Quote:
Originally Posted by COcyclist
I have experimented with flush coroplast wheel covers. You can make a compass out of an old yardstick with a hole drilled for a screw to spin it in the coroplast and another hole for a sharpie marker. Cut them out with old fashioned tin snips. I used 3 wire ties each and just snipped them to remove them. I did a study of them if you search posts started by me. There was a slight improvement but I think I get more of an improvement from my homemade belly pan/diffuser.
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I’ve seen that lower drag cars are more sensitive to changes than higher drag cars. Obviously my Hyundai Ioniqs base CD is 0.24 which is lower than even the Honda insight. Hyundai even made almost fully closed wheel divers for the “ blue” variant which has the highest rated mpg of all the trims. They used moon discs when going for the land speed record for a hybrid vehicle at the salt flats. So for this particular model, I’m assuming fully covered wheels are the lowest drag option. Looking at a lot of CFD study on spinning wheels, it’s not just the turbulence of wheel spokes adding drag, but even having a slight opening for brake cooling still has air coming out of the wheel area and it gets injected into the wheel wake and increases the wake size and turbulence. I have no idea how much of an mpg increase actually happens with closing up my 90 percent factory closed rims, but cfd shows better attached air flow, smaller wheel wakes, and increased base pressure at the rear. So in theory those things should help my cavity fins and rear fender skirts perform better.