Ethanol blended gasoline, hurting engine performance, i'm afraid... Options

[saleeka]

This past weekend, I encountered a scenario that got me thinking about ethanol in gasoline again- is it hurting vehicle performance? It all started with a trip over to Wisconsin. On the way home, I had to fill the car up, so I pulled into a station just before I crossed back into MN. I've been filling my car up with premium fuel for quite some time, as I have always felt that it's made a difference in the performance of my car, even more so now that my car has 185,000 miles and has lost a lot of its original power. I noticed that the station I was at had premium fuel that was rated at 91 octane. Typically at home, the station I frequent sells 92, so immediately I thought to myself that I may notice a difference and experience decreased performance. I certainly did not expect it to make the difference that it did. There was a very noticeable improvement in the power that car was putting out! Now that I’ve used up half the tank and have seen that this wasn't a fluke, I started to ask myself why this particular tank of gas was making that difference, and it occurred to me just now.

Here in MN, it's been law for years that all gasoline sold in the state be at least 10% ethanol. After some research, I found that in WI, gasoline that is 91 octane or higher does not have this similar requirement. I then decided to read up on ethanol gasoline blends. I found that for ethanol blends to be used efficiently, the engine burning the blend should have higher fuel injection pressure or larger injectors than that of an engine that runs on gasoline alone, thus explaining why the ethanol-free gas in my car is "creating" more power... Annoying! This is also why only EFI engines can tolerate ethanol blended fuel without re-tuning of various parts of an engine's fuel supply system (cars without electronic oxygen sensors cannot compensate for the difference in energy the fuel contains. I'd also argue that some EFI systems, like our older ones, don't do a good job of adjusting, either. Most vehicles in the USA can only tolerate up to a 90/10 % split without big problems). More discouraging facts: ethanol blends have larger amounts of water in them compared to gasoline, and they also contribute to accelerated engine wear thanks to the "drying" effect alcohol has...

All this info makes me suspect that my car isn't as tired and worn out as I once thought. I'm now thinking it's the gas blends we are required to use in this state. For those of you who have easy access to ethanol-free gasoline, I'd strongly recommend selecting that choice over the blend.

[Galcobar]

There's E85, which is ethanol with 15 per cent gasoline, and then there's ethanol-blended, which is gasoline with some quantity (usually less than 15 per cent) of ethanol.

E85 requires a fuel system with nitrile rather than rubber for hoses and the like, as it can eat some materials. Most vehicles since the mid-1990s have a fuel system which can withstand ethanol in the gas, but E85 requires a little more work. E85 contains less energy per litre, meaning you will get lower MPG, but it burns cleaner. E85's corrosive properties will also break down deposits which have built up on injectors, often leading to the fuel system failing -- it's not the fuel, it's all the crap you built up in your fuel system over the years, which is why switching is generally not recommended for older cars without extensive preparation.

E85 and gas can be run on the same vehicle, but this requires some extra engineering. Actually, this is a way the domestics get around fleet emission requirements; they make large-engine vehicles flex-fuel capable and claim their fleets are cleaner, but know that 90 per cent of those vehicles will never see E85.