Am I Running Lean?

[IanSzgatti]

octane booster?

The higher the altitude above sea level, the lower the octane requirement. As a general rule of thumb, for every 300m or 1000ft above sea level, the RON value can go down by about 0.5. For example an 85 octane fuel in Denver will have about the same characteristics as an 87 octane fuel on the coast in Los Angeles.
It's a common misconception amongst car enthusiasts that higher octane = more power. This is simply not true. The myth arose because of sportier vehicles requiring higher octane fuels. Without understanding why, a certain section of the car subculture decided that this was because higher octane petrol meant higher power.
The reality of the situation is a little different. Power is limited by the maximum amount of fuel-air mixture that can be jammed into the combustion chamber. Because high performance engines operate with high compression ratios they are more likely to suffer from detonation and so to compensate, they need a higher octane fuel to control the burn. So yes, sports cars do need high octane fuel, but it's not because the octane rating is somehow giving more power. It's because it's required because the engine develops more power because of its design.

Oxygenators can be found in some fuel injector cleaners and are, pretty much, just what they sound like: compounds that increase the amount of oxygen available for fuel combustion. You remember from high school chemistry that a fire can't burn without oxygen? Well, it's the same inside your engine's combustion chamber. It needs adequate oxygen to burn the fuel. Unfortunately, in most circumstances, we just aren't getting enough, either because the volume of air coming through (remember, air is only about 20 percent oxygen) isn't sufficient, or because the engine can't manage the heat load that a leaner mixture (one containing more air per unit of fuel volume) would generate. Oxygenators are, in general terms, flammable compounds that contain at least a portion of the oxygen they need for combustion as part of their own composition. Gasoline, in its basic, unaltered form, contains absolutely no oxygen. It must rely totally on airborne oxygen for combustion. Oxygenators can enhance combustion by assuming some of the burden of providing combustion oxygen.

You may have heard about some new fuel additives from the oil companies called *MTBE, ETBE and TAME. These are ethers and the letters stand for Methyl Tertiary-butyl Ether, Ethyl Tertiarybutyl Ether, and Triamyl Methyl Ether. The first two compounds are made by reacting Methanol or Ethanol with isobutylene and all three have found considerable success as gasoline additives, yielding significant oxygen to the combustion process. Given that we can't ever get enough oxygen from the limited amount of air the engine can suck down the throat to affect really efficient, complete combustion of the fuel, some oxygenators can provide additional "free" oxygen to enhance the combustion process. It might be worth it for you to investigate by identifying and using some of these products when going on these higher altitude trips.
One thing that strikes me is that your engine ought to be in good mechanical condition if you are to use these products with benifit. Your ignition has to be able to burn the air/fuel mixture efficiently so that any oxygenates you add don't make there way into the exhaust and cause the management system to lean out too severly.
On the other hand, due to the high elevations, these products might be just the thing you need to keep up with or even pass the pack.

*found on the ingredients lable of fuel injector cleaners