350 Z Aerodynamics
The Z's role as symbolic flagship of Nissan is an important one, and the Nissan 350Z design reflected that role. The prior Z car, the 1990-1996 300ZX, was a technological showcase. It demonstrated that the corporation's engineering talent could build a car every bit the match of long-respected sports and GT cars, such as the Porsche 944 or the Corvette -- and then some.
©2007 Publications International, Ltd.The 2003 Nissan 350Z was designed to be practical in terms of technology and price.But in so doing, the prior 300ZX lost the scent of the affordable-performance trail pioneered by the original Datsun 240Z. In contrast, the 350Z's engineering was best described by the term "appropriate technology." There was no ultra-trick systems that might push its price too high. No Super HICAS 4-wheel steering, as on the 300ZX. No twin turbochargers. No active damping. No voice-recognition functions. No variable-induction manifold. And so on. Although the new Z was right up to the minute in features and technology, there was nothing that was untrue to the original Z concept. After all, what good is it to build the best car in the world if only a few can afford to buy it? To deliver everything customers expect of a high-quality, state-of-the-art sports car, a good foundation is crucial. Nissan called the unit-body structure of the 350Z a High Damping Body, in essence a dynamic spring with a stabilizing effect. The body wasn't designed to achieve just high static-bending and torsional-rigidity numbers. The rigidity was designed as a dynamic system with the tires and suspension in place in order to improve driving stability and ride comfort. It resulted in a body with significantly higher torsional and bending stiffness than that of the previous 300ZX.
©2007 Publications International, Ltd.
©2007 Publications International, Ltd.
The unit body of the 350Z was designed to be rigid yet devoid of performance-robbing weight. But the body wasn't just stiff for stiffness' sake. It had been analyzed not only on computers but also through multiple trial-and-error procedures using actual prototypes. This resulted in the placing of extra beef where it needed to be for strength, and the removal of excess fat where a weight reduction would contribute to performance and efficiency. Key structural elements of the car's design included a double-panel floor, a double front bulkhead and large-section door sills. The double-panel floor gave the necessary foundation for future bodystyle variations. Roof rails and side panels were laser welded for a strong, accurate fit.
And a rear strut brace, bolted and welded in place, restored any rigidity lost by adopting a rear hatchback and foregoing the traditional steel rear bulkhead of a notchback coupe bodystyle.350Z AerodynamicsIn developing the 350Z's body, engineers spent lots of time in Nissan Technical Center's wind tunnel testing the 350Z aerodynamics. But not for the reasons you might think.©2007 Publications International, Ltd.The underside of the car was designed to be perfectly flat and reduce lift.This was a sports car, bulging with muscularity and character -- not some bar-of-soap science experiment.
The bragging rights for the car with the world's lowest coefficient of drag would have to wait. Instead, the aerodynamic work was directed primarily at attaining zero body lift. Increased stability would be the benefit, with lower wind noise a pleasant side effect. By managing the airflow under the car, the tendency of the body to lift during high-speed driving was eliminated and the car felt as if it was driving in a vacuum. The precise handling experienced at low speeds could also be enjoyed at high speeds. The myriad changes that resulted from this research were subtle, but important.
For starters, the 350Z's floor was designed to be as flat as possible, with few pieces protruding and creating drag. The exhaust system was routed to hug the underbody, with the crossflow muffler laid out flat. The fuel tank was tucked up under the floor beneath the luggage area. The front bumper and engine undercover were shaped to help compress the air and increase its velocity -- thus decreasing the pressure and creating a vacuum under the car, sucking it to the ground. At the rear of the engine, undercover airflow was dispersed to reduce lift. Air was guided and further hustled along through floor side farings and underfloor deflectors. In addition to a rear diffuser to reduce rear lift, the
For starters, the 350Z's floor was designed to be as flat as possible, with few pieces protruding and creating drag. The exhaust system was routed to hug the underbody, with the crossflow muffler laid out flat. The fuel tank was tucked up under the floor beneath the luggage area. The front bumper and engine undercover were shaped to help compress the air and increase its velocity -- thus decreasing the pressure and creating a vacuum under the car, sucking it to the ground. At the rear of the engine, undercover airflow was dispersed to reduce lift. Air was guided and further hustled along through floor side farings and underfloor deflectors. In addition to a rear diffuser to reduce rear lift, the Track model featured a small chin spoiler behind the bumper and an equally minimal deck spoiler at the rearmost edge of the hatch door. Considering the not-inconsiderable bulges over its wheelhousings, the base 350Z netted a respectable 0.30 coefficient of drag. For the Track model, the Cd dropped to a rather slippery 0.29.
POWER & SOUND OF THE Z
350Z Power and SoundThe Nissan 350Z power and sound befit a true sports car. Continuously Variable Valve Timing Control System (CVTCS) aided drivability and maximized low- and midrange torque. It also reduced valve overlap at idle for smoothness, and at cruising speeds it was configured to enhance fuel economy.
©2007 Publications International, Ltd.Exhaust sound was maximized at low engine speed and toned down for normal cruising.Furthermore, CVTCS eliminated the need for an exhaust gas recirculation valve because the increased valve overlap it allowed permitted sufficient exhaust-gas to re-enter the combustion chambers and reduce combustion temperatures, thereby reducing oxides of nitrogen. To accomplish its tasks, CVTCS incorporated a 32-bit microprocessor for fast response. It analyzed a number of parameters including engine speed, engine load, throttle position and road speed. The processor directed a duty-cycle electric solenoid atop each cam cover to vary the oil pressure to the intake-cam timing-chain sprockets. As oil pressure changed, it moved the position of vanes inside the sprockets, rotating them relative to the camshafts and thus varying the intake-valve tinning. The result of all these efforts was a potent, tractable powerplant that was well-suited to a car intended to be both sporty and refined. In the inaugural 2003 350Z, the 3498-cubic-centimeter dual-overhead-cam, 24-valve V-6 produced 287 horsepower at 6200 rpm and 274 pound-feet of torque at 4800 rpm. That was up substantially from the VQ engine's applications in the Pathfinder and QX4 SUVs. Though peak power occurred at 6200 rpm, maximum torque was moved a bit higher in the rev range. Redline was 6600 rpm, signing off earlier than the 300ZX's 7000-rpm limit.
The Sound of Z Power From the very start, a core goal of engineers working on the 350Z engine was to deliver a powerful sound from the intake and exhaust, without high-pitched, "tinny" mechanical sounds or the low-frequency booming or rumbling that can grow tiresome on long trips. From driving Italian exotic cars, such as the Maserati 3200GT and the Ferrari 360 Modena, F355 and F40, Nissan studied the "emotional" aspects of intake and exhaust sounds. Benchmarks for the 350Z's induction sound were the BMW M Coupe, Porsche Boxster, and Nissan Skyline GT-R. The exhaust sound was maximized at low engine speed (1000-3500 rpm), but quiet at normal cruising. And intake sound maximized at high engine speed (3500-6000 rpm) -- especially at wide throttle openings -- but toned down during cruising. Nissan used straight intake ducts and removed the 0.5 harmonic to give a "clear" intake sound. A variable intake manifold was not used in the 350Z. The 350Z's exhaust had reduced back pressure and was freer flowing than in any other Nissan. Its equal-length exhaust-manifold branches fed a large-diameter single pipe, which fluted to dual outlets aft of the rear axle. A complete dual system was discarded due to cost, weight and aerodynamics.
©2007 Publications International, Ltd.Exhaust sound was maximized at low engine speed and toned down for normal cruising.Furthermore, CVTCS eliminated the need for an exhaust gas recirculation valve because the increased valve overlap it allowed permitted sufficient exhaust-gas to re-enter the combustion chambers and reduce combustion temperatures, thereby reducing oxides of nitrogen. To accomplish its tasks, CVTCS incorporated a 32-bit microprocessor for fast response. It analyzed a number of parameters including engine speed, engine load, throttle position and road speed. The processor directed a duty-cycle electric solenoid atop each cam cover to vary the oil pressure to the intake-cam timing-chain sprockets. As oil pressure changed, it moved the position of vanes inside the sprockets, rotating them relative to the camshafts and thus varying the intake-valve tinning. The result of all these efforts was a potent, tractable powerplant that was well-suited to a car intended to be both sporty and refined. In the inaugural 2003 350Z, the 3498-cubic-centimeter dual-overhead-cam, 24-valve V-6 produced 287 horsepower at 6200 rpm and 274 pound-feet of torque at 4800 rpm. That was up substantially from the VQ engine's applications in the Pathfinder and QX4 SUVs. Though peak power occurred at 6200 rpm, maximum torque was moved a bit higher in the rev range. Redline was 6600 rpm, signing off earlier than the 300ZX's 7000-rpm limit.
The Sound of Z Power From the very start, a core goal of engineers working on the 350Z engine was to deliver a powerful sound from the intake and exhaust, without high-pitched, "tinny" mechanical sounds or the low-frequency booming or rumbling that can grow tiresome on long trips. From driving Italian exotic cars, such as the Maserati 3200GT and the Ferrari 360 Modena, F355 and F40, Nissan studied the "emotional" aspects of intake and exhaust sounds. Benchmarks for the 350Z's induction sound were the BMW M Coupe, Porsche Boxster, and Nissan Skyline GT-R. The exhaust sound was maximized at low engine speed (1000-3500 rpm), but quiet at normal cruising. And intake sound maximized at high engine speed (3500-6000 rpm) -- especially at wide throttle openings -- but toned down during cruising. Nissan used straight intake ducts and removed the 0.5 harmonic to give a "clear" intake sound. A variable intake manifold was not used in the 350Z. The 350Z's exhaust had reduced back pressure and was freer flowing than in any other Nissan. Its equal-length exhaust-manifold branches fed a large-diameter single pipe, which fluted to dual outlets aft of the rear axle. A complete dual system was discarded due to cost, weight and aerodynamics.
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