Is ethanol a good thing or bad?

The gas station I use says the gas contains up to 10% ethanol.
Is ethanol good or bad for the car, in general? If it's good, why only 10%? If it's bad, why put it in the gas at all?
How about for a turbo car (WRX)?
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On 12/20/2009 10:37 AM, james wrote:

Newer cars are OK. It apparently messed up my snow thrower last year as manufacturer says not to use it as it attacked seals. When gas station tanks here were converted to hold it, they had to clean all the tanks as residues could have dissolved in the E10 and messed up cars. It cannot be transported by pipeline for the same reason. Car manufacturers have taken this into account.
Government mandated E10 as it is supposed to keep down pollution. Data to me is doubtful but agribusiness had a lot of bucks to convince congress.
Pure ethanol only has about 60% the energy value of gasoline so mileage will be slightly lower with E10.
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On 12/20/2009 07:37 AM, james wrote:

I hate the stuff. I keep a running spread sheet on my 2006 Forrester's gas mileage. December - February, all the gas stations down here, except one, dope there gas with Alcohol. My gas mileage drops from an average of 24.5 MPG to 14 MPG. So, watch your gas mileage. Very expensive to run!
Alcohol in the gas also is purported to screw up your catalytic converter. Reference:
http://www.odyclub.com/forums/showthread.php?threadid7483
And, since Subi just replace my CAT due to a P0420, no, and I mean no Alcohol will ever pass my Subi's lips ever again.
My 2 cents,
-T
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Good luck to you, but in my area, high ozone, all gas must have ethanol in it. I would gladly by pure gas for my snow thrower, as mentioned above, and all my other home and garden equipment.
The ethanol requirement is actually an oxygenate requirement, i.e. gas must contain a percentage of oxygenated compounds. The oil companies discovered methyl t-butyl ether satisfied the requirement, was cheaper and raised octane much more than ethanol. Unfortunately a ppb in your water makes it taste bad and everybody banned it.
All the mandated botique gasolines make gas more expensive and sometimes scarce.
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If someone went from 24.5 to 14, that is more than just ethanol. The energy content of ethanol is abotu 70% of gasoline. So if it is doped with 10% ethanol, the theoretical loss just from that would be about 3 percent. You could add other factors in to explain the loss that have nothign to do with ehtanol, like lubricants not getting up to temp as fast in cold weather, thus creating more drag. Cold startups use more fuel since it doesn't atomize as well. However, even if you were to account for all that, you should only get slightly higher losses. If a car is experiencing a nearly 50% loss in mileage, something else is going on.
Subarus won't have problems with the seals being attacked by ethanol. The seal technology has addresed that. People run E85 in these engines with no issues.
In the early days of ethanol carbureted engines, or those with dirty fuel injectors had problems on cold start up. The fuel wasn't atomized well enough and would reach the chamber walls in droplets, which would clean the film of oil off the cylinder walls. This isn't an issue with newer engines though.
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james wrote:

It does boost the octane a couple points. I had a pickup years ago that would ping with regular unleaded but ran fine with the 10% ethanol. This was a fuel injected engine. One other advantage is gas lines won't freeze up. The alcohol will prevent it. Heet and those other gas line anti freeze products are just alcohol.
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On Sun, 20 Dec 2009 16:46:08 -0600, Dean Hoffman

The BIG problem with ethanol is what makes it work so well as a fuel drier - it's affinity for water. When it has absorbed all the water it can hold at one temperature, a small drop in temperature can cause "phase separation" where the ethanol and water "drop out" of the gasoline. When that happens, believe me, it's NOT pretty. When that bollus of hooch hits the fuel pump and injectors, NOTHING runs right, if at all.
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snipped-for-privacy@snyder.on.ca wrote:

So you've actually seen this happen? The only problems I've heard of were way back when ethanol first came out. Some vehicles had problems because of rubber components deteriorating because they weren't designed for ethanol. The other problems were caused when people switch to ethanol blends. The blend cleans the gunk out of the fuel system and fuel filters plug. I got curious so took a quick look online. Storage tanks have sensors on them to alert the operators if the water level in the storage tanks gets too high. Vehicle fuel tanks are also supposedly warmer than the storage tanks so the phase separation reverses itself once the fuel is in the tank.
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On Sun, 20 Dec 2009 20:46:09 -0600, Dean Hoffman

Yes I've seen it happen. I've seen it happen in snowmobiles too, and the 2 stroke engine is quickly destroyed by running lean and without lube. Generally it is more of a problem on vehicles without sealed tanks (pre-evap emission).
It's REALLY nasty when you get a "cold snap" - and the reason Mogas with Ethanol is FORBIDDEN for aircraft use, even when a Mogas STC is in place. It gets colder as you go up and sooner or later, if there is any moisture in the fuel, you are in TROUBLE.
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It's bad but not too bad for modern cars. But if your car was not designed with 10% ethanol in mind, not only it will have earlier failure of some engine components (seal would be the first to go, I think) but it will also have slightly lower fuel economy. In a nutshell, 10% ethanol in gasoline is an indirect tax you pay to subsidize farm industry. The subsidies are absolutely required because ethanol is economically not viable in the USA in comparison to gas.
In theory they add ethanol for two reasons: 1. To reduce dependence on foreign oil. 2. To reduce pollution because ethanol burns cleaner.
In practice, 1) above is economically too expensive by way of using ethanol and 2) is completely false because ultimately every process of making ethanol pollutes environment a lot more.
DK
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james wrote:

My dealer once told me not to use more than 15% ethanol gasoline, but that is for a 2000-spec car. Newer cars might be able to tolerate higher percentages.
    Yousuf Khan
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Now for a minority report. :-)
I converted my 1999 OB to run on any mix of gasoline and ethanol. When I announced this here almost two years ago, I got tons of warnings, but none of them has panned out. My fuel injectors, pump, tank, hses, -- all are OK.
What I did not expect was the increase in performance on E85. The car has more pickup then before. I am not an automotive engineer, but I suspect that the higher octane the permits more spark advance. (I learned about the "knock sensor" recently.)
Last year the price3 of E85 was 25% lower than regular gasoline. My miles per dollar increased by about 10%, although my miles per gallon was 15% lower. My 16-gallon tank now takes me only 3090 miles instead of 400 miles.
This year, E85 is relatively higher, so I switched back to the usual E10. If the car lasts another 100,000 miles (as I expect) the price of gasoline may go back up above $4 per gallon, and I will be sitting pretty.
The conversion was simple. All I did was to insert a computer chip into the electrical control line of each cylinder to give it a richer range of mixtures. Ethanol is a fine fuel, but the energy density is 30% lower than that of gasoline. So your check-engine light will come on, complaining about lean mixtures, if you don't use the chip. It is available for about $100 per cylinder. Installation is easy if you can reach your fuel injectors.
Many hasty authors write that MPG must go down in proportion to the lower energy density, but it is not so in my Sube. Again, it is probably because of the very high octane and the adjustments that the on-board computer can make to the tuning. Internal compustion engines waste most of the energy as heat, so any improvement in burning efficiency makes up for some of the loss of MPG.
So bring on the cheap Brazilian ethanol!
Uncle Ben
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On 12/21/2009 11:12 AM, Uncle Ben wrote:

Very interesting observations. A priori ethanol has lower energy value but engines, as you point out, are not that efficient and an efficiency increase could make up for lost energy.
As for Brazilian ethanol, agribusiness bought themselves a big tariff on it:
http://www.greencarcongress.com/2006/12/congress_extend.html
Wonder if it has been or will be extended.
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Yes, the subsidy for corn alcohol is intended to protect an infant industry, as is the tariff on Brazillian alcohol. But the oil business has big subsidies too. I hope both go away.
Cellulosic ethanol is coming, but I worry about the cost.
I apologize for all the typos in my post above. But this is a smart crowd, and I'll bet nobody was misled.
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Uncle Ben wrote:

WOW 193 MPG gotta get me some of that !!!!
<couldn't resist. We don't even get ethanol down here>
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If only! :-) Make that 350 miles highway range on E85, 400 on gasoline, more or less.
Where are you?
In Albany, NY, (state capital) we have six stations that include E85. The state has a subsidy for stations to provide it. But west of here in the state, there is only 1 station in 300 miles or so -- in Rochester, NY, last time I checked.
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Uncle Ben wrote:

Tauranga. New Zealand We have Regular 91 and Premium 96 with two chains (BP & Shell) pushing 98. Our octane rating may be different to yours.

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