In my location, socal, the highest we have at most gas stations are 91, and thats all I put into my cars. I even put 91 into my Jeep Wrangler. I figure for $2 more a tank, its worth it to put in better gas.

-Josh

 

The G37 is .made to run on 91 octane , But in Florida Premium gasoline is 93 octane.
Unless you fuel up at Wawa..They have 91 octane premium gasoline..I have been using it for about a month now and the engine runs a lot quieter when idling and there is no loss of power in the engine..

Plus it is sligisly less expensive than 93 octane premium..

Hope this helps...My theory is , If it says to use 91 octane , then use 91 octane..

Be safe

 

Agree. Car is factory tuned to run on 91 octane, so unless you are running an aftermarket tune which takes advantage of 93 octane, it's not worth the extra money.

Also, many have proven that the car will run fine on 87 octane, albeit with less timing advance/performance.

 

IF, and a big IF, you can find a gas station that sells 91. Most around my area sell 87, 89, and 93. No 91. Come to think of it I can not recall any gas stations- that I frequent- that sell 91.

Oh well. Been using 93 since day one. No issues. Yeah, it costs a few pennies more, but the grin on my face when I step on it.... priceless.

¯\_(ツ)_/¯

 

understandable. When I visit my family back east, I’m envious of the 93 octane that’s available, but I’m normally in an underpowered rental car that runs 87 octane. I understand why the western US transitioned from MTBE based octane to ethanol, but I’m also not sure why the timing maps aren’t setup for 93 and don’t back down based on knock sensor input (same process that allows 87 octane). I believe its related to the emissions created when higher octane fuels are not fully burned

 

Strange how different regions and retailers make decisions, because 91 is available everywhere around here. It certainly is noticeable on fill-up between my car tuned for 93 and the wife's @87.