Petrol/Gas Noob question about the Gasoline Octane required

[scottmatheina]

I take possession of my Grenadier Trial Master in a few weeks, and just doing some research.

So Google tells me this below, and I've also seen videos say 91 is the required gasoline.

The 2024/2025 INEOS Grenadier gasoline (petrol) models are powered by a 3.0L BMW turbocharged inline-six engine (B58). The recommended fuel type is Premium Unleaded (91 octane or higher) for optimal performance, though it can run on a minimum of 87 octane if necessary.
Key Fuel Details:

• Engine: 3.0L BMW Turbo Petrol, Straight-Six
• Recommended Fuel: 91+ Pump Octane Number (Premium)
• Minimum Fuel: 87 Pump Octane Number
• Fuel Capacity: 23.7 gallons (approx. 90 liters)
• Economy: Approx. 14-19 mpg combined, depending on driving conditions

The engine is engineered for high torque, utilizing the 3.0L engine to provide power for both on-road and off-road driving, often requiring premium fuel to maintain performance and prevent engine knock.

My question is: since this engine was designed for cross-globe "overlanding," there is no way 91 is actually required, and the above says 87 is the actual minimum, which makes sense. So "91" isn't required.

So the actual question is, does anyone have any experience running with 87 vs 91? I'm in the US and don't plan to do any cross-globe overlanding anytime soon, but I'm just curious about the recommendation to use 91 when it should run just fine on 87, since the vehicle is specifically built to operate in backcountry conditions on low-quality gasoline. So I get the recommendation, just wondering if anyone has experience, or a strong opinion on the Gasoline octane you prefer?

Looking forward to getting the new Grenadier in a few weeks, so any answer is welcome, just curious!

 

[Tenac]

Most modern turbo engines operate more efficient on 91 or higher octane. Gas threads can turn into oil threads in a blink of the eye. The engine has software to adjust, though I am sure there are limitations there my guess is 87-93 is probably very safe range to play within. Me however I always prefer higher octane ratings. I like more performance etc....

 

[Krabby]

" a strong opinion on the Gasoline octane you prefer"

I cannot speak to anything other than the fact BMW recommend 91 so that is what makes most sense to use. I personally use a higher grade than that but wouldn't go below the 91.

If you don't mind me asking, what's wrong with just using the 91? Sure, it might save a buck on a fill up but nothing substantial enough in my mind to go to a spec below what the manufacturer recommends.

 

[Silverjay]

Not enough data to be statistically significant. I ran 3 tanks of 89 to compare to the 2,200 mile baseline on 91 octane. On 91 I run 15.1 mpg hand calculated. The 3 tanks of 89 averaged 14.4 also hand calculated. No perceived difference in performance around town or on the highway. If I did the math right it was under $70 a year to run 91 with the mpg difference. I stopped playing with it.

 

[Tenac]