keeping the heat in the pipe is there to make the power, yes. BUT the amount of heat produced, exceeds the quantity needed, and in alot of cases when on a long haul, gets TOO hot, which is not good. Thats why keepin the engine bay, cool (it will still be VERY hot regardless) is a good thing. Why do you think people are putting all the hood/belly pan venting systems in? (example: frog skins, screens). The dirty, hot, under-hood air is not good for the motor to injest, and fresh, cool air is better for it, which is what people strive to get (cold, fresh air into motor-thus, under hood)......
btw, the only reason people keep the clutch side vents in is so they belt doesnt get wet.
I'll have to agree with what jesse said. Your pipe will remain hot, even without a hood. Maybe not quite as hot as with but still hot enough. Keeping the clutches and belt cool is a good idea, but not to get snow or water on them is another thing. I would think even a fine screen would allow some water or powder to get through. Even with no hood, it will still be possible to overheat the engine.
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