California 91 octane, more detonation prone?

[Roundybout]

Kids and I have been driving dirt bikes this summer. Air cooled 4-stroke 125cc. They spec 90 octane minimum. Very sensitive to air temp and engine temp in reguards to how well they run with the current jetting. On our route we stop at several stations to fill up (goes quick with only a gallon). There is one particular station that sells 91 ethanol free and we used that. It felt like they were two jet sizes too rich. Back at Sunoco for their 93 and they ran the best. Mobil 91 which we start out with is a little lean. Fuel injected vehicles probably never notice the difference. But with such tiny jets and 8hp you really notice the variance in pump fuels.

[In-Tech]

Thank You Truckedup, I just downloaded it again and it works Is there a glossary of the acronyms?

[NewbVetteGuy]

David, is there a fuel zone map somewhere that meer mortals can access?
Is this variation within a state thing just an issue in California or is this a common practice in many states?

https://www.api.org/~/media/Files/Polic ... ts-Map.pdf

Perfect! Thanks.

Adam

[sbs]

In 2001, I moved two 49-state cars into CA. Both saw mpg drop by ~20% on CA gas. They were both low-hp Honda/Acura sedans factory-specced for 87 & 89 octane. I didn't notice any other effects.

In 2004, I moved two different cars out of CA, each gained ~20% mpg on non-CA gas. One was a CA-spec Mitsubishi sedan, one was my 49-state vette. Both factory specced for 91. The CA-spec car was the most dramatic change of the four. It was always a dog on CA gas and still not fast but a noticeable SOP improvement after we left so I assume it was pulling timing on the CA stuff.

[David Redszus]

David, is there a fuel zone map somewhere that meer mortals can access?
Is this variation within a state thing just an issue in California or is this a common practice in many states?
Adam

Fuel specifications on a state by state, month by month, basis can be found in ASTM D4814.

California has four major fuel volatility zones: North Coast, South Coast, South East, and Interior,
which change monthly. It has two octane reduction zones, North and South Coast, by month.

In addition it has several Ozone non-attainment zones, by county.

Arizona has three fuel zones, Nevada has two.

Fuel specifications for all states will change on a monthly basis except Hawaii which has the same
fuel year round.