Get ready for 15% Ethanol

[beanoil]

While E15 on the surface may seem harmless, remember that octane at the pump is the total of all the ingredients in fuel. With ethanol having an octane of 113, you can bet that the base fuel will be dumbed down,(if E15% stays at the regular grade 87) and have more trash in it than ever. If that fuel absorbs water and separates, now you have an 84 octane petroleum product and even more water/ethanol mix. If you fill up regularly, likely no problems. If it sets a while, YMMV. E15 is still not approved for motorcycles, ATV, or OPE.

 

[Rmay635703]

Originally Posted by beanoil
While E15 on the surface may seem harmless, remember that octane at the pump is the total of all the ingredients in fuel. With ethanol having an octane of 113, you can bet that the base fuel will be dumbed down,(if E15% stays at the regular grade 87) and have more trash in it than ever. If that fuel absorbs water and separates, now you have an 84 octane petroleum product and even more water/ethanol mix. If you fill up regularly, likely no problems. If it sets a while, YMMV. E15 is still not approved for motorcycles, ATV, or OPE.


Because blending octane is non-linear due to vapor point inflection some e10 87 octane mixes are already 84 octane gas + ethanol.

So what you describe is what happened when e10 became standard but...

Part of the reason for e15 is that manufacturers want higher octane specs, even 1 point higher is good for them, we may find the feds standardize to 88 or 89 octane as the minimum going down the road 5 or 10 years.

What's funny is in the 60's and 70's super unleaded could be 95 or more octane, what's old is new I suppose

 

[CR94]

Originally Posted by Rmay635703
... What's funny is in the 60's and 70's super unleaded could be 95 or more octane, what's old is new I suppose
Huh? As far as I know, unleaded of any octane rating was rare in the '60s, and began to appear only in the early '70s. Amoco did advertise unleaded premium earlier for a while.

Was that 95 octane by the currently favored (R+M)/2 method, or Research method only, which would've been consistent with marketing back then?

 

[Nyogtha]

Research method only back then.

I remember initial gasohol efforts in the 70's, fell flat on its face in the marketplace and was only available as unleaded. I don't remember gasohol at all in the 60's, only unleaded gasoline I knew of then was Marine White, and its octane rating was nowhere near premium.

 

[Nyogtha]

Originally Posted by Rmay635703
Originally Posted by beanoil
While E15 on the surface may seem harmless, remember that octane at the pump is the total of all the ingredients in fuel. With ethanol having an octane of 113, you can bet that the base fuel will be dumbed down,(if E15% stays at the regular grade 87) and have more trash in it than ever. If that fuel absorbs water and separates, now you have an 84 octane petroleum product and even more water/ethanol mix. If you fill up regularly, likely no problems. If it sets a while, YMMV. E15 is still not approved for motorcycles, ATV, or OPE.


Because blending octane is non-linear due to vapor point inflection some e10 87 octane mixes are already 84 octane gas + ethanol.

So what you describe is what happened when e10 became standard but...

Part of the reason for e15 is that manufacturers want higher octane specs, even 1 point higher is good for them, we may find the feds standardize to 88 or 89 octane as the minimum going down the road 5 or 10 years.

What's funny is in the 60's and 70's super unleaded could be 95 or more octane, what's old is new I suppose

I've never heard of "vapor point inflection" before. Can you explain this phenomenon further especially with relation to octane?

Toluene for example has a very high octane but a low vapor pressure for gasoline boiling range substances, normal butane also has a high octane rating with a high vapor pressure (volatility) for gasolibe boil8ng range substances, just to name two.