Excellent post !! :thumbsup: :thumbsup: The more air the better !! :grin_nod:NVMYRC said:If you are a doubter, leave it on! When I did my first 3 mods I left the lid on. I did have a gain but was very unsatisfied. I took the lid off and BAM, huge difference for me. This information and anything you might possibly want to know about airboxes, lids, etc, etc is already here. The search function works wonderful or you can even just scroll through several pages of posts and you will find all kinds of stuff. Bottomline though you can test this yourself. Do your mods, leave your lid on and then test with it off. Anybody that told you that airbox stuff doesn't know jack about Raptors or pretty much any modern ATV. If you cannot pressurize the box, like with ram air on crotchrockets, then you cannot get the venturi effect. Our airboxes are not pressurized. Hope that clears it up a little for you.