In the July 2019 issue of Car & Driver, the performance and gas mileage of four vehicles which run on regular 87 octane gas were compared to running them on premium 93 octane gas. One of the cars tested was a 2019 Dodge Charger R/T, with a 5.7 Hemi. The results showed that there was virtually no improvement in performance or gas mileage when using the higher octane gas. However, the horsepower and torque increased from 318 wheel hp. to 332 hp. and 364 lb.-ft. to 387 ft.-ft. They attributed the increases to the engine controller advancing the ignition timing until it detected knocking. Here are the test specifics (87 vs. 93 octane): 0-60 mph.= 4.9 sec.; 0-60 mph.= 4.9 sec. o-100 mph.= 11.9 sec.; 11.7 sec. 1/4 mile= 13.5 [email protected] mph.; 13.4 [email protected] mph. 75 mph. fuel economy= 23.2 mpg.; 23.5 mpg.