Colorado Octane

I use 87 octane in my truck and it runs fine, but we are going to Colorado next month and from my past experiences out there, the regular grade is 85 octane. For you guys with 3rd gens in Colorado (or you who have been or to or live in areas with 85 octane gas) do you use 85? Do you add octane booster or do you use the 2nd grade up? I don't remember what that is out there as it's been about 10 years since my last trip out west.

Thanks

 

Generally I run the cheapest stuff I can find. One of the many reasons to buy a Toyota over a Lexus - no premium fuel.

 

There's 85, 87, and 91. I still put in 87.

 

85. Every time. Nothing else.

 

85... change in altitude (air) requires less octane for same burn performance. Never a knock or any engine issues, 66000 miles on Taco so far.

 

Just make sure you consider your drive back. I filled up with 87 in Colorado Springs because I was heading back to KS. 6,800 ft down to 1,000 ft. Wouldn't want to be running 85.

 

This. It is all I use here in Utah.

 

I live in Colorado Springs and always run 87. If there's no 87 and I have to decide between 85 and 89/91, I go with the higher octane.

 

I use 87. I think the truck runs more smooth on it, but I doubt you'd have issues running 85. I've used it before as well, and notice that my "miles to empty" is a lower number when I do, so the engine will compensate for it. No danger either way.

 

Same here, When I'm in CO I just run 87+. Id rather not find out that 85 is not OK for my engine on the 500mi drive back to home in KS.

 

The owners manual says 87 or Higher, I would use that if you are still under warranty.

 

87 or higher. I get real ethanol free gas in Durango @87 (awesome mileage with the good stuff)and when it’s a choice between 86 and 88 I get 88..top tier gas. Even down as low as Pecos Texas they try to sell 86and I have to go midgrade there. When I find 87 top tier I am happy to use it wherever.

 

Good grief people. Your truck is not going to explode because you're running 85 at lower elevation. Just don't tow 5k lbs up steep passes or enter tractor pulls and you'll be fine.

 

Way to go overboard with that one. No one said explode. 85 is sold in higher elevations because less oxygen requires less octane. Its fine to run at higher altitudes. Seems like a simple idea to buy appropriate octane for where you will end up, especially since its available. Can't tow 5k lbs up a steep pass in a flat state btw because you already left steep passes. But I digress.

 

Guys it’s not like there’s a 2000 ft. Cliff at the boarder and all of the sudden poof 85 won’t work...

I’d venture that with modern tech you could run 85 at sea level and not knock albeit yes with a power loss due to retarded timing.

I’ll also add that there should be no change in feeling of power or mpg here between 85/87 (here at altitude), unless the car needs 89 at sea level. The vehicle is tuned to run an equivelant of 87 at sea level (85 here). 87 here would be wasting the “extra octane”. Yes I’ve stopped at gas stations where they were out of 85 (because we all use it (and destroy engines)) and run a tank or two of 87 here and there. Still average 19.5 mpg and still merge on the highway between 80-90mph.

Remember this, octane as you know it isn’t relative to potential power output. It is more akin to flash point, or ignition stability. The motor is designed to use x amount of air, x amount of fuel and send a spark when those thresholds are met. It can add or remove compression (within reason) with valve overlap. In general terms; 85 is good from a-c, 87 from c-e there is some overlap otherwise driving from coast to coast would destroy motors based on some of y’alls logic.

So from over 20 years of car ownership and driving in Colorado, use whatever doesn’t knock; for many of us that’s 85.

 

I have always used 85- no issues what so ever.

 

You use a lower octane rating in higher elevations. That's why you 85 in the mountains. Less air at altitude, lower combustion pressures, and less need for high octane.

 

Yup, same for me (I’m just west of you). I used to be an octane nazi as a youngster. Only running premium. Then realized regular gets me the same mpg and unless racing or towing heavy, no noticeable power loss.

What did catch me off guard, driving out west 20 Years ago, is going through CO, up my first mountain pass, the car just would not accelerate. Had to keep it in 2nd or even 1st the whole way up. Until the ecu had time to calibrate, it felt like I was missing a few cylinders.

 

Or perhaps your timing was retarding. Oxygen sensors and knock sensors signals to the ECU work pretty quickly to adjust fuel mixture and timing advance or retard. Going over a pass is a loaded situation where knock is likely even if you are not hearing it.
All higher alttitude causes is less oxygen availability meaning if we had carburetors the engines would run “rich” the solution manually (with a carb)is to slow the amount of fuel through the fuel mixture jet. The same thing happens with fuel injection, the potential is better mileage and lower power density.
Driving around town the lower octane is adequate.
Climbing 4K feet in 20 miles at 65mph. Not so much.

 

I've pulled a small trailer (3000#) out west several times and always used the cheapest stuff.

Only noticeable effect:

Going north in Nebraska my economy goes to shit. Same for the return trip.

Pretty sure one of those noname rural gas stations (I think SE Montana) resulted in compromise of a Visa card.

For everything else, mileage was relevant to towing speed and incline/ decline, with speed being the most impacting factor.