Timthetoolman

A little qualification: when I say 200k miles really is saying that if no problems are seen on a quite a number of vehicles running low octane that is a reasonable indication of low octane not shortening the life of engine.

ANY failure octane related before this would be an indication of concern--proper records and maintenance applies...

scs2338

Compression ratio is what determines the need for higher octane fuel from all the information that I have ever read. Since the pilot wasn't quite the same in 2014 I compared compression ratios between the 2016 pilot and the 2016 mdx. Both have the same 11:5:1 ratio. I feel like this is confirmation enough to conclude that regular gas can be run in the MDX if it can be run in the pilot. What do you guys think?

mrgold35

I wonder if the Pilot lower HP rating of 280 hp is because of 87 gas since the MDX/Pilot have the very similar engine/compression? My 19 MDX owner's manual only recommends 91 Octane; but, the inside gas door cover states 87 Octane minimal with 91 recommended.

moose66

To me it is 91 for maximum performance/HP vs. 87/89 for workable performance/HP. The low octane rating will do in a pinch, but the highest octane is the best. Have to believe 91 octane was what Honda/Acura used for testing and published performance/output numbers.

wilspainar

I have a RLX and a MDX both 14's and I use 87 octane. On the RLX I have driven about 60k miles using only 87octane. I haven't noticed any performance difference using 87 or 93.

JADS

I have a 2015 MDX and strarted out using the 87 octane gas since it was cheaper. Then I did some tests of mileage with both octanes over several tanks of each and trying to keep the driving conditions the same. I found that I get about an 8% improvement in mileage with premium gas which at Costco is about 10% more expensive. So for me a 2% premium isn't worth using the lower octane gas. And as others have noted the engine is designed for premium gas so it is best to use it.
I did the same test with my 2004 Nissan Murano and found not much difference in the mileage so I have used regular in it for the past 16 years and the engine still runs fine. That engine isn't a high compression engine like the one in the MDX so I think that is the difference.