[Sovereign]

According to the owner's manual, this vehicle is premium fuel recommended, but it is not required. I have been running it on regular because I am cheap. I recorded my best-ever fuel economy (35.5MPG) on the highway with nearly all premium fuel (it was an experiment).

Thus, I am deliberately trying to see if a notable difference may be had in "regular" driving with premium fuel over extended periods of time, or if I should stick to only throwing in premium when driving long distances.

Current prices: $3.37 regular, $3.57 premium (87/93 respectively)

Percent difference: 0.20 / ((3.37 + 3.57) / 2) = 5.76%

Required "MPG improvement" is equal to the percent difference to break even. Savings per mile kick in after that.

Assuming (which may not be true) that adding roughly 33% of a tank worth of premium fuel means the "desired improvement" should drop with the portion of premium vs. regular in a tank, the MPG improvement adjusts accordingly.

Fuel replaced today: 5.627 / 17.2 = 32.72% of tank

New required break-even MPG improvement (32.72% of 5.76%) - 1.88%

Unfortunately, I am well-aware that 2% changes are often lost in statistical noise with the car computer/pump introducing error. However, I hope that a 5% or more change would be noticeable.

I will update this thread as I learn whether this is a worthwhile venture.

Before anyone says "You're wasting money because premium fuel is pointless," remember this vehicle has a recommendation for higher-octane fuel--putting high-octane in an engine not tuned for it is a waste. Higher-octane in an engine that CAN take advantage of the higher octane--that has the makings of an experiment.