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Octane ratings are a bit different over here, to what you guys use in the US. Our 'regular' fuel is 91 octane, 'premium' is 95 and 'ultimate' is 98. Fuel cover on my vehicle says to use anything from 89 to 100. I choose to use 98 (the best fuel available). The advantages are: more power, cleaner burning (just look at the plugs) and better economy. You may pay a bit more at the fuel station, but go that bit further down the road and end up with a engine that loves you. Nothing shits me off more than being stuck behind an under-powered vehicle, climbing a hill under full throttle, leaving me in their wake of un-burnt cheap fuel emissions.

This right here.

Shell or Sunoco 93 Octane in all of our BMWs. Don't hear many people cal it High Test anymore. Always try and keep it above 1/4 tank to avoid excessive wear on the fuel pump. In my opinion it is worth the couple extra bucks for fill-ups. many claim that these engines run better with 93 Octane as opposed to 87 and I have verified this.

BLUF: When running at operating temperature an N62B48 ran with slightly lower rough running values when running 93 Octane as opposed to 87 Octane. Deeper explanation is below.

When home between assignments I work at a shop in Georgia and have access to an AutoLogic Diagnostic Computer. This computer is an extremely powerful tool with the ability to program and code BMWs given you have the proper software and know how. One of the features of the AutoLogic computer is the ability to read rough running values of certain vehicles, I did this test on 2006 750iL N62B48 motor with approximately 113,00 miles on it. Unfortunately I no longer have the saved screenshots as this was done several months ago and they were deleted off the hard drive. Customer complained the car felt like it was running rough despite having not DTCs. Hooked the vehicle up and found no current or saved DTCs. First thing I asked after scanning the vehicle was what octane gas he was running in it. He only fueled at Shell but was running 87 Octane with the occasional tank of 91 every several fill ups.

I explained to the customer that I only ran 93 Octane in BMWs and that wee that all our customers do to keep their motors in the best possible condition.


This was one of the first vehicles I diagnosed with the AutoLogic system and eager to see what
Vehicle was ran with both 87 and 93 Octane fuel from the same Shell station, while the car was at operating temperature. Rough running values were approximately .10-.15 lower across all 8 cylinders when the test was done with 93 Octane fuel. Lower values are better for this test. Values around .70 or higher suggest poor combustion. The values in this car ranged from .45-.55 with the 87 Octane and .30-.45 with the 93 Octane meaning the car ran smoother with the 93 than with the 87. Keep in mind that this test was done in the real time and not in a lab or experimental facility where we could control every variable. The parameters that we had control of such as engine oil and water temperature, ambient air temperature, fuel, and testing environment were kept constant for both tests. These values are approximate since I don't have the screenshots anymore.

Sorry for the long post/rant but the more information the better.

93 octane only here... when in Cali had to use 91. I'm not brand loyal but I avoid Costco and Sams like the plague. We had costco customers come in with dead fuel pumps on Mercs and Bimmers alike. Costco stepped up and paid for the pump replacements though after a certain number of occurrences.

93 octane required. Shell, BP, or Sunoco.

93 / 100 mix at the track to prevent detonation on the long straights.

http://img.photobucket.com/albums/v1...4E809BD664.jpg

^This - no track for me but 93 at Shell, Sunoco or BP only

93 will be going in from now on thanks all

Hey, Buff those pipes!

Sorry for the Hi-Test Geezer term. Pumped gas in high school when 103/104 octane was leaded gas at $.36 @gal and when it went to $.50 a gal I thought that was high.

Back in the "Gas War" days I saw $.19 for 103 Octane

In my area, 93 is not available, so I used the "best", which is 91.