[aerohead]

I've been reviewing some articles on "turbulators","vortex-generators",and "dimple-tape".All these devices were originally intended for aircraft applications.Placed at the point of maximum camber of a wing or propeller,the device would thicken the turbulent boundary layer,allowing a little additional energy from the free-field to help energize the boundary layer and move the point of separation as far back as possible.If the wing stalled,it would recover sooner.Shock-waves emanating from propellers,with tips near MACH would enjoy reduced pressure gradients at the trailing edges and up to 50-percent noise reduction.There is a penalty in skin friction,however,the claim is that profile drag is so reduced, as to more than compensate.Fuel economy improvements up to 8-percent are claimed for aircraft.Cessna is to use them on wing struts.As to automobiles,the only application I've ever seen designed for,is with notch-back style cars with steep backlight angles.A late 1980s HONDA Accord was the original demonstration vehicle used by the inventor.With respect to an automotive induction system,you might want to bear in mind that the entire system is operating in a positive pressure gradient,unlike a wing or propeller.Ram-air pressure makes sure the air charge makes it's way all the way into the combustion chambers.Should there be any aerodynamic losses taking place within the intake tract,it would be more a consequence of an improperly radiused turn in the ducting.Any elbow of less than a 1-1/2-diameter radius will experience interior wall flow separation and attendant increase in pumping-losses.It would be difficult to imagine that in this day and age,that an improperly configured inlet tract would make it into production.And as I know I'll catch hell from members for saying this again for the thousandth time,when I was at Bonneville,I made runs with no intake tract and no air cleaner and it made absolutely no difference to engine performance at 6,000 rpm.I can't imagine how vortex generators could possibly make a measurable difference inside your air box.If you want to experiment,take meticulous records,measuring everything,especially atmospheric data at the times of your tests.Good luck on the project.