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Bad_Ax wrote the following in another thread - "Going back many years, the high altitude regions (i.e. Colorado, Wyoming, Montana) had lower octane fuel due to lower air pressure at local altitudes of nearly 2 psi resulting in lower cylinder pressures. Moden cars with higher compression and the increasing presence of boosted engines are making these octane adjustments obsolete.
The question of lower altitude Western states having lower octane gasoline is directly related to a thing called CaRFG3 otherwise known as California Reformulated Gasoline Phase 3. In typically misguided fashion the California Air Research Board determined that the phase-out of methyl tertiary butyl ether (MTBE) in California's gasoline would save lives and protect the environment. MTBE was a blending agent that also raised the octane level of gas. Many states have substituted methional for MTBE and maintained the octane rating. Toyota did not exactly agree with the substitution of methional for MTBE and made its position known as I'm sure other automakers did. https://www.arb.ca.gov/fuels/gasolin...yota_prstn.pdf Then there is the complicated issue of patents for reformulated gasoline and the pipeline distribution system serving most of the Western states. https://autoweek.com/article/car-new...ops-california. In the case of Alaska and Michael D the issue is that Alaska, while producing a lot of oil, lacks the refining capacity to provide for the needs of the state so much of the motor fuel and jet fuel in shipped up from the West Coast refineries, which for efficiency sake and regulation produce maximum 91 octane gasoline. https://autoweek.com/article/car-new...ops-california So Alaska is stuck with the fuel that is mandated for CA because refineries can't alter production to serve the needs of a very small population."
If you read the above links, I have some updates. California has its own low emission formula of gasoline. We have replace MTBE with ethanol. Premium is 91 octane. So if California is shipping gasoline to Alaska, why is Alaska's Premium only 90 Octane?
Hib Halverson wrote the following in another thread - I've heard all kinds of terms applied to gasoline in some western states..."crap gas", "junk", "s**t gasoline" and so forth, but I've seldom, if ever, read any scientific-based criticizm other than that the pump gas is 91-oct.
Automakers are pushing to have Premium gasoline octane raised to 95 Octane so that it will be easier to meet upcoming fuel economy requirements.
I updated / corrected the entries for GA.. Looking at the revision history, I see the person maintaining the Wiki page is a "stickler" for resource citing, and has reversed many edits..
Well, I've lived here for over 20 years, I know what's available at the pump, so, it's not my problem if the source cited for GA says we only have 91 (we have 93).
Last edited by Dan_the_C5_Man; 09-20-2018 at 10:33 PM.
In PA Sunoco used to sell 94 Ultra. I don't remember exactly when it was they stopped but I haven't seen it in some years period that quietly went away
In PA Sunoco used to sell 94 Ultra. I don't remember exactly when it was they stopped but I haven't seen it in some years period that quietly went away
I remember that stuff. Always too expensive for the beaters I owned at the time I lived there.
I am in British Columbia and 94 is available at Chevron only and for a short period of time last year November to about February this year Washington state had Mobil at 93 but it has since disappeared.
Please look for your State. As you can see most states are currently blank. If it is blank, please update it with the octane number for each grade of gasoline. Only takes a minute to do at this link https://en.wikipedia.org/wiki/U.S._S...tane_Standards
I thought most states had 92 or 93 octane Premium, but so far that is not the case.
More and more newer cars are coming with higher compression ratios, and I hope that ups the demand for higher octane fuels.
Is Alaska receiving an RBOB with out the ethanol?
Most of those articles I saw linked were pretty old. CA has been on (or past?) CARB Phase III for years.
MTBE was phased out many years ago in CA, and then later in the lower 48, IIRC. During the switch from MTBE to ethanol, there where a lot of issues as the 2 do not mix well (causes a brown sludge).
Most refiners make a MOGAS blend (RBOB for the lower 47, and CARBOB for CA, not sure what AK uses), which is not on spec until ethanol is added. Ethanol has a higher octane - about 110-115, so the blendable fuel is much lower on octane - until E is added. The other specs are not ontest until e is blended as well. RBOB is the blend that becomes on test after it has 10% e mixed in to it. Which is done at the last point, normally the truck (ethanol can't even be pumped by pipeline, due to it's propensity to absorb water, LOL)
If you do not add e, the octane (and other specs) will be off-test. Octane will be low.
In CA, Chevron used to be able to meet the CARB specs even without an oxygenate. But then the state mandated it be blended (as an oxygenate) at 10%.
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FWIW, I too have heard lots of stories of the CA crappy gas, etc.
However, I'm not so sure about that.
Olefins are what causes gasoline to gum up - CA has the lowest Olefinic content.
Aromatics and benzene content are also much lower, good things.
So having been riding the "CA has crappy gasoline" train and agreeing with that for years, until I see real data I question that.
The switch from MBTE to E was clunky, granted. Ethanol is a great solvent, and cleaned the **** of of many fuel systems, causing all kinds of problems. Bertram, a very high end boat maker, had their gasoline fuel tanks - which were made out of fiberglass - dissolve, and become a huge fire problem, and the resin in the FG became a gel, LOL.
But beyond that I haven't seen much proof (scientific). The newer cars are all designed for the fuel we have now, and seem to be doing OK...
Last edited by Chiselchst; 09-27-2018 at 03:55 PM.
09-17-2018, 05:57 PM
Gasoline Octane The Good, The Bad, and The Ugly
