Quote:
Originally Posted by MaestroAl
If your engine is designed to run on 95RON, run it on 95RON because 98/99RON will never pay for itself and makes absolutely no sense whatsoever. If your car is tuned to use 98RON then use 98RON. Simples.
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Agree with your comments, but with our BMW engines this is where it all gets a bit ambiguous... quote from BMW in their brochures.
Quote:
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BMW recommends the use of RON 95 super unleaded petrol. Unleaded RON 91 and higher with a maximum ethanol content of 10 % may also be used. Output and fuel consumption figures apply to RON 98 fuel.
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RON 95 is
not 'super unleaded' and BMW's own performance/fuel tests are done with RON 98. Other BMW data suggests the engines are designed for RON 98 and using lower octane ratings has a slight decrease in power and increase in fuel consumption.
My car (535i engine) has on the fuel cap, in bold print.. "Ron 95 unleaded petrol" and underneath (RON 91 - 99). In the user manual RON 95 is recommended and then says "fuel qualities with 91 RON and higher are permitted".
In clear print as a stand alone statement,
BMW recommends BP fuels
I personally think BMW has to say RON 95, as not all fuel stations have other options in the UK. If they said "use, or BMW recommend RON 98" we'd have a big issue with finding the fuel in some areas.
Of course our petrol engines will adapt to the fuel used, but RON 98 is going to be the nearest match to the claims BMW make for performance.
I'm using Esso super unleaded RON 97 in my 535i. It's the lowest price difference locally for a premium fuel, (can't get RON 98 around here). Esso, in their spec' sheet state is has double the additive/cleaning values as their standard Esso unleaded RON 95 fuel. As I can be making short trips I do it for that alone, as if anything can help keep the engine A1, that is best practice as far as I'm concerned.
Was same for the diesel, the additive package to help keep the dirty old diesel cleaner inside was the main reason for using BP Ultimate. The fact it was sweeter, pulled better mid range and gave a couple more mpg, were all bonuses.
A couple of videos from Fifth Gear may be worth watching.
HighlandPete