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Old 03-08-2003, 12:39 AM
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ck42 ck42 is offline
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Join Date: Nov 2001
Location: Holly Springs, GA
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"Conversely, If the ALDA is adjusted for too much fuel, there will be excessive fuel that can't be burned at full load and speeds above 4K RPM and will end up lowering combustion temps and creating more smoke....BUT max boost pressures *will* have been achieved"

"NO NO NO NO!!!!! Too much fuel raises combustion pressures and temps to the point where things melt. The relationship between rich/lean is exactly the opposite in diesels and gassers. Run a gasser lean you get lots of power and melted exhaust valves, scored cylinder walls, melted pistons, etc. Run it richer and she cools down makes good power, more fuel-cooler still and power drops off. Diesels keep making more and more power as you add more and more fuel until they overfuel and start melting things. RT"


RT....I'm still not convinced on this point. Given a fixed engine condition, an increased fuel ratio will not be able to be burnt completely w/o additional oxygen. This unburnt fuel is my reasoning for the lowering of combustion temps.
It's only when boost pressures are INCREASED that the oxygen levels are increased thereby allowing the higher fuel ratio to be taken advantage of.

If I'm missing something here....it's a doozy.

Chris
'85 300SD
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