I ran my Mav without one for a while. But then I noticed the new belt was .250 narrower after a few hundred miles. Don't know if it was the efing texture that ///AIRDAM puts on the CVTech or sand, so I put the cover back on. As soon as I get my skids I'll install a new belt and run it without the cover again. After blowing a belt on my Rino, I took the cover off and ran it for 3000 miles on one belt. Heat is what kills the belts, so yes running it without one will make your belt last a lot longer. And on ours there's a fan behind the primary that pulls outside air in and then pushes it through. So that air will push a lot of sand out.