Need to be aware that North America uses the average of MON+RON ratings (also know as AKI = (MON+RON)/2). I think Australia like the EU uses just the RON rating (or E10 perhaps). 91 to 94 octane in North America is premium (94 most places, 91 here at 5,000+ feet). I think if you are running 91 RON octane in Australia I think you are running way too low a grade as that would be like 87 or 85 AKI rating here in North America.
... snip .... I doubt anywhere in Australia worries about altitude for the RON octane rating required. If I lived at sea level I would probably run whatever premium is there, usually 94 AKI.
....
As nhoj quoted in post #182 earlier,
Recommended Fuel
Use premium unleaded gasoline with
an AKI (RON+MON)/2 octane rating of
91,
or an RON octane rating of 95.
here in Oz, where our 'Standard' ULP is
91 RON (basically equivalent to your 85 or 87 AKI over there) the Recommended fuel for Spyders is
95 RON, altho they will '
run' on our 91... just not so well. Both 95 & 98 RON are considered 'Premium' over here, AND we can have Ethanol added to our fuel too. Usually the Ethanol stuff is somewhat cheaper than the 'equivalent' non-ethanol gas, and anything under 10% doesn't need to be stated/declared at retail selling points but is often clearly identifiable by the lower price; while anything 10% or over must be clearly labelled & identified; and we can get up to E85, which is usually only used in specially manufactured & appropriately tuned vehicles! :shocked:
Back to the good stuff - before I got the ECU Upgrade done on my V-Twin RT, it would run 'OK' on our 91 RON, but it did get noticeably better milage & performance on 95 or 98 RON (I run log-books, & meticulously track all of this sorta stuff & more!
) After the ECU Upgrade, the high revving high compression V-Twin really only just 'tolerates' 91 RON, and full throttle applications are not enjoyable for me or the engine, so it's an 'only in emergencies' thing now!! But the RT still runs as perfectly as I can measure on 95 RON; and the
only time 98 makes
ANY measurable difference that I can detect (apart from to my wallet!
) is on the track, where there's a measurable
performance gain - not a massive gain, but it
IS measurable, even with just a stop-watch!
Altho anywhere but the track, there's just no point for me in running 98 RON, cos not only is 98 RON significantly more expensive than 95 RON, but there's just
NO milage advantage; in fact, for me/my Spyder/its tune, there's a penalty - when I'm just cruising along & staying within the speed limit on 95 RON, I'll reliably get 38-40 mpg for tank after tank; cruising the same distances/speeds/roads on 98 RON, I
NEVER get better than 35 mpg, and
usually won't get better than about 31-32 mpg... So when you consider that our 'usual cruises/trips' are at least 1000 km one way, and that we're paying a bit over $2.00
per litre for 95 RON &
at least 20-25 cents
per litre more than that for 98 RON (often more!) - the less range I get from 98 RON not only puts us at risk of running out of gas between some of the servo's (that are frequently 320 km/200 or so miles apart in our wide open spaces) but it also adds the need for an extra couple of tanks full of gas to do that sorta trip length, and
ALL THAT means that if I'm running 98 RON, we hafta carry extra gas &/or it costs something like an extra $100 just to get there!! :banghead:
So I run 95 RON whenever I can, apart from on the occasional track day where I am chasing the last smidgeon of extra performance.
hyea:
Ps: We do have lower emission standards here than in Europe & many other countries, so we don't always get the latest & 'greatest' models of vehicles & our fuel isn't always of the highest quality when it comes to emissions etc. And we
DO have some areas where 'high altitude' &/or 'Alpine Fuel' is not only a good idea, but in certain times of the year, it's essential - sure, our Great Dividing Range isn't anywhere near as high as the Rockies or many of the North American 'high altitudes', but they are high enough, and extensive enough too! Besides, in most of our higher reaches, we've got the added issue of dealing with high ambient temps for much of the year too; so we don't get any benefit from the colder & therefore denser/better oxygen content per cylinder you generally get over there as you climb!! So 'Alpine Fuel' is actually a pretty big thing here, even if the majority of the population is never impacted or even aware of it! :lecturef_smilie:
