Octane Question?

[guyrobert]

I recently got a CMR tune from DC Performance they have given me a 91 octane tune and a 93 Octane tune.
In Vancouver they only have 92 Octane @ Shell and 94 Octane @ Chevron
I have been told that Octane standards are different in Canada vs the US also that US gas has 10% ethanol added.
Does anyone have the "goods" on gas?

 

[TNVIPER]

I do not know how Canada calculates octane. I do know that the higher the elevation the less octane you need....that is why 91 is sold in a lot of areas of the US..91 performs as well as 93 in higher elevations..

 

[guyrobert]

I know there is a differance in some weights and measures.
In Canada a 12 oz beer is 341 ml in the US it is 355ml, so a Canadian beer is aproximatly 1/2 oz less than a US beer and a Canadian 1 oz shot glass is 1/24th smaller than a US 1 oz shot glass.
We are at sea level here and some people have told me that CDN 91 octane is equivilent to 93 in the US.
I am interested in getting the straight goods!

 

[TNVIPER]

According to this "Shell Canada" article the US & Canada use the same octane measurements...though it does mentions that some "less scrupulous" stations in Canada will post a different rating to show higher octane..

http://www.shell.ca/home/content/ca-en/shell_for_motorists/carcare/about_fuels/encyclo_gasoline_octane.html





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[guyrobert]

From the state of Oregon info on Octane -oregon.gov/ODA/MSD

How is Octane rating determined?
Gasoline is subject to 2 testing methods to establish it's octane rating. The motor method, runs gasoline through an engine under load.
The research method runs the gasoline in a free running engine. The octane rating you see displayed on the pump is an average of the 2."

The Shell Canada web site says that the research method will produce signifigantly higher octane ratings (they use this measuremnt in Europe)
and that they only use the motor method which produces a lower octane rating.
And this doesn't factor in any addition of any ethanol.
I am still ????

 

[TNVIPER]

You are misunderstanding the article..

"The value that relates most closely to actual driving conditions is the average of these two values: Road Octane Number = (RON + MON)/2. This Road Octane value is the one referred to in Shell stations: Shell Bronze gasoline has an octane rating of 87, Shell Silver is 89 and Shell V-Power is 91."

The rating the US & Canada use is the average of Research Octane Number (RON) + Motor Octane Number (MON). This average is called "Road Octane Number"....

The Europeans use RON which will show a higher Octane than what we use.

 

[guyrobert]

Thanks for pointing that out, still looking for the effect that the addition of ethanol has.

 

[TNVIPER]

Thanks for pointing that out, still looking for the effect that the addition of ethanol has.

The 10% ethanol gasoline is what the pump says whether it be 87, 91 or 93........the E85 ethanol gas is 100+ octane. Both are rated the same way as straight gasoline..(RON + MON)/2..........

 

[guyrobert]

Thanks for the help.. found this on the nrcan.gc.ca web site

"Vehicle performance
Using a 10 percent ethanol blend (E-10) does not significantly affect a vehicle's fuel economy or horsepower. Although 10 percent ethanol-blended gasoline contains only 97 percent of the energy of pure gasoline, this is partially compensated for by the improved combustion efficiency of the ethanol-gasoline blend that the added ethanol provides. Overall, use of E-10 increases fuel consumption by an average of 2 percent compared with pure gasoline. However, this is only a slight difference when compared with other factors that have a larger impact on fuel economy"

 

[TNVIPER]

Correct..Ethanol by itself has a very high octane rating....I think close to 110.......but remember that octane is not a rating for power...it is a rating of resistance to igniting...you just need higher octane to stop pre-ignition....using 93 octane gas in a engine designed for 87 octane is a waste of money and will probably result in less power..