April 22, 2005

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Test Drive:
2005 Infiniti G35X
Review and photos by Greg Wilson

In designing an all-wheel-drive system for a rear-wheel-drive luxury car, automotive engineers are faced with the challenge of providing the superior traction and stability of an all-wheel-drive system without detracting from the balanced handling of the car's rear-wheel-drive platform.

Engineers at BMW, Mercedes-Benz, Porsche, Lexus, and Cadillac have all approached this problem in different ways, but Infiniti's Attesa E-TS AWD system may have the edge in pure sophistication.

Introduced on the Infiniti G35X in December, 2003 and also available in the FX35 and FX45, Infiniti's Attesa E-TS (Advanced Total Traction Engineering System for All Electronic Torque Split) all-wheel-drive system consists of a lightweight electro-magnetic clutch (compared to a typical oil pressure clutch) that provides variable torque distribution ranging from 50:50 front/rear up to 0:100 percent front/rear. This allows the system to run in rear-wheel-drive only on dry roads.

From a standing start, the G35X's AWD system splits torque 25/75 front/rear, but quickly reverts to full rear-wheel-drive in dry conditions. In slippery conditions, the system automatically and continuously adjusts front/rear torque as road conditions warrant up to 50/50. Sensors continuously monitor vehicle speed, throttle position and wheel spin at all four wheels.

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When entering a corner in the G35X, torque distribution is usually 100% to the rear. Once into the corner where the rear wheels may begin to lose some grip, torque is fed to the front wheels as needed to increase stability and traction. Back onto the straight, torque distribution reverts to 100% rear.

For comparison, none of the G35X's German competitors are capable of this. The Audi A4 quattro can transfer up to 50% of the engine's torque to the rear wheels; the Mercedes-Benz C-Class 4Matic up to 60%; and the BMW 330Xi up to 62%.

Critics of Infiniti's system will argue that unless all four wheels are being driven all the time, there may be a response time-lag should the car suddenly hit glare ice or other slippery surfaces. During my week with the G35X in mostly wet conditions, I didn't experience any hesitation in response. The G35X, though 85 kg (187 pounds) heavier than the rear-wheel-drive G35, handles like a rear-wheel-drive G35, but is far more stable in wet conditions. I found the throttle a bit sensitive when first applied, but this has more to do with the electronic throttle and transmission.

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I didn't get a chance to drive it in the snow, but in addition to its Attesa AWD and VDC (stability control) the AWD system includes a selectable Snow-Mode button which allows the driver to fix the front/rear torque distribution at 50:50 at speeds up to 19 km/hr). This improves traction when starting on very slippery surfaces. Certainly, when compared to the rear-wheel-drive G35, the G35X is better suited to Canadian Winter weather conditions.

But it's not only in Winter that AWD is useful: AWD provides improved stability on dry roads too. Even in Summer, road grime, sand, rubber residue, frost, wet patches, and ice can make driving hazardous. Drivers tend to drive faster on dry roads, and a sudden change in surface grip can have even more serious consequences. AWD provides extra stability and safety.

As I've said before, a sign of a good AWD system is that you don't notice it's there. Instead of understeering, oversteering, or losing control in wet conditions, the G35X tracks in the direction it's supposed to without any bumps and jerks from the driveline.

G35X for 2005

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Though the G35 was introduced in the 2003 model year and the G35X a year later, there have already been some upgrades for 2005. It's not obvious, but the G35 and G35X have been given a modest styling upgrade including revised headlights, new dual-circle taillights, a new hood and trunk, new bumpers, and new seven-spoke alloy wheels.

Inside, there have been subtle changes too. Higher quality dash materials include real aluminum trim or genuine rosewood trim instead of birds-eye maple. New Stone (gray) and Wheat (beige) interior colours join the previously available Graphite (black). The centre instrument panel has been redesigned - notably,

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the oval clock has been moved into the upper digital display area, some of the buttons have been repositioned and are easier to operate, and the floor shifter has eliminated the separate gate for the manual shift mode (it still has a manual shifting feature).

On models with the 5-speed automatic transmission, the 3.5-litre 24-valve DOHC V6 now has 280 horsepower, up from 260 last year, while torque jumps 10 ft-lbs to 270. The RWD G35 equipped with a six-speed manual transmission adds 18 horsepower boosting it to 298. Other changes include larger standard brake rotors on RWD models and a new Aero Package with 18-inch wheels and tires, rear spoiler, a sport-tuned suspension, and a viscous limited-slip differential.

Interior impressions

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In the compact luxury class, the G35 is fairly roomy with noticeably more rear legroom than some of its competitors. Its high quality leather upholstery is standard, and features perforated seat inserts for extra cooling. As before, the power seat adjustment buttons are on the right side of the driver's seat near the centre console, and on the left side of the front passenger seat (the driver's seat is 8-way and the passenger seat is 4-way). For the driver, it takes a while to get used to this unusual position, but the buttons are easier to see than those typically found out of sight on the left side of the driver's seat cushion.

The rear seats in my test car included the optional adjustable reclining feature, which is great for long trips, and a centre pass-through for skis. Folding seatbacks are not offered on the G35X.

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As before, the display screen for the heater is found on top of the dash, and it includes an outside temperature gauge, compass, and integrated analogue clock. An optional 'hideaway' navigation screen pops up from the centre dash and provides a bright, colour map with visual and audible directions to your destination. It includes Nissan's unique 'bird-view' which gives a more 3-dimensional look to the display.

Standard equipment includes an excellent Bose audio system with an AM/FM/in-dash six-disc CD changer with seven speakers, speed-sensitive volume control and steering wheel audio controls.

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My test car had the optional 'Premium and Navigation System' ($6,300) which includes a real-time satellite-based navigation system with a DVD map, power moonroof, dual-zone climate control, driver's seat memory, reclining rear seats, and power tilt and telescopic steering wheel. When the steering wheel tilts and slides, the entire instrument pod tilts up and down with it so that the gauges are not obscured - good idea.

Standard safety features are dual-stage front air bags (with front occupant sensor), front side airbags in the seats, and front and rear curtain air bags for head protection. As well as front and rear crush zones, the G35X includes a feature that allows the engine to drop downward in certain collisions; a breakaway drive-shaft to prevent intrusion into the passenger compartment; and a retracting brake pedal that helps reduce lower leg injuries in a severe crash.

In a 40 mph frontal offset crash test conducted by the Institute for Highway Safety, the 2003 G35 scored the best rating possible, a "Best Pick".

Performance is balanced

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Though heavier than the G35, the G35X doesn't seem to lose much in performance. Motor Trend clocked a 2004 G35X from 0 to 60 mph in 6.5 seconds, and a 2003 G35 RWD in 6.2 seconds. The difference isn't significant and now that both models have 20 more horsepower, they should be even faster.

The G35's engine isn't as refined or a smooth as some of its competitors, and acceleration is accompanied by a sporty exhaust note. But on the highway, it's quiet and revs comfortably below 2500 rpm at 100 km/h.

Current Transport Canada fuel consumption figures reveal that the G35X is only marginally less fuel efficient than the G35, offering 13.5 L/100 km city and 9.1 L/100 km hwy, compared to 12.8 L/100 km city and 8.5 L/100 km hwy. Compared to other AWD cars in its class, the G35X is about average.

As before, the handling of the G35X is assisted by its balanced front to rear weight distribution. Its longitudinally mounted V6 is positioned well back in the frame helping to provide a 52/48 front/rear weight distribution. As well, the G35X's fully independent multi-line suspension offers a very comfortable ride, assertive handling and excellent stability. Standard Vehicle Dynamic Control (VDC) helps prevent spinouts.

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Standard tires are P215/55R-17 inch, and four wheel disc brakes with ABS, electronic brake force distribution (EBD) and brake assist (BA) provide extremely short stopping distances in its class.

The G35 is 'Recommended' by Consumer Reports and its 'Predicted Reliability' is rated 'Very Good'.

Verdict

There's no doubt that the 2005 Infiniti G35X provides superior traction and stability in winter weather conditions, but its unique AWD system also provides rear-wheel drive-like handling in dry conditions.

Technical Data: 2005 Infiniti G35X

Base price	$42,890
Options	$6,300 (Premium and Navigation package)
Freight	$1,267
A/C tax	$100
Price as tested	$50,557
Type	4-door, 5-passenger mid-sized luxury sedan
Layout	longitudinal front engine/all-wheel-drive
Engine	3.5 litre V6, DOHC, 24 valves
Horsepower	280 @ 6,200 rpm
Torque	270 ft-lb @ 4,800 rpm
Transmission	5-speed automatic with manual shift mode
Tires	P215/55VR-17
Curb weight	1664 kg (3,668 lb.)
Wheelbase	2850 mm (112.2 in.)
Length	4747 mm (186.5 in.)
Width w/mirrors folded	1753 mm (69.0 in.)
Height	1466 mm (57.7 in.)
Cargo capacity	419 litres (14.8 cu. ft.)
Fuel consumption	City: 13.5 L/100 km (21 mpg) (Imperial gallons)
	Hwy: 9.1 L/100 km (31 mpg) (Imperial gallons)
Recommended fuel	Premium
Warranty	4 yrs/100,000 km
Powertrain Warranty	6 yrs/110,000 km
Assembly location	Tochigi, Japan

Greg Wilson is a Vancouver-based automotive journalist and editor of CanadianDriver

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