The Infiniti FX45, specifically the facelifted version produced from 2006 to 2008, represented a significant offering in the burgeoning luxury crossover segment. Positioned as the performance-oriented variant of the FX line, it distinguished itself with a naturally aspirated 4.5-liter V8 engine and standard all-wheel drive. This iteration, falling within the first generation (FX I) of the model, aimed to deliver a blend of luxury, sporty handling, and robust power, appealing to buyers seeking an alternative to more traditional SUVs and sedans. The 2006 facelift brought subtle styling revisions and refinements to the interior, further solidifying the FX45’s position as a premium vehicle.
Technical Specifications
| Brand | Infiniti |
| Model | FX |
| Generation | FX I (facelift 2006) |
| Type (Engine) | 45 V8 32V (319 Hp) AWD |
| Start of production | 2006 |
| End of production | 2008 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Crossover |
| Seats | 5 |
| Doors | 5 |
| Fuel consumption (urban) | 15.7 l/100 km (15 US mpg, 18 UK mpg, 6.4 km/l) |
| Fuel consumption (extra urban) | 12.4 l/100 km (19 US mpg, 22.8 UK mpg, 8.1 km/l) |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 6.3 sec |
| Acceleration 0 – 62 mph | 6.3 sec |
| Acceleration 0 – 60 mph | 6 sec |
| Maximum speed | 225 km/h (139.81 mph) |
| Weight-to-power ratio | 6.3 kg/Hp, 159.1 Hp/tonne |
| Weight-to-torque ratio | 4.3 kg/Nm, 232.4 Nm/tonne |
| Power | 319 Hp @ 6400 rpm |
| Power per litre | 71 Hp/l |
| Torque | 466 Nm @ 4000 rpm (343.7 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 |
| Engine oil capacity | 5.8 l (6.13 US qt | 5.1 UK qt) |
| Coolant | 10 l (10.57 US qt | 8.8 UK qt) |
| Kerb Weight | 2005 kg (4420.27 lbs.) |
| Max. weight | 2478 kg (5463.05 lbs.) |
| Max load | 473 kg (1042.79 lbs.) |
| Trunk (boot) space – minimum | 776 l (27.4 cu. ft.) |
| Trunk (boot) space – maximum | 1826 l (64.48 cu. ft.) |
| Fuel tank capacity | 90 l (23.78 US gal | 19.8 UK gal) |
| Length | 4803 mm (189.09 in.) |
| Width | 1925 mm (75.79 in.) |
| Height | 1674 mm (65.91 in.) |
| Wheelbase | 2850 mm (112.2 in.) |
| Front track | 1593 mm (62.72 in.) |
| Rear (Back) track | 1640 mm (64.57 in.) |
| Drive wheel | All wheel drive (4×4) |
| Number of gears and type of gearbox | 5 gears, automatic transmission |
| Front suspension | Independent, type McPherson with coil spring and anti-roll bar |
| Rear suspension | Independent multi-link spring suspension with stabilizer |
| Front brakes | Disc |
| Rear brakes | Disc |
| Assisting systems | ABS (Anti-lock braking system) |
| Tires size | 265/50 R20 |
Powertrain & Engine Architecture
The heart of the 2006-2008 Infiniti FX45 is the VK45DE 4.5-liter V8 engine. This engine, a member of Nissan’s VQ family, is a 32-valve, naturally aspirated powerplant. It utilizes a cast aluminum block and cylinder heads, contributing to a relatively lightweight construction for its size. The VK45DE employs a multi-port fuel injection system, delivering fuel directly into each intake port for optimized combustion. The engine’s valvetrain features dual overhead camshafts (DOHC) with continuously variable valve timing (CVTCS) on both intake and exhaust valves, enhancing both performance and fuel efficiency. The engine’s 466 Nm (343.7 lb-ft) of torque is readily available at 4000 rpm, providing strong acceleration. Paired with the VK45DE is a five-speed automatic transmission, designed to handle the engine’s substantial power output. This transmission features adaptive shift control, adjusting shift points based on driving conditions and driver input.
Driving Characteristics
The FX45’s driving experience is markedly different from its 3.5-liter V6 siblings. The V8 delivers a significantly stronger surge of power, resulting in a 0-60 mph time of around 6 seconds. The five-speed automatic transmission, while not as sophisticated as some modern eight or nine-speed units, provides smooth and responsive shifts. The all-wheel-drive system, typically operating in a rear-biased configuration, enhances traction and stability, particularly in adverse weather conditions. The FX45’s suspension, tuned for a balance between comfort and handling, provides a relatively firm ride, minimizing body roll during cornering. Compared to the FX35, the FX45 offers a more refined and powerful driving experience, albeit with a slight penalty in fuel economy.
Equipment & Trim Levels
The 2006-2008 Infiniti FX45 came generously equipped as standard. Interior features included leather upholstery, power-adjustable heated front seats, a Bose premium audio system, and a navigation system. Standard exterior features included 20-inch alloy wheels, automatic headlights, and a power liftgate. Optional extras included a rear-seat entertainment system, adaptive cruise control, and a panoramic sunroof. The interior design emphasized a sporty and luxurious aesthetic, with metallic accents and a driver-focused cockpit layout.
Chassis & Braking
The FX45 utilizes a robust chassis with independent suspension all around. The front suspension employs a McPherson strut design with coil springs and an anti-roll bar, while the rear features a multi-link setup, also with coil springs and a stabilizer bar. Braking duties are handled by four-wheel disc brakes with standard ABS (Anti-lock Braking System). The FX45’s braking performance is strong and consistent, providing confident stopping power. The vehicle’s relatively heavy weight (around 2005 kg or 4420 lbs) necessitates the robust braking system.
Market Reception & Comparison
The Infiniti FX45 was generally well-received by automotive critics, who praised its powerful engine, sporty handling, and luxurious interior. However, its fuel economy was often cited as a drawback, particularly compared to the FX35. The FX45 competed with other luxury crossovers such as the BMW X5, Porsche Cayenne, and Acura MDX. While the FX45 offered a unique blend of performance and luxury, it often came at a higher price point than some of its competitors. Reliability reports generally indicated good overall dependability, although some owners reported minor issues with the electronic systems.
Legacy
The VK45DE engine, while not known for being particularly fuel-efficient, has proven to be a durable and reliable powerplant when properly maintained. The 2006-2008 Infiniti FX45 remains a desirable vehicle in the used car market, particularly among enthusiasts seeking a powerful and distinctive crossover. Its unique styling and robust V8 engine continue to appeal to buyers looking for an alternative to more mainstream luxury vehicles. Regular maintenance, including timely oil changes and fluid checks, is crucial for ensuring the long-term reliability of the FX45’s powertrain.
