[CaptOz]

I contacted Shell Australia to determine our (Australian) equivalent octane compared to yours (USA). I received some results that may assist with mapping.

As you most likely know Australia use the RON octane rating and you use AKI.

The conversion is: (RON + MON) / 2 = AKI

In Australia we have two high-end premium grades of fuel available:

• 98 RON
• 100 RON (includes 5% ethanol)

So, using Shell’s information, I have calculated the following ratings:

Shell V-Power 98: (98 RON + 85 MON) / 2 = 91.5 AKI
Shell V-Power Race 100: (100 RON + 89 MON) / 2 = 94.5 AKI

Note: Shell V-Power 98 is far more available than the V-Power Race 100 octane grade.

Cheers.

CaptOz

[LOK11atXEDE]

Originally Posted by CaptOz

I contacted Shell Australia to determine our (Australian) equivalent octane compared to yours (USA). I received some results that may assist with mapping.

As you most likely know Australia use the RON octane rating and you use AKI.

The conversion is: (RON + MON) / 2 = AKI

In Australia we have two high-end premium grades of fuel available:

• 98 RON
• 100 RON (includes 5% ethanol)

So, using Shell’s information, I have calculated the following ratings:

Shell V-Power 98: (98 RON + 85 MON) / 2 = 91.5 AKI
Shell V-Power Race 100: (100 RON + 89 MON) / 2 = 94.5 AKI

Note: Shell V-Power 98 is far more available than the V-Power Race 100 octane grade.

Cheers.

CaptOz

This probably should be in the Australian Regional sub-forum but your calculations seem quite correct. Having tuned on both continents with both US fuel grades and both Australian fuel grades, I'd say it also ties up fairly well with anecdotal evidence of where ignition timing should be given the corrected numbers, but I would put the V-Power Race down a whole point to about 93.5AKI in my professional opinion. I have found this seems to hold true for many NA and FI engines in the last 14 years of tuning in Australia and the US. .

Cheers

[CaptOz]

Originally Posted by LOK11atXEDE

This probably should be in the Australian Regional sub-forum but your calculations seem quite correct. Having tuned on both continents with both US fuel grades and both Australian fuel grades, I'd say it also ties up fairly well with anecdotal evidence of where ignition timing should be given the corrected numbers, but I would put the V-Power Race down a whole point to about 93.5AKI in my professional opinion. I have found this seems to hold true for many NA and FI engines in the last 14 years of tuning in Australia and the US. .

Cheers

Thanks for your insight Lachlan. I had no idea about octane differences until I started reading this forum.

Cheers.