Dec
17
Will the E15 15% Ethanol Mix Be a Problem For You?
December 17, 2009 | 5 Comments
Its looks like it will be August 2010 before the U.S. Environmental Protection Agency comes in with the whether or not of the adding of 15% ethanol to gasoline fuel called E15 instead or in addition to the 10% E10 mix used widely now. Much press and media attention is being touted for both views, one being its great and the other being its trouble. Both points are true; the task is to figure out if it’s a problem for oneself.
Much is made of the loss of mileage claims for ethanol substitutes. Most are PR stunts, leaving the ill and uninformed with an impression that may be false. The hard chemical reality is that ethanol has lower energy and higher resistance to ignition than gasoline products, even the very high-octane gasoline blends. An ethanol fuel only engine could have a compression ratio as high as 16:1. Its little wonder ethanol was accepted warmly by racing groups.
Ethanol doesn’t have as much energy by volume as gasoline by about a third. In a linear thinking a drop in mileage should come in for E10 at about 3 1/3rd percent. That is complicated by the added boost to octane. In modern computer controlled engines with knock sensors that octane can be quite beneficial if the engine’s compression ratio is high enough to exploit the added octane. Higher compression increases engine efficiency that can level out the mileage loss or improve it. Most, but not all engine computer controllers will seek efficiency up to pre-ignition – those engine owners get a worthwhile advantage from ethanol blends. Whether E15 will take that further is again about the engine’s compression ratio and the sophistication of the computer’s controller.
Another consideration is that ethanol doesn’t ignite as easily; especially in cold weather cold starts. But a little gasoline in the blend solves that problem; even current E85 users don’t notice an issue for cold starting if their engine is in good condition. Fuel injection that does a good job sets up very easy to ignite fuel mix conditions solving any problems up to E85.
Lastly, alcohols have oxygen in the molecules, which can react with fuel system parts. Corrosion, degradation, and other chemical reactions can occur if the materials manufacturers choose to build fuel systems are wrong for oxygenated fuels. The oxygen issue isn’t limited to alcohols; some blame can be assigned to other additives. For older, cheaper, and in particular smaller engines – oxygenates can cause serious problems.
For U.S. autos, most vehicles less than 15 to 20 years old are not going to experience problems other than what age and wear present anyway. E15 might cost an additional 2% loss of mileage or not. But that’s in the hands of the fuel marketers for higher compression engine owners. A poorer grade of gasoline with 15% ethanol can still be low octane. It will be interesting to see if the EPA acts intelligently enough to mandate minimum octane levels, say around 90 for r/m octane rated products.
The biggest problems are going to be for small engine owners. Small gasoline engines are notorious for low cost parts in a highly competitive market. Lawnmowers, snow blowers, chainsaws, boat engines and other small engines may well experience problems with fuel system materials. The older the engine, the lower the price of the engine the more likely that the engine was built with inferior materials. Most are carbureted, so the exasperation level would run high.
This writer has two worthwhile experiences about transitioning to ethanol blends. First was an early 1960s MontgomeryWard lawn mower. The path to using E10 reliably was replacing the metal fuel tank with a plastic one, the metal line to the carburetor with modern hose, an inline filter, and a carburetor kit. The effort worked for a while. A teardown found the fuel bowl had corroded again, an issue solved by using a quality enamel base paint. The mower ran fine for years. The lesson was that ethanol can be used with material upgrades.
Volvo1975 Model 240. Click image for the largest view.
The second was a 1975 Volvo that had mechanical fuel injection, solid-state ignition, but no computer control. The engine though was a detuned for the U.S. market model, still with 10.5:1 compression. E10 worked well, with fuel mileage in the low 20s. Purchased used, and checked over time, a compression test revealed weak valve springs. When the valve springs were replaced mileage improved significantly into the upper 20s. A close review of the service information offered that the European model had much earlier ignition timing suggesting more advance would help. A timing adjustment to the European specification proved to be too much, but backing off just a couple degrees pushed mileage to over 30, well beyond the highway mileage test when the model was sold new.
The Volvo lesson was instructive. Available compression, examination, upgrades and research and testing allowed a much more full exploitation of E10’s opportunity. Most of the work was due to the vehicle’s age, the valve springs in particular, and done over the course of the first months of ownership. The innovative part was simply to test drive to find the ignition advance, as there was no knock sensor, computer or variable ignition distributor to do it automatically.
E10 can be exploited with an engine with the compression to use E10’s qualities. That is dependent on the fuel marketer’s willingness to blend to higher octane. Lower prices across much of the U.S. make E10 a great deal for the modern higher compression engine owner. You might want to check that owner’s manual and see what your engine’s compression ratio is.
Stay on top of the maintenance. Efficiency losses from poor tune of ignition and fuel systems is an essential maintenance task, mileage will affect parts like those valve springs and doing the work can give substantial improvements. If the compression is there, the tuning and maintenance up to snuff, and you choose 89 or 90 octane E10 or E15, alcohol fuel blends can pay off quite nicely.
For small engines, owners and service personnel will learn what this writer has learned; it’s about the materials, which are inferior now. There isn’t much involved beyond careful inspection and installing better parts.
Say you have a premium fuel engine and wish to use E10 or E15. Octane booster additives are very pricey, usually more than just buying premium, so here’s a tip. Add isopropyl (for even more ignition resistance) in the form of “Isoheat” or other isopropyl gas line dehydrator; say about one bottle to ten gallons. Works for me, and saves about 15¢ a gallon.
Comments
5 Comments so far
It is nice to view an article that provides useful information about ethanol blends in gasoline. So many of the articles out there are based on wild political views and personal beliefs that it is hard to find truth. Thank you for providing the public with some useful information.
Agreed – a good article without the BS you normally have to wade through.
Brazil has 25% of ethanol and plenty of imported cars (many from the US) and they run just fine.
That should shut up people like this guy whose claims come only from silly lawn mowers and old cars.
Still, America insists in claiming ethanol is not an answer.
In the meantime, Brazil has saved 800 million tons of CO2 since the beginning of its ethanol program 30 years ago.
And what has America done during that time? Talk about lawn mowers and old cars!!!
Hi, Thank you! I would now go on this blog every day!
Thank you
Lewis-
there are 18 million outboard motors in the US and NONE of them are designed to run with 15% ethanol. Thousands of boaters with expensive outboards have had damage form ethanol. E10 has been an disaster for boaters and using E15 will void the warranty of every outboard motor sold in the USA. These are not “silly lawn mowers and old cars”. My twin outboards cost $26,000.
NO E!15