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86 octane as regular gas in New Mexico?
drobs
Member Posts: 22,620 ✭✭✭✭
This was a new one to me. All the gas stations in NM (IIRC) were advertising 86 Octane as Regular gas. Mid Grade was 88. Not sure what Premium was.
Found myself using 88 most of the trip.
I always considered 87 octane to be regular. Is this something new?
Found myself using 88 most of the trip.
I always considered 87 octane to be regular. Is this something new?
Comments
At higher elevations they run lower octane fuels since lower atmospheric pressure means lower engine compression. Basically the higher altitude lets them get away with "cheaper" fuel. I lived in Flagstaff AZ for years and even though we were at 7000+ feet I guess we were too close to lower elevations, they only have 87-92 octane fuel there.
That makes sense, never seen that before.
In places like CO its not uncommon to see 85 octane "regular unleaded"
Yep, we have them here in MT too!
At higher elevations they run lower octane fuels since lower atmospheric pressure means lower engine compression. Basically the higher altitude lets them get away with "cheaper" fuel. I lived in Flagstaff AZ for years and even though we were at 7000+ feet I guess we were too close to lower elevations, they only have 87-92 octane fuel there.
That is basically it. As the pressure decreases gasolines resistance to knocking increases. Gasoline which would cause an engine to ping at sea level will not do so at higher elevations. There is a complicated formula to calculate this, but it involves the use of both the Motor Octane Number and Observed Road Octane Number, neither of which are on the gas pump. The little yellow sticker on the pump with the octane number inside it is the Anti Knock Index which averages the Reasearch Octane Number and the Motor Octane Number. An increase in altitude of around 1500 feet increses gasoline's resitance to knocking by about half a point, at least for road cars. Since nearly all of New Mexico is above 3000 feet, 86 octane fuel works as well as 87 octane fuel would at sea level.
Aviation fuel's ocatane ratings are entirely different and involve so called Performance Octane Numbers, which are unrelated to fuels used in road cars.
quote:Originally posted by KAMsales
At higher elevations they run lower octane fuels since lower atmospheric pressure means lower engine compression. Basically the higher altitude lets them get away with "cheaper" fuel. I lived in Flagstaff AZ for years and even though we were at 7000+ feet I guess we were too close to lower elevations, they only have 87-92 octane fuel there.
That is basically it. As the pressure decreases gasolines resistance to knocking increases. Gasoline which would cause an engine to ping at sea level will not do so at higher elevations. There is a complicated formula to calculate this, but it involves the use of both the Motor Octane Number and Observed Road Octane Number, neither of which are on the gas pump. The little yellow sticker on the pump with the octane number inside it is the Anti Knock Index which averages the Reasearch Octane Number and the Motor Octane Number. An increase in altitude of around 1500 feet increses gasoline's resitance to knocking by about half a point, at least for road cars. Since nearly all of New Mexico is above 3000 feet, 86 octane fuel works as well as 87 octane fuel would at sea level.
Aviation fuel's ocatane ratings are entirely different and involve so called Performance Octane Numbers, which are unrelated to fuels used in road cars.
I assume the effects differ for diesel engines? Since it comes in one form for road use, there must be an increase in the volume of air consumed by the engine?
quote:Originally posted by kristov
quote:Originally posted by KAMsales
At higher elevations they run lower octane fuels since lower atmospheric pressure means lower engine compression. Basically the higher altitude lets them get away with "cheaper" fuel. I lived in Flagstaff AZ for years and even though we were at 7000+ feet I guess we were too close to lower elevations, they only have 87-92 octane fuel there.
That is basically it. As the pressure decreases gasolines resistance to knocking increases. Gasoline which would cause an engine to ping at sea level will not do so at higher elevations. There is a complicated formula to calculate this, but it involves the use of both the Motor Octane Number and Observed Road Octane Number, neither of which are on the gas pump. The little yellow sticker on the pump with the octane number inside it is the Anti Knock Index which averages the Reasearch Octane Number and the Motor Octane Number. An increase in altitude of around 1500 feet increses gasoline's resitance to knocking by about half a point, at least for road cars. Since nearly all of New Mexico is above 3000 feet, 86 octane fuel works as well as 87 octane fuel would at sea level.
Aviation fuel's ocatane ratings are entirely different and involve so called Performance Octane Numbers, which are unrelated to fuels used in road cars.
I assume the effects differ for diesel engines? Since it comes in one form for road use, there must be an increase in the volume of air consumed by the engine?
Diesel engines are fired by injection of the fuel, so there is no spark knock issue to contend with. On a gasoline engine, higher octane fuel is more resistant to igniting prematurely (spark knock) during the compression cycle prior to the ignition system firing the spark plug.
Where were you in NM? I just did a two lane tour from Hobbs to Alamogordo to Las Cruces. Got to go through Roswell and some other cool places.
We drove from, call it Springfield MO, to Rio Rico AZ.
Took 54 Southwest and stopped in Tucumcari for the night on the way down. Also made a stop at White Sands NM to look around the next day:
Going back NE, took 70 all the way through and had dinner in Roswell didn't spend much time there then stopped in Clovis (that place STINKS!) for the night.
It was 2 12hr days of driving each way. I treated it like work - 12 hours behind the wheel is a new record for me. Think next time we'll fly down and rent a car...
Pretty scenery.
I believe this is AZ on the way to Bisbee / Tombstone:
I brought an empty surplus 5 gal jerry can and spout that I filled up while we were in AZ. Didn't need it but it was nice to have along JIC.
Question for you Lonnie - I hear they only allow you so many hours on the road per day for OTR. Just wondering what that is? Thinkin about a CDL.
Lance
I didn't tank up with the lower octane stuff though, figuring I didn't want a residual of it in my tank as I approached the Pacific Coast.
Went out through MT and such, along the northern route. Came home via the southern one through CO. That was an experience, climbing a 12,000 foot pass in a 93 Tempo with a 4 banger engine and 110,000 miles on the clock, 2 people in the car, and a bunch of stuff in the trunk. Just as we crested the pass in 2nd gear and started downhill, I put it into drive again, and the engine cut. Vapor lock.
That's another experience, trying to stop a car with power brakes with an engine that's cut out on the downhill off of the Rockies, and pull over with the power steering out.
Somewhere, if you dig back through my posts to 2003, you'll find my posts about that trip.
Hey Drobs, where did you stay in Rio Rico, I used to go to a conference there yearly. Usually nice birds to look at and javelinas on the lawns in the afternoon.
quote:Originally posted by kristov
quote:Originally posted by KAMsales
At higher elevations they run lower octane fuels since lower atmospheric pressure means lower engine compression. Basically the higher altitude lets them get away with "cheaper" fuel. I lived in Flagstaff AZ for years and even though we were at 7000+ feet I guess we were too close to lower elevations, they only have 87-92 octane fuel there.
That is basically it. As the pressure decreases gasolines resistance to knocking increases. Gasoline which would cause an engine to ping at sea level will not do so at higher elevations. There is a complicated formula to calculate this, but it involves the use of both the Motor Octane Number and Observed Road Octane Number, neither of which are on the gas pump. The little yellow sticker on the pump with the octane number inside it is the Anti Knock Index which averages the Reasearch Octane Number and the Motor Octane Number. An increase in altitude of around 1500 feet increses gasoline's resitance to knocking by about half a point, at least for road cars. Since nearly all of New Mexico is above 3000 feet, 86 octane fuel works as well as 87 octane fuel would at sea level.
Aviation fuel's ocatane ratings are entirely different and involve so called Performance Octane Numbers, which are unrelated to fuels used in road cars.
I assume the effects differ for diesel engines? Since it comes in one form for road use, there must be an increase in the volume of air consumed by the engine?
I pretty routinely drive from Albuquerque to lower elevations with no knock or ping problems and no problems changing gas.
Hey Drobs, where did you stay in Rio Rico, I used to go to a conference there yearly. Usually nice birds to look at and javelinas on the lawns in the afternoon.
He Dog,
We got $65 a night via Expedia at:
http://www.esplendor-resort.com/
Place had a patio which was handy for taking luggage out of the truck right up to the room. Was in a nice suburban area right off of Hwy 19. Expensive food and drinks in the restaurant. Looked at the menu then found a little Mexican joint down the road. Decent but spendy $12 breakfast buffet at the hotel.
Found a little shortcut over hwy 82 just to the south of the Hotel.
Almost got a speeding ticket on that road. Police Officer pulled me over for doing 45 in a 35. I wasn't paying attention. I informed I had a CCW license and was carrying. He let us go and mentioned in AZ no license is required and "Welcome to the Wild West where anyone can carry a gun."
I think he was looking for drunks.
You gonna be headed back to Africa, or will you be here to join us in Tulsa? Be good to see you again.
Same place we stay during the conference, used to be part of the Country Club across 19. Next time come by here and I will buy the breakfast. Huevos Rancheros so good you will want to move here.[^]
You gonna be headed back to Africa, or will you be here to join us in Tulsa? Be good to see you again.
Heading back Monday. Nice to get a parole extension for a lil longer.
Might head to the range today and get some distance shooting in. Try some 400 yd paper.