Smartie loves 93 Octane!!

[NY Smartie]

Put 7 gallons of 93 octane in yesterday, and man, there was a nice difference!! perhaps it was 2 parts imagination, 1 part fact, but it sure seemed to be a lot more responsive (transmission-wise), and smoother in the acceleration, and definately better power.

I guess it's kinda obvious, but it took me by surprise. way I figure it, a 93 octane fill up is only 70-80 cents more than a fill up with 89 or 91 ( 91 is rare in some areas IIRC).

will advise if I see any better gas mileage.

[PassionforPassionCT]

91 is non existent here, so it looks like I will be using 93. The price increase over regular is huge though. But getting better than 22 mpg is fine with me.

[NY Smartie]

well, IIRC, the minimum we should put in is 89 right? even then, at least by me, 93 is about 10 cents more a gallon. the least one, 87 I think, is substantially cheaper.

[Old smart]

In my area the norm used to be 87, 89 at 10¢ more, and 93 at 10¢ more again, a spread of 20¢. Now the stations are having mini-wars with the 87 and are jacking up the 89 and 93 to compensate (way up!). The spread is now 30¢ to 40¢. Diesel is about +60¢.

[knutliott]

The stations around here are usually 87, 89 at +15¢, and 92 at +30¢. The smart calls for a minimum of 91 RON with a preference for 95 RON, but all of the stations here show the (R+M)/2 rating. As I recall it's usually a difference of 4-7 rating points so our 87 is probably the equivalent of the 91 that the smart car sets as a minimum and our 92 is probably the equivalent of about RON 98.

I have heard reports that using the lower octane fuel cuts your gas mileage by about 4 mpg, so even with a 30¢ per gallon difference the math says it's worth it to buy premium.

[xcrew229x]

At 92 octane, mine got 40 mpg..... at 89 octane, mine got 40 mpg...... at 87 octane, mine got 40 mpg......... the calculator doesn't lie. I noticed no power difference.

[Old smart]

As usual, the Euro-English 451 Operators Instruction provides specific information on fuel quality that we in the US are apparently not trusted to have. It says:

“Premium unleaded,
EN 228, at least
95RON/85MON”

95RON/85MON is 90PON by (RON + MON)/2, the Pump Octane Number we see on our pumps. As I recall, in the UK the pumps are labeled by RON only. So, the recommendation is 90PON, just one click above 89. BUT, it still says "at least," and I note many comments on the Euro sites about better performance with better gas. Better gas isn't just about higher octane it is also about the better formulations and additives that come with it. We have so many local/seasonal designer and E10 blends that it complicates calculating the MP$ (miles per buck, or ¢PM).

N.B. "EN 228" is a EU designation for "E05," a 5% ethanol formulation.

[SmartCard]

Originally Posted by xcrew229x

At 92 octane, mine got 40 mpg..... at 89 octane, mine got 40 mpg...... at 87 octane, mine got 40 mpg......... the calculator doesn't lie. I noticed no power difference.

of course, unless you drove the EXACTLY the same way on each tank, a comparo between the 3 octane ratings is moot.

[spdickey]

Here is Southern California its 87 89 or 91 with a few places selling 93. With premium now over $4.00 most places I'll stick with Costco 91 for now at $3.99. I did get a half tank of Arco 89 yesterday, no real change noticed.

[saronian]

The US manual says:

Minimum Posted Octane 91 (Avg. of 96 RON/86 MON)
Unleaded gasoline containing oxygenates such as ethanol, IPA, IBA and TBA can be used provided the ratio of any one of these oxygenates to gasoline does not exceed 10%; MTBE must not exceed 15%.

The ratio of methanol to gasoline must not exceed 3% plus additional cosolvents. Using mixtures of ethanol and methanol is not allowed. Gasohol, which contains 10% ethanol and 90% unleaded gasoline, can be used.

These blends must also meet all other fuel requirements, such as resistance to spark knock, boiling range, vapor pressure, etc. Turn off the engine before refueling.

In Northern California 91 is the maximum posted octane available.