Octane

[VoodooMedMan]

What the heck is up with 86 octane? Was in Texas before and never saw it. Just gased up in El Paso and there was 86 88 and 91. I opted for 88. Wasn't going to jack up my truck.

 

[Boschma]

I noticed that when we moved here....
Been using 86 in all our normal vehicles and they run fine.

Use 88 in my wife's Denali.

 

[Stainless]

I had to go up one grade for the F-150 work truck when I was traveling to Carlsbad NM. It had the anemic 4.6 that would ping if you had more weight than a suitcase in it.

 

[VoodooMedMan]

Looks like you can get away with lower octane at higher elevations because of less oxygen density in the air. Problem is when you are filling up and passing through though. Thinking you might have an issue. I know my ECM would adjust but I just didn't want to chance it's cheaper than California anyway. Will see what the gas is like when I get to where I'm going.

 

[STV_Keith]

Looks like you can get away with lower octane at higher elevations because of less oxygen density in the air. Problem is when you are filling up and passing through though. Thinking you might have an issue. I know my ECM would adjust but I just didn't want to chance it's cheaper than California anyway. Will see what the gas is like when I get to where I'm going.

On the right track, but I believe it's because with lower ambient air pressure, there is less cylinder pressure and therefore a lower static and dynamic compression ratio. At sea level, we have roughly 1000millibars or 100kPa or 14.7psi (all the same value in different scales). For instance, El Paso is 3800' above sea level, the ambient pressure in kPa is only about 90.

 

[VoodooMedMan]

On the right track, but I believe it's because with lower ambient air pressure, there is less cylinder pressure and therefore a lower static and dynamic compression ratio. At sea level, we have roughly 1000millibars or 100kPa or 14.7psi (all the same value in different scales). For instance, El Paso is 3800' above sea level, the ambient pressure in kPa is only about 90.

View attachment 408147

Okay. I'll just believe you on that. [emoji16]

Just seemed weird to me especially because I've never seen it at the higher elevation in Ca.

But then again I'm leaving Ca for a reason.

 

[Bobby V]

Okay. I'll just believe you on that. [emoji16]

Just seemed weird to me especially because I've never seen it at the higher elevation in Ca.

But then again I'm leaving Ca for a reason.

Yea we got it the first 500 times that you don't like CA. :cool Now take some more of the haters to Texas. We don't need them.

 

[Kylemenz1]

Yea we got it the first 500 times that you don't like CA. :cool Now take some more of the haters to Texas. We don't need them.

Hey...If you like low octane fuel that gets poor mileage, flash flooding rain, crazy biker gang shoot outs, crazy religious cults, and Texacans who hate people from California. Then Texas is the place for you! [emoji106]

 

[VoodooMedMan]

Yea we got it the first 500 times that you don't like CA. :cool Now take some more of the haters to Texas. We don't need them.

It was only 400 times.

 

[VoodooMedMan]

Hey...If you like low octane fuel that gets poor mileage, flash flooding rain, crazy biker gang shoot outs, crazy religious cults, and Texacans who hate people from California. Then Texas is the place for you! [emoji106]

You forgot tornadoes.

 

[Stainless]

You forgot tornadoes.

and rattlesnakes