2007 IMPORT TECH REPORT

Motor,  Dec 2006  by Weissler, Paul

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Nissan/Infiniti

Nissan has three new frontdrive sedans-Versa, Sentra and Altima-and Infiniti's brand-new G35, the car that proved that a great-handling, more powerful competitor to the BMW 3 Series could come from Japan.

The Altima continues with the 2.5L Four, but a new family of smaller Fours provides a 120-hp 1.5L for the Versa and a 147-hp 2.0 for the Sentra. Although the engines are similar in shape and share some bolt-on parts, the 1.5 is much smaller and is 39 lbs. lighter, at 209 lbs. They have different bore centers and separate assembly lines. Nissan gets the needed volume for each by sharing engines with Renault. The compact designs have relatively large valves that require narrow-diameter spark plugs.

Although all the Nissan Fours are the highest in their class in horsepower, what sets them apart technologically is the optional continuously variable transmission (CVT) from Nissan s JATCO affiliate. It improves fuel economy and acceleration.

Although an econobox, Versa is an upscale model in Japan, which explains why it's larger than the Fit and Yaris. It also offers an express-up power window on the drivers side, which requires initialization-after the battery is disconnected, of course, but also if the window is partly opened and/or closed many times without a full closure.

The 2007 Altima, on a new "world" platform shared with Renault, has the fourthgeneration 3.5L V6 (80% new parts), including WT on intake and exhaust as an option, with horsepower up from 245 to 270. The former two-belt accessory drive was changed to a single serpentine belt. V6 problems with torque steer were solved by lowering the engine mounting ½ in. and positioning the front axle shafts more parallel to the ground.

The 2.5 was freshened up to reduce NVH, using 100 new parts (out of about 500 total).

Altima also gets a hybrid model. Nissan buys Toyota's hybrid system and integrates it with a modified version of the Nissan 2.5 Four.

The Infiniti G35 sedan got a major overhaul (expect similar changes when the coupe comes out in the spring). The platform is second-generation front midships, and the 3.5 V6 is rated at 306 hp, 268 ft.-lbs. of torque. The 2006 base engine was rated at 280/270, although a high-performance manual transmission model with intake/exhaust WT was rated at 298/260. The new engine is rated according to a revised testing standard, so 2007 horsepower improvements are likely to be even greater. Internal changes also boost the engine redline 1000 rpm, to 7600.

The G35 has optional four-wheelactive steering. Front steering is variable ratio-from 12:1 up to 18:1. The motor-controlled rear steering is modest (under 1°), but makes a noticeable difference in hard cornering. It's similar to the system used last year in the Infiniti M series.

HID (high-intensity discharge) headlights in the G35 sedan are in a sculptured housing with a computercontrolled internal motor drive that pivots the outboard light into turns. The rear taillamps incorporate an array of LEDs.