octane at high altitude.

[chibianh]

Hi guys. quick question regarding gasoline octane levels for the us Yaris. Here where I live, the available gasoline octanes are 85, 87, and 91. The manual recommends 87 octane, but I'm assuming that's for sea level. Would running 85 be okay?

[why?]

Probably. I think at higher altitudes lower octane becomes more potent, or something like that.

Either way, using an octane 2 points lower would make the car a little less peppy and maybe hurt fuel economy a little bit.

I doubt it would do any serious damage.

[silverRS]

yeah for sure, but if you run high test in it the engine will run slightly better as well as last longer.

[corey415]

yeah for sure, but if you run high test in it the engine will run slightly better as well as last longer.

That hasn't been proven. I have read multiple sources that say adding higher octane when not required is simply throwing money away.

The Yaris motor requires 87 octane. Putting in 85 octane won't damage the motor; I am pretty sure it has a knock sensor. The motor will have to retard it's timing so that means you will get less performance and perhaps lower fuel economy.

[chibianh]

That hasn't been proven. I have read multiple sources that say adding higher octane when not required is simply throwing money away.

The Yaris motor requires 87 octane. Putting in 85 octane won't damage the motor; I am pretty sure it has a knock sensor. The motor will have to retard it's timing so that means you will get less performance and perhaps lower fuel economy.

THat's understood, but like I mentioned in my original post, we have 85, 87, and 91 here at 6000ft above sea level. 87 octane is lowest elsewhere I've traveled. I'm just wondering if 85 octane @ 6000ft = 87 octane @ sea level. :)

[why?]

That hasn't been proven. I have read multiple sources that say adding higher octane when not required is simply throwing money away.

The Yaris motor requires 87 octane. Putting in 85 octane won't damage the motor; I am pretty sure it has a knock sensor. The motor will have to retard it's timing so that means you will get less performance and perhaps lower fuel economy.

All tests done the manufacturers use 93 octane fuel. There is a reason for that.

I do not know if it will increase engine life, but higher octane fuel will give a slight bump in power and fuel economy. The emphasis should be on slight.

[Uglyboyed]

i usually use 91 since here in florida its the middle. we got 87,91, and 93. but hey if i can use 87. it"ll be alot better for me. but on the other hand i get better milage with the higher octane. maybe like 2-3 miles a gallon.

[chibianh]

thanks guys... i think I'll be using the middle one... 87 octane. :)

[Ziv]

I believe we had a page about Octane, well, not specifically at high altitude. but I believe that would be helpful also, please check the pages we have posted probably months ago.

[yariman]

Most fuel refiners blend their fuels for specific areas such as high altitudes. They blend to compensate for the decrease in oxygen etc. If you use your local fuel, the 87 octane should work just fine.:wink:

[fearturtle44]

If the car says to use 87 octane and you use a higher octane, your are wasting your money. Higher octane does nothing to help.

If your car says to use high test, then use high test as the engine was manufactured to run the higher octane.

Kevin