[19bonestock88]

My assessment is based on both coastdown(on points where I usually EOC) and instant MPG measured at 55mph...

I completed the mod at work so I tested it on my commute home, and found that in places I usually coast in, I’m arrivig st the other end at a slightly slower speed... for instance there’s a section where I arrive st the top of a slight downhill at around 40mph and at the end, almost a mile later I usually arrive at 38-40mph depending on surface water and temperature... the night I tested the mod, I arrived at 34mph...

Additionally, I found that my instant MPG at 55mph(with severe misfire and being in open loop) dropped from ~31-32 to around 27-28... with the engine making so little power, the extra drag is plainly evident...

HOWEVER...

I made a couple mistakes during construction that I addressed...

1. I put the leading edge of the Kamm on the sealant seam at the top of the back glass, making a 8-10mm lip for air to jump

2. I used metal strapping material taped to the trailing edge(underside) to keep the trailing edge straight but as low as I had the sides pulled down it bulged up in the center and pushed the center up to a flatter angle than I wanted...

I accidentally tore the thing off backing up at around 20mph and when I put it back on I addressed the above flaws(but I didn’t have/lost the metal strip) so the center of the Kamm now saga, but only when the car is stopped... it lifts above around 35mph, to be flat across its width