Quote:
Originally Posted by COcyclist
I added side skirts attached to the rocker panels and small dams in front of the rear tires last spring. My fuel log seems to show an improvement in mpg. From what I have read, it is better to keep air under the car flowing backward to help fill in the trailing wake.
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In that case, flow fences should work well.
These could be made with 4" square PVC roof gutter drain pipe, cut diagonally corner to corner, to make 2 L shaped pieces. Then use those to clamp and secure the Coroplast sheeting to the underbody.
These could feed the diffuser vanes at the rear, or just act as long diffuser vanes going front to rear.
Such 4" square PVC drain pipe might make pretty good rocker skirts, too. Cheap. light, easy to work with, easy to find at Home Depot, etc..
However, another school of thought holds that undercar flow spreads laterally and such dispersal means less air under the car dragging against the underbody and giving the car unwanted lift. In that case, maybe it's best to use the flow fences to channel the undercar air obliquely out the sides.
Probably best to apply undertray, then tuft test to video actual airflow patterns at highway speed, then install wheel fairings/strakes at whatever orientations best enhance the flow.
Thoughts?