Can you expand on your statement? Looking for the correct information.
Some info I have gathered:
Local station gets 87 and 93 delivered and is mixed at the pump.
Alcohol will raise the octane but has less BTUs so less mpg
Local station last I checked was about 50 cents more (maybe 60) for 89 vs 87
Blending 87 with higher octane (91 93) to get 89 was cheaper than pumping 89 at the same pump
100% gasoline (no alcohol, octane 91 I believe) has given me 24+ mpg (rated 21 mpg ) on the highway with my 5.7. First time I was only able to add 12 gallons on the fill up to my 26 gallon tank, 2nd time I believe 18, so I still had alcohol in the gas. I have a tendency to believe there is a diminishing return on 100% gasoline, for example 5% alcohol delivers the same mpg as 0% alcohol. I do know my mpg increased by about 10% or better (again highway) by adding pure gasoline. Not cost effective as it was about .60 more per gallon.
Have not reached a conclusion on octane and mpg as the variables change too much (no consistent conditions) for my driving habits. The few times I did try to attempt to vary the octane I got better mpg with 87 than 91, again I draw no conclusions from my personnel experience. My 2001 Dodge Ram SLT came with a tag that said to use 87 unless towing or carrying a load.
For the most part I use Top Tier gasoline, primarily Costco.
Tests show quality gasoline keeps engines 19 times cleaner
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