When is the best time to buy the latter? The main difference between regular unleaded petrol and premium-branded unleaded is that the latter will have an increased octane rating, also known as research octane number RON. The benefits of using a fuel with a higher octane rating includes improved engine performance and lower consumption. Improvements you are more likely to notice, however, include improved acceleration, better pulling power at low revs and a smoother and quieter drive when on the move.
Premium or super unleaded petrol also contain additives designed to keep your engine clean, so your car will perform better for longer. Inside the fuel cap of some new cars will be a label showing what RON is recommended when refilling. The number shown will be either 95 or This is important to remember because 95 is the typical research octane number for regular unleaded, while it is 98 for premium unleaded.
If a car only shows RON 98 inside the fuel cap, then the car should only use a premium unleaded fuel in order to function properly. Picking a premium petrol fuel over regular unleaded is most beneficial for high-performance engines. Not only are they put under a lot of strain, they are also under more risk of suffering engine knocking, especially if they use a turbocharger or supercharger.
Whether you can notice the difference subjectively, though, is down to how attuned you are to your car. Extreme cases of detonation can badly damage an engine. This cylinder head from a very highly tuned competition engine looks like it has been nibbled by rats. Related articles. Latest Drives. Ferrari Competizione review. Cupra Formentor VZ2 1. View all latest drives. Read our review Car review. The trend that's changing the way America moves is far subtler than any good click-generating headline would have you believe.
Electric vehicles are decades away from showing up en masse at country-music concerts, county fairs, and Tractor Supply parking lots.
True go-anywhere autonomy will prove as elusive as finding satisfying vegan bacon. The trend we're really living is the story of smaller engines working harder, in everything from family crossovers to six-figure autobahn barges. Downsized but hardly diminished, many of these shrunken engines are more powerful than their predecessors, thanks to turbocharging, variable valve timing and lift, direct injection, and the advanced computer controls tying these all together.
Today's engines are so sophisticated that even mainstream nonperformance vehicles can benefit from running on higher-octane premium fuel. Vehicles such as the Ford Escape and Mazda 6 are advertised with power figures made on octane fuel, although both companies are quick to note that these vehicles will happily run on What automakers rarely say is what, precisely, are the benefits of paying for premium.
That ambiguity can be expensive. Raising the octane rating also known as the anti-knock index doesn't change the energy content of a gallon of gasoline. A higher octane rating indicates greater resistance to knock, the early combustion of the fuel-air mixture that causes cylinder pressure to spike. 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.
0コメント