Thanks for your input, well because of the massive undertaking to build a reliable and efficient flat fan system it would take many hrs and cost loads i have decided to stick with me 11 blade and fiddle with the shroud and consider building some internal dividers . FYI.. I did a load of research and found the old ELVA porsche race cars that ran the quad cam 4 cylinder carrera engine also ran a unique flat fan system, same sort of ideas as the 935, and even though there were only half a dozen race cars built i found a guy in the states that actually has a complete original fan complete unit off an ELVA porsche,
I emailed him to find he wanted a mere 12K USD for it!!!... well that blew that idea out the window. but if some one wanted to invest there is a opportunity to replicate it and probably would be a good demand on selling them.