Getting educated about gasoline...

[Wis Bang]

A new to me full size pickup had me taking close interest in my MPG. I managed to add 1 MPG w/ the BP VRS Sunoco and Valero and another w/ a tonneau cover on the bed. Pulling the little jonboat I noticed I don't need to use the Tow/Haul mode with the higher shift points and that helped improve my 'round town' mileage too!

 

[LBrown59]

Back in the late 40. early 50s
we'd buy white or drip gas for our lawn mower engine powered go cart.
It was perhaps 10 or 20 cents a gallon cheaper than regular gas.

 

[Big Wave D]

LBrown59:

That is a new one to me. What is drip/white gas and how does it differ from standard gasoline?

 

[crazyal]

One thing that rarely gets talked about is how refineries distill raw oil. Over the years they have learned how to get the most bang for the buck from each barrel. Why make something that sells for $1 a gallon when you can make something for not much more work that sells for $2 a gallon.

One reason asphalt is so widely used is that one of the byproducts of the refinery process was an oil sludge that couldn't be used for anything else. I think it was about 10%, now I heard they are down to less than 2%. I don't think it's a large leap to assume what they are making for gas is not of the same quality.

 

[V1Rotate]

Some of the small airports will sell 100 octane avgas to anyone who walks in, as long as you bring your own gas can. Be aware however that this fuel is not taxed as "over the road" and is illegal to use in any vehicle that is driven on the road. Also be aware that avgas contains lead which will ruin catalytic converters and other emissions equipment. The lead will also cause deposits to form on sparkplugs, which means they must be pulled out and cleaned periodically (this is a regular procedure on small aircraft).
The only advantage to using 100 octane avgas might be to high compression engines in race cars which are not driven on the street. All other types of power equpment and farm machines will see no performance increases, only possible increased maintenance.

 

[Redneck in training]

Here is energy content of common fuels:
Ethylalcohol (Ethanol) 77000 BTU/gal
Gas has 124000 BTU/gal
10% Ethanol blend 119000 BTU/gal
15% Etanol blend 117000 BTU/gal
#1 diesel 135000 BTU/gal
#2 diesel 140000 BTU/gal
Vegetable oil 140000 BTU/gal

Diesels engines have better mileage, beside better thermal efficiency, due to diesel packing more energy/gal.

Gasoline engines have somewhat lower mileage on Ethanol blend than on gasoline fuel due to lower energy content.
Ethanol blend fuel is hygroscopic (atracts water from air) and can corrode internal parts of the fuels system. It is rarely a problem with cars because the fules is replaced offten but it might be a problem for engines that are not used too offten in ex. boats.

 

[jonyyuma]

Hi Redneck, How do you feel about paying more for less power and mileage? I understand there is also a cold start problem with over 10% ethanol? I guess the Government will give us a choice in blends? Jy.

 

[Redneck in training]

The real issue is that it takes about 9 gal of fuel to make 10 gal of Ethanol. Ethanol is just a scheme to keep price of corn high to benefit farmers I suppose. But I would rather benefit our farmers than send money to Middle East. There are few plants converting biomass to ethanol already in operation. Don't know how profitable they are but it makes more sense.

 

[Duffster]

Hi Redneck, How do you feel about paying more for less power and mileage? I understand there is also a cold start problem with over 10% ethanol? I guess the Government will give us a choice in blends? Jy.

How do you figure you are paying more?

The real issue is that it takes about 9 gal of fuel to make 10 gal of Ethanol.

No it doesn't. Current returns are ~1.6 times. Considering much of the input energy is not usable motor fuel the real yield would be quite a bit higher than that.

 

[Diamondpilot]

The lead will also cause deposits to form on sparkplugs, which means they must be pulled out and cleaned periodically (this is a regular procedure on small aircraft).
The only advantage to using 100 octane avgas might be to high compression engines in race cars which are not driven on the street. All other types of power equpment and farm machines will see no performance increases, only possible increased maintenance.

I totally disagree with this. While it may cause some deposits on spark plugs it the benefits are worth it for me to run in mall my 2 stroke stuff. For me that is a Weed Eater, Leaf Blower, Snow Blower, and a Chain Saw. Yes, it cost a few $$$$ more but I only use about 5 gallons of it a year and it about $1 more per gallon so its cheaper than a new $80 carb like I had to replace on a 3 year old Snow Blower.

In Indiana where I live all fuels used on Road must contain 10% ethanol. The only places that can sell non ethanol fuels are marinas, airports, and co-op's. Same is true for diesel, all must contain 5% bio. This became law 2 years ago.

The best thing you can do for all 4 stroke engines is spend $20 at WalMart and get Sta-Bil Marine Fuel Stabilizer. Its not the red stuff, that is junk. This is a black color and is formulated for ethanol blended fuels. I run it in all my 4 stroke stuff except my truck. 2 boats, riding mower, and generator. One $20 container treats over 300 gallons so its very affordable.

Chris