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If I understand it correctly, the oem resonator, silicon tube mod, and Smart Madness intake all get cooler air to the engine from the driver side "scoop" on the rear fender (451). Any mod with an exposed cone air filter, (i.e. visible from inside the engine bay) is pulling in air heated by the engine. Or at least hotter air because with the resonator removed, the side vent is now scooping air into the engine compartment instead of the intake.

What I don't quite understand; the oem resonator has a longer route to "smooth" throttle response meaning a slight restriction of airflow? I seem to remember that doing away with the resonator doesn't really improve or degrade throttle response, but might make it harsher under some throttle/load conditions? I think the differences are going to be minimal between the methods that pull in air through the fender, as the computer controlled fuel injection/engine management system adjusts itself based on data from the sensors. I am not sure if the system compensates as well for the cone filters in the engine compartment.

In contrast my Kawasaki motorcycle from the 80s has four cylinders with a 32mm carb for each cylinder. All four pull air from a plastic resonator box which only has one intake port that is about the same size as one carb. If you remove the resonator box, the carbs can pull 4x the air and the bike will run so lean it has to be re-jetted to compensate as it has no fuel injection/engine management capable of doing that.

Both the Smart and Kawasaki resonators have internal baffles and a somewhat convoluted air path that seems counter intuitive to me. Presumably these were designed using some sort of air flow dynamics, computer modeling, or some other arcane method. So;

Smart 451 with modified or no resonator using cool air + engine management = no worries?
Smart 451 with modified or no resonator using hot air + engine management = marginally less performance/efficiency?
Both may sound different (throatier) than OEM?
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