Suspension, Brakes, Drivetrain discuss the wondrous effects of boost and your miata...
Sponsored by:
Sponsored by:

Brake duct inlets for NB's

Thread Tools
 
Search this Thread
 
Old 03-01-2017, 01:43 PM
  #1  
Newb
Thread Starter
 
Ryan Graf's Avatar
 
Join Date: Mar 2017
Posts: 4
Total Cats: 0
Default Brake duct inlets for NB's

I bought a singular motorsports brake duct kit but surprisingly noticed no one was selling inlets. What are people using? Designed and printed my own but i figured someone else was out there making something better.

Ryan Graf is offline  
Old 03-01-2017, 05:44 PM
  #2  
All-round "Good Guy"
 
Lokiel's Avatar
 
Join Date: Dec 2009
Location: Brisbane, AUSTRALIA
Posts: 993
Total Cats: 245
Default

Good idea.

Here's a few additional suggestions:

The top of the foglight recess is flat so you will get a better fit if you flatten the top:


I bought a set of DemonTweaks Air Ducts and trimmed them to fit:



Note: The Demon Tweaks grilles mount to the flat ridge in the duct.

I also made a backplate for the rear so that the pop-rivets have something to hold onto (they'd pull-through the bumper).
If you're attaching via bolts, you can probably just get away with large washers on the bolts since you don't want then to "pull through":


I would've liked the ducts to be deeper so that there was a longer section to clamp the hose to, mine are barely the width of a clamp:


Your ducts need to have a parallel section at the rear, not tapered, for the hose clamps to mount securely, otherwise they'll slip off.
Lokiel is offline  
Old 03-01-2017, 06:08 PM
  #3  
Newb
Thread Starter
 
Ryan Graf's Avatar
 
Join Date: Mar 2017
Posts: 4
Total Cats: 0
Default

Good feedback man.

I suppose i could flatten the top to get a few more MM of clearance. I just used 4 3mm machine screws to hold the inlet into the bumper.



My 2.5" hose has not arrived yet so i haven't got a chance to test-fit. I agree my taper at the exit may be insufficient - i added a little extra flare at the end which is hard to see so the hose clamp stays put.

I wanted to make sure i had an integrated screen to help prevent rocks and rubber at the track from entering the ducting and potentially tearing a hole.

Great job with your DIY btw.
Ryan Graf is offline  
Old 03-01-2017, 06:29 PM
  #4  
Junior Member
iTrader: (1)
 
unplugged92's Avatar
 
Join Date: Jun 2014
Location: Toronto, ON, Canada
Posts: 133
Total Cats: -7
Default

Looks awesome, I was thinking about adding a mesh inlet when I do my ducts. I wonder if anyone ever had any issues with debris going into the ducting and getting stuck in the rotor.
unplugged92 is offline  
Old 03-01-2017, 06:35 PM
  #5  
Newb
Thread Starter
 
Ryan Graf's Avatar
 
Join Date: Mar 2017
Posts: 4
Total Cats: 0
Default

Originally Posted by unplugged92
Looks awesome, I was thinking about adding a mesh inlet when I do my ducts. I wonder if anyone ever had any issues with debris going into the ducting and getting stuck in the rotor.
I spend a lot of time at the track and know especially when i'm behind someone on slicks i get a lot of rubber thrown at me. My big concern was having a duct get compromised then somehow damage a brake line. I saw a video recently of an EVO that had a brake duct get wrapped around a front axle, tear a brake line, lost all hydraulic pressure and then crashed due to no brakes. Obviously we don't have a front axles to deal with but when it comes to potential avoidable safety issues i thought this was cheap insurance and should prevent larger debris from entering the ducts.
Ryan Graf is offline  
Old 03-01-2017, 11:46 PM
  #6  
Newb
 
shlbygt's Avatar
 
Join Date: Sep 2014
Posts: 23
Total Cats: 3
Default


Not a great photo, but the best I have at the moment.
I used an aluminum duct flange from Aircraft Spruce.
ALUMINUM FLANGES FOR DUCTING from Aircraft Spruce
I used the 4" to 3" flange, connected to a 3" to 2.5" straight silicone reducer, with a short piece of 2.5" aluminum tubing to connect the reducer to the 2.5" duct.
The 4" flange fills the fog light hole well.
The silicone reducer is sandwiched against the backside of the bumper cover with a couple of thin aluminum "L" brackets for a tight fit with no holes to drill.
shlbygt is offline  
Old 03-02-2017, 01:12 AM
  #7  
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Default

Fwiw something that would rip your brake line out or brake duct hose out would demolish a 3d printed screen.

Also screens block more flow than you think.
aidandj is offline  
Old 03-02-2017, 07:27 AM
  #8  
All-round "Good Guy"
 
Lokiel's Avatar
 
Join Date: Dec 2009
Location: Brisbane, AUSTRALIA
Posts: 993
Total Cats: 245
Default

Originally Posted by unplugged92
Looks awesome, I was thinking about adding a mesh inlet when I do my ducts. I wonder if anyone ever had any issues with debris going into the ducting and getting stuck in the rotor.
My duct hose vents into my Cold Air Box which has the air filter for the turbo in it - no way would I risk running without it.

As aidandj pointed out, the mesh will block a lot of air (supposedly household flyscreen mesh blocks 50% of airflow in your house).
The foglight recess will be a high pressure area when moving though so you're still getting a lot of air through it (ie. much more than 50%).
Lokiel is offline  
Old 03-02-2017, 08:12 AM
  #9  
Newb
Thread Starter
 
Ryan Graf's Avatar
 
Join Date: Mar 2017
Posts: 4
Total Cats: 0
Default

Originally Posted by aidandj
Fwiw something that would rip your brake line out or brake duct hose out would demolish a 3d printed screen.

Also screens block more flow than you think.
The screen is not 3d printed it is stainless steel weave. I calculated a 40% reduction of air flow due to the screen but that's perfectly fine for my application with street tires.
Ryan Graf is offline  
Old 03-03-2017, 03:14 PM
  #10  
Supporting Vendor
iTrader: (3)
 
emilio700's Avatar
 
Join Date: May 2005
Posts: 7,325
Total Cats: 2,372
Default

ALUMINUM FLANGES FOR DUCTING from Aircraft Spruce Mobile
__________________


www.facebook.com/SuperMiata

949RACING.COM Home of the 6UL wheel

.31 SNR
emilio700 is offline  
Old 03-14-2020, 02:39 PM
  #11  
Newb
 
Scott Kimball's Avatar
 
Join Date: Mar 2020
Posts: 2
Total Cats: 0
Default

Thanks for the info. I just ordered the "4 to 3" flange from A/S. So yes, the link is still good. Going to order the 2.5" brake duct kit, but I wanna know what everyone recommends for the piping as well as a good source.
Scott Kimball is offline  




All times are GMT -4. The time now is 04:48 AM.