89 Octane Test

[VimyJJ]

I'm going to run the J on a full tank of Marathon 89 octane with "up to 10% ethanol" from my usual gas station and see how it goes. The ambient temperature is dropping so knock shouldn't be as much of a concern. Be aware that in a high compression engine built with tight tolerances any amount of knock is very bad. Someone mentioned that the newer Nissan/Infiniti engines say premium fuel is "recommended" but this is most likely because new engine management systems are much more adept at anticipating knock conditions than older ones.

I'll inform the board of the results.

[VimyJJ]

Ran a full tank of the 89 octane and got 22.45 mpg which is down from the 24+ mpg I have been getting of late running 93. My driving conditions were nominal. So, my intial off the cuff impressions is that running lower octane gas reduces fuel efficiency more than one saves in cash at the pump.

I'll run a full tank of 93 again to see if I get back to my previous mpg numbers.