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Which fuel?
Posted: Wed Feb 20, 2019 12:14 pm
by robster
Picking up my B8 on Fri and wondered what fuel to use.
Ran 95 in my S4 but do I need to use 99 in the RS?
Re: Which fuel?
Posted: Wed Feb 20, 2019 12:20 pm
by Surrey Sam
Congrats.
Running lower RON fuel will pull engine timing, even on a S4. The engine will run fine on 95 though, as the ECU will just adapt, but it'll run slightly better on 98/99. Dyno figures also support that fact, especially when tuning the 4.2 V8.
Re: Which fuel?
Posted: Fri Feb 22, 2019 6:41 pm
by johnnydog
Shell V Power is regarded by many as the best fuel for the RS, both for cleanliness and performance, although Tesco Momentum 99 is also supposed to perform well. I have used Tesco Momentum in the absence of a Shell garage, and not notified any difference in performance. There is also a big price difference between the two which equates to a decent saving per tankful if price is a consideration.
Re: Which fuel?
Posted: Fri Feb 22, 2019 7:48 pm
by HPsauce
It's definitely RTFM, but almost all performance Audis run "optimally" on 99 (or so) Octane petrol, but will run happily on 95.
Both my S8's (32 and 40-valve) would actually run on much much worse than that being N/A but usually got fed 99.
Even my little Volvo (250bhp T5 turbo) gets "optimum performance and fuel economy" on 99RON according to the manual.
So they all get fed on V-Power or Momentum. I find Momentum just as good and significantly cheaper, plus Tesco is nearer.