Not too sure about the city/country thing. I had trucks carting fuel out of Shell refinery for 10 years and it all comes out the same pipe - every brand. And I hear they use butane and other waste gases to raise octane to certified standard. It's all downhill, or up in the air, after the refinery gate.
John. On 26 June 2013 06:44, Ian Mc Phee <[email protected]> wrote: > Dr Hodges the the mogas STC man offers an octane checker device for sale. > City 98 sometimes has butane bubbled thru it at refiners to up octane > rating. This fuel quickly looses it's octane rating taken up in air > especially hot days. Country the 98 is USUALLY a better fuel but > occasionally city 98 gets to country and it bad news at Uralla NSW in > summer is (3500ft asl) Avgas keeps constant Oct rating even if out of date. > VW does not need lead but any engine only needs 20 percent Avgas for lead > lubrication. The rest is for octane rating only. Ian > On 25/06/2013 5:21 PM, "Laurie Hoffman" <[email protected]> wrote: > >> Rob is right on the mark though. >> With our H36, if we use 91ULP in remote locations, aside from a drop in >> power, it will often want to run backwards on shutdown. >> Occasionally at home it exhibits these same symptoms although we use only >> 98. >> It looks like our 98 may well have been 91 by the time we used it at >> times. >> Goodness knows what the RON of 91 could be after extended storage! >> >> *Regards* >> *Laurie Hoffman >> >> * >> * >> * >> >
