91 octane ethanol free gas question

[Cav Trooper]

If I run ethanol free 91 octane, do I need to make any adjustments to timing and or carb?

[Mark]

I been using 87 no alcohol gas in my mutt with no problems

[rickf]

Most likely not but to your wallet yes! You don't need to run premium gas in a 151, if you can get the non alcohol in regular go with that and you will actually gain just a hair more power.

[kmam]

Interesting. In Australia 91 has ethanol but because it is below the legislated limit, about 4% I think, they don't have to label it as such and generally tell people there is no ethanol! Consequently I use a higher octane rated petrol that genuinely does not have ethanol in it. Costs more, but I figure the miles I do are so low that the hit to my wallet is insignificant.

[Cav Trooper]

I only asked about 91 because I have not found any 87 around the Cincinnati area and have been told there is a station about 10 miles away that sells 91 or similar octane non alcohol, leaded gasoline. I'm going on a road trip this next week with a 5 gallon gas can to see and if my wallet doesn't scream to loudly I'll buy some to try.

[m75]

https://www.sunocoracefuels.com/fuel-fi ... &range=300

This is from Sunoco. Shows a few locations around your target area. If you follow their link to their various fuels, you'll see quite a variety of lead/unleaded fuels of various octane levels. They appear to come in 5-gallon containers. To be sure of a particular vendor actually stocking something you're interested in, contact them before you go, in case it needs to be pre-ordered.

[rickf]

But that only covers their race fuels, not something you need nor really want to run in a low compression motor. It will not run as well as you may think.

[milstencil]

Here's a link to all the stations that have non ethanol fuel in the US and Canada.
https://www.pure-gas.org/
Rick

[tbh726]

So now a gas station next to me is now selling 91 ethanol free. From the above there is still a question... which is better 91 ethanol free or 87 with ethanol with a little mystery oil thrown in? i have a new fuel pump and rebuilt carb in my 151a2... from what i understand the ethanol is hard on the rubber/diaphragms. does ethanol eat everything up fast? what is everyone's preferred choice? does it matter points vs electronic ignition? if you do 91 ethanol free would you still use Mystery oil?

tim

[lpcoating]

Did you rebuild with an NOS kit or a kit that uses materials for today's gas? I use ethanol free whenever possible and I always give a shot of Mystery Oil, no matter what gas I use. I had my A2 fuel pump rebuilt with modern materials.

Guy

[rickf]

Ethanol up to 10% will not seriously degrade your rubber parts. But, you have to be careful about phase separation. That is what happens if the moisture content in the gas gets above 7%. Then the alcohol separates out of the gas and that will cause all kinds of damage to rubber and metal since it now has the water in it and alcohol is the perfect solvent. Premium gas is designed to burn slower than regular gas to prevent preignition in high compression engines. Since it burns slower it also produces less power in a low compression engine. So really all you are doing is spending premium money to get a little less performance. You may find gas with no alcohol in it but I seriously doubt you will find gas with lead in it in this country. Leaded gas was outlawed in the 70's. You could still get it in Mexico for a while although Pemex was not really known for it's high quality gasoline. Might still have there, haven't been there is 35 years.

[Mark]

you could put lead additive in the gas,

[rupert's]

Curious! Very low octane numbers, in Spain there are only 95 and 98. Obviously I always add 95 to 151 and additive for lead ... I think this is the case throughout Europe.

[rickf]

Do they still use leaded gas over there? And yes or no I am sure they are not using alcohol in the gas. Even though alcohol raises octane it also lowers mileage since it takes twice as much alcohol to get the same power as gasoline. That said, pure methanol will give massive horsepower to a very high compression engine due to its very high octane numbers. But you need to be running 12:1 or higher compression and if it is even the slightest bit cold you will need to start on gasoline.

[raymond]

There are 2 ways of measuring octane with as much as a 12 point difference between numbers.

There is the Research Octane Number (RON) and the Motor Octane Number (MON).

The RON is measured with an engine at low speed (600 RPM) with a variable compression ratio.

The MON is measured with a similar engine but at a higher RPM, preheated fuel, and variable ignition timing.

The RON is usually around 10 points higher than the MON.

In the U.S. and Canada octane for highway motor vehicles is reported as an average of the 2 methods.

In most of the rest of the world and the U.S. and Canada before roughly 1970, the octane number posted is or was usually just the RON.

That is why posted octane levels outside the U.S. and Canada are much higher even though the gasoline is essentially the same spec.

It is also why the posted octane levels in the U.S. and Canada back in the days of "muscle cars" and high levels of lead were also much higher.