Seems 99% people here think there is no difference in quality of fuel here versus quality of fuel in America. There are many articles about our inferior fuel in comparison. I will gradually link in reports of this. In my time building big V8's and speaking with engine builders of pro race applications , the common issue they had when importing US built engines was they were getting no where near the power they were getting in the States because of their fuel type (comparison to 98oct), and always needed to de-tune US engines as our 98 just could not make the power their pump fuel could.
Many of us beleive that just because our fuels may have the same octane readings when tested, must mean they will perform the same, wrong. The US buy a much cleaner, purer fuel than what the Australian government purchases. Australia opts for a resin pumped fuel to increase octane, which decreases purity and strength. This is not done in the States however. Over the next few coming days I will put together proof and links to this thread which will give a more outlined and detailed report to this. Talk to any pro engine builder in this country and they will all tell you this is true. I for one have asked so many as I was sceptical on this being true.
From top bike engine builder in NSW.
"Mostly they just tip oxygenated race gas into them and go. The guys that were doing heads were just machining current CR250 head profiles into the stock head. This requires building up the squish land with MIG but the head dome has sufficient meat to cut the hemisphere. This is on 250s, mostly they leave 300s alone, who needs more grunt from a 300? Their fuel is so good the bikes run fine, even stock CR250s run well on US gas, they run horribly on our fuel." __________________
Dirt Bike Factory
The Illawarra's KTM and Husaberg dealer
Online parts, modern shop, expert tuning by 3x Mr Motocross Anthony Gunter
02 4229 7431
"98 burns slower than 95 and therefore requires more spark advance, a factor in decreasing top end power. It's MON that turns on a motor, our fuels have high RON values because they are very dense. The oil companies then load them up with burn rate enhacers so that the chassis computers don't have to wind in heaps of spark advance at high rpms. I dont have access to a varicomp test motor any more so I cant conduct a MON test.'
There are only two base load refineries in Sydney, Caltex at Kurnell and Shell at Rosehill, they then sell base product to the others who cook up their own additives etc.
Shell premium is the strongest on the dyno but BPs 95 works fine at the track, I only ever use Shell on the dyno so as to cut the variables as much as possible (even stale fuel will drop HP).
Optimax is the only one that 2Ts seem to dislike, it's supposed to be 780g/l but I've tested it above 800. Fuel mixes are serious secrets, there's no way the chemists will tell you much. It's so much better in the states where fuel is sold by MON rating.
In the old days everyone knew lead (tetraethyl lead) was the octane improver and the blends were virtually identical irrespective of supplier. These days they are very secretive about what they put in as additives. I know that the manufacturers use sulfur and manganese based organics in some fuels but thats about all I've been able to find. I'm sure there are many other additives being used.
91(MON) fuel equates to 100(RON) or 95(PON)