The Jaguar XJ X358 R 4.2 V8 Automatic, produced from 2007 to 2009, represented the pinnacle of performance within the X358 generation of Jaguar’s flagship sedan. Positioned as the high-performance variant, the ‘R’ model offered a substantial upgrade over the standard XJ models, both in terms of engine output and dynamic capabilities. The X358 itself was a significant refresh of the XJ series, building upon the X350 platform with revised styling cues inspired by the earlier Jaguar models, and a greater emphasis on luxury and refinement. This particular variant aimed to compete with high-performance luxury sedans from German manufacturers like BMW and Mercedes-Benz, offering a unique blend of British elegance and potent V8 power.
Technical Specifications
| Brand | Jaguar |
| Model | XJ |
| Generation | XJ (X358) |
| Type (Engine) | R 4.2 V8 (395 Hp) Automatic |
| Start of production | 2007 |
| End of production | 2009 |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Sedan |
| Seats | 5 |
| Doors | 4 |
| Fuel consumption (economy) – urban (NEDC) | 17.9 l/100 km (13.1 US mpg, 15.8 UK mpg, 5.6 km/l) |
| Fuel consumption (economy) – extra urban (NEDC) | 8.7 l/100 km (27 US mpg, 32.5 UK mpg, 11.5 km/l) |
| Fuel consumption (economy) – combined (NEDC) | 12.1 l/100 km (19.4 US mpg, 23.3 UK mpg, 8.3 km/l) |
| CO2 emissions (NEDC) | 289 g/km |
| Fuel Type | Petrol (Gasoline) |
| Acceleration 0 – 100 km/h | 5.3 sec |
| Acceleration 0 – 62 mph | 5.3 sec |
| Acceleration 0 – 60 mph | 5 sec |
| Maximum speed | 250 km/h (155.34 mph), Electronically limited |
| Emission standard | Euro 4 |
| Weight-to-power ratio | 4.2 kg/Hp, 239 Hp/tonne |
| Weight-to-torque ratio | 3.1 kg/Nm, 327.3 Nm/tonne |
| Power | 395 Hp @ 6100 rpm |
| Power per litre | 94.1 Hp/l |
| Torque | 541 Nm @ 3500 rpm (399.02 lb.-ft. @ 3500 rpm) |
| Engine layout | Front, Longitudinal |
| Engine Model/Code | AJ34S |
| Engine displacement | 4196 cm3 (256.06 cu. in.) |
| Number of cylinders | 8 |
| Engine configuration | V-engine |
| Cylinder Bore | 86 mm (3.39 in.) |
| Piston Stroke | 90.3 mm (3.56 in.) |
| Compression ratio | 9.1:1 |
| Number of valves per cylinder | 4 |
| Fuel injection system | Multi-port manifold injection |
| Engine aspiration | Supercharger, Intercooler |
| Valvetrain | DOHC |
| Engine oil capacity | 6 l (6.34 US qt | 5.28 UK qt) |
| Coolant | 12.35 l (13.05 US qt | 10.87 UK qt) |
| Kerb Weight | 1653 kg (3644.24 lbs.) |
| Max. weight | 2263 kg (4989.06 lbs.) |
| Max load | 610 kg (1344.82 lbs.) |
| Trunk (boot) space – minimum | 470 l (16.6 cu. ft.) |
| Fuel tank capacity | 85 l (22.45 US gal | 18.7 UK gal) |
| Max. roof load | 75 kg (165.35 lbs.) |
| Permitted trailer load with brakes (12%) | 1900 kg (4188.78 lbs.) |
| Permitted trailer load without brakes | 750 kg (1653.47 lbs.) |
| Permitted towbar download | 75 kg (165.35 lbs.) |
| Length | 5091 mm (200.43 in.) |
| Width | 1860 mm (73.23 in.) |
| Width with mirrors folded | 1898 mm (74.72 in.) |
| Width including mirrors | 2104 mm (82.83 in.) |
| Height | 1462 mm (57.56 in.) |
| Wheelbase | 3034 mm (119.45 in.) |
| Front track | 1556 mm (61.26 in.) |
| Rear (Back) track | 1546 mm (60.87 in.) |
| Drag coefficient (Cd) | 0.32 |
| Minimum turning circle (turning diameter) | 11.7 m (38.39 ft.) |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the rear wheels of the vehicle. |
| Drive wheel | Rear wheel drive |
| Number of gears and type of gearbox | 6 gears, automatic transmission |
| Front suspension | Double wishbone, Transverse stabilizer |
| Rear suspension | Double wishbone, Transverse stabilizer |
| Front brakes | Ventilated discs |
| Rear brakes | Ventilated discs |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Power steering | Hydraulic Steering |
| Tires size | 255/35 ZR20 |
| Wheel rims size | 9J x 20 |
Powertrain & Engine Architecture
The heart of the XJ R was the 4.2-liter supercharged V8 engine, designated AJ34S. This engine was a significant departure from naturally aspirated Jaguar engines of the past, utilizing a Roots-type supercharger with an intercooler to dramatically increase power output. The engine featured a 9.1:1 compression ratio, multi-port fuel injection, and double overhead camshafts (DOHC) with four valves per cylinder. The supercharger, driven by the engine’s crankshaft, forced air into the cylinders, boosting horsepower and torque. The AJ34S engine was known for its smooth power delivery and distinctive supercharger whine. The six-speed automatic transmission, sourced from ZF, was specifically calibrated to handle the engine’s substantial torque output. This transmission featured a torque converter lock-up clutch for improved fuel efficiency at cruising speeds.
Driving Characteristics
The XJ R 4.2 V8 Automatic delivered a markedly different driving experience compared to the standard XJ models. The supercharged engine provided effortless acceleration, with 0-60 mph times consistently around 5 seconds. The automatic transmission, while smooth, was tuned for performance, holding gears longer and downshifting quickly in response to throttle input. Compared to the naturally aspirated 4.2-liter engine, the ‘R’ offered a significant increase in power and torque, resulting in a more engaging and dynamic driving experience. While not as overtly sporty as some of its German rivals, the XJ R provided a comfortable yet capable grand touring experience. The rear-wheel-drive configuration contributed to a balanced chassis, although traction could be a concern in wet conditions.
Equipment & Trim Levels
The XJ R came standard with a comprehensive list of luxury features, including leather upholstery, wood veneer trim, heated and cooled front seats, a premium sound system, and automatic climate control. Unique to the ‘R’ model were sport seats with increased bolstering, a sport steering wheel, and exterior styling cues such as a mesh grille and unique alloy wheel designs. Optional extras included a rear seat entertainment system, adaptive cruise control, and a panoramic sunroof. The interior was designed to provide a luxurious and refined environment, with a focus on craftsmanship and attention to detail.
Chassis & Braking
The XJ R featured a fully independent suspension system with double wishbones at both the front and rear, along with transverse stabilizers to reduce body roll. The suspension was tuned for a balance between comfort and handling. Braking duties were handled by ventilated discs on all four wheels, coupled with an Anti-lock Braking System (ABS). The braking system was more than adequate for the car’s performance capabilities, providing confident stopping power. The XJ R’s chassis was reinforced compared to the standard XJ models to handle the increased power and torque.
Market Reception & Comparison
The XJ R 4.2 V8 Automatic was generally well-received by automotive critics, who praised its powerful engine, luxurious interior, and comfortable ride. However, some critics noted that its fuel economy was relatively poor, and its handling was not as sharp as some of its German competitors. Compared to the standard XJ models, the ‘R’ offered a significant performance upgrade, but at a higher price point. Against rivals like the BMW 750i and Mercedes-Benz S550, the XJ R offered a unique blend of British luxury and performance, but often lagged behind in terms of outright handling prowess.
Legacy
The AJ34S engine, while robust, is known to require diligent maintenance, particularly regarding timing chain tensioners. Regular oil changes and careful monitoring of coolant levels are crucial for long-term reliability. Today, the XJ X358 R 4.2 V8 Automatic represents a compelling value proposition in the used luxury car market. Its combination of performance, luxury, and relative rarity makes it an appealing choice for enthusiasts seeking a distinctive and rewarding driving experience. While maintenance costs can be higher than more common luxury cars, the XJ R offers a unique and rewarding ownership experience for those willing to invest in its upkeep.
