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      08-10-2021, 09:15 AM   #1
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Brake vent ducts

Has anyone removed/opened these at the track for better brake cooling?

Is it safe to have them permanently open?
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      08-10-2021, 11:38 AM   #2
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I remove mine whenever I go to a track just because BMW recomends it, and it is easy to do, and then reinstall them at the end of the day. Opening them will obviously increase the air flow, and potentially lower the temps of the calipers; pads; rotors; wheels; and tires to some extent. I am willing to trust the engineers on this, but I am still curious. I see tire temps as high as @ 175F (dash display) with them open. Maybe I will leave them in place sometime to see if the temps go higher. Science! Mom and Dad would be so proud.

I also don't understand why BMW has covers over these vents in the first place. They don't completely block the flow, just reduce it by what appears to be about 50% -70%. They do state clearly that the covers need to be in place during all driving other than on a track, but I have not seen a reason stated for this. Anyone?
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      08-10-2021, 12:51 PM   #3
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Quote:
Originally Posted by Boomer 2019 View Post
I remove mine whenever I go to a track just because BMW recomends it, and it is easy to do, and then reinstall them at the end of the day. Opening them will obviously increase the air flow, and potentially lower the temps of the calipers; pads; rotors; wheels; and tires to some extent. I am willing to trust the engineers on this, but I am still curious. I see tire temps as high as @ 175F (dash display) with them open. Maybe I will leave them in place sometime to see if the temps go higher. Science! Mom and Dad would be so proud.

I also don't understand why BMW has covers over these vents in the first place. They don't completely block the flow, just reduce it by what appears to be about 50% -70%. They do state clearly that the covers need to be in place during all driving other than on a track, but I have not seen a reason stated for this. Anyone?
Quote:
Originally Posted by Boomer 2019 View Post
I remove mine whenever I go to a track just because BMW recomends it, and it is easy to do, and then reinstall them at the end of the day. Opening them will obviously increase the air flow, and potentially lower the temps of the calipers; pads; rotors; wheels; and tires to some extent. I am willing to trust the engineers on this, but I am still curious. I see tire temps as high as @ 175F (dash display) with them open. Maybe I will leave them in place sometime to see if the temps go higher. Science! Mom and Dad would be so proud.

I also don't understand why BMW has covers over these vents in the first place. They don't completely block the flow, just reduce it by what appears to be about 50% -70%. They do state clearly that the covers need to be in place during all driving other than on a track, but I have not seen a reason stated for this. Anyone?


I took my car up to Vegas when the temperature was around 110 f and my tire temps only got to like 135f with the brake ducts in.
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      08-10-2021, 08:55 PM   #4
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I didn't know about the brake duct covers so I did two days on the track with them in place. Tires got up to 215F before I backed off. On the third day, the tires just took a tiny bit longer to make it above 200F.

You two must be driving slower to see such low temperatures
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      08-10-2021, 08:57 PM   #5
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Quote:
Originally Posted by Boomer 2019 View Post
I also don't understand why BMW has covers over these vents in the first place. They don't completely block the flow, just reduce it by what appears to be about 50% -70%. They do state clearly that the covers need to be in place during all driving other than on a track, but I have not seen a reason stated for this. Anyone?
They block junk going into the rotors along with a stream of water on wet days.

It's a good idea to clean up on the covers on a regular basis because they might clog up with bugs, rocks, plastics, etc
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      08-10-2021, 10:45 PM   #6
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Quote:
Originally Posted by Boomer 2019 View Post
I also don't understand why BMW has covers over these vents in the first place. They don't completely block the flow, just reduce it by what appears to be about 50% -70%. They do state clearly that the covers need to be in place during all driving other than on a track, but I have not seen a reason stated for this. Anyone?
As Ximian said - it's to keep crap out of your rotors. I just did my first detail after 900 miles and decided to remove the covers. I have the carbon package so these intakes are vacuums for leaves, pebbles, dead bugs, and even a screw. Im glad that didn't get shot into my rotor/wheel/heat shield.

Was originally thinking of taking these off for spirited back road drives - but now I think I'll leave them on 100% of the time except for track days.
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      08-11-2021, 09:25 AM   #7
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Does anyone have pictures of this or instructions on how to remove?
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      08-11-2021, 11:08 AM   #8
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Quote:
Originally Posted by jonahk View Post
Quote:
Originally Posted by Boomer 2019 View Post
I also don't understand why BMW has covers over these vents in the first place. They don't completely block the flow, just reduce it by what appears to be about 50% -70%. They do state clearly that the covers need to be in place during all driving other than on a track, but I have not seen a reason stated for this. Anyone?
As Ximian said - it's to keep crap out of your rotors. I just did my first detail after 900 miles and decided to remove the covers. I have the carbon package so these intakes are vacuums for leaves, pebbles, dead bugs, and even a screw. Im glad that didn't get shot into my rotor/wheel/heat shield.

Was originally thinking of taking these off for spirited back road drives - but now I think I'll leave them on 100% of the time except for track days.
It's interesting that they would leave the carbon fiber intakes so open for everything off the road to be sucked in but the brake duct vents they recommend closed when not on track. :
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      08-11-2021, 01:06 PM   #9
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Quote:
Originally Posted by corbs09 View Post
Does anyone have pictures of this or instructions on how to remove?
Turn the steering wheel to full lock to get access to one side. The duct would be in front of the inside shoulder of the tire so just squeeze from the top and bottom and it should pop off easily. Turn the steering wheel in the other direction to get access to the other side.

There's a good view of the duct in this video at 2:01 -

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      09-06-2022, 09:27 PM   #10
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Quote:
Originally Posted by McLaren720s View Post
Has anyone removed/opened these at the track for better brake cooling?
Yes, I remove them at track days now that I know about them. Makes a noticeable difference in pad/rotor wear, tire temps, and fully eliminates the scary pinging sounds coming from the rotors after laps with the ducts in place.

Quote:
Originally Posted by McLaren720s View Post
Is it safe to have them permanently open?
I still want to know the answer to this question.

I'm going to reinstall mine when on the street in an abundance of caution.
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      09-09-2022, 09:09 AM   #11
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Removing the dust shields should help with airflow.

You lose some protection from gunk and debris but it's worth it. Hopefully, someone like Racing Brake will sell a kit with SS pistons (i assume the OE ones are aluminum) along with high temp boots and seals like they offer for the F8x's blue brakes. That, coupled with some girodiscs and dust shield removal should help a lot.
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      09-10-2022, 10:33 AM   #12
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I removed them at the track day I did. Had no major brake problems, but I still did have some pinging after a couple sessions.
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      09-10-2022, 09:08 PM   #13
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My car barely gets driven on the street (except to and from tracks) so I have left them off for now. Will re-install after the next track event.
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      09-12-2022, 04:06 PM   #14
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Ive posted this before, but i drive with these on all the time..massive reduction in brake temp
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      09-12-2022, 06:14 PM   #15
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Ive posted this before, but i drive with these on all the time..massive reduction in brake temp
Where did you order these from? Everywhere I can find doesn’t shop out of UK to North America?
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      09-12-2022, 07:07 PM   #16
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i am also using the speed engineering brake duct system. fairly easy install. +1
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      04-18-2023, 07:36 AM   #17
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Quote:
Originally Posted by Jkurahara View Post
Where did you order these from? Everywhere I can find doesn’t shop out of UK to North America?

https://southernbm.com.au/products/s...8x-m3-m4-nzlnm
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      04-21-2023, 06:44 PM   #18
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Quote:
Originally Posted by jocamero View Post
Yes, I remove them at track days now that I know about them. Makes a noticeable difference in pad/rotor wear, tire temps, and fully eliminates the scary pinging sounds coming from the rotors after laps with the ducts in place.



I still want to know the answer to this question.

I'm going to reinstall mine when on the street in an abundance of caution.
Most definitely keep the duct guard on for everday driving.
The amount of stones and debris stuck in it every time I remove it, is alarming. Especially when you have CCBs and have to be extra careful.

In fact, I keep them on even on on track most of the time as well, since CCBs afford you a luxury of not worrying about overheating, unless you go full push mode - which I learned quickly is not really the purpose of this car (stock) anyway.
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      04-25-2023, 08:25 PM   #19
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I've heard they ask you to keep them on for gas mileage reasons. There's more drag with them off, and the advertised mpg was calculated with it on. Similar to how some cars default to auto start/stop on.
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      05-29-2023, 02:51 PM   #20
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Kind of a dumb question but did you manage to remove the piece with the wheel still on?
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      05-29-2023, 08:26 PM   #21
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Quote:
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Kind of a dumb question but did you manage to remove the piece with the wheel still on?
Not dumb, but yes with the wheels turned its easy to do.
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      05-31-2023, 02:13 AM   #22
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