What Fuel grade do you use in your 650

[JBF650]

I use nothing but the top octane rated fuel type 98. I know it says 95 is fine but for The Shark, 98 it is always.
Noting all the issues that earlier N63 V8 versions of our 6ers had with injectors problem's and oil leaks.... I'm wondering if people were putting in rubbish fuel too? this may have compounded injector problems at least yes?

[NorthCountryGuy]

93.

[AccordTR]

Originally Posted by JBF650

I use nothing but the top octane rated fuel type 98. I know it says 95 is fine but for The Shark, 98 it is always.
Noting all the issues that earlier N63 V8 versions of our 6ers had with injectors problem's and oil leaks.... I'm wondering if people were putting in rubbish fuel too? this may have compounded injector problems at least yes?

I add octane boost (mmt free) and boost my tank to roughly 100. Keep in mind us in North American have a different octane rating system.

[thebmw]

Remember, octane has nothing to do with quality of gasoline. 93 octane is sometimes 40 or 50% more than 87 octane but 87 octane only yields about a 10% decrease in gas mileage at worst. The car will recognize the lower octane and change air fuel ratio has to avoid knocking. There really is no meaningful advantage to using 93 or even 100 octane for a daily driver.

[jjasonSU]

91 or 93
I dread the carbon buildup issues.

My wife's audi 2.0T calls for 91 but I often alternate and use 89

[murph914]

The higher octane allows forced induction cars to be tuned to burn more fuel without the damaging effects of detonation. All that it does is keep the gas from sparking off until a tiny bit later. No correlation to quality, power, or anything else. If your tune is meant to use 93 or 91 then if you put lesser octane in the car should sense it and dial back the engine. So if you have an aftermarket tune, it's probably to use 93 octane. If you have a stock tune then just use what BMW recommends. You could use 87 if you wanted, and the engine should recognize that and dial back the engine more, but I always considered that a waste of the money you spent for the 650 over the 640. Just go for the diesel if that's you goal.

[thebmw]

Originally Posted by jjasonSU

91 or 93
I dread the carbon buildup issues.

My wife's audi 2.0T calls for 91 but I often alternate and use 89

I dread carbon build-up issues as much as anyone else. But octane has nothing to do with that.

[JBF650]

Perhaps there is a difference regionally .... 98 octane here in Australia is Ultra premium unleaded , 95 is premium and 91 is regular then there is an 89 ethanol blend...
So my Shark always gets ultra premium unleaded, in fact all my cars have always had 98 ....

[thebmw]

Originally Posted by JBF650

Perhaps there is a difference regionally .... 98 octane here in Australia is Ultra premium unleaded , 95 is premium and 91 is regular then there is an 89 ethanol blend...
So my Shark always gets ultra premium unleaded, in fact all my cars have always had 98 ....

The formula for measuring octane is different regionally. So in America regular is 87, mid-grade is 89, and premium is 93, unless you live in California where it's 91 because of their wonderful lawmakers who seem to despise the internal combustion engine.

[ezmaass]

I use 93. As others have said, modern ECUs will adjust - no damage if you put in a lower octane, just a bit less power.

That said, the brand (and using "top tier" gas) may matter more than the octane level. This is essentially looking at the detergents used and the "cleanliness" of the fuel. But to be honest, most stations (at least here in the US) should be safe... and unless you're keeping the car for half a million miles, I'm not sure how much any of it really matters.

[thomasrodco]

93 for me

[Opie55]

Can't usually get 93 in Colorado. Only 91. Supposedly it's an altitude thing, but not sure why.

[Walt White Coupe]

My gas cap door says to use 89 octane fuel.

[Opie55]

Originally Posted by Walt White Coupe

My gas cap door says to use 89 octane fuel.

Hmm, I thought these cars were premium for sure. I'll have to look at my owner's manual. I don't think my car has a filler door label.

[Walt White Coupe]

Originally Posted by Opie55

Hmm, I thought these cars were premium for sure. I'll have to look at my owner's manual. I don't think my car has a filler door label.

Here's mine on my 2013 650ix:

[Opie55]

Oh, that's the minimum, not the recommended.

[Qsilver7]

I use 93 AKI. ...and if that's not availabe...I use 91 AKI.

Just an FYI (since this thread goes back a couple of months)...as mentioned already, different countries/regions use different methods for calculating octane.

So those that are throwing out nbrs without indicating the calculation method...may already know...but for noobs unfamiliar with the different octane rating methods may be getting confused by the numbers (only).

• Australia uses the RON method (Research Octane Number)
• Some countries/regions use the MON method (Motor Octane Number)
• The USA & Canada uses AKI method (Anti-Knock Index (AKI) or (R+M)/2)

[Walt White Coupe]

Originally Posted by Opie55

Oh, that's the minimum, not the recommended.

So here is what the operation manual says:


Given this advice, I generally use 89 unless it's in the heat of summer even though BMW says "This has no effect on engine life."

[Opie55]

Originally Posted by Walt White Coupe

So here is what the operation manual says:


Given this advice, I generally use 89 unless it's in the heat of summer even though BMW says "This has no effect on engine life."

Well, you save a few bucks that way. Probably more than a few.

[Yorkie36]

Here in the U.K the lowest octane is 95, I normally go for the premium fuel which is 97 or 99.

I still had a problem and ended up replace all 8 injectors, plugs and coils.

[Cadmus130]

Has anyone had any stalling issues after filling up with 93?

I was using 91, had no issues, I put 93 in today and boom, immediate stall right out of the station.

[arucano]

I always use 93 all the time in the M6. Switching from 91 to 93 should not cause a problem. The ECU will adjust for the 93 after you step on it a couple times. There should be any reason for the fuel change to cause the stalling.