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Old 04-23-2019, 10:03 AM   #7 (permalink)
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Little Red - retired - '05 Honda Civic EX
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Originally Posted by woodstock74 View Post
Was looking over the car and spotted this aero device at the trailing edge of the rear fender:

Any ideas what it does? Separates the flow so it reattaches and energises before the outboard sharp edge quarter panel/bumper trailing edge?
I first noticed these at an auto show a couple years ago and was curious about their function. Turns out it isn't an aerodynamic device at all, but is required to meet a FMVSS requirement that rear tires remain inboard of bodywork to 50 degrees past vertical. Some manufacturers use a small plastic add-on:

2018 Mazda Miata

But at this year's Chicago show I noticed some of these are being molded into bumper covers now rather than added as a separate piece:

2019 Jaguar F-Pace

2019 Lexus NX

Originally Posted by woodstock74 View Post
Close up of the trailing edge underfloor panel:

Has two interesting aero shapes of unknown function. Anyone enlightened/familiar with what they might do?
Toyota includes those fins for stability on all their cars. Generally, airflow under a car spreads outward and these help straighten the flow at the back (unlike the faux "diffuser" vanes seen on a lot of rear bumper covers these days).

2018 Toyota Camry

2018 Toyota Sienna

2020 Toyota Corolla Hybrid

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