Opinion: 91 octane is superior. Especially if you have an MT

Mostly highway, in north Texas. Some side street. Went right through downtown Dallas. I kept speeds around 60 on the highway.

 

Tried 91 on my 19. Did 2 tankfuls just to be sure over a little over a month with no differences in my daily driving and filled at the same Shell station I always do about a mile from the house. Sensed no difference and either did my mileage keeper app doing the calculations. Tank prior with 87 Shell - 20.6. Two tanks of 91 Shell V-power - 20.8 and 20.5. Following tank of 87 Shell - 21.1 (slightly more highway driving on that one so I attribute the minimal gain to that). Just don't see it making an appreciable difference and 87 Shell meets top tier just like 91 V-power so I doubt any worthwhile long term effects.

 

So if my 2019 Tacoma says minimum octane is 87 but here in New Mexico regular is 86 and mid grade is 88 do you spend the extra money for mid grade or is regular gas with 86 octane fine, assuming the truck runs OK with this fuel ?

 

87 is the lowest recommended octane

 

If you can't find the recommended 87 octane, then go to higher octane not lower as lower octane could damage your engine but higher octane will cost more but will not damage your engine.

 

I’ve been running 86 on all my vehicles except for my bike (Indian Springfield) which requires high octane. They all run absolutely fine on 86, no damage to anything.

 

Myself, I wouldn't gamble on deviating from what Toyota recommends as minimum octane. But I also go with "severe service" intervals if doing anything other than flat highway driving, so I for sure take the conservative "do whatever to make the truck last long term" approach.

 

86 is pretty much the standard here. Why they do that instead of bumping it up one more like most normal states is beyond me. The vehicle doesn't notice a plus or minus one octane difference but my wallet sure does.

If we were talking two or three below I’d pony up the extra thirty cents a gallon, but as it is I haven’t noticed one whit of difference between them.

The price difference of about thirty cents a gallon going from 86 to 87-88 is quite a jump. It’s bullshit but that’s the man for you - Always crapping on the little guy...

 

I believe 86 instead of 87 octane is used in areas of higher elevation. Not sure where I heard that though...

 

Hmm, would make sense being NM. Is Colorado an 86 state also?

 

I've never seen 86 here.

 

Well, I moved to New Mexico from Colorado, they both have 86 octane regular and 88 mid grade.

 

Regarding 85 vs 86; I believe Ford had a minimum of 86 octane at higher elevation...

Lower octane at higher elevation is a holdover from carburated engines. You won't find a modern vehicle that endorses the practice. To the contrary, you will find auto manufacturers and .gov specifically warn against it.

As an aside, auto manufacturers have been lobbying for 95 RON as the new regular.