I'm using 94 Octane gas in my E38

[geoprz]

Could there be any problems when using 94 high octane then the suggested 91 octane?

[Pelican Parts]

Are you using it as your standard gas or just once in a while?

[ColtonBH]

Theres not gonna be problems using it on an engine with fairly advanced timing and compression (ie the M62) there's not going to be any benefits though, so I'm not sure why you would spend the extra money for it

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[Jamos]

Yup no problems, other than wasted money :)

[oldroller]

Could there be any problems when using 94 high octane then the suggested 91 octane?

Probably going to start a discussion with this suggestion, but you would be better served by running a non-ethanol fuel. The supply near my location is an 89 Octane non-ethanol, currently $2.59 gallon.
Ethanol attacks rubber and Viton/butyl seals, hoses, and fuel pump components much more aggressively than gasoline, especially if left sitting for extended periods of time.
The effects are minimized by regular flow and exchange of fuel by regular fill-ups.

With the percentage of ethanol in fuels gradually increasing, more degradation is inevitable. Our cars were produced prior to the ethanol production (1% in 2001, 3% in 2006 of total fuel production) and manufacturers lagged behind in
critical component changes compatible with ethanol. The decision to eliminate ethanol in my E38 was made due to the large number of fuel/ethanol related issues I have been personally involved with on other vehicles, the age of the car and a decidedly stubborn'old school' mentality, and is mine alone.

You can draw your own conclusions.

[Jimmy E34]

Your 'high' octane is not that high in comparison to what we have here in Australia.

A lot of our gas/fuel stations here offer 91, 95 and 98 octane. I've put 98 octane in my car since I first purchased it. I guess it's a bit of a waste, but I think the higher octane does does get slightly better fuel economy.

[ColtonBH]

I assumed US. That's true, the US uses (R+M)/2, whereas many other use RON (the "R"). I don't know which Canada uses, but if it uses (R+M)/2, you have higher than necessary octane, if it uses RON, you're under the BMW recommendation, but are probably fine. Some members here use US spec 87 without issue, others (myself included) swear by only using 91+.

The method in calculating octane is usually printed on the octane sticker on the pump

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[Qsilver7]

Ditto...94 AKI octane vs 94 RON octane...represent completely different octane ratings. A simple Google search about the different octane ratings will quickly clear up any confusion or misconception when only the "octane number" is being bantered. In these types of threads...the calulation method needs to be identified first so that everyone is on the same page. AKI, RON, or MON? :)

BMW gives a "recommendation" & "requirement" in regards to fuel octane...which may be slightly different depending on your engine/model year. But as seen in the section below from an owners manual...there's a recommendation, a required minimum, as well as what can be expected if you choose to use something different than the recommendation or minimum requirement.


http://bimmerboard.com/members/q/original/Fuel%20Specification.jpg

Again...the calculation method for octane has to be considered. The USA uses AKI...and Australia uses RON...and some countries use MON. AKI octane rating "number" is always lower than RON due to it being the average of RON & MON (as Colton BH wrote in post #7)....but usually 91 AKI is about equivalent to 95 RON...93 AKI is about equivalent to 98 RON. AKI = RON+MON/2

https://youtu.be/zf-OYXlhJis


https://youtu.be/zf-OYXlhJis

[xboss]

Your 'high' octane is not that high in comparison to what we have here in Australia.

A lot of our gas/fuel stations here offer 91, 95 and 98 octane. I've put 98 octane in my car since I first purchased it. I guess it's a bit of a waste, but I think the higher octane does does get slightly better fuel economy.

I can buy 101 @ the 76 gas station still