What is the difference between 89 and 91 gas

When I use ethanol gasoline, my mileage drops into the 13 to 15 miles per gallon range. When using non-ethanol gasoline, my mileage goes up to the 23 to 27 mileage. What about 85 octane? Which is the best gas for ur car if a mechanic tell u u get the high percentage for ur car to help clean gas line out. I thought that octane was gasolines ability to hold oxygen therefore at higher elevations where the air is thinner the gasoline cannot hold as much oxygen resulting in a lower octane rating.

Is this correct? When your cars engine with carburetor is tuned for sea level driving, the gasoline octane rating should be determined on the compression ratio of the engines combustion chamber.

The carbureted engine will start to smoke black smoke, too much fuel and start running erratically! Old hot rodders such as myself always carry a case with different sized main jets, and stop before the erratic behavior begins.

This is where you better have knowledge of how to disassemble your carb and reassemble it after changing jets. When higher-octane fuel is flowing through its injectors, the engine controller can take advantage of the elevated knock threshold and dial in more aggressive timing and higher boost pressures to improve performance. To understand how higher octane affects acceleration and efficiency, we assembled a four-wheeled quartet sampling a broad spectrum of the market.

The Honda CR-V stands in for a swath of affordable crossovers and sedans with its turbocharged 1. At the intersection of effortless speed and opulent luxury, the BMW M5 Competition squeezes horsepower from its twin-turbo 4. Ford's F is America's best-selling vehicle and is equipped here with its most potent engine, the hp EcoBoost twin-turbo 3. We performed acceleration runs, mile fuel-economy loops at 75 mph, and dynamometer pulls, running each vehicle on two different fuels and completely draining the tanks in between.

The differences likely would have been exaggerated by extreme summer heat, which exacerbates engine knock, but we sniffed out differences even with the engines huffing cool midwestern spring air. Even as it's sucking down as much as Honda asks for 87 octane and makes no claims that raising the fuel octane will lift performance.

Based on our testing, premium fuel might as well not exist in the CR-V's world. We could see this coming. During a similar Car and Driver test 18 years ago, an Accord powered by a 3. The modern CR-V, with half the displacement but rated at just 10 fewer ponies, makes the same argument: don't waste your money on premium.

Switching from 87 octane to 93 yielded a 7-hp gain on the dynamometer, but that advantage was lost in the noise at the track. There, the CR-V's zero-tomph and quarter-mile times both tracked a tenth of a second slower on the expensive stuff.

While fuel economy at 75 mph ticked up from Honda built its reputation on a line of unassuming, egalitarian motorcycles in the '60s. Nearly 60 years later, the company's identity is still predicated on the same sensible and modest ethic, right down to the fuel that you put in the tank. BMW explicitly warns about engine damage from doing so, and while that seemed unlikely in such mild temperatures, using the cheap stuff would have been wildly out of touch with what an owner would do at least until this M5 reaches its fourth owner sometime in BMW requires octane fuel at a minimum, with 93 recommended, so we did just that, switching between the common forms of premium gas depending on which state you're in.

Are Californians, with their watered-down premium, leaving something on the table? You might save money on gas, but in this situation, you get what you pay for.

Research by AAA found that these vehicles saw a slight increase in performance and fuel economy using premium gas. Depending on what and how you drive, commuters looking to get from Point A to Point B may not notice the difference or care. At the end of the day, it all comes down to your preference.

Your car, your rules. Type: Car Ownership. Published: January 11, So, what's the difference between premium and regular gas? Do you fill up with Regular or Premium Unleaded? Can you feel a difference in performance? Leave me a comment and letschat! March 15, What types of fuel grades for cars are there? Is a higher octane fuel worth the price?