2006 Infiniti M45 Sport Sedan

The 2006 Infiniti M45 Sport Sedan represents a significant point in Infiniti's evolution, showcasing a blend of luxury, performance, and advanced engineering. This article delves into the technical aspects of the M45 Sport, exploring its engine, drivetrain, suspension, braking system, and key electronic features.

Engine and Performance

At the heart of the 2006 M45 Sport lies the VK45DE engine, a naturally aspirated 4.5-liter V8. This engine is a member of Nissan's acclaimed VK engine family, known for its robustness and smooth power delivery. Let's examine its key components:

• Cylinder Block and Heads: Constructed from aluminum alloy, the cylinder block and heads contribute to the M45's relatively light weight and improved thermal efficiency. The aluminum allows for quicker heat dissipation compared to cast iron. The V-configuration, with a 90-degree bank angle, provides inherent balance and reduces vibrations.
• Valve Train: The VK45DE utilizes a dual overhead camshaft (DOHC) configuration with four valves per cylinder (32 valves total). This arrangement allows for optimal airflow and combustion efficiency. The valve timing is fixed, meaning it lacks variable valve timing technology like VVEL (Variable Valve Event and Lift) found in later Infiniti models. However, the DOHC design still enables a broad torque curve.
• Intake System: The intake manifold is designed to optimize airflow into the cylinders. A key component is the electronic throttle control (ETC), which replaces the traditional mechanical throttle cable. ETC provides precise throttle response and allows for integration with vehicle stability control systems. The air intake system also includes a mass airflow (MAF) sensor that measures the amount of air entering the engine, allowing the engine control unit (ECU) to precisely calculate the correct air-fuel mixture.
• Fuel Injection: The M45 uses a multi-point fuel injection (MPFI) system. Each cylinder has its own dedicated fuel injector, mounted close to the intake valve. MPFI offers improved fuel atomization and distribution compared to single-point injection, resulting in better combustion efficiency and reduced emissions.
• Exhaust System: The exhaust system is designed to minimize backpressure and maximize exhaust flow. It typically includes catalytic converters to reduce harmful emissions, mufflers to dampen noise, and resonators to tune the exhaust note. The M45 Sport's exhaust system is tuned to provide a sporty and aggressive sound.

The VK45DE in the 2006 M45 Sport produces approximately 335 horsepower and 340 lb-ft of torque. While these numbers might seem modest by today's standards, they provide ample power for spirited driving. The engine's smooth power delivery and responsive throttle make it a pleasure to drive in various conditions.

Drivetrain

The 2006 M45 Sport is equipped with a 5-speed automatic transmission. This transmission features adaptive shift control (ASC), which adjusts shift points based on driving style and road conditions. ASC can detect whether the driver is driving aggressively or cruising, and it will adjust shift points accordingly to optimize performance or fuel economy. The transmission also offers a manual shift mode, allowing the driver to manually select gears for greater control.

The M45 Sport is a rear-wheel-drive vehicle. The drivetrain components include:

• Torque Converter: The torque converter is a fluid coupling that transmits power from the engine to the transmission. It also provides torque multiplication at low speeds, which helps with acceleration.
• Transmission Gears: The transmission uses a series of gears to provide different gear ratios. Lower gears provide more torque for acceleration, while higher gears provide better fuel economy at cruising speeds.
• Driveshaft: The driveshaft transmits power from the transmission to the rear differential.
• Rear Differential: The rear differential splits the power from the driveshaft between the two rear wheels. It also allows the rear wheels to rotate at different speeds when turning. The M45 Sport includes a Viscous Limited-Slip Differential (VLSD), which enhances traction by limiting wheel spin when one wheel loses grip.

Suspension and Handling

The 2006 M45 Sport features a sophisticated suspension system designed to provide a balance of ride comfort and handling performance. The front suspension uses a double-wishbone design, while the rear suspension uses a multi-link design. These designs offer excellent control over wheel movement and provide precise handling.

Key suspension components include:

• Coil Springs: Coil springs provide the primary support for the vehicle's weight and absorb bumps and vibrations.
• Shock Absorbers: Shock absorbers dampen the oscillations of the springs, preventing the vehicle from bouncing excessively. The M45 Sport features electronically adjustable shock absorbers. These shocks can be adjusted to provide a firmer or softer ride, depending on the driver's preference. The suspension is managed by the Vehicle Dynamic Control (VDC) system, and drivers can choose between "Sport" and "Comfort" modes via a center console switch.
• Anti-Roll Bars: Anti-roll bars (also known as sway bars) connect the left and right wheels and reduce body roll during cornering. The M45 Sport has thicker anti-roll bars compared to the base M45, which contributes to its improved handling.
• Bushings: Bushings are rubber or polyurethane components that isolate vibrations and reduce noise. They are located at the connection points between the suspension components and the chassis.

The M45 Sport's suspension is tuned for a firmer and more responsive ride compared to the base M45. This, combined with the VLSD, provides enhanced handling and cornering capabilities.

Braking System

The 2006 M45 Sport is equipped with a four-wheel disc braking system. The front brakes use ventilated rotors, which provide improved heat dissipation and prevent brake fade. The rear brakes also use ventilated rotors. The braking system includes:

• Brake Calipers: Brake calipers house the brake pads and use hydraulic pressure to press the pads against the rotors.
• Brake Pads: Brake pads are made of a friction material that grips the rotors to slow the vehicle down.
• Master Cylinder: The master cylinder is the heart of the braking system. It converts the force applied to the brake pedal into hydraulic pressure.
• Anti-lock Braking System (ABS): ABS prevents the wheels from locking up during hard braking, allowing the driver to maintain steering control.
• Electronic Brake-force Distribution (EBD): EBD distributes braking force between the front and rear wheels based on vehicle load and road conditions. This helps to optimize braking performance and prevent skidding.
• Brake Assist: Brake Assist detects when the driver is making a panic stop and automatically applies maximum braking force.

Electronic Features

The 2006 Infiniti M45 Sport is equipped with a range of electronic features designed to enhance safety, comfort, and convenience.

• Vehicle Dynamic Control (VDC): VDC is a stability control system that helps to prevent skidding and loss of control. It uses sensors to monitor vehicle speed, steering angle, and yaw rate. If VDC detects that the vehicle is starting to skid, it will automatically apply the brakes to individual wheels and reduce engine power to help the driver regain control. VDC works in conjunction with the ABS and EBD systems.
• Traction Control System (TCS): TCS limits wheel spin during acceleration, preventing the wheels from losing traction. It uses sensors to detect wheel spin and will reduce engine power or apply the brakes to the spinning wheel.
• Navigation System: The optional navigation system provides turn-by-turn directions. It uses a GPS receiver to track the vehicle's location and displays the route on a screen in the center console.
• Infiniti Voice Recognition: This system allows drivers to control certain vehicle functions using voice commands.
• RearView Monitor: This system uses a camera mounted on the rear of the vehicle to provide a view of what's behind the car when backing up.
• Adaptive Cruise Control (Intelligent Cruise Control): This system maintains a set distance from the vehicle ahead.

In conclusion, the 2006 Infiniti M45 Sport Sedan is a technically sophisticated vehicle that offers a compelling blend of performance, luxury, and technology. Its robust V8 engine, sophisticated suspension, and advanced electronic features make it a rewarding car to drive and own. While newer models offer more advanced technology, the M45 Sport remains a testament to Infiniti's engineering prowess during the mid-2000s, and its design and engineering continue to resonate with automotive enthusiasts today.