I seem to get 16.3 mpg with #93, and 14.7 with #87.
I am going to test some more to see whether this result is consistent.

Anyone else did a real-life test between these 2 grades?

 

I have not tried this on my GX470, but with my previous Acura RL, lower octane grade always returned crappier MPG reading. Its expected.

 

I get a 1 MPG difference, I do have a heavy foot, helps me justify the difference in the cost. But sometimes the difference at the pump is a 50 cent difference between 87 and 93...then 87 wins

 

Has anyone tried 91 versus 93? In my area 93 gas is hard to find and it's over $5 a gallon. 91 is much more common and a lot cheaper.

 

In my area 93 is only less than 5 cents more than 91, so I cannot justify buying 93, I guess we will rely on you to do this 87 v.s. 91 test. Let us know you result!

 

Here's the thing, you bought a premium vehicle, why use cheaper gas?

If you actually figure it out, it only costs a couple hundred dollars a year more to burn premium (depending on how much you drive). When you're spending $5000+ annually, it's a drop in the bucket.

It recommends premium fuel, that's what you should use. It will get slightly better MPG and run smoother. on the flip side, if the vehicle calls for regular, don't waste your time and money with premium. It does nothing for you.

I never understood why someone would buy an expensive car/truck and then cheap out on the gas. It's like buying an expensive Nikon/Canon camera and then putting crappy off branded lenses on it.

 

Curiosity! man, money is not always why people do things
At least this is what I was thinking, I just wanna find out / feel the difference