Fuel Economy

[roxy1]

Originally Posted by why?

sure they did. I remember reading that on all the car ads, oh wait, no I don't. every single one made sure you knew it was always 93.

starting in 2004, the EPA started using indolene across the board, a standardized test gasoline free of additives. it has a MON of 87 and RON of 96.5, thus yielding a pump octane of 91.5. before 2004 they used a variety of octanes, depending on what a given car was designed to run on.

using an ethanol free/additive free test gasoline give the best possible mpg numbers. the higher octane itself does squat for mpg numbers.

if I fill up with an ethanol free gasoline I will immediately realize a 7%-10& increase in fuel economy for that tank. my records over the last 15 years also tell me filling up with a higher octane fuel that has ethanol gains me absolutely no measurable fuel efficiency gain over 87 octane.