View single post by Greg Fletcher
 Posted: 01-05-2011 09:55 pm
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Greg Fletcher



Joined: 03-11-2005
Location: Lake Nacimiento, California USA
Posts: 421
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I saw Richard Reyman at West Coast Cylinder Heads not long ago and he had an interesting story about that goofy looking factory air box which may shock many owners. He dyno'd a performance 907 engine he had built and tried it with and then without the factory air filter assembly. The factory air box ADDED several horsepower to the run (nothing else was different). He tried it multiple times with the same results. Has to do with the way the air is directed into the carbs (Dellortos). The factory airbox assembly is bit more sophisticated that it looks. So not only does the factory air box quiet down the engine roar, it also helps performance. When you run without filters (which is a very bad idea in itself) or bolt on K&N air filters, you are essentially removing a small performance advantage over the stock system.