I've seen Don's ram air. There's a big problem with it in that it is not actually a ram air. That fact alone would not be a problem except for the fact that his system, while increasing the volumetric efficiency of the engine (see my post on theoretical intake of 300E, this forum), the additional air it does intake is extremely heated. Since the engine compartment is so well sealed on these vehicles, it gets extremely hot under the hood. I know the intake box is down low, but its hot down there too. Just stand next to an idling 300 E and feel the heat blasting out from under the car, especially in summer. Not only that, but the box is directly behind the cooling fan so it sucks in all the hot air from the radiator to the front, and the manifold (1000 F plus on gas engines). Hot air is 1) much less dense than cold air (so you could actually decrease the actual amount of air that is taken in) and 2) increases the tendency to knock or pre-detonate since air is heated when compressed in the cylinder; hot air just gets that much hotter than cold air. The result is that the engine knocks that much sooner, which the car (even with the omni pack) compensates for by retarding the spark which, again, reduces power, increases emmisions, and reduces fuel economy. That is why ALL cars' intake hoses take in air from outside the engine compartment. (Any other Mech. Engineers out there will also agree that maximum thermodynamic efficiency results from the greatest temperature differential between processes.) It's also why superchargers and turbos have intercoolers-- to cool the air the compressor heats up!
I am working on a new design that will draw all air from outside the engine compartment. The cooler, the better. When complete, will advise. In the mean time, I have a request in to mercedes to find out how much air the stock setup passes. Stay tuned; I welcome your comments!!

Don Drake

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Don Drake

1990 300E 125k Miles
1994 S420 100k Miles