MPG difference in fuels Pure gas vs alcohol

[reluctantartist]

Ok i know there are lots of posts on this but what I am trying to do is get a baseline for my car depending on the fuel type and be able to compare so I know if it is running right. On my westy I got the factory stated mileage or even better if i was careful about my driving on straight gas, but my source dried up and noticed my mileage did drop 10%. So on one tank I was getting slightly over 18 mpg in city driving and I thought was ok considering the extra idle and heater checking which i think is still in need of adjustment. But it would be nice to know what people are getting and on what fuel. Personally I hate the alcohol fuel even the volvo s60 get better mpg when it is straight fuel when I can find it. It seems it would be more green to use straight fuel because of the MPG difference but that is a different topic.
_________________
1982 Westy, 1974 412 Variant... Yes, Aircooled's are great! Oh and I do have modern computer controlled vehicles too, but I just don't care about them.

[raygreenwood]

A couple of things with pure alcohol.

Alcohol has 18% less available BTU/energy. But it does vaporize really well ...until ambient temps get too low.....so if you are getting the same milage...realize that you are running lean. The only reason you are not getting detonation is the very high octane of straight alcohol.

But....the cooling effect of the alcohol as it evaporates...depending on how its injected....can help air charge to be more dense.

So you get leaner burn, higher levels of air in the AF ratio....and resulting higher piston, crown temps.

But.....the issue in light of whats mentioned above...the pluses and minuses....the problems, that have been found with running straight alcohol on the street is a medium to long term issue of piston erosion and micro cracking similar to what some of the LP gas engines had when they were injecting fuel and vaporizing it at the port instead of with a heater up kn the manifold.

This is primarily due to the issues of cool charge and high flame temp. There are added to this....some of the aluminum corrosion issues that happen after hot shut down with unburned alcohol on erosion areas of the piston.

I know these things from working around people years ago doing R&D on alcohol and Natural gas engines.

Its one of the reasons why they produce E-85 instead of just going to straight alcohol.

That being said I had the chance in college to run, about 10 tanks of straight, ethanol through my 2nd 412. It ran very well but had to have a couple of adjustments.I dont think I ran enough through to get an idea of what the long term effect or damage might, be......but it, definately wiped out a set of fuel lines. It ran quite well though in hot weather.

As for is it, greener?......NO. Methanol....yes not bad. Ethanol? No.

1. At 18% lower btu available. ..and only getting the same milage by the skin of your teeth and the high octane....you will need to richen up to survive long term. At that point you will fjnd...ad I did...and virtually everyone has without a, modern computerized in jection system. ....your NOX emmisions will be a little better but your hydrocarbon output will be worse. Without a modern catalysts...and even then.....you cant, fix this.

2. Facts: in this country we make ethanol primarily with corn (when cellulosic ethanol gets off the ground I will change my mind....maybe).

Personally I dont care about the argument that ethanol from corn takes away from food production.

Corn ethanol requires more nitrogen fertilizer to grow than any other crop. Ammonium nitrate fertilizer requires large amounts of propane to produce. Not only is this fossil fuel use not figured in.....it is creating a vast farm, fertilizer run-off issue in watersheds.

This same ethanol corn....in wet summers requires VAST amounts of propane to dry the corn to be able to ship in in rail cars.....which is why Iowa and Nebraska alone created a propane shortage nationally last, year......also not figured into the cost of ethanol.

The silage or mash from the expended corn....is usually hailed as a benefit product for cattl3 feed. In actuality. ....the industry is producing so much waste mash.....that the cattle industry 3 years ago noted that they could only make use of approximately 65% of the mash.....the rest went into land fills.
With the cattle fleets/herds at an all time low......they cannot make use of more than about 40% of the waste mash right now.

So.....you have very costly, high waste, more polluting, lower energy output fuel being produced at a competive level to gasoline....only by virtue of a massive Federal tax subsidy.

At this point in time.....ethanol by the USA method.....has not one GREEN attribute.

This is not even to mention what its use has done to the nylon and butadiene based plastics and rubber industry.....in order to use ethanol in modern cars.....which has spurred constr7ction of about a dozen large refineries with, resulting air quality issues.

Until they start using somethjng more sustainable than, corn......there is nothing, green about ethanol in the US. Ray

[Donnie strickland]

Ray, I assumed he was talking about mpg of E10 blend vs. straight gasoline. Reluctantartist, is that it?

And I agree completely about the myth of ethanol being "green".
_________________
71 Elm Green FI A/T Squareback

[reluctantartist]

yes i was talking about e10. I know there is a noticeable difference in my westfalia so I am not expecting it to be as good as it could be in the 412 but it would be nice to know what to expect.
_________________
1982 Westy, 1974 412 Variant... Yes, Aircooled's are great! Oh and I do have modern computer controlled vehicles too, but I just don't care about them.

[raygreenwood]

[Donnie strickland]

Ray, I've used both straight gas and E10 in my D-Jet Squareback, and I'd say your 5% estimate is pretty accurate in my experience.
_________________
71 Elm Green FI A/T Squareback