The 2018 Jaguar XJL with the supercharged 5.0L V8 gets 18 MPG combined. To be clear, the XJL 5.0 isn’t bought by someone seeking exceptional fuel efficiency. It’s acquired by drivers who prioritize effortless power, the distinctive growl of a supercharged V8, and the exclusivity that comes with owning a long-wheelbase Jaguar flagship. Fuel economy is simply a cost of doing business.

City and highway performance

The EPA estimates 15 MPG in the city and 23 MPG on the highway. These figures reflect the nature of the supercharged V8. City driving, with its constant stop-and-go, forces the engine to work harder off-boost, negating any potential fuel savings. The weight of the long-wheelbase XJL (well over two tons) also contributes to lower city MPG. On the highway, the XJL settles into a comfortable cruise, allowing the eight-speed automatic transmission to select taller gears and improve efficiency. Even on the open road, the temptation to exploit the supercharger’s readily available power will invariably decrease fuel economy.

Annual fuel cost

The EPA estimates an annual fuel cost of $3,200 for the 2018 Jaguar XJL 5.0L. This figure is based on driving 15,000 miles per year, with an assumed fuel price reflecting the national average. Your actual fuel costs may vary significantly depending on your driving habits, the prices at your local gas station, and the grade of fuel you choose to use. This model requires premium fuel, which has a significantly higher cost per gallon than regular.

Real-world expectations

While the EPA figures provide a baseline, real-world fuel economy for the XJL 5.0L is often lower. Aggressive driving, frequent short trips, and extended idling can all negatively impact MPG. Owners who prioritize performance and the thrill of the supercharged engine will naturally see lower numbers than those who adopt a more sedate driving style. A realistic expectation for mixed driving is often in the 14-17 MPG range. Highway driving, conducted at consistent speeds, might push the figure closer to 22 MPG, but achieving the EPA’s 23 MPG requires considerable restraint.

How it compares

Compared to its competitors, the XJL 5.0L’s fuel economy is predictably poor. The Mercedes-Benz S560, with its twin-turbo V8, offers a more acceptable 17 MPG city and 27 MPG highway. The BMW 750i xDrive, another twin-turbo V8 competitor, achieves 17 MPG city and 25 MPG highway. Even the aging Lexus LS 500, with its twin-turbo V6, manages only 19 MPG city and 30 MPG highway. The Audi A8, with its more modern mild-hybrid V6, trounces the Jaguar at 22 MPG city and 29 MPG highway. These differences matter to some luxury car buyers, who may prioritize efficiency alongside performance and prestige. Those drawn to the Jaguar badge, the distinctive V8 soundtrack, and the exclusivity of the XJL likely accept the fuel economy penalty as part of the experience. For those considering other Jaguar models, all Jaguar fuel economy data are readily available for comparison. You can also browse XJL MPG across all years.

Tips to maximize efficiency

Gentle acceleration is key to saving fuel in the XJL 5.0L. The supercharger delivers instant power, but using it frequently and aggressively will rapidly deplete the fuel tank. Focus on smooth, gradual acceleration to minimize the demand on the engine.

Use cruise control on the highway to maintain a consistent speed and avoid unnecessary acceleration and deceleration. Cruise control helps optimize fuel consumption by preventing speed fluctuations that waste gas.

Ensure that your tires are properly inflated. Underinflated tires increase rolling resistance, forcing the engine to work harder and reducing fuel economy. Regularly check and maintain the recommended tire pressure.

Minimize idling. The XJL’s V8 consumes a significant amount of fuel while idling. If you anticipate stopping for more than a minute or two, turn off the engine to conserve fuel. Although the car does have auto start/stop, this is not always active and may often switch off when certain high-drain systems are active (HVAC, heated seats, etc.).

Schedule regular maintenance. A well-maintained engine operates more efficiently. Follow the recommended maintenance schedule for oil changes, air filter replacements, and spark plug replacements to ensure optimal fuel economy.