17/24 mpg|
|CO2 emissions||1.13 lb/mile (est)|
|On sale in the U.S.||Now|