Spouse did me a favor and filled up my car for me. Said it was surprisingly cheap. car feels slightly down on power. Gas mileage however, is THE SAME. I kid you not, just did 230 miles and its averaging 22.5 mpg imperial, with the roof rack, with 20s and the pirellis. 25 mpg before i started hauling.

 

That's generally what happens with modern ICE engines. The electronics in the engine adjust the timing for the octane of the fuel I believe, thus giving you less power. Pretty much any engine can run on 87 just not optimally. For example in CA we only get 91 octane compared to 93 octane in the rest of the country - certain high performance vehicles are down on power when they are driven here.

 

If saving 4-5$ per fill up is worth even a slight potential of long term issues via detonation (or other items related to insufficient octane level), knock yourself out. Seems like a wild choice for someone whom can afford a luxury vehicle

 

Agreed! Put the good stuff in it.

 

The angle I was coming from was more to show how this vehicle could behave if you put in lower quality gasoline. Say for instance, you're crossing the Makgadikgadi Salt Pan and you only have 87 octane gas, this would seem like a helpful thing to know. Kinda reminds me of this clip . If my wife finds herself needing to tow a 20 ton truck, its nice knowing I got her a car that can do that and not one that scream luxury and pompous douchbaggery

 

In that context, your experiment makes much more sense, carry on!

 

That's good to know - for future trips to Mexico and farther south.

 

Defenders are known to work with different octane gasolines. On numerous trips to South America and Africa, we had to use lower octane gas as it was the only available fuel at the time. We carried octane boosters with us that we put in the tank when filling up with lower grade gas. Never had an issue, and of course always best to use premium gas when available.

 

We're running into gaps in having Premium available at the local gas stations. There are several large chains here that don't sell it. They have 87, 88 and 91REC which is offroad gas (and labeled as such). And that 91 is way more than regular premium.
My neighborhood is full vehicles that use premium and our corner station is a midwest brand that decided to only have Rec fuel for premium.