Tony, I've used the formula posted in several places, as well as a few "plug your info in" sites and all of them say w/ 4250-4500 max rpm and 85-90% v.e. (I've tried different combos), the cfm comes out about 300cfm give or take. I guess that some vendors of the 32/36 Weber are over estimating the advertised cfm a tad. I think duals would work great as well but was hoping the performance of one would be better than adequate. At 280 cfm, it appears not.
