Why is mid grade more expensive

[Rmay635703]

Originally Posted by Skippy722

It is midway between 87 and 91 though, and most manufacturers tune for 91 or 92 AKI when they're recommending premium. Having 87, 90, and 91 in an area like that doesn't make much sense.


In my area 90 no longer exists which is a shame given our elevation.

It used to be 90 octane was e15 and cheap, now 89 is e10 and expensive

 

[Triple_Se7en]

Skip
That 91' seems heavy into the West Coast. 91 is not our Premium, probably east of the Missisippi and north of the Central Plains. Depending on the grade of gas, our Premiums are either 92 or in most cases, 93. So 89 octane is not midway of 87 and 93. Our mid-grade and my basic math classes say 90 octane should be mid-grade here in the upper Midwest.

 

[vavavroom]

I don't get hung up on AKI, which is just the average of RON and MON. Every car manual states minimum and best performance requirements.

 

[Rmay635703]

Originally Posted by Vern_in_IL
Originally Posted by Kestas
Originally Posted by Vern_in_IL
mid grade is 87 WITH ethanol. Ethanol bumps it up to 89.

Premium, the old 91 is now 93 with ethanol.

Are you saying 87 and 91 have no ethanol?


Depends how it's blended!

Depends if you are getting ethanol free 87 or 85+10e(87) I've seen 90 mid grade before. Most mid grade is 89, some premium is 91, now most is 93(91+e10)


I found a "cheap" Premium station but looking at "mid grade" what is even the point?

Kwik Trip 88 is only $2.14 a gallon so it makes the rug pricing laughable too but the Premium isn't $1.50 more, it's only a dollar more than Kwik trip 88 which is still a rip off

 

[y_p_w]

Originally Posted by vavavroom
I don't get hung up on AKI, which is just the average of RON and MON. Every car manual states minimum and best performance requirements.

While it is the average, the numbers are important. A difference of 2 is actually quite large. And the "spread" of nearly all fuel sold is such that there's strong correlation between RON and AKI. It's enough that some US owners manuals state a minimum AKI or RON assuming that they will be equivalent.

 

[Skippy722]

Originally Posted by Triple_Se7en
Skip
That 91' seems heavy into the West Coast. 91 is not our Premium, probably east of the Missisippi and north of the Central Plains. Depending on the grade of gas, our Premiums are either 92 or in most cases, 93. So 89 octane is not midway of 87 and 93. Our mid-grade and my basic math classes say 90 octane should be mid-grade here in the upper Midwest.


Everything is centered around California, since they not only have the most amount of registered vehicles of any state by an incredible margin, but the residents also buy the most amount of new cars of any other state. Because of that, manufacturers cater to them.

 

[y_p_w]

Originally Posted by Skippy722
Originally Posted by Triple_Se7en
Skip
That 91' seems heavy into the West Coast. 91 is not our Premium, probably east of the Missisippi and north of the Central Plains. Depending on the grade of gas, our Premiums are either 92 or in most cases, 93. So 89 octane is not midway of 87 and 93. Our mid-grade and my basic math classes say 90 octane should be mid-grade here in the upper Midwest.


Everything is centered around California, since they not only have the most amount of registered vehicles of any state by an incredible margin, but the residents also buy the most amount of new cars of any other state. Because of that, manufacturers cater to them.

Nearly all new cars sold in the US are tuned for AKI octane of 87, 91, and 93 (which is near impossible to find in California). I got my first car back in 1995 when most premium sold in California was 92 AKI, and the owner's manual for my Integra GS-R said 91 AKI minimum.

I remember hearing that some Saab cars were tuned for maximum performance on 90 AKI. Some (maybe most?) motorcycles are tuned for 89 AKI.

Quote
https://manuals.bmw-motorrad.com/manuals/BA-Extern/IN/BA-INTERNET-COM/PDF/R_0A01_RM_0416_01.pdf
Recommended fuel grade
Super unleaded (max. 10 % ethanol, E10)
95 ROZ/RON
89 AKI

Alternative fuel grade
Regular unleaded (Power- and consumption-related restric- tions. If e.g. the engine is
to be operated in countries with low fuel grades at 91 re- search octane number, then the motorcycle must first be programmed appropriately at your authorised BMW mo- torcycle dealer.) (max. 10 % ethanol, E10)
91 ROZ/RON 87 AKI