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It is also important to look at the 90 percent boil point. The higher the 90 percent temperature, the more difficult is to vaporize and combust the gasoline. In this case, unburned gasoline passes the exhaust pipe as lost horsepower. When gasoline burns out the exhaust pipe, the jetting is drastically wrong or end boiling points are too high. It also interferes with the proper exhausting out the combustion chamber by introducing reverse shock waves, but that is another story. About the top-end distillation point. "You need to be careful on higher end of the distillation characteristics, more so than the lower end. When the 90 percent is in the 260-275 degree range, that is about as high as you want to go. Above that, the gas can't vapor quickly enough to burn and produce more power. "Racing gas can also have a tail on it. That means the final boiling point is too high. The last 10 percent of fuel is getting harder to vaporize it. Probably would not vaporize on higher rpm applications. You are consequently losing power because you are not burnig all the fuel possible. If the 90 percent boil point is at 250 or 260 degrees but the end point is another 100 degrees higher, you conceivably have 10 percent of the fuel that is going to be very difficult to vaporize and burn. "If the 90 percent is at 240 degrees and the end pointis 260 degrees, the chance of burning that last 10 percent is much greater. That equates to more complete combustion, more power, and better performance. |
