I know you guys in the states use 93 octane fuel, however thats basicly our standard grade here (91) and we also have 96 premium and 98-100 top grade. So whats the difference running a J.D.M FD on 98 vs 93 on the U.S market model?

I have been told that both the fuels are identical but I kinda think thats incorrect. So how much of the information on this forum being mostly american based is actually correct for New Zealand with things such as detonation blowing seals etc. My intuition would tell me that due to the grade of fuel we use, the chances of detonation would be lower however im not quite sure if there actually is any difference?

Im still looking at rx7's so this information is important for me to make a decision, and maybe help others in the future when the higher grade fuels roll out in the states.

 

US uses (RON+MON)/2
I think outside US, uses only RON which is the higher number.
RON and MON is the different ways of measuring Octane Number (ON)
So it is possible US has 98 RON and 84 MON which yield 91 Octane in US which is equivalent to your 98 Octane.

 

Research and Motor octane and Reza is right, research is usually a fair amount higher. The difference is the test conditions of the motor. I seem to recall the test motor being run at a different RPM, I could be wrong as it's been 10 years.

Kevin T. Wyum

 

The MON and RON are two different tests altogether for octane rating. Pure heptane gets a score of 0 and pure isooctane gets a score of 100. The performance of any fuel tested gets a number on this sliding scale (which doesn't necessarily end at 100... you can do better than isooctane).

The difference in the two numbers is called "sensitivity." For gasoline fuels, this number is usually about 10-12. This means that the (R+M)/2 is about 5-6 points less than RON.

So yes, US 92-93 is NZ 98.

Take care,
Shad