What happened to 92 octane in SFO?
 

Has anyone noticed that the octane rating has dropped from 92 to 91? Am I missing something?

Yup,
Everywhere I go only has 91 octane now. Just a way to cut costs/lower gas prices I suppose.

Actually from what I've heard, the reason for the change from 92 to 91 is due to the phasing out of an additive called MTBE. They now use ethanol as a substitute for MTBE, which was outlawed because it was found to pollute groundwater. I don't really believe this since other states have 92 & even 93 octane gasoline and don't use MTBE.

Here in N.J. Sunoco has 94 octane.

Tops out at 93 octane in Texas, but when I travel to the midwest, I have to settle for 91...

I heard there are several reasons for dropping to 91 octane. A couple are technical reasons from the sister of the hairstylist of the accountant of a guy who works at the Tosco refinery. The one I remember best is that they can lower the price of premium by lowering the octane.

Guys I know who run dataloggers note that they aren't seeing more knock sensor activity with the lower octane gas. Maybe it's a matter of time until the the remaining 92 octane gas is completely out of the supply system.

BTW, it started in the Bay Area in July with full implementation by August 1st.

Regards,
Sixto
91 300SE