15 MPG combined. That number looms over the 2018 Jeep Grand Cherokee SRT 4WD 6.4L. It’s also a number irrelevant to most buyers of this tire-incinerating SUV. These buyers aren’t comparing it to fuel-sipping vehicles. They want the thundering sound and strong acceleration that only a naturally aspirated 6.4-liter Hemi V8 can provide, and they’re willing to pay for it at the pump.

City and highway performance

The EPA estimates 13 MPG in the city and 19 MPG on the highway. The city figure reflects constant stop-and-go driving in urban environments, making the engine work harder and consuming more fuel. The highway number, while still low by modern standards, shows the benefits of the eight-speed automatic transmission. Once cruising, the engine settles into a lower RPM, for better efficiency. Heavy-footed drivers won’t even achieve these figures, especially given the Hemi’s tempting power. For all Jeep fuel economy data, check out the relevant pages.

Annual fuel cost

The EPA estimates the annual fuel cost for the 2018 Jeep Grand Cherokee SRT at $3,850. This is based on driving 15,000 miles per year, with 55% of those miles in the city and 45% on the highway, using national average fuel prices. Your actual costs could vary based on driving habits, location, and fuel prices. This is a realistic baseline to consider. It underscores the SRT’s need for premium gasoline. Compare this to GRAND MPG across all years, including less powerful and more efficient trims.

Real-world expectations

Expect to fall below the EPA estimates in real-world driving. The Grand Cherokee SRT is a heavy vehicle, and its powerful engine is very responsive, tempting drivers to use its full potential. Aggressive acceleration, frequent braking, and extended idling will all hurt fuel economy. Expect single-digit MPG during spirited driving. Highway trips, driven conservatively, might get you closer to 19 MPG, but consistent fuel-sipping isn’t this vehicle’s strength.

How it compares

The 2018 Grand Cherokee SRT doesn’t have many direct competitors when you consider its combination of performance, practicality, and price. A similarly sized and powerful BMW X5 M, while offering slightly better handling, commands a higher price and manages only 16 MPG combined. A Dodge Durango SRT with the same engine offers nearly identical fuel economy. Even more common SUVs such as the Ford Explorer with the 3.5L V6 manage only 20 MPG combined. These comparisons illustrate that if horsepower and a V8 soundtrack are priorities, fuel economy is simply a trade-off. The SRT buyer isn’t looking for efficiency; they’re buying an experience.

Tips to maximize efficiency

While squeezing every last drop of fuel from a Hemi-powered Grand Cherokee might seem pointless, you can mitigate the damage with a few changes. Avoid aggressive acceleration and braking. The SRT’s engine management system responds quickly to throttle inputs, but smooth driving yields the best results.

Use the eight-speed automatic transmission. It’s designed to keep the engine in its most efficient operating range. Using the paddle shifters can decrease fuel efficiency if you’re not careful, as it encourages higher RPMs.

Ensure your tires are properly inflated to the recommended pressure. Underinflated tires increase rolling resistance, forcing the engine to work harder and consume more fuel. Check your tire pressure regularly, especially during temperature fluctuations.

Minimize idling. The SRT’s engine consumes fuel when idling, especially when cold. If you anticipate being stationary for more than a minute or two, turn off the engine.

Consider using the Eco mode, if equipped. This mode alters the engine and transmission tuning to prioritize fuel efficiency over performance. While it might tame the SRT’s power, it can make a difference during everyday driving; consider this, even if it’s rarely used.