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Old 10-24-2013, 02:42 AM   #680
jasaircraft
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Join Date: Aug 2009
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Quote:
Originally Posted by Ziggyrama View Post
Not really. It does not work like that. Unfortunately, it is not that simple. The muscle car example was just an illustration of how overlap can affect an engine. In our case, it really depends on the scenario. Load is just one axis. You also have to consider RPM. Some low load situation call for fair amount of overlap to produce internal EGR effect which yields better fuel economy and lower emissions. In high load situations, you typically do not want lots of overlap because the positive pressure on the intake side will force the charge into the chamber and the engine does not rely heavily on scavenging to improve volumetric efficiency. I say typically because the exhaust side also influences this and depending on what you're running there, the overlap requirement may change. The more flow you can get on the exhaust side, the more you might be able to use overlap to improve VE.
Hi Ziggyrama
If you had to switch intake only avcs (because wiring wise and time mandate it) in an on/off manner (lets agree off is 0deg and on in 30?)
How would you switch it? rpm or load based? of use both axis?
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