Ideas Needed: Why sudden drop in mpg?
I always seem to average right around 8.5 mpg however the return leg of this last trip I saw averages around 7.5 and that concerned me. I'm looking for reasons this could have happened. 1) The ret...
Forum Discussion
wallynm wrote:
higher octane hence less knock but less or fewer Btu's per gallon hence less MPG
427435 wrote:
I think your understanding is wrong---------at least in Minnesota. Actually, ethanol makes it easier to rate a gas as higher octane.
I'm not sure what you're saying here. E10 at 87 octane has the same octane as regular gas at 87 octane but about 97% of the BTU's. Premium gas has 91-93 octane and approximately the same BTU's as regular gas. Premium gas, however, allows more compression before pre-igniting.
