My Brake Ducts Build

Discussion in 'Fiesta ST Chassis Upgrades' started by CrookedRacer, Mar 19, 2015.

  1. CrookedRacer

    CrookedRacer Active Member

    I just burnt through another set of pads in just one weekend, and even though it was only 55 degrees out, I was still getting brake fade near the end of my sessions.

    So I bought some duct scoops and some silicone duct, and set to work duplicating (for the most part) Golfguy11800's build.

    This is just a build thread. It's not done yet. I'll post as I get stuff done. But what I've done so far (the scoops) will be staying on the car all the time, and the silicone duct itself will be removable. I'll put it on and take it off at the track or just before/after I run.

    I placed my ducts a little farther apart than Golfguy's, but still in the forward-facing section of the front skirt to catch as much pressure as is practical. From the back of the collectors, I plan to have an almost straight shot back to the lower control arms, and then a bend to follow the control arms to the general area of the hub.

    First, I cut my collector scoops along the top and bottom nearly to the bend using the grinder with a cutting wheel, marking where I wanted to cut with some painters tape. I guess I took at least 3/4" off of each side. That left me with about 3 1/2 inches of overall height to the scoop opening. It also left nice tabs on each side that would accept the rivets.

    I took the skirt off the car to make my cuts - first with a 3/4" spade drill at each corner, and then with a utility knife for the straight lines connecting the corners. Here are a couple pics with the skirt put back on.



    I then held the skirt up to the bumper lip, marked the lip for cutting, and used the same 3/4" spade drill to cut corners of the cutout to the bumper lip. I used a right-angle grinder with a cutting wheel to cut the straight parts between the holes. (The bumper is harder than the skirt, so a knife doesn't "cut it". Ahem.) The bumper cuts will be invisible if I ever decide to replace the cut-up skirt with a fresh new one for resale.

    Then I clamped the scoops where I wanted them to be, drilled 3/16" holes, and riveted them on using the stainless #10 washers as.. well, fender washers (both inside and outside).


    I used 3/16" diameter rivets, in the 1/2" length. You can get these rivets and the rivet tool at Home Depot. I also used a #10 stainless washer on each rivet on both sides of the skirt/scoop sandwich. The washers give the rivets a larger bearing surface so they won't get sucked through the softer plastic on the expanded end. They're really on there.



    Tonight I will try to cobble all the support and strapping and clamps and so forth that will guide the air to the hub area.
    bryramos, Sekred and Chuckable like this.
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  3. Chuckable

    Chuckable Member

    Great thread :thumbsup: Sub'd for updates.
  4. Slowclimb

    Slowclimb Active Member

    Looks have a shot from the front of the car a little further back to see what it looks like with the car in the shot?
  5. CrookedRacer

    CrookedRacer Active Member

  6. CrookedRacer

    CrookedRacer Active Member

    Then I screwed two clamps on, and cut a length of hose, and zip tied it to the scoop, and to the intercooler pipes.


    And that's it! I did this between my first and second track sessions here at VIR. I even had an off track excursion and everything held on.

    With the Hawk DTC-60's plus this cooling, I never had brake fade again for the rest of the day. Also, the pads seem to be holding up pretty well. I am hopeful I'll actually get multiple events out of this setup.
    bryramos, RodMoe and Flaco1 like this.
  7. CrookedRacer

    CrookedRacer Active Member

    The passenger side hangs a little lower to clear the intercooler pipe, but it hasn't dragged or touched the ground at all.
    Last edited: Mar 22, 2015
  8. CrookedRacer

    CrookedRacer Active Member

    This is before the hoses were installed. And I figure my license plate is all over the web by now... I'm getting tired of obscuring it in photos.

    Sekred likes this.
  9. CrookedRacer

    CrookedRacer Active Member

    You have to get down really low before you can even see the duct scoops.


    This is with the ducts installed.
    BlackBird likes this.
  10. CrookedRacer

    CrookedRacer Active Member

    Today i cut about three inches of slack out of the passenger side to try to encourage the duct to stay below the thinner section of the ic pipe.

    On my next session i will mount a camera down there to see what's actually going on at 125mph. And whats going on under acceleration out of turns, for that matter. That's when i suspect the brakes are still in use.
    djdennehy likes this.
  11. Turboduck01

    Turboduck01 Member

    Excellent thread, thanks for posting the pictures and the write up. What ducts did you go with and where did you get them? I don't think I saw that in your posts. Sounds like they worked like a charm!
  12. djdennehy

    djdennehy Active Member

    Good stuff going on here...
  13. CrookedRacer

    CrookedRacer Active Member

    I will post a complete parts list when i get home.
    Turboduck01 likes this.
  14. CrookedRacer

    CrookedRacer Active Member

    Ok, I got home, but at midnight last night. Now I'm actually home with a bit of time...

    If you would like to do this yourself, you might need some or all of the following:

    1) Duct.
    2) Scoops.
    3) Cushioned Stainless Cable Loom Clamps.
    4) Cable Ties.
    5) 1/4"-20 x 5/8" pan head machine screws and 1/4" star-type lock washers
    6) 1/4"-20 tap & drill set (or alternatively, just a 1/4" drill AND some 1/4"-20 nylon lock nuts for the other side)
    7) 3/16" diameter x 1/2" long rivets + rivet tool
    8) #10 stainless flat washers (for both ends of each rivet to make a solid sandwich)

    I think that covers it, not including tools. The major tools I had to use:

    Angle grinder with cutting wheel
    Cordless drill
    rivet tool
    3/4" spade bit
    3/16" drill bit
    1/4"-20 tap & drill (again, optional).

    You use way less than half the duct with this project, so you could save with a group buy.
    Chuckable, Golfguy11800 and Sekred like this.
  15. Golfguy11800

    Golfguy11800 Member


    Glad I was able to offer some help on what to do and more importantly what NOT to do.

    These look great.

    I will caution others looking at this thread who get excited from this design:

    If you ever bottom out your car, get airborne, or really decompress your suspension (100mph into the dip of a small radius valley) these will probably get ripped off like mine did.

    I am drafting up a fog light approach but this way is by far the most straight shot and easiest setup. If you only track your car on that nice smooth pavement then you should be 100% worry free with this setup.
  16. CrookedRacer

    CrookedRacer Active Member

    Yeah, thanks again, Golfguy! You were indeed the inspiration and the pioneer here. I loved the look of your intakes, so I duplicated it pretty much exactly.

    I took the ducts off at the end of the weekend by just cutting the zipties and unscrewing the hose clamps from the control arm. The duct scoops are on the car permanently, but they hang no lower than the front skirt. So there's no risk, really. I don't need the ducts for the street. I don't do canyon runs or anything... cops here on the east coast are pretty vigilant.

    When it's time to go on track again, it will only take some more zip ties, a screwdriver, and about 5 minutes to put them back on.

    Here's a video I made last night with the footage from below the car. I was simply curious to see what the ducts were doing at high speed. But I got a lot more than that!

    The great news is that the ducts are solidly attached, they don't flop around, and they're evidently doing their job. The rotors don't stay red very long.

    It was really neat to see the brakes getting red-hot at turn-ins, the tire compressing, shifting, and rolling over the rumble strips at apexes.

    My theory is that at Summit Point, the brakes probably remained red-hot most of the way around the track as I neared the end of sessions.

  17. ISO100

    ISO100 Member

    Awesome video! They certainly cool off quickly!
  18. Golfguy11800

    Golfguy11800 Member

    I want others to note the added benefits of this design...

    Since you are not mounting the dump ends of the ducts directly on the rotor shield, you will not have to worry about the hoses binding up under lock to lock turning. If you do mount the hoses to the rotor shields it becomes very tricky to try and find the sweet spot of dumping the duct at the center of the rotor (best efficiency location) vs. the usability and ergonomics when driving on the street when you still need to use full lock on your cars.

    Race cars never have their wheels turn as much as stock cars i.e. pulling out of a parking garage or making a tight right turn at 2mph so mounting to the rotor guard would work.

    CrookedRacer, again, great job on these. Glad I could help! I may end up trying this out myself.

    btw, what pads are you running? I had a concern that if we switch to endurance pads, then the brake ducts would make the pads run too cold so they would always be chasing the operating temperatures and high coefficient of friction levels.
  19. BRGT350

    BRGT350 Well-Known Member Staff Member

    awesome job!

    I doubt you can find room to fit these, but on my Mustang, I installed a pair of 3" marine blower fans inline with the brake ducts. When I am on a cool-down lap or in the pits, I turn them on to help feed cool air to the brakes.
    [​IMG]Mustang early may 2009 008 by Bryan Redeker BRGT350, on Flickr
    [​IMG]Mustang June 2009 006 by Bryan Redeker BRGT350, on Flickr

    On another version of my Mustang brakes, I made an aluminum plate with an inlet pipe welded to it. The plate attached to the spindle where the heat shield mounted from the factory. The brake ducting connected to the inlet pipe. I haven't got around to doing this again with the current brakes, but also haven't really tracked the Mustang or needed to work on the brakes since upgrading to 13" Brembo rotors and PBR calipers.
    CrookedRacer likes this.
  20. CrookedRacer

    CrookedRacer Active Member


    I'll post some pad compound reviews on some separate threads.

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