SOHC at 89 Octane

[Big Bear Bob]

I maybe wrong, but I believe the manual ssaays something about using a higher octane over certain elevations.

Again I could be wrong but the truck seems to run a little better when I use 89 over 87, and we live between 7000 and 8000 feet.

If I'm wasting my money, please let me know. Normally it's only about $.10 more per gallon here for 89 over 87, but if this could hurt the truck, or if it's a waste I sure would like to know.

Thanks in advance
BBB

 

[Bshmastr]

You use lower octane at higher altitudes. The lower air pressure means lower cylinder pressure and less likelihood of pinging. In Denver (5000+ ft), 85 octane is the norm for vehicles that take 87 at lower altitudes.

 

[Big Bear Bob]

Thanks, I appreciate the info, and like the idea of saving a few bucks.

Is it ever a good idea to run higher octane fuels at this or any other altitude?

 

[MONMIX]

It is no lie my 2000 4.0 SOHC runs better on 87 than on 89 or even 97. It's true

 

[VairKing]

Originally posted by MONMIX
It is no lie my 2000 4.0 SOHC runs better on 87 than on 89 or even 97. It's true

Well it should, thats what Ford engineers designed/tuned it to run on...

 

[Big Bear Bob]

Hate to question, but I swear the truck seems to run better with 89 octane every time I climb the mountain which crests at 8450 feet. I just had the truck tuned too, But the rate of climb on the 18 from the high desert is pretty radical, and the truck feels like I'm towing something when running 87, and seems to have a much easier time when I burn 89. But maybe its the type of gas I'm burning
ussually Arco, or Ultramar.

 

[DocVijay]

In reality a 2 point difference in octane won't give that much of a sensation power gain. It's just a measure of resistance to pinging. Also, higher octane fuels are usually more refined and have better detergents to clean the engine. If you were to add up the price difference over a year it wouldn't be that much. A low octane fuel has just enough detergent to minimize deposits. You'll still get some A high octane fuel actually has enough detergent to remove existing deposits and keep new ones from forming. The alternative is to use some fuel system cleaner every few thousand miles. They are the same stuff in the fuel, only concentrated.

As an experiment, fill up a whole tank with 91 or even 93 octane, and see if it feels better. Then you'll see if octane really makes a difference. I use Premium all the time in all my cars. It's the old "ounce of prevention is worth a pound of cure" saying.

 

[Big Bear Bob]

Thanks for the response, I too have read in the manual that 87 octane was recomended, but coming up that very steep incline with 89 does seem to make a difference. Maybe it ws just cleaning out the injectors. I'll try going back to 87 next time I refill and go down the hill.

Thanks again