Well, how committed are you to the experiment, and what's your budget look like? There are ways of creating variable compression, namely forced induction (boost: a turbocharger!). It's a lot easier to deal with differing fuel energy contents with fuel injection than with carburetion; there are DIY engine management systems with provisions for a fuel specific gravity sensor so that the fuel curves are adapted on the fly to whatever percentage of alcohol you care to run...

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan is mostly correct about the parts that will need to be changed BUT in my experience in working on my brother's Mustang for the last 3 race seasons we have not experienced any tank, line, or hose failures. Keep in mind that this car meets all NHRA rules so you are limited to 9" or less of rubber fuel line and has anodized fittings. Still using the factory fuel tank and the electric pump that he had when he was running petrol.

Like everything else, you need to filter through all the pro's and con's. I for one like to do things differently. That is why I chose to spend money on a slant and not a V8.

I grew up on a farm and when we bought fuel in bulk we would have to keep track of mileage and pay the road taxes at the end of the year. I see DOT fuel checks all the time around here. Some of these guys just don't get it. I once heard the fine was $1000.00 plus taxes on ALL of your bulk fuel purchased in the last 2 years if you are caught with dyed fuel in your non-farm use truck!!! Most of you wouldn't believe how much fuel a farmer goes through in two years

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Chris'
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What year Mustang?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I don't believe that ethanol is as hard on the fuel system as methanol.

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Official Cookie and Mater Tormentor.

That's definitely true.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan, it's a 1983 convertable.

We really thought we would have needed a new fuel pump by now (it's an old Carter pump we bought at a swap meet). We are still crossing our fingers to get through the season.

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Chris'
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But biodiesel SMELLS so good!

No kidding, one of the off-site airport parking shuttle fleets here in town is using Biodiesel, and the smell is very distinctive. Sorta like a cross between french fries and the smell of an old glow-plug model airplane engine fuelled with alcohol/ castor oil mix.

And honestly biodiesel makes a bit more sense than ethanol. You can pretty much use natural plant oils directly, rather than having to ferment and distill, which consumes a lot of energy.

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Ethanol reduces Carbon Monoxide and Hydrocarbon emissions but tends to increase Oxides of Nitrogen and aldehydes. And that's without counting the pollution released in the energy-intensive production of ethanol.

Biodiesel, no, quite the opposite...it burns much cleaner in all respects than petroleum diesel...and biodiesel is not at all energy-intensive to produce.
True. Then again, corn sweeteners ought to be kicked right out of our food supply, 'cause it looks more and more like they are very, very bad for our health. And they make things taste gross compared to real sugar. But that's a separate debate!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

My favorite carbonated vice- no corn sweetner:

http://www.dublindrpepper.com/

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Berry, berry true. I do want to do a bio-diesel experiment sometime too. but right now I got no diesel car! One day I will find a beater cheap, and then I'll be raiding the McDonalds after hours for fryer grease

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-76 Cordoba, 360 4bbl
-68 Valiant, 273 2bbl
-67 Dart /6 4bbl, Leaning Tower of Power!!!

Collecting legitimate taxes is not Nazism. Comparing paying for the roads you drive on with exterminating millions of people is kind of deranged, so don't let's get carried away.
On- and off-road fuel formulations are sufficiently different that a fairly quick lab test will determine what kind of fuel it is. Fifth Amendment rights don't enter into it any more than they enter into drunk-driving tests. You don't hafta say "You caught me, officer, I was driving drunk", and you don't hafta say "You caught me, officer, I was driving on untaxed fuel", but that's pretty much irrelevant, 'cause they can easily and legally figure out if you were or weren't doing either of those things even if you clam up and don't say a word.
And yet...such degradation does occur in many fuel system and carburetor materials found on '60s-'70s vehicles when ethanol even in low concentrations (10-15 percent) is present in gasoline. This is not a theoretical argument, though perhaps it is a case of your having never seen it. That, however, does not mean it doesn't happen. I had the dubious honour of living in the first state to decide that ethanol was no longer a contaminant in gasoline, but rather a desirable additive, and I watched that stuff eat fuel pump valves, carburetor castings, and assorted other fuel system parts. Call it high hygroscopicity, call it lack of appropriate cosolvents, call it what you want, but directly or indirectly, 10-12 percent ethanol in the gasoline caused significant and rapid degradation in the fuel systems of multiple cars.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Second that, why else would you have to order a car/truck with the "Flex-Fuel" option? The fuel delivery system has to be changed. I know Ford works that way. I also know that Aluminum is a no-go anytime ethenol is used. Keep in mind, the real damage occurs when the mixture just sits there, not when it moves.

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225 Cubic Inches of Iron-Head American Muscle

225 bored .040 /.100 off block, Schneider Cam 224@.050~ .480 lift - Stock valves, blended bowls, Offenhauser intake with 500 Edelbrock carb

Yet another reason why the domestic auto makers are lossing money. If they would just build it for E85 they would only need to stock one part. Let the end user decide what fuel blend they want to use.

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Chris'
Autobody
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I have a question about "marked" fuel.

I have never heard of this before, maybe my relatives (second cousins were all farmers) just never used it or brought it up.

is it basically a die that is mixed into the fuel, just to mark it as untaxed? does it carry a much higher octane rating? has this stuff always been around?

if it is "untaxed", does this just refer to road taxes and not sales taxes?

Yep, untaxed fuel is generally dyed for visual identification. This is for exactly the reasons (tangentially) mentioned here: to help stop road tax evasion. Aside from racing gasoline, it is rare to find off-road gasoline of higher octane than can be bought for on-road use, because most of the agricultural and industrial equipment for which this gasoline is intended uses low-compression engines. However, for quite awhile after leaded on-road gasoline was withdrawn from the market, leaded gasoline was still available for boats (might still be, in some locations) and it is still available for airplanes, but not for too much longer in North America. While you used to be able to buy leaded airplane gas as long as you weren't pumping it directly into a car (I did that sometimes anyhow and the vendor didn't seem to care), the regulations have tightened up considerably, and now you can't buy the stuff without a valid (and validated) aircraft tail number.

Aside from that, the primary difference in formulation between on-road and off-road gasoline and diesel is that the on-road stuff has to meet stricter regulations for such things as Sulphur content, vapour pressure/volatility, and other factors that influence exhaust emissions and the life and effectiveness of automotive emission control devices.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.