words: Bryan Joslin

As driving enthusiasts, we've probably all fantasized at one point or another about having a different car for every possible condition or mood. Since for most of us that dream will remain one, we settle instead on a compromise car. Often that comes in the form of a sport sedan. At the core of the sport sedan ethos is the belief that changing priorities (hauling around kids, clients, and co-workers) shouldn't mean sacrificing the thrill of driving. By definition, a sport sedan should possess a potent engine, a lively chassis, superb brakes, and a driving environment that caters to the person behind the wheel.

For decades, the BMW 3-series has been synonymous with "sport sedan," a market segment its forbears practically created. Virtually everyone else has attempted to copy the formula since then, and until recently the only ones to even come close to translating the blueprints have been other Germans. But one challenger in particular has been closing in on the magic — Infiniti's G sedan. For 2009, the 3-series got a mild facelift while the G got another 22 horsepower, thanks to the G coupe's VVEL 3.7-liter. But is power alone enough to establish a new benchmark? To find out, we pitted a 2009 335i against a 2009 G37.

335.jpg

When the fifth generation of 3-series arrived in 2005, BMW knew better than to mess with success. The new sheetmetal was an edgier interpretation of the basic shape that evolved out of the third generation from the early '90s. But dynamically the E90 model, as it's known to fans and BMW employees, was everything we'd come to expect from a 3.

The engines offered at launch were naturally aspirated sixes of identical 3.0-liter displacement but with different induction systems, resulting in either 215 or 265 hp in the 325i or 330i, respectively. The 330i was capable of hitting 60 mph from rest in 6.1 seconds; it was a respectable, if somewhat unexceptional, figure among its contemporaries. BMW quashed that criticism for the 2007 model year by adding a twin-turbo variant that delivered 300 horsepower and 300 lb-ft of torque, endowing the newly christened 335i with the ability get to 60 in just 5.4 seconds. The addition of turbocharging altered the car's personality in a major way, its massive torque curve providing near-M levels of thrust.

For 2009, the 335i is still the top non-M 3-series, and — halfway through its lifecycle — BMW has treated the E90 to a freshening. Though the changes are largely cosmetic — new front and rear bumpers and lights, mildly revised interior, a greatly improved iDrive controller — BMW modified the chassis slightly to increase front and rear track (by 6 and 24 mm, respectively). The twin-turbo engine, however, remains unchanged.

g37_1.jpg

Ever since the G35 sedan made its debut in 2003, it's had missile-lock on the 3-series' roundel. Based on the same architecture as the Nissan 350Z, it had all the makings of a genuine sport sedan from the beginning. The 3.5-liter V-6 initially produced 260 horsepower, though output eventually rose to 280 and then 306 by the time the G lineup (both coupe and sedan) received its makeover for 2007.

For 2009, Infiniti bumped the engine's displacement to 3.7 liters, bringing horsepower to the 328 mark (two fewer than the G coupe). The new VQ37VHR allows the G37S to bolt to 60 mph in just 5.0 seconds with its six-speed manual; that's a full 0.4 seconds quicker than the last G35 sedan we drove. The company also developed a new sport package — sport seats, sport suspension,18-inch wheels, a limited-slip diff, and the coupe's Akebono brakes — to go head-to-head with BMW's popular option pack.

stackup.jpg

For a company whose middle name is literally "Motor," its engines are expected to be special, and the one in the 335i doesn't disappoint. Its aluminum block employs a bedplate construction that incorporates the bearing caps into the lower half of the block, minimizing vibration and boosting rigidity. A pair of compact turbochargers, each fed from three cylinders, quickly converts exhaust gasses into positive manifold pressure on the intake side, all but eliminating turbo lag. Direct injection precisely meters and times the delivery of fuel for optimized combustion.

The resulting powerplant is lightweight yet granite-solid, with silken-smooth delivery throughout its operating range. It conveys its power with a level of exactitude that rivals that of a blueprinted-and-balanced racing engine. At idle, it's silent and unwavering; under load, it's a workhorse without the slightest hint of resistance. BMW engines have always been good; this one is brilliant.

The G's engine represents an evolution of the venerable Nissan VQ35 family. Its aluminum block uses molybdenum cylinder liners, and micro-polished single-piece camshafts act on the valve train, which now includes variable lift and timing. To achieve the extra displacement, the stroke has been stretched from 81.4 to 86.0 mm while retaining the engine's 95.5 mm bore. The 3.7 is more of a revver than a torque machine. Power peaks at 7000 rpm, with max torque of 270 lb-ft arriving at 5200 rpm.

The G37 jumps on command, responding instantaneously to prods of the throttle, and rips its way through the tachometer with the zeal of a 4-year-old opening presents on Christmas morning. The VQ has always been a bit of a rowdy engine, with a timbre that more closely resembles that of a small-block V-8. There is certainly more engine noise transmitted to the cabin of the G37 than the 335i, but only when the throttle is really being worked; the sound is its own audio track anyway, enhancing the driving experience.

engines_1.jpg

A choice of six-speed transmissions, one manual and one automatic, feeds power to the 335i's rear wheels. Purists will likely select the manual (ours was so equipped), though the ZF-sourced auto is a better alternative than you'd expect. BMWs have always had a reputation for shifters that lack a real direct, mechanical feel, and nothing has changed with 335i. Nevertheless, the throws aren't overly long or heavy, and the gear ratios are perfectly spaced for the powerband. Clutch action is much like the shifter itself — fairly light, but communicative nevertheless.

pullquote.jpg

The Infiniti's standard gearbox is a seven-speed manumatic, but a six-speed manual is available, and it brings the sport package with it. First gear will run out before you've cleared a large intersection, but the remaining five speeds are spaced well. Unlike the vagaries of the BMW's gearbox, the G37S's shifter conveys a more mechanical feel. Its action lies somewhere between the bolt action of a Miata and the somewhat unrefined engagement of something like a Mustang. The clutch pedal requires a bit more effort than the BMW's but serves as a pleasant reminder that there is indeed real performance under foot.

As good as the powertrain is, the 335i just wouldn't be a sport sedan if its chassis were soft. Here again, BMW has stuck to what works, employing a strut-type front suspension with multiple pivot points plus the extensive use of aluminum to keep weight down. The lightweight alloy is also present in the rear's five-link setup. The ride quality is characteristically German — firm and precise over minor surface imperfections, unflappable when the corners get tight. There is just enough tension in the chassis to give it a lively persona, but not so much as to make it feel twitchy. With the stability and traction control switched off, the 335i can easily be coaxed to hang its tail out with the right combination of steering and throttle. A limited-slip diff isn't offered.

Our 335i tester was equipped with the standard variable-assist power steering, which provides accurate feedback and has a natural weight to its movement. The three-spoke leather steering wheel is well shaped and padded without being overly sculpted. Active steering is an option, but more serious drivers may find its constantly changing ratio unpredictable during spirited jaunts. Four-wheel discs with aluminum calipers do an excellent job of scrubbing speed from the 3600-pound sedan while providing decent feedback through the pedal.

The G37 borrows its chassis bits from the Nissan 350Z, using a double-wishbone front suspension with a multi-link rear setup. Ride quality is very similar to the BMW's — firm, but not overly stiff — but the G seems a bit more responsive, more eager to react to small inputs than the 335i. Weight is not a factor here, since the Infiniti checks in at an almost-even 3615 pounds. The G37S's steering even borders on twitchy on-center, but once you're moving through a turn it feels more predictable. The Infiniti lacks the BMW's hefty steering, but doesn't feel over-assisted.

The G37S boasts impressive braking hardware: 14-inch vented front discs are squeezed by 4-piston calipers, while 2-piston grippers work on 13.8-inch vented rears. Stopping performance is predictably strong, and the pedal communicates well what's happening under the standard 18-inch alloys.

3int.jpg

In standard form, the cockpit of the 335i is a simple affair. Without the clutter of the navigation system's requisite iDrive controller and dash hump, the instrument panel is a clean and uncomplicated place. The gauges' white numbers on black dials are easy to read at a quick glance through the sport steering wheel while the radio and ventilation controls are equally straightforward.

The 335i's cabin is an exercise in Teutonic restraint — the dash and doors are topped in black leather-grained vinyl while the seats, lower door panels, and dash panels in our test car were trimmed in a neutral tan. Dark walnut wood trim is the standard accent in the 335i, but ours was fitted instead with the optional-at-no-cost brushed aluminum. Throw in BMW's excellent sport seats with their thigh extensions and adjustable-width side bolsters, and you have a near-perfect environment from which to carve canyons or cruise the interstate.

gint.jpg

By comparison, the G37's interior is a bit busier. Take the center stack, for instance. Even without the optional navigation package, there is a seven-inch color monitor in the center of the dash, which also serves as a multi-function display for the climate-control and audio systems. The gauges feature backlit white numerals in a ring of purple within a black dial, and at night the white backlighting is accented with a red glow from the center. Visually, there's a lot going on.

Materials are remarkably similar to those in the BMW, with black leather-like plastics covering the dash and door caps, and lighter-colored materials accenting the lower sections. Instead of wood trim, Infiniti uses aluminum accents with a Washi paper effect; the treatment is simple ,classy, and unique to the brand. The G37's sport seats are chunky in appearance, but actually fit a bit more snugly than the BMW's, and feature the same range of adjustments. While the BMW has adjustable side bolsters on the seat backs, though, the Infiniti's bolsters flex in and out on both the back and thigh sections.

Practicality is a key ingredient to any sport sedan; otherwise we'd all just buy coupes and roadsters. The 3-series sedan is relatively compact by modern standards, but it still offers decent space for four adults and wide-swinging rear doors to load little ones into car seats. The trunk is ample with 12 cubic feet of easily accessible cargo space, though folding rear seats cost extra (they're part of the $1150 cold-weather package).

The G37 feels like a larger car than the 335i from the driver's seat. That's because it is: It's nearly nine inches longer, sits on three and a half inches more wheelbase, and is more than an inch taller. For the extra bulk, interior space is only mildly more accommodating than the BMW. The trunk is larger at 13.5 cubic feet, and folding rear seats are standard. However, the trunk opening is narrower than the BMW's by a lot, and the lower ledge is much higher, limiting what may or may not fit.

belt_1.jpg

The BMW 3-series is still every bit the definitive sport sedan; the 335i in particular exemplifies the type of car that blends everyday practicality with a genuinely exciting driving experience. However, with the 2009 G37S, Infiniti has done an amazing job of capturing the essence of the concept and executing it with a distinctly Japanese twist. It feels like an interpretation rather than a copy of the 335i formula.

The real difference lies in the price. A 2009 335i with leather, sport package, cold weather package, premium package, premium audio, and comfort access (keyless locks and ignition) will run a hefty $48,450. And that's without navigation. Scheduled maintenance is included at that price for four years or 50,000 miles, which is a definite consideration. But to get the same level of equipment in the Infiniti, you'll spend just $37,565.

For the world's carmakers, the 3-series will probably remain the segment's benchmark for years to come, although in the marketplace the G37S should gain significant ground. If price were no factor, the 335i would certainly emerge as the best example of the breed based on its additional level of polish and poise. But for many, the nearly 30% difference in price will be worth a small sacrifice in refinement.