The Infiniti M II (Y34) 45i, produced from 2002 to 2004, marked a pivotal moment for Nissan’s luxury division in the North American market. Positioned as the flagship sedan, the 45i showcased Infiniti’s dedication to performance and refinement. Built on the Y34 platform – a rear-wheel-drive chassis designed to challenge established European luxury brands – this generation M aimed to deliver a more engaging driving experience than its front-wheel-drive predecessors. The 45i, with its potent V8 engine, epitomized this ambition. Though a relatively brief production run, superseded by the M35 in 2005, the Y34 series laid the foundation for Infiniti’s subsequent success in the luxury sedan category.
Technical Specifications
| Brand | Infiniti |
| Model | M |
| Generation | M II (Y34) |
| Type (Engine) | 45i V8 32V (344 Hp) |
| Start of production | 2002 |
| End of production | 2004 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (urban) | 13.9 l/100 km (16.9 US mpg) |
| Fuel consumption (extra urban) | 10.8 l/100 km (21.8 US mpg) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 5.8 sec |
| Acceleration 0 – 62 mph | 5.8 sec |
| Acceleration 0 – 60 mph | 5.5 sec |
| Maximum speed | 235 km/h (146.02 mph) |
| Weight-to-power ratio | 5.2 kg/Hp |
| Weight-to-torque ratio | 4 kg/Nm |
| Power | 344 Hp @ 6400 rpm |
| Power per litre | 76.5 Hp/l |
| Torque | 451 Nm @ 4000 rpm (332.64 lb.-ft. @ 4000 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | VK45DE |
| Engine displacement | 4494 cm3 (274.24 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 93 mm (3.66 in.) |
| Piston Stroke | 82.7 mm (3.26 in.) |
| Compression ratio | 10.5:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | DOHC |
| Engine oil capacity | 5.6 l (5.92 US qt | 4.93 UK qt) |
| Coolant | 9.8 l (10.36 US qt | 8.62 UK qt) |
| Kerb Weight | 1790 kg (3946.27 lbs.) |
| Max. weight | 2190 kg (4828.12 lbs.) |
| Max load | 400 kg (881.85 lbs.) |
| Trunk (boot) space – minimum | 380 l (13.42 cu. ft.) |
| Fuel tank capacity | 80 l (21.13 US gal | 17.6 UK gal) |
| Length | 5009 mm (197.2 in.) |
| Width | 1770 mm (69.69 in.) |
| Height | 1463 mm (57.6 in.) |
| Wheelbase | 2800 mm (110.24 in.) |
| Front track | 1509 mm (59.41 in.) |
| Rear (Back) track | 1509 mm (59.41 in.) |
| Drivetrain Architecture | Rear wheel drive |
| Number of gears and type of gearbox | 5 gears, automatic transmission |
| Front suspension | Transverse stabilizer |
| Rear suspension | Transverse stabilizer |
| Front brakes | Ventilated discs |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Tires size | 235/45 R18 |
Powertrain & Engine Architecture
The 45i’s core was the VK45DE, a 4.5-liter naturally aspirated V8 engine. This engine, a member of Nissan’s highly regarded VQ engine family, was celebrated for its smooth operation and inherent reliability. The “DE” suffix signified dual overhead camshafts (DOHC) and electronic fuel injection. The VK45DE boasted a 60-degree V-angle, contributing to its compact dimensions and balanced operation. It employed a multi-port fuel injection system, precisely delivering fuel to each intake port. The engine generated 344 horsepower at 6400 rpm and 451 Nm (332.64 lb-ft) of torque at 4000 rpm. A 5-speed automatic transmission was coupled with the VK45DE, engineered for smooth and responsive gear changes. While not a cutting-edge transmission by contemporary standards, it harmonized well with the engine’s power delivery and the car’s grand touring character.
Driving Characteristics
The 45i delivered a markedly different driving experience compared to M models equipped with the smaller V6 engines. The V8 provided abundant power for effortless acceleration and confident highway cruising. The 0-60 mph dash was completed in roughly 5.5 seconds, making it a genuinely quick sedan for its era. The automatic transmission, while refined, wasn’t particularly focused on sportiness. Gear ratios were calibrated for comfort and fuel economy rather than aggressive performance. Compared to an M with a manual transmission, the 45i felt less engaging, but it offered a more relaxed and polished driving experience. The rear-wheel-drive configuration contributed to a balanced feel, though the car’s weight (approximately 3946 lbs) was perceptible during cornering.
Equipment & Trim Levels
As the top-tier M model, the 45i came standard with a comprehensive array of features. These included leather upholstery, power-adjustable front seats with memory settings, a premium Bose sound system, automatic climate control, and a sunroof. Optional extras encompassed a navigation system, heated seats, and a rear-seat entertainment system. Interior trim typically featured woodgrain accents, enhancing the luxurious ambiance. The exterior distinguished itself with unique badging and often incorporated larger alloy wheels compared to lower trim levels.
Chassis & Braking
The Y34 chassis utilized an independent multi-link suspension system at all four corners, designed to provide a comfortable ride and competent handling. The front suspension incorporated a transverse stabilizer bar to minimize body roll. The rear suspension also benefited from a stabilizer bar. Braking was managed by ventilated discs at the front and solid discs at the rear. Anti-lock brakes (ABS) were standard equipment. The power-assisted steering offered a light and responsive feel. The suspension tuning prioritized ride comfort, emphasizing a smooth experience over exceptionally sharp handling.
Market Reception & Comparison
The Infiniti M II 45i generally garnered positive reviews from automotive journalists. It was lauded for its powerful engine, comfortable ride, and luxurious interior appointments. However, some critics pointed out that its handling wasn’t as precise as that of certain European competitors. Fuel economy was also a concern, with the V8 engine exhibiting substantial gasoline consumption (16.9 mpg city / 21.8 mpg highway). In comparison to the M35 (powered by a 3.5-liter V6), the 45i offered considerably more power but at the expense of increased fuel consumption and a higher purchase price. The M35 was frequently considered the more pragmatic choice for buyers prioritizing fuel efficiency and value.
Legacy
The Infiniti M II 45i, despite its relatively short production lifespan, remains a sought-after vehicle among enthusiasts. The VK45DE engine is renowned for its durability and reliability, and well-maintained examples can continue to provide years of dependable service. However, as with any older luxury vehicle, maintenance expenses can be substantial. Parts availability can also present a challenge. In the used car market, the 45i commands a premium over other Y34 models due to its powerful engine and luxurious features. It represents a unique chapter in Infiniti’s history, demonstrating the brand’s ambition to compete with the leading players in the luxury sedan segment.
