Related: Automotive Chassis
Although Infiniti has not been getting as much attention in the market as its premium competitors seem to have, the company is not standing still when it comes to rolling out with new products. In March, 2001, it brought out the third-generation Q45, which was followed in October of that year with the new I35 (successor to the I30 sedan). And there's more to come within the next several months, as the company begins to redefine itself as a builder of performance-oriented luxury vehicles. One vehicle that certainly fits that description is the just-released G35 sport sedan, which has the front-engine/rear-wheel-drive setup that will become more prevalent in the lineup. And yes, that means that Infiniti is entering the fray in a big way not just against marques like Lexus and Acura, but BMW and Mercedes, as well.
The 2003 Infiniti G35 is on a new platform. It's designated "FM." Not quite "frequency modulation," although one could argue that by placing the vehicle's V6 engine so that its center of gravity is located just behind the front axle there's not only a 52:48 front/rear weight distribution, but that there's improvement in handling, stability, and ride quality. (Which is one way to modulate bumps, shakes, vibrations, and other frequencies.) "FM" actually signifies "Front Midship," as in reference to the engine location.
This architecture contributes to a vehicle weight ratio of 52:48. (The base curb weight is 3,336 lb.) Actually, the 52:48 ratio is by design. Rather than going for a 50:50 weight distribution, the front is 2% heavier so that the front wheels are preloaded, such that when the car is accelerated while coming out of a curve, the balance is 50:50. It also means that the nose carries sufficient weight so that turn-in and front-end bite are enhanced. (As this is a sport sedan, it is meant to do things like be driven hard into turns.)
Another aspect of the FM platform that relates to this driveability is described by Kazutoshi Mizuno, chief vehicle engineer, Nissan Technical Center (Atsugi, Japan). He says the architecture helps create what he calls the "flat ride concept," which controls the pitching and yawing of the passenger compartment without compromising the ride or handling.
Just as the engine is, comparatively speaking, moved back, the 20-gal. fuel tank is moved forward. In this case, it is forward of the rear tires, below the rear seat. This results in a 14.8-ft3 trunk.
The four-wheel independent multi-link suspension system is a study in aluminum. The material is used for all major components up front, including the upper and lower control links, the axle housing, and the compression rod. The rear suspension uses an aluminum subframe, axle housing, A-arm, and lower link. Up front, the use of aluminum rather than steel results in a mass reduction of 25%. At the rear, the savings is 20% versus steel.
However, as many people will be quick to point out (especially people associated with the steel industry), aluminum components are more costly than their ferrous counterparts. So what gives? After all, pricing for the vehicle has been announced (base MSRP is $27,100) and it is cost-effective compared to the cars with which it is in competition (including the Acura TL-S, BMW 330, Lexus IS300, Audi A4, and Mercedes C 320). There are a few answers to this question.
One comes from Randy Fior, regional product manager, Product Planning, with Infiniti: "This shows our commitment to dynamic performance." As this is no run-of-the mill suspension architecture and execution, the commitment is there.
Another comes from Jack Collins, vice president, Product Planning, Nissan North America: "At higher volumes, aluminum is reasonable." Higher volumes? They're thinking on the order of >30,000 for the first year of sales for the G35. Which isn't exactly "volume" in the context of many vehicles. But Collins goes on to note that there is a G35 coupe scheduled for the fall, and the FX45 concept crossover is expected to be rolling out by the spring of 2003, as well.
(The Altima has a similar aluminum-intensive suspension system that has had some of the competitors in that market segment scratching their heads. Collins confirms that the same approach of higher volumes is behind that, too.)
One more thing: the hood is aluminum, too. (But the preponderance of the body is steel.)
And under the hood, the 260-hp, 3.5-liter, double-overhead cam, 24-valve V6 engine is fabricated with an aluminum alloy block and heads. The pistons are coated with molybdenum.
The case for the five-speed automatic transmission is a high-pressure alumi-num die casting, which is said to provide high rigidity. (Note: as this is a "high-performance premium sport sedan," there will be a six-speed manual transmission coming for it. It will come after the G36 coupe and the Nissan Z get fitted with theirs.)
Most people who buy a G35 will probably never see the underside of the car. Yet the under floor surface was of concern of Mizuno and his engineers. Mizuno was a team manager of Nissan's LeMans and Group C racing programs. In racing, all of the aspects of a vehicle are examined from an aerodynamic standpoint. The underside is key with regard to reducing lift. So the G35 is designed with that in mind. Especially the G35 with the aero package, which includes a rear spoiler. The space between the front bumper and the rear edge of the engine undercover are designed to compress the airflow. That has a result of increasing the velocity of the air. That reduces lift. Then the airflow is diffused, only to be recompressed and diffused again as it moves along the underside of the car past the muffler and the fuel tank. The result (taking into account the sheet metal on the top side, too), is a coefficient of drag of 0.26 and zero front and rear lift. Without the spoiler, there is a 0.27 Cd.
Most people who buy a G35 will probably be heavily influenced by the outside of the car. Its styling. Although the car is 185.5-in. long, it has a long wheelbase, 112.2 in., which means the front and rear overhangs are comparatively short. (The length of the passenger's cabin is the same as the more substantial Infiniti Q45.) The front is said to have a "catamaran" style. This is because the fenders are raised up in relation to the hood. Not only does this provide an aero advantage, but the seams along the tops of the fenders are advantageous when cornering.
The G35 has structural stiffness that is as much a function of design as it is of manufacturing.
As for the first: There are such features as a dual bulkhead engine compartment that functions as a body stabilizer and sound attenuater. As for the second: the G35, which is built at the Nissan plant in Tochigi, Japan, features laser welded body panels: the roof and the body sides are joined with a laser rather than spot welds, thereby enhancing rigidity.