85 octane???
07-23-2007, 02:13 AM
#12
2nd Gear Member
Join Date: Nov 2006
Location: Manchester, UK
Posts: 346
RE: 85 octane???
Like most European countries in Aus they use RON as the octane rating the Americans use a combination of RON and MON. MON is 10 less than the RON figure typically.
So 98octane
Is 98 + 88 = 186
186 / 2 = 93.
93 octane US is what 98 Octane there is.
100 octane V power = 95 octane US.
Basically same as it is here in the UK except we get 95 and 99 as the fuels so 91 and 94 octane. Other places sell 92 / 93.
So 98octane
Is 98 + 88 = 186
186 / 2 = 93.
93 octane US is what 98 Octane there is.
100 octane V power = 95 octane US.
Basically same as it is here in the UK except we get 95 and 99 as the fuels so 91 and 94 octane. Other places sell 92 / 93.
07-23-2007, 08:41 AM
#17
1st Gear Member
Join Date: Apr 2005
Location:
Posts: 125
RE: 85 octane???
getting back to the point; i just took a trip from Omaha to El Paso and came back through Colorado; once i hit the higher elevations, such as west Texas and NM it was common to see 85 Octane in all the gas stations; it is not THE E 85; I was driving my Taurus andtried the 85 Octane and seemed OK; all the stations had 89 and 91 also; but i agree, it must be due to the elevation because once you go away then the 87 became the lowest available. It is deceptive but I think El Paso was nearly 6 thousand feet or so above sea level.
Yes I was also surprised as this was the first time I saw 85 Octane - here in Omaha we have 87, 89, and 91 - BP does 92 - my stang is tuned for 91 so I only use Shell 91 or BP 92.
Yes I was also surprised as this was the first time I saw 85 Octane - here in Omaha we have 87, 89, and 91 - BP does 92 - my stang is tuned for 91 so I only use Shell 91 or BP 92.
07-23-2007, 08:55 AM
#18
2nd Gear Member
Join Date: Dec 2006
Location: Boise, Idaho
Posts: 278
RE: 85 octane???
I lived in Montana for 20 years. 85 Octane has been standard "regular" unleaded there for as long as i can remember. Highest octane you can get there is 89.. All my cars over those years ran fine on 85. All were set at the factory to run on 87+. I never had detonation or any issues. (unless I ran timing at +15 degrees or more,...but it was a chevy so who cares.....)
I think the elevation and lower oxygen content at 5000' has a lot to do with it.
Lower oxygen per liter of air = lower power /slower burning + lower octane gas (faster burning) = compromise that seems to work....
I think the elevation and lower oxygen content at 5000' has a lot to do with it.
Lower oxygen per liter of air = lower power /slower burning + lower octane gas (faster burning) = compromise that seems to work....
07-23-2007, 10:30 AM
#19
2nd Gear Member
Join Date: Jun 2005
Location: Denver, CO.
Posts: 281
RE: 85 octane???
I'm also in colorado.
The altitude affects gas burning and consumption. Just like boiling a pot of water- it boils at a lower temperature. Altitude changes lots of stuff.
You should not have any problem burning 85-octane fuel in your mustang.
Of course me calling the kettle black. I use only 91 octane in my car. (91 is the highest non-race type fuel i've seen here) The reason I use 91 is because of my tune and timing. I don't want to risk any preignition issues.
Additionally, as far as I can remember, if your car is not designed to run higher octane then using it does virtually nothing. It wont increase fuel mileage or burn "cleaner." High octane ignites at a higher temperature. It "resists" detonation more efficiently.That is why it is used in high compression or forced induction applications, because the added heat and pressure will cause lower grade fuels to prematurely ignite.
You're safe running 85, running 87 won't hurt anything but running 91 is useless unless you need it for some other reason like forced induction/tune/timing etc.
The altitude affects gas burning and consumption. Just like boiling a pot of water- it boils at a lower temperature. Altitude changes lots of stuff.
You should not have any problem burning 85-octane fuel in your mustang.
Of course me calling the kettle black. I use only 91 octane in my car. (91 is the highest non-race type fuel i've seen here) The reason I use 91 is because of my tune and timing. I don't want to risk any preignition issues.
Additionally, as far as I can remember, if your car is not designed to run higher octane then using it does virtually nothing. It wont increase fuel mileage or burn "cleaner." High octane ignites at a higher temperature. It "resists" detonation more efficiently.That is why it is used in high compression or forced induction applications, because the added heat and pressure will cause lower grade fuels to prematurely ignite.
You're safe running 85, running 87 won't hurt anything but running 91 is useless unless you need it for some other reason like forced induction/tune/timing etc.
07-23-2007, 01:01 PM
#20
2nd Gear Member
Join Date: Jun 2006
Location:
Posts: 448
RE: 85 octane???
Not only altitude, but also humidity. Low humidity environments require higher octane, because the knock potential goes up. The whole point of using Higher Octane fuel is to get more power out of the engine, but this can only happen when ignition timing is advanced to take advantage of that octane. Modern computer controlled cars can automatically advance or retard ignition timing in response to the knock sensor, but reducing knock has nothing to do with maximizing horsepower. To do that, you need to advance timing, and you can only do that if the gasoline octane is high enough.
Therefore, if your mustang is running a stock timing tune, than all the octane in the world is not going to increase your horsepower one iota.
Therefore, if your mustang is running a stock timing tune, than all the octane in the world is not going to increase your horsepower one iota.