Brains and Brawn: More MPG and More HP Under the hood, the 306-hp, 3.5-liter ...

BY ERIK JOHNSON

Redesigned for 2007, the second-generation Infiniti G35 sedan was good. Really good. Good enough to get all up in the faces of the competition and fall only to the benchmark BMW 3-series in its last comparison test. Good enough to have been invited to join us for a 40,000-mile fling. Good enough, in fact, to have secured itself a place on our 2007 10Best Cars list. But now it’s dead. And we don’t care.

We don’t mourn too deeply, you see, because the G35 has been replaced for 2009 by the G37. It’s still a second-gen G sedan, of course, but one that has been revised in several major areas.

Brains and Brawn: More MPG and More HP

Under the hood, the 306-hp, 3.5-liter V-6 has been kicked to the curb in favor of the 3.7-liter unit from the G37 coupe. The move adds 22 horsepower and variable valve timing to the sedan’s arsenal, with output now standing at 328 galloping ponies. Torque rises by just one, to 269 pound-feet, but the smooth-spinning six serves up adequate grunt no matter where the tach needle is pointing.

Fuel economy is unchanged for the manual-transmission model, but the rest of the lineup—which now uses a seven-speed automatic in place of the old five-speed—sees gains of 1 mpg in the city and 2 on the highway to 18/26 for rear-wheel-drive cars and 18/25 for the all-wheel-drive G37x. We recorded our observed fuel economy, but then either a staffer took the logbook home for bathroom reading or a sticky-fingered Infiniti PR rep snatched it up in the middle of the night, because it’s gone now.

Curiously, the additional power didn’t do a lot for the G37 at the test track, where we logged a 0-to-60-mph time of 5.2 seconds and a quarter-mile run of 13.8 seconds at 104 mph. Although quick, those digits lag 0.1 second each behind the best runs posted by its 3.5-liter predecessor (5.1 seconds and 13.7 at 104 mph). Admittedly, the results of various G35 Sports ranged as high as 5.5 seconds to 60 and 14.1 seconds through the quarter, and our G37 was a nearly factory-fresh car with a green motor, so there’s a chance the latest G could improve its results. Curb weight could also be a bit of a factor, as the G37 rang in at 3703 pounds, 120 pounds more than the slimmest G35 Sport we had previously weighed.

Maybe it didn’t shine on the test track, but the G37 sedan does burn brightly in the refinement department, an area where the G35 fell decidedly short. Infiniti quelled the G’s buzzy engine and quivering shifter somewhat last year, but things are even better now, with the only hint of engine harshness at the lofty tiptop of the tach—redline is still 7600 rpm—rather than throughout.

The six-speed manual also seems better behaved, with less vibration than before. The throws remain short but high-effort, the latter a trait shared with the clutch. We also sampled the seven-speed automatic in a G37 Sport, and between mostly invisible full-auto operation, a well-programmed sport mode, and throttle-blipping, paddle-actuated downshifts, it’s not a bad option for folks who don’t want to row their own. Upshifts in manual mode could be smoother and more quickly effected, though.

It Takes More than a Big Engine to Catch a 3-series

Rear-drive G37 Sport models also swipe the G coupe’s bigger brakes, with 14.0-inch front and 13.8-inch rear rotors squeezed by four- and two-piston calipers, respectively. (Non-Sport G sedans make do with 12.6-inch front and 12-inch rear binders.) The new setup continues the G tradition of serving up fade-resistant performance and lots of feel. Again, however, the revision didn’t show up in the test numbers, with the G37 taking 160 feet to stop from 70 mph, compared with 157 feet for the G35. Frankly, either number is good; the car has great brakes.

The steering is also revised for rear-drive G37 Sports, as they adopt the G37 Sport coupe’s quicker-ratio rack; it’s talkative, lively, and accurate. We greatly prefer this setup to the steering in base and all-wheel-drive cars, which, in addition to being slower, sacrifices some feel. Infiniti claims the interior is tweaked a smidge, too, but the only immediately noticeable change is the switching of the seat-heater controls from toggle switches to rotary knobs. The cool “Washi” metal trim—inspired by handmade Japanese paper—and phenomenal steering wheel remain.

Enough Incremental Improvement for a Paradigm Shift?

Although the G37’s changes don’t seem to add much quantitatively, they do make for a better car. The G’s largest and perhaps only handicap in its head-to-head meetings with the 3-series—its sometimes rough character—has been addressed. Although the ride can still border on too harsh, the balanced chassis, the awesome brakes, the big power, the tenacious grip, and the communicative steering are all still there. The newfound refinement might not be enough to finally vault the Infiniti over the BMW in a comparison test, but we’re champing at the bit to find out.

2009 Infiniti G37 Sport Sedan - Specs

VEHICLE TYPE: front-engine, rear-wheel-drive, 5-passenger, 4-door sedan

ESTIMATED BASE PRICE: $35,000

ENGINE TYPE: DOHC 24-valve V-6, aluminum block and heads, port fuel injection
Displacement: 226 cu in, 3696cc
Power (SAE net): 328 bhp @ 7000 rpm
Torque (SAE net): 269 lb-ft @ 5200 rpm

TRANSMISSION: 6-speed manual

DIMENSIONS:
Wheelbase: 112.2 in Length: 187.0 in Width: 69.8 in Height: 57.2 in Curb weight: 3703 lb

C/D TEST RESULTS:
Zero to 60 mph: 5.2 sec
Zero to 100 mph: 12.8 sec
Zero to 130 mph: 23.3 sec
Street start, 5–60 mph: 6.2 sec
Standing ¼-mile: 13.8 sec @ 104 mph
Top speed (governor limited): 156 mph
Braking, 70–0 mph: 160 ft
Roadholding, 300-ft-dia skidpad: 0.89 g

FUEL ECONOMY:
EPA city/highway driving: 17/25 mpg

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