More Engine, More Gears

By Halloween, the 2008 Infiniti G35 sedan will be in costume. And though Infiniti's sport sedan won't be haunted by Nismo or Autech, there might still be an opportunity to get scared and choke on candy corn. The G is going to the party as a 2009 Infiniti G37 sedan.

This party is the October 2008 launch of the Infiniti brand in Western Europe. Infiniti doesn't have the obligatory diesel engine ready to go, so it's putting its best gasoline V6 in all Euro-spec Gs. And since the company has already whetted our appetite for the 3.7-liter VQ37VHR V6 with the 2008 G37 coupe, there wouldn't be much point in sending both G35 and G37 sedans down the line in Tochigi, Japan.

So we, too, get the 2009 Infiniti G37 sedan. We also get a new seven-speed automatic transmission to go with it — in addition to last year's six-speed manual gearbox, of course.

Neither of these upgrades makes the 2009 Infiniti G37 radically quicker than the 2008 G35. But they put a slightly nastier edge on what is already the rawest of the rear-drive, entry-level luxury sport sedans.

Too Fast for Napa
Napa Valley is where we meet up with the 2009 Infiniti G37 sedan, and this presents a quandary for our inner wine enthusiast. The G37 is not the sort of car you drive between wine tastings. For that, you might rent a Sebring convertible, which feels a little tipsy before anyone has a drop of wine.

So on this warm (and yes, dry) fall day, the 2009 G37 sedan is the main event. Alas, all the little blacktop roads running between Napa's vineyards, along with its 55-mph divided highways, are a bit limiting in this car. There aren't nearly enough opportunities to seek out the 3.7-liter V6 engine's 7,600-rpm redline.

Still, between corners, the V6's midrange is every bit as complex and exciting as we remember it being in the G37 coupe. You're looking at negligibly lower power ratings for the V6 in the G37 sedan, which offers 328 horsepower at 7,000 rpm and 269 pound-feet of torque at 5,200 rpm (versus 330 hp and 270 lb-ft in the coupe), but the two engines are otherwise identical. Bore and stroke is still 95.5mm by 86.0mm; compression is still 11.0:1; and you still have Infiniti's VVEL (Variable Valve Event and Lift) working on the intake valves.

When it's time for a downshift, we notice one other similarity between the G37 coupe and sedan: the deep exhaust note. Whereas the 3.5-liter VQ35HR V6 in our long-term 2007 Infiniti G35 Sport sedan was disappointingly mum after a neatly executed heel-and-toe downshift, the 3.7-liter is allowed to make a fuss — even in the sedan.

A Better Automatic
The shifts themselves feel pretty, good, too, thanks to the upgraded transmission offerings on the 2009 Infiniti G37. The seven-speed automatic transmission that debuted on the 2009 FX50 and FX35 also replaces the G's five-speed automatic this year.

Rear-drive Infiniti G37 sedans and coupes can be equipped with either this automatic or the carryover six-speed manual. The seven-speed is standard for all-wheel-drive Gs, including the newly available G37x coupe.

Compared to the old five-speed, the seven-speed automatic has significantly shorter 1st, 2nd, 3rd and 4th gear ratios. In fact, it's geared more aggressively than even the six-speed manual gearbox. And like the old automatic, it matches revs on downshifts and can be controlled via shift paddles if you get the sport package.

Infiniti says the 2009 G37 sedan should be a couple tenths of a second quicker from zero to 60 mph — perhaps even a half-second, one official tells us. The last automatic-equipped G35 sedan we tested ran a 5.5-second 0-60. The BMW 335i is the one to beat here, of course, as that car goes to 60 mph in 5 seconds flat with a six-speed automatic.

The seven-speed G37 should also deliver better fuel economy than the G35. It has an extra overdrive gear, and the final-drive ratio is 3.357:1 compared to 3.692:1 on the automatic G35. Combine these changes with the efficiency benefits of the new V6's variable valve lift, and you're looking at a probable EPA rating of 18 mpg city/26 mpg highway (versus 17/24 on the G35), says Infiniti.

Maybe You Should Do It Yourself
Six-speed manual G37 sedans shouldn't give up more than 1 mpg to the automatic, though, and we think there's a stronger argument for doing your own shifting in 2009 Infiniti G37 sedans and coupes.

We've had our grievances with Infiniti's six-speed gearbox in both the G35 sedan and the G37 coupe, but as we find a groove through a series of turns on Napa's Dry Creek Road, they're far from mind.

The clutch take-up in this particular G37 sport sedan has the kind of subtlety and refinement we expect in a premium-brand sedan. The shift lever also feels pretty fluid through the gates, yet it retains that mechanical weightiness so characteristic of Infiniti and Nissan performance cars.

If our test car is any indication, Infiniti might have finally gotten everything worked out with this transmission. And that bodes well for the manual-shift G37 at the test track. Our long-term G35's clutch issues are well documented, and still it managed a 5.5-second 0-60 time (5.2 seconds with 1 foot of rollout like on a drag strip) and a 13.9-second quarter-mile at 102 mph.

It's Only About Value If You're Boring
Whenever an Infiniti G35 sedan wins a comparison test, it invariably ends with this disclaimer: It wasn't the best car, but it was the best value.

And in some ways, this kind of backhanded compliment is justified. Neither the 2008 G35 nor the 2009 Infiniti G37 sedan has a best-in-class interior. And if you're picky about your entry-level luxury sedan's ride and handling balance, you'll probably gravitate toward the supreme refinement of a 3 Series.

In 2009, though, the G has gotten a little too interesting to be the value leader. It'll still be priced competitively, of course, as Infiniti estimates a base 2009 Infiniti G37 Sedan with the seven-speed automatic will come in around $33,000 — less than a grand more than the '08 G35 sedan with the five-speed auto. Same goes for the G37 Sport with the six-speed manual, which should cost about $34K. Put the sport package on an automatic-equipped 2009 G37 Journey and you're looking at about $36,500.

But value doesn't enter the picture on Dry Creek. Instead, we're thinking about how stiff and composed our 2009 Infiniti G37 sedan's chassis feels through the lumpy corners, and how much we like the torque and drama of the 3.7-liter V6. We're enjoying the drive.

Edmunds attended a manufacturer-sponsored event, to which selected members of the press were invited, to facilitate this report.