Also, my 1999 Honda Jet Ski runs great on E10 and always has.

Fritz said ‘I agree that as a country we need to move away from gasoline dependent locomotion. It is a national security and balance of trade nightmare.’

Ethanol is here and now. We all may have to make small concessions toward gaining energy independence and national security.

Please do your part.

Shortly thereafter I noticed the signs advertising Shell premium’s ethanol-free formulation have been removed. Shell assured me in an e-mail its premium grade gasoline is still ethanol free. Ominously, no explanation for the signs disappearing was offered.

This is a documented problem with ethanol fuel blends in marine use. Many boats have used polyester resin in their construction, including fiberglass fuel tanks. (Poly is cheaper, quicker, and in general easier to work with than epoxy resin.) Ethyl and methyl alcohols absolutely will react with the polyester resin and the resulting gunk will migrate through the entire fuel system, gumming up everything. I’ve seen it and it’s nasty. The only reliable fix is to clean out the fuel system and redo the tank with epoxy resin.

The only way to test this stuff accurately is to do it in a lab, under strictly controlled conditions.”

You make excellent points here. Even lab testing is to some degree arbitrary because it involves the construction of a virtual driving loop, which may or may not reflect an individual driver’s route and driving habits. This is the limitation of EPA/CAFE but any circuit/regime you can devise will have the same problem. Even if everyone drives the same (which they certainly don’t) Nebraska is flatter than San Francisco and that is just a fact.

All this said, the average consumer can measure his/her own fuel consumption with useful accuracy, but it requires some discipline and a consistent methodology — which includes knowing when a tankload will not be representative.

Variances of that degree are invariably due to the measuring regime. By definition. The car and the fuel are not changing in that magnitude, so what is? The driving route and regime, and the measuring methodology.

It is a fact that many consumers are not very good at monitoring their own mileage — or driving economically for that matter. Their findings are in large part impressionistic. That’s how utter frauds like the Tornado succeed in the marketplace. People find mileage improvements (or losses) for psychological reasons.

Typical driving scenario: driver starts car, warms up 10 min. Drives to the grocery store (4 miles) then sits outside ten minutes while wife picks up items, then drives back. Or sits in the Starbucks drive-through, any one of a hundred scenarios. But the point is: how many mpg do you get when the car is sitting still? Minus zero: the car is burning fuel but the odometer is not turning.

Obviously, this does not apply to your Prius with start/stop but there are still a number of other things that can skew your results. For one, overfilling the tank. First, the method makes it impossible to get the same fill every time. Next, it loads fuel into the evaporative system and there is no way to know how much.

I am VERY skeptical about that. Just because a car dealer says it doesn’t make it true. (You may have noticed this about car dealers.) First we need to know what is the dealer’s capability for analyzing ethanol content in fuel. Nil in virtually all cases. They can test for water and Reid vapor pressure and that’s about it. So how do they know it’s “ethanol damage”? You can’t tell by eyeball. What you mainly need to identify damage due to excess ethanol in a fuel is a predisposition toward that belief. On all reasonably current cars (1996-on) the fuel system components are validated up to E20.

One has to wonder if the extra 7 cents (or whatever) kick-back per gallon for adding an extra 10% ethanol to the gas is too much to resist for the oil companies.

20% ethanol in a non-flex-fuel vehicle obviously will void the warrantee. It’s also not legal.

But what the hell? Virtually nothing the government is doing now is legal, anyway; why should the oil companies behave any differently?!

I do have to wonder how much ethanol is really in the fuel. 20%? 30%? And by extension, how much WATER.

Magoo, Psych, I’ve tested all of my cars with care (and multiple times) over the years and can tell you that I do know how variances happen, and of course, my figures of 6% to about 25% (or, now, 34%) are outside of the lab.

But we don’t all live in the lab. I’m talking real life situation, here.

I’ll guess that The One will be pushing us to “legal” E20 before his first administration is out. We’ll be wondering how come a) our cars don’t run right and we get no MPG and b) our oil imports increase c) our dollar exports continue to increase and d) our money will decrease in true value and purchasing power. Of course, the additonal question for Joe Average with a car warrantee, is whether the auto companies will honor them (with mis-fuelling by E20) or not?

Don’t say I didn’t warn everyone!

Exactly right. The problem with these anecdotes is that we have no idea whether they are calculated properly or are actually comparable to one another. If you don’t fill the tank properly, don’t measure usage properly and don’t drive the same loop each time, then you can’t use these results at all.

The only way to test this stuff accurately is to do it in a lab, under strictly controlled conditions.

As I noted, I get the same kind of variation in my fuel economy as does Menno, even though I am buying fuel from the same service station, filling the tank in the same fashion, and measuring my usage as accurately as possible. The differences in my case are obviously not due to ethanol, because that’s a given in every instance.

If your test results vary from 6% to 25% going in, you have a faulty test procedure. You can’t say with any reasonable certainty what you are measuring, let alone what it might indicate.

No offense but gas station owners and small engine mechanics are not authorities on fuel chemisty and performance. If you of a mind to conduct a little science of your own and measure your fuel consumption, first you need a disciplined and consistent fill procedure. So far you don’t have one because you are overfilling the tank. That will account for the wild swing in measured consumption more than any variances in the vehicle or the fuel.

Once you have a consistent fill procedure — same pump, same fill level every time — then you need a test loop. You must cover the same route in the same approximate elapsed time or you are comparing apples to oranges. Only when your results are reasonably consistent can they be reliable.

My pal and his wife were over having supper and a movie tonight, and his family owns a gas station (in fact, a BP station). I told him about the Prius and the MPG loss and he said that 35% off the MPG for E10 is pretty much normal! He hears complaints about it all day long. Especially since BP were the last stations in the area to have non-ethanol polluted fuel, and “everyone” in the know was going to BP to get real fuel.

My experience with efficiency reductions is more between 6% and about 25%. My pal is a small engine mechanic and expert and he has NOTHING GOOD TO SAY ABOUT ETHANOL AS A MOTOR FUEL.

Experts can bleat all day long about “shouldn’t have any problems” and “only 3% to 5% efficiency loss is normal” but the people actually driving the vehicles and spending the money on fuel seem to have a different story.

With all due respect (simply trying to be helpful) that is a bad practice if you are trying to conserve fuel or measure fuel consumption with any accuracy. The extra fuel is mainly loading the car’s evaporative emissions system. Stop at the first pump shutoff, as generally specified in the owner’s manual, and recommended by virtually all consumer automotive authorities.

You know, it’s not like E10 is anything new. Over 20 years ago it was widely marketed as “gasohol” and it has never really gone away. Unleaded gasoline invariably contains a signficant percentage of ethanol or something very much like it (ethers, butane, etc) as octane additives. The “pure gasoline” folks are talking about here does not exist, and it would be worthless in your car anyway. Generally speaking, the only reliable way to get “E0″ (zero ethanol) gasoline is to order it from a fuel lab — which I have done on occasion in order to quantify the effects of ethanol blends in road use.

I can’t share the full results here as they are not my property, but Oak Ridge National Laboratory and others have conducted similar tests with similar findings.

http://www1.eere.energy.gov/vehiclesandfuels/features/int_blends_rpt_1.html

To cut to the chase, here is what E10 does in a late model (2002-on) passenger vehicle, averaged over a representative group of cars and light trucks in the North American market, in my experience:

Carbon monoxide: 14.8% reduction
Non-methane hydrocarbons: 10.0% reduction
Fuel Economy: 3.2% reduction

What do you think the odds are that 108k btu gas or less was included in the E10 when it was tested by the industry? I’d say zero.

I also find that the onboard computer is inaccurate. It is almost always optimistic, and the results are often 5-10% higher than what I calculate when comparing the change in odometer reading to the amount of fuel needed to fill the tank between fillups.

The problem here is sample bias. You may think that your driving is consistent, and the mileage should therefore be the same, but it isn’t. So the mileage may vary, even when all factors seem to be equal, because they aren’t equal.

Toyota wants you to use E10 ethanol, because of its detergent value. The company that made your car wants you to use it.

There is no logical way to blame the fuel for 100% of the changes in fuel economy. Obviously, if you have a phobia about ethanol and are looking for excuses to blame the fuel, then the facts aren’t going to matter, regardless.

Incidentally all the VPower shell pumps in the chicago area (that Ive been to) are 10% ethanol

That’s because Shell sells the “Top Tier” fuel that several automakers want you to use, and Top Tier fuel is supposed to have ethanol in it.

The ScanGauge is a damn accurate tool.

I’m really not sure what could be causing these apparent inaccuracies, as far as I can tell, the Prius calculates instant mileage the way most modern cars do – by taking injector pulse-width (how much fuel is delivered) and a reading from the ABS sensors (how fast are you moving).

That’s all the data one needs. MAP, IAT, TPS, CLT, etc., all irrelevant. All that matters is how much fuel is squirted into the engine and how far did you travel.

I’ll check the densities again. But that really can’t account for the instants being that far off.

Incidentally all the VPower shell pumps in the chicago area (that Ive been to) are 10% ethanol

I suspected for years that I couldn’t trust the automatic computers because there would be every incentive for the manufacturer to make them appear better than normal. But then I learned that the external computers, like the ScanGaugeII, are supposed to be extremely accurate about fuel consumption, so the built-in computers obviously would be at least as good.

If the type of fuel you use can throw off a ScanGauge so easily, I probably should cross it off of my birthday list.

The running tally MPG meter is seemingly running 15% out

explains the difference in you computer reading and you actual measured mpg. The running tally is an average of the gas mileage since the last time it was reset. So if you ran 3 tanks of gas and average 40 mpg then your 4th tank was 30 then the overall average would be 40+40+40+30=150/4=37.5 is what the computer would read even though you last tank was 30mpg. If you reset the computer each time you fill up the computer mpg and your actual calculated mpg would be very close.

The fact that these two “technologies” should find themselves fighting with each other is something that only John Cleese could truly appreciate.

OK, so after about 7 or 8 weeks of running E10 (aka gasohol), the Prius is obviously purged of 100% gas. So, in the interest of science and for further discussion sake, I just went and filled up Prius. It’s 23 degrees F. It had 154 miles on the trip meter, trip computer said 37.9 mgp, the filler (running at the lowest flow /first click at the station near home) clicked off at 3.8 (US) gallons, so in line with my usual practice, I pushed another gallon in. I’ve never had gas on my shoes yet.

Computer readout 37.9 mpg

154 miles / 4.8 gallons = 32.8333 MPG.

So that’s about 10% better than I had anticipated and estimated (which is good) but still the car is using about 34% MORE FUEL compared to my historical winter norm of 44 mpg on pure gasoline.
(Obviously bad).

The running tally MPG meter is seemingly running 15% out (bad) when, over nearly 70,000 miles in 2 Prius cars, it’s usually nearasdamnit right.

Before I bugged out to the station, I made a mental note. 33 mpg real or better, and I’ll reconsider keeping “Pope Prius” – so for now, until and if I don’t see a drastic change (obviously taking into account my normal winter 44 mpg, spring/fall 50 mpg and summer 48 mpg bogey points), down the road it goes once gas hits $3 a gallon and people start to excrement their shorts over the price of gas yet again.

(My pal named the car “Pope Prius” as it is white, whereas the 2005 car was silver and remained nameless).

Non-optional. EPA mandated. This is (right, wrong, or indifferent) a pollution mitigation step.

Ethanol may suck, but it is nothing compared to the environmental nightmare that was MTBE.

BTW – If you think E10 is hard on your car, just be thnakful that your weren’t in CA when MTBE was the oxygenate of (non) choice.

I see. You wanted us to go digging in the “Deposit Control” section!

I really just want to see some real numbers for a large sample of cars. It would be nice to look at EPA test results for both E10 and 100% gasoline to see how it affects your specific car. I can buy 100% gas (premium) here for 5% to 10% more than the “May Contain Up to 10% Ethanol” pumps. It’s almost certainly not worth it, especially since the possible E10 might not even contain any ethanol, depending on the blend. But it would be nice to know for sure.

Interesting study, GeeDashOff. That’s the sort of thing we need to see more of. I was surprised to see some ethanol blends perform better than pure gasoline in some engines during that test.