Quote:
Originally Posted by davis449
This isn't entirely true. There exist vehicles where "premium fuel is recommended for maximum performance". I owned a 1993 Nissan Maxima SE that fell into this category. There are modern Toyota's and Cadillac's (just two examples) the fall into this category as well. Their ECU's are set, specifically, to run the lowest and highest octane gasoline and will adjust to perform better (i.e. produce more, verifiable HP) if higher octane fuel is used. This is not to be confused with, say, the clause in your BMW owner's manual that says basically "you can use 87 octane if you absolutely have to, but fill it up with premium as soon as you possibly can". This statement in the owners manual is always in cars that are designated "Premium Unleaded Fuel Only" (I have seen it in every manual from Mercedes, Audi, and BMW that I've owned from model years 1995-2016). If you have no such statement regarding premium fuel, then you are indeed pissing away money putting in more expensive gas as the ECU will not adjust parameters to give you better performance. Then, of course, there's those of us with tuned engines where you really should use fuel with the octane rating required by the tune that's flashed.
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What is "premium" in this case? Premium is not an octane rating it is an octane range. The industrial standard is 91 and up is premium.
As mentioned before, in my 335i when I am running my aggressive tune I must run the higher 95 octane (98 here in Germany)
When I say run the lowest octane your car can take I am referring to the lowest octane the manufacturer recommend (look inside your filler door)
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2009 118i Monaco Blue "Maximillion"
2009 335i Saphire Black M Sport "Leopold" Cobb stage 2 aggressive tune, Mishimoto FMIC, Cobb charge pipe, Cobb catted down pipes, Forge diverter valves, BMS inlets and DCI, Cyba scoops and M Individual Audio retrofit and M3 gauge cluster retrofit.
2011 328i Titan Silver M Sport "Franzel" <--Wife's car