high altitude gas

[2TimingTom]

So I was reading through the owner's manual and saw something about how Ford recommends using 87 octane regardless of altitude- even though octane requirements decrease as altitude increases.

Here in the Denver area, regular gas is 85 octane instead of 87. I've always pumped regular regardless of where I lived- CO or KS (regular is 87 in KS).

My dad used to have a 1994 Mazda B4000 and I'm pretty sure he pumped 85 octane and he would say he would get pinging.

What do you high altitude drivers pump?

 

[Attacking Mid]

We use 85 octane, and I've not noticed any pinging or other ill effects.

AM.

 

[techieman33]

85 should be fine, but if you do start to notice pinging then you should switch to 87

 

[2TimingTom]

Thanks. I've always run 85 here so I guess I'll continue.

 

[Maniak]

I'm pretty sure the newer X's have knock sensors and will pull the timing back if they detect ping which nets you less power.

That said, at the high altitudes you can get away with less octane But with FI and o2 sensors the altitude doesn't affect pinging as much since the ECM changes how much fuel it puts into the engine based on how much air it can get in and how the exhaust "smells" to the ECM.

~Mark