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Old 09-22-2006, 08:09 PM
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SAVAGEJIM
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Default RE: half-tank lean problem!!!


ORIGINAL: HPI Staff


ORIGINAL: SAVAGEJIM

If I am missing something, please let me know.
What you're missing is that all R/C fuel tanks do basically the same thing, slightly rich when full, slightly lean when empty. The problem comes when people tune their engine too lean, then it gets really lean toward the end of the tank and the engine rapidly overheats. The solution is to run a little on the rich side. Richen it up so that it runs good at 1/2 tank. When tuned properly you can run all day long without overheating.


(Real cars get around this problem by using a fuel pump and a pressure regulator)
Thanks for the info.

I originally considered that the increased empty volume from the fuel being used up would cause a pressure drop, but I was under the assumption that the volume change would be too small to affect the pressure out of the tank and going into the engine. I guess that is what I get for assuming. I did'nt do any formal calculations since I do not know the dimenstions of the inside of a Savage tank, but I guess if I did, I would have discovered that this factor would have been significant and contribute to leaning.