JeepGrand Cherokee 2017 5.7 V8 HEMI Fuel Consumption (Economy), Emissions and Range. Fuel Consumption - Economy - Combined: 18 MPG 13 L/100 km 22 MPG UK: Fuel Consumption - Economy - Open road: 26 MPG 9.2 L/100 km 31 MPG UK: Fuel Consumption - Economy - City: 12 MPG 19.6 L/100 km 14 MPG UK: Someversions have been modified to make more than 10,000 horsepower in Top Fuel racing applications. The New HEMI. After 1971, Chrysler and Dodge stopped 89Octane with 5 fills = 18.8 mpg average. 87 Octane with 3 fills = 17.8 mpg average. 87 Octane/Superchips Economy tune with 7 fills = 18.6. 60 mile per day commute. 60% Highway @67-70 mph with lots of hills. They have recently switched over to summer mix fuel which I've been noticing +1mpg. However when it comes to fuel efficiency, it's natural for drivers to wonder about the miles per gallon (mpg) that this engine offers. The official figures state that the 5.7L HEMI® V8 engine with eTorque achieves an estimated 17 mpg in the city and 23 mpg on the highway for 2WD models, while 4WD models attain 15 mpg in the city and 22 mpg RT 5.7 HEMI V8 (370 Hp) Automatic : Start of production : 2019 year : End of production : December, 2023 year : Powertrain Architecture : Internal Combustion engine : Body type: Sedan : Seats : 5 : Doors : 4 : Performance specs; Fuel consumption (economy) - urban : 15.7 l/100 km 14.98 US mpg 17.99 UK mpg 6.37 km/l: Fuel consumption (economy Chrysler300C 5.7 Hemi V8 Fuel Consumption (Economy), Emissions and Range. Fuel Consumption - Economy - Combined: 19 MPG 12.1 L/100 km 23 MPG UK: Fuel Consumption - Economy - Open road: 27 MPG 8.7 L/100 km 32 MPG UK: Fuel Consumption - Economy - City: 13 MPG 18.1 L/100 km 16 MPG UK: Aslong as it's top tier fuel, 87 is fine. IF you want the maximum HP the engine is capable of making, use 89. I haven't noticed a fuel economy increase with 89, my Hereare the 8 best tuners/programmers for your 5.7 HEMI RAM/DODGE/JEEP. 1. FLASHPAQ F5 #3845 In-Cab Tuner – For 1998-14 RAM 1500 & Durango. 2. DiabloSport Predator 2 #7302 programmer for 5.7 HEMI RAM 2500. 3. TheBig Horn came standard with the 3.6-liter Pentastar eTorque V-6 that offers an EPA fuel-economy rating of 20/25/22 mpg city/highway/combined for the 4×2 and 19/24/21 mpg for the 4×4. TheHemi-powered 2500HD’s work ethic is a long way from wimpy. Its claimed payload is 3300 pounds, and with a 4.10:1 rear axle (our test truck was so equipped; add $570, which includes a limited e3RF.