Thread: DIY brake ducts
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      10-05-2019, 07:49 PM   #99
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Drives: 2017 M2 - Mineral Gray, 6spd
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Originally Posted by FlyingLow78 View Post
OK, so I did some airflow observations with a normal wheel well and then the Porsche ducts installed to observe the difference.

As you would expect, there is a lot of turbulent air in the wheel well. I taped bits of yarn to the control arms so I could observe the airflow and they get thrashed around pretty good. At low speed there appears to be a suction effect near the tire's leading edge, but it dissipates quickly as you go faster. There is also a channel of slightly more laminar flow running out from the radiator and along the interior edge of the wheel well (maybe because of the Coanda effect). The yarn in this area definitely followed the curvature of the wall, even with the Porsche duct installed.

I then installed a Porsche air deflector with bits of yarn attached. The video clearly shows the air being collected and very little spilling over the top. The spillage is mostly along the inner edge where the radiator outflow is and a bit over the top. The last photo shows the yarn pointing in the general direction of the flow observed in the video.

Because of the hub carrier shape, I recommend heating and curving the tip of the deflector to allow a little more "scoop" action and for clearance. I see some of you have already done that, though.

My next test will involve modifying the backing plates with some 2.5" flanges to accept hoses from the LCA scoops I had 3D printed. I can't really observe them working with yarn in the airstream, though.

Megator The scoops are here, courtesy of MagnusT

Any ideas how I can objectively compare the cooling effects between the Porsche scoops and the 3D printed ducts?

So far, my only idea is to go on a deserted portion of the autostrada at night with one cooling solution on each front corner and Go Pro cameras mounted in the wheel wells. I can get the brakes really hot and sync the videos to see which rotor cools more quickly.
Wow, that is some dedication. You must have a sailing background because this is the technique they use to see how the sails are going, bravo.

At any rate, I thin vids will be helpful to show airflow, but temperature strips should help as well. Available on amazon.