Which octane for new Ford V-10
The manual says 87, but for better performance (hot weather, towing) use 91 OR HIGHER. Just wondering what the real world experience has been. The dealer gave us a full tank, but you know he put 87 in...
Forum Discussion
T18skyguy wrote:
The gas companies adjust octane for the localities they serve. When they can use lower octane it saves them refining costs. You will see lower octane in the high country like Moab, Utah, which is at roughly 4000 feet. At that elevation the air is thinner, and the compression ratio lower as a result,(that's why we complain about power up high) so they cheap out on the gas. You can run 85 octane all day on level ground in cool weather with no problems, but when you go to climb the Grapevine it might be different. There are so many factors; engine condition, temperature, pressure, load, it can be real hard to pin it down to one situation
Um, the compression ratio has nothing to do with elevation. That's a mechanical ratio of of cylinder volume at full stroke vs cylinder volume at top dead center. The reason you loose power is the O2 is less at elevation, messing up your mixture ratio.
Al
