Topic: Brake Rotor Airflow

We are upgrading the brakes on our craptastic racing machine and the new front rotors are sourced of a newer-ish form mustang 2015-2020..  the airflow on these come  from the front face outboard side of the rotor, not the rear side like older conventional brake rotors..

Any thoughts on the change in design as to why they did this vs the air entering the back spindle side of the rotor?

The rotors are 14” in diameter and 1.25” thick so I think there is enough of a heat sink for them to be ok..

Just curious as to why the design change and is it better or worse..  we don’t have air ducts to our brakes..

Re: Brake Rotor Airflow

I'm a bit confused what you're asking. There's a vehicle out there that tries to feed air into the outer circumference of the rotor, from the rear?

Rotors conventionally (I want to say always) cool from the inner hub to the outer circumference, with air flowing outward through the vanes.

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Re: Brake Rotor Airflow

I think he’s saying that the air comes from the outside (through the wheel) rather than from under the car, but still feeds center to outside (centrifugally) like you are describing.

Honestly I have no opinion on the performance pro/con of sourcing the air through the wheel versus around the hubs under the car.

Re: Brake Rotor Airflow

Yep.  Buddy of mine has these same brakes from a '15 Mustang GT on his Lemons car. It's like the rotors are on backwards.  Very weird.  I guess the premise is the airflow comes from the outside of the wheel side.   Makes running traditional ducting a moot point.

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Re: Brake Rotor Airflow

Looking at RockAuto it appears as though one could get replacement rotors that are fed air
in the more traditional manner. What's difficult to tell is whether the vanes in the vents will pump air
through the rotor, or not, for the front-side feed rotors. It doesn't appear as though there are L/R-sided
rotors in the Standard Replacement category.

Front-side air supply may not provide enough cooling since there is no forced air. Dunno.
Maybe Ford is using the low pressure under the car to draw the air through the rotor. Seems optimistic to me.

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Re: Brake Rotor Airflow

Hmmm, I think I understand what's going on(?) ... When I was in FSAE, my senior advisor/professor was into building drag bikes, he worked with Harley's. He said he doesn't like imports because anytime he touches them he make less power, but with Harley's he can do ANYTHING and it'll make more power; I feel like this can be applied to Ford. I'm usually an OEM is best and the engineers knew what they were doing sorta guy, but some of the stuff I've seen on domestic vehicles really makes me wonder. I wouldn't overthink it... as long as there's airflow it'll make a world of difference. Wheel wells are traditionally high pressure/low velocity.... just shove some clean air in there.


@DelinquentRacer: I've never been under a mustang newer than the foxbody but do they have a flat belly to generate low pressure? This sounds way too intricate for a mustang! haha

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Re: Brake Rotor Airflow

I prefer to do flow from inside, not outside. since its easier for me to do a duct to cool the wheel bearing, and that air can go into the rotor. If you doing the mustang, earlier model GT had the same rotor size, but inside intake.

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8 (edited by DelinquentRacer 2022-05-17 10:45 AM)

Re: Brake Rotor Airflow

Haven't been under one lately, but with CAFE and Drive-by Noise Standards were
seeing more and more undertrays and plastic smoothing panels. AND You can get video displays underneath, too.
https://st.hotrod.com/uploads/sites/21/2015/10/2016-ford-mustang-shelby-gt350-first-drive-14.jpg

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Re: Brake Rotor Airflow

VKZ24 wrote:

Yep.  Buddy of mine has these same brakes from a '15 Mustang GT on his Lemons car. It's like the rotors are on backwards.  Very weird.  I guess the premise is the airflow comes from the outside of the wheel side.   Makes running traditional ducting a moot point.

I'm not sure it would be moot.  Our car being FWD, there is not much room to try to force air into the center of the rotors, and that space would be right next to the rubber cv boot.  So I use ducts to direct air at the caliper A few races ago we damaged one of our two ducts without realizing it until the race was done.  We had twice the pad wear on that side that was not getting cooling air as we did on the other.  So clearly our ducts that just point at the caliper make a difference.

10 (edited by rozap_ 2022-06-13 02:00 PM)

Re: Brake Rotor Airflow

Not sure if there are too many bends here for good airflow. Hella ran out of brakes by the end of ORP last year. But now we have decent pads and fluid (lol we're dumb), bigger vented rotors and bigger calipers, plus this ducting (and still only like 60 hp). Anyone think this is totally wrong for airflow? https://i.postimg.cc/85WNNBG6/duct1.jpg

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11 (edited by Camper Van Someren 2022-06-13 03:32 PM)

Re: Brake Rotor Airflow

rozap_ wrote:

Not sure if there are too many bends here for good airflow. Hella ran out of brakes by the end of ORP last year. But now we have decent pads and fluid (lol we're dumb), bigger vented rotors and bigger calipers, plus this ducting (and still only like 60 hp). Anyone think this is totally wrong for airflow?

Looks good to my inexperienced eye, just make sure you have checked it for all wheel positions (full lock both ways, full compression and rebound).

I got frustrated trying to run a duct and just put some home-made deflectors on the tie rod. Not sure if they made a difference, but the brakes worked great last weekend at HPR.

https://scontent-dfw5-1.xx.fbcdn.net/v/t39.30808-6/274550613_10100508755932708_4675799543783398707_n.jpg?stp=cp0_dst-jpg_e15_fr_q65&_nc_cat=111&ccb=1-7&_nc_sid=1480c5&efg=eyJpIjoidCJ9&_nc_ohc=Ez7L3E9XWyUAX8Esbtr&_nc_ht=scontent-dfw5-1.xx&oh=00_AT_8D-AaR2OGJLY8_ZbdJrkRr_Vcl_18-PZf2SMiTHi6aA&oe=62ACB00D

Re: Brake Rotor Airflow

Thanks. Yep, works fine at full lock. Will report back with results after ORP.

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Re: Brake Rotor Airflow

Here I thought we were discussing what rotors to use on a Chrysler (or DeSoto) Airflow. Never mind, carry on…

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