Quote:
Originally Posted by Phase
If I cut a hole in the back side of the rear fender, how would it hurt drag though? May not improve it but I don’t see how it would hurt. Still a thought
The rest separation trap seems interesting though like what the Prius prime has too. Pretty much just a small partial box cavity. Which should be easy to fabricate
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If you've looked at some of the pressure coefficient distributions shared here at EcoModder.com, you'll notice that the 'deadwater' base pressure behind cars can be HIGHER than forwards on the body, where air is moving faster.
Look at VMAN 455's website and Edgar's, or Edgar's book.
If you were to arbitrarily open a pathway like that, you could easily see air flowing forwards through the breach, exactly what you're trying to avoid.
It doesn't hurt BMW and Lexus and Mercedes to drop a few million dollars on CFD or wind tunnel time to 'dial-in' such small details.
In this instance, you'd want to drop your money on the pizo ports, Tygon tubing, and Magnehelic so you could 'know' in advance if the IONIQ could produce rearwards-directed flow from the wheelhouse. It's not a given.
Besides those openings need to be fully-skirted, something Mercedes wasn't willing to do, but would have had lower drag if they had.