I've been reading up on fuel differences between 93 octane non-ethanol gasoline vs. 93 octane E10. The owner's manual says to use a top tier 93 octane fuel. We have 93 octane in North Carolina, but some stations have 93 or 89 non-ethanol, but they are a non-top tier fuel carrier. Apparently, a top tier fuel has more detergents than a non-top tier fuel. The detergents are designed to reduce the build up on the valves, for example. I wonder if there are detergents that can be added to a non- top tier fuel or is there an additive to use to significantly reduce the effects of alcohol on the engine and fuel components? Or perhaps...there's really no serious effects of E10 on our engines? This seems to be a highly debated issue. What are your thoughts?
You can add "detergents" to gasoline. One way -- probably the "best" way -- is to add Techron. But the off the shelf stuff is concentrated and while it works well is really intended to be a once in a while -- great while -- treatment. For instance a tank or two *before* a scheduled oil change.
Techron is not something I'd use every tank unless you can buy Chevron gasoline which is of course treated with Techron. With a previous car I found a switch from Shell V-Power to Chevron Supreme had the engine running noticeably better in less than a tank of Chevron gasoline. Rather surprised me as Shell V-Power is a pretty good gasoline.
Really though the best course is to just fill up with a top tier fuel from a busy station. Use the appropriate grade of octane. 93 is good if you can get it. 91 works.
If you can find 93 ethanol free and the price difference is not too bad compared to 93 with ethanol run ethanol free gasoline. The ethanol is not that big of a deal to the engine or fuel system components -- ran gasoline with "10%" ethanol in a number of cars over the years some cars obtaining 160K to over 315K miles with no harm to the engine or fuel system components -- but ethanol free gasoline contains a bit more chemical energy and engine performance (gas mileage) will be better. Whether it is better enough to offset the price difference you'll have to determine by some disciplined fuel economy testing.
If you track your car try to arrange to fill up the tank -- how full you have to decide -- with lead free race gasoline.
Race gasoline has an elevated octane rating which is overkill and the engine will not be able to take advantage of it but it does buy some extra margin as it is unlikely the engine controller will ever have to dial back timing due to detonation.
But racing gasoline offers more than just elevated octane number. It is designed/blended to burn well (really well) at higher engine speeds. So try to have as little street gasoline in the gas tank as is practical and put as much racing gasoline in the gas tank -- to have a "pure" racing gasoline as possible -- for when you visit the track.