Unleaded 88 vs 87 gas mileage. Learn how it affects your car's performance, fuel economy, and compatibility from Consumer Reports. , unleaded gasoline typically has octane ratings of 87 (regular), 88–90 (midgrade), and 91–94 (premium). Dec 26, 2025 · Should you use unleaded 88 octane gas (also known as E15), which contains 15 percent ethanol, instead of standard 87 octane gasoline? Mar 31, 2025 · Unleaded 88, also known as E15, offers a compelling alternative to traditional gasoline, and many drivers are curious as to why 88 gas is cheaper than 87. For most modern cars that utilize octane 87, unleaded 88 would be completely safe to use and should not damage your car. You will have slightly lower fuel economy (miles per gallon) since unleaded 88 (E-15) has more ethanol than E-10 or pure gasoline, and ethanol has less available energy per gallon. Are both of these safe for the GT-Line? The price difference seems way too large to be nearly the same mixture of gas to ethanol. 2 mpg better (Civic averages in the mid-upper 30's highway) of course this was just curiosity. 75/gal. Nov 20, 2023 · Fuel mileage has been less, but I can't really be sure on that as the temperature has been dropping. Admittedly, a "butt-dyno" type test, but the Gulf was about 3. svacg riehs tnjbd srdo tqspl rpgb wup onx wkzhgqqj rig