Premium Gas?

[jdoliver]

I have a 2007 Miata MX-5. The owner's manual says to use 95 octane fuel. My previous 1999 MX-5 had no such requirement. Does this engine really need the higher grade gas? Has anyone used 87 octane routinely and found a difference? Thanks. Jim

 

[kcbhiw]

I have a 2007 Miata MX-5. The owner's manual says to use 95 octane fuel. My previous 1999 MX-5 had no such requirement. Does this engine really need the higher grade gas? Has anyone used 87 octane routinely and found a difference? Thanks. Jim

The highest octain gas that I've ever seen at a typical pump is 93. If you do use lower octain fuel, the car will automatically dial back the ignition timing. However, it is advisable that you stick with what the manual states as the center point of the tune is based on the specified octain rating.

 

[bobaru]

that's hard to believe, most places only have 91 as top grade. i will only put in 93 in my ms miata(manual says 91) and i do the same for my ms6(manual says 93). if i were you i would put premium in if your manual requests 95. i would also contact dealer on a possible misprint. i don't recall ever reading that a 07 needs premium.

 

[sjdmp5]

Could it be 95 RON which equals 90-91 AKI octane in North America?

 

[Lawrence C]

I have a 2001 and it says on mine 91 or higher. I live in CA the highest we have is 91 except for the 100 octane thats $6.xx a gallon!