Whats the right fuel for my 540i?

[jochen 4]

I put $50 of 91 unleaded in my 540i today, but thought I'd ask the combined experience of Bimmersport fans what you think the best fuel for a 540 V8 would be?

I've got performance to spare, so don't really care about needing more kilowatts. 282 HP is enough for me :-)

But wondering if the engines run better and more economical on 85 or 98, then they do on 91, taking the cost of fuel into account.?

The (Amercian) manual says:

Use unleaded gasoline only.

Recommended octane rating: 91 AKI.

BMW engines are equipped with knock sensors and will adapt automatically to different octane ratings, provided that the minimum octane requirement (87 AKI) is met.

Fuels with higher octane ratings will provide enhanced performance and lower fuel consumption, while the use of fuels with low octane ratings will have an opposite effect.

Thoughts?

[lidistick 70]

http://www.faqs.org/faqs/autos/gasoline-fa.../section-1.html

I think the US of A have 91 as their 'premium' fuel.. like we have 98 as premium. The standard fuel has 87octane there.

Japan is 100 octane as standard AFAIK. Higher octane allows the engine to advance the timing much further before pre-ignition.

Some engines obviously benefit from this. I'm not sure if your V8 will

[cainchapman 0]

96 is the minimum I'd be using. I dyno'd the car on 95/96 and had 165kW on 98 it was 172kW (same dyno). For the small difference in cost per litre. I go with the higher octane rating.

[martyyn 2]

Go for the highest you can get Jochen. The V8's especially love the higer octane.

[Huttey 0]

I use BP ultimate 98 on both the 320 and 540 which is working fine for me

I use BP ultimate 98 on both the 320 and 540 which is working fine for me

[Rona318ti 0]

Jochen

I was looking for the same thing for my Rangie V8 and came up with this below. 92US octane is 96NZ and 87US octane is 92NZ. i would stick to 95NZ octane to be safe and sure.

Cheers

In most countries (including all of Europe and Australia) the 'headline' octane that would be shown on the pump is the RON: but in the United States and some other countries the headline number is the average of the RON and the MON, sometimes called the "roaD Octane Number" or DON, or (R+M)/2. Because of the 10 point difference noted above this means that the octane in the United States will be about 5 points lower than the same fuel elsewhere: 87 octane fuel, the "normal" gasoline in the US and Canada, would be 92 in Europe.

[my_e36 43]

I think, to sum up, is to get the 98. I too can notice the extra power difference, that equates to using less right foot to get you going, meaning using less fuel.

[isis 16]

in Australia, all BMW's are tuned for 95 and higher and they do say it on the fuel gauge and the fuel flap.

I think there might be drastic consequences for those that are skimming and using 91! If you can afford to buy it, please use some decent fuel in it!

[10hove 0]

in Australia, all BMW's are tuned for 95 and higher and they do say it on the fuel gauge and the fuel flap.

I think there might be drastic consequences for those that are skimming and using 91! If you can afford to buy it, please use some decent fuel in it!

Weve had quite a few BMW coming in recently with poor performance and high fuel usage , and one common thread has been that as fuel prices go up more people are running 91 octane , while the car will run on this the resultant adjustment the computer make to avoid knocking robs so much power (especsially for 318s) that most people are haveing to use way too much throttle (and Fuel) to just get the car going especailly on short stop go runs> 95 or 98 will actually produce more power and economy

cheers

hove

Edited July 23, 2006 by Alex ten Hove

[jochen 4]

Thanks everyone.

I filled up today on 91, and did a 155km drive, and got 11.7 L/100km

I'll keep the trip comp going until the tank is empty and see what I get.

When she is empty I will fill up on 95 and observe the difference!

Jochen

[RvT 9]

I have been using 91 for the past 30,000km / 3 years without any issues in my 540. There is ample power and has never missed a beat.

[SKT174 1]

Just had a look at the Jap owner's manual, it says above 95 octane premium gas required.

[StylesM5 0]

Had a look at putting LPG into the Territory yesterday. Running 20,000kms / year I will pay back the $4k installation costs in 18 months. At 99 octane too, it certainly has some benefits.

There is a 55 litre donut tank that replaces your spare tyre and with tyre technology what it is these days, when was the last time you had a flat?

Worth thinking about.