Also, as a previous poster noted, ethanol has a high octane rating, making it appealing to manufacturers and retailers for use in Premium grade gasoline since it is a cheap octane booster in the sense that it is already used as an oxygenator and approved as an additive by the AQMD, after the outlawing of MTBE this is an important factor, so it is a no brainer octane rating booster. The downside to this is that ethanol lacks the BTU or energy content of gasoline so drivers suffer a mileage loss by using gasohol, regardless of octane rating, and the alcohol is a great attractant for water and therefore increases the rate of corrosion in fuel system components as well as the degradation of many different fuel lines as the rubber in non ethanol compliant lines is disolved by the polar solvent qualities of the alcohol.
it is dictated by law in Oklahoma which blends have E10 and which don't. We have 100% gas stations but they will carry an E10 blend for midgrade and label the other two 100% gas. you can definitely tell the difference too.
I'm reading misconceptions about ethanol here. Yes, it cheaply boosts octane, it attracts and absorbs water, it dissolves old-fashion synthetic rubber, the same butyl-types used in synthetic rubber tires, and it contains less energy than pure gas. Ethanol has about 60% as much energy as pure gas, but at a 10% mix it drops mileage only slightly. That is true, but it also has great benefits. Modern vehicles were designed for it so it does not damage your fuel system unless you have an old vehicle with non-neoprene gaskets, seals and lines. Ethanol doesn't damage neoprene. When I was a young man people routinely added "dry gas" (mostly alcohol) to their gas to avoid winter driving problems caused by water forming in the tank, hence the name. Most claimed to increase mileage. This was false unless you had a dirty fuel system to begin with. Now there's no need for it. When you take all factors into account 10% ethanol makes sense for almost all of us, except those with certain old cars, motorcycles, and boats with plain rubber fuel system parts. The rest of you are worrying about nothing. Is ethanol a good replacement for gasoline? Hell no, but it's an excellent additive for almost everyone. Not only does ethanol take water out of your system it also dissolves dirt and deposits, so your engine stays cleaner all the time, especially fuel injectors. Fuel injection loves 10% ethanol, so there you go. Way more benefit than downside.
When you take all factors into account 10% ethanol makes sense for almost all of us......your engine stays cleaner all the time, especially fuel injectors. Fuel injection loves 10% ethanol, so there you go.
Update to an old thread, with terrible & inaccurate information. Fuel injected vehicles lose 8% to 5% mpg using only 10% ethanol in gasoline. To get the energy out of ethanol, ethanol engines with 16:1 compression ratios are needed. Newer cars are built, only to reduce corrosion problems with ethanol, but ethanol blended gasoline still subtracts mpg from new cars. Diesel engines need diesel fuel, ethanol engines need ethanol, & gasoline engines need 100% (ethanol-free) gasoline for best efficiency.
Oh, one more thing about premium gas. The most important thing to remember is this. If your vehicle knocks and pings without it you need it. Otherwise you're just wasting your money
I disagree. Many high performance engines produced in the past 25 years have electronic engine management systems that detect "knock and ping" called "Detonation" and will retard the timing electronically until the detonation is eliminated. Retarding ignition timing REDUCES engine output.
Retarded timing will make your engine less powerful than the same engine running a higher octane fuel. So the guy next to you with the higher octane fuel is going to beat you when the light turns green. And the more retarded timing also shows up in fuel economy, although admittedly this is a stretch, as detonation can rarely occur under highway cruise mode at light throttle openings.
If you want the full performance potential the manufacturer built in, use the minimum octane fuel they specify.
You won't hear "knocking and pinging" even if using junk fuel, because the system turns the timing down until it goes away.