Octane Requirement

[fredweb]

I find it odd that the hawk requires 90 octane or higher. The compression ratio of the engine is 9:1 which should run just fine on 89 octane and any higher would not provide any improvement in performance. Anyone have any insight.

[humanbeing]

RON (90 was the lowest octane in China) vs AKI https://en.wikipedia.org/wiki/Octane...MON.2C_and_AKI

[SpudRider]

The Chinese, Research Octane Number (RON) is typically 4-6 octane higher than the R+M/2, Anti-Knock Index (AKI) used in the United States and Canada.

https://en.wikipedia.org/wiki/Octane...MON.2C_and_AKI

Therefore, a Chinese RON octane of 90 is roughly equivalent to a U.S./Canada AKI octane of 85.

[mjstef]

Only thing i can get Ethanol free anymore here is 91 octane so thats what i run....

[bogieboy]

as someone who tries to get that last little bit out of everything, I run 93 (when I can find it, sometimes settle for 91-r+m/2 octane) and ill tell you what... I gain 4mph with the 93 over the standard 87-89 octane. may be due to poor quality of the lower grades, may be due to the ethanol. ... don't know don't really care....LOL I just know that extra 4mph is handy to have on tap...

[2LZ]

Here in CA, searching for good gas is like trying to find the pot of gold at the end of the rainbow. In my county, we have better gas but it's still 91 octane, tops and it's usually ethanol gas depending on the station. Just ask the hoses in my chainsaws, blowers and weedeaters. Replacement of those lines becomes an annual project. Ethanol eats them to pieces.
I get a measurable difference between regular and ethanol gas. Both in MPG and power. The stuff is junk. How it's supposed to be better for the environment, while burning noticeably more of it is beyond me. Seriously...a minimum of a 3 MPG difference in both my Jeep and Challenger. It's garbage.