NACA brake cooling duct project

[GJarrett]

...checking back in on my original post here. The hoses didn't last long and were way too kinked; I am not sure they ever did much good. I am now converting to what some of you have done with the tunnels while keeping my NACA scoops. I bought a set of Vorshlag oversized deflectors and will see if the NACA scoops feed enough air to them to do the job. I plan to run Sebring in a couple of months and will see how well it works.

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[GJarrett]

Update after running at Sebring this week. I kept the NACA ducts while ditching the hose routing (with all of its twists and turns that certainly restricted much of the airflow) and had the ducts direct airflow directly to Vorshlag air deflectors pushing the flow to the rotors. I also installed the minimal PP brake dust covers to allow more of the airflow access to the rotors.

Wow. What. A. Difference. At the VIR event referenced earlier in this thread, my front rotors/calipers initially read in the 215 degree range after the first session's cool down lap, then rising to 250-260 degrees after the last session cool down lap. This week at Sebring my highest temp reading was only 174 degrees! My EBC pads were too thin to survive another track day and I did not receive new track pads in time, so I was stuck using stock Ford pads - and they did not overheat.

NACA ducts + Steeda 2 piece rotors + Vorshlag deflectors + PP dust shields = Successful Fix!

 

[NightmareMoon]

Update after running at Sebring this week. I kept the NACA ducts while ditching the hose routing (with all of its twists and turns that certainly restricted much of the airflow) and had the ducts direct airflow directly to Vorshlag air deflectors pushing the flow to the rotors. I also installed the minimal PP brake dust covers to allow more of the airflow access to the rotors.

Wow. What. A. Difference. At the VIR event referenced earlier in this thread, my front rotors/calipers initially read in the 215 degree range after the first session's cool down lap, then rising to 250-260 degrees after the last session cool down lap. This week at Sebring my highest temp reading was only 174 degrees! My EBC pads were too thin to survive another track day and I did not receive new track pads in time, so I was stuck using stock Ford pads - and they did not overheat.

NACA ducts + Steeda 2 piece rotors + Vorshlag deflectors + PP dust shields = Successful Fix!

have any pics of the ducts at the wheel well? I’m curious. Have a aftermarket splitter which doesn’t have the PP1 aero scoops so I’m thinking kinda the same route.

 

[GJarrett]

No photos but I'll take some within the next week and post 'em here. The scoops are located a little bit inboard of where the deflectors catch air and don't quite line up to direct the airflow completely and directly onto the deflectors. The scoops have about 2-3" of tunnel going up into the wheelwell to provide a base to slip the ductwork and clamps (that I removed and don't use now) onto, so I cut out some of the outside half of the tunnels to help "incentivize" the air to travel outward a little bit more towards the deflectors after exiting the scoop. When I noticed the slight misalignment between the scoops and the deflectors, I actually thought of riveting an additional piece of aluminum plate onto the deflectors to make them even bigger and extend inward to line up better with the scoops, but the results as-is were so great that I have ditched that idea now as unneeded and will leave as is. You can look at @Plimmer post #20 and note that he extended his deflectors way inboard to line up with his tunnels - the Vorshlag deflectors are very big but don't reach that far in.

I just re-read this thread and can further clarify my update. I noticed my earlier follow up post where the next day on VIR after I started running a lot harder, the rotors were "in the low 300s range". This week at Sebring the calipers were what read 174 degrees; the rotors were 200 or thereabouts. So I still lowered the temp another hundred degrees after ditching the hoses and using the Vorshlag deflectors instead. Before I started this project and had the stock setup, I estimate my temps were at least double what they are now, if not higher - while running as a novice at an easier pace than I do now. Another comparison that highlights the effectiveness of this mod is that my rear brakes now read higher temps than my front.

I also assume the tunnels utilized by @SVO MkII and @Plimmer as shown in posts #19 and #20 would be a lot more effective than the NACA scoops.... but those tunnels are $$$ and the scoops are cheapo

 

[SVO MkII]

have any pics of the ducts at the wheel well? I’m curious. Have a aftermarket splitter which doesn’t have the PP1 aero scoops so I’m thinking kinda the same route.

 

[GTP]

I just re-read this thread and can further clarify my update. I noticed my earlier follow up post where the next day on VIR after I started running a lot harder, the rotors were "in the low 300s range". This week at Sebring the calipers were what read 174 degrees; the rotors were 200 or thereabouts. So I still lowered the temp another hundred degrees after ditching the hoses and using the Vorshlag deflectors instead. Before I started this project and had the stock setup, I estimate my temps were at least double what they are now, if not higher - while running as a novice at an easier pace than I do now. Another comparison that highlights the effectiveness of this mod is that my rear brakes now read higher temps than my front.

This is pretty much my experience with the deflectors that I am making and selling:
I improved the design of my brake air deflector vanes.

 

[GJarrett]

have any pics of the ducts at the wheel well? I’m curious. Have a aftermarket splitter which doesn’t have the PP1 aero scoops so I’m thinking kinda the same route.

Well I'm a little slow but here's a photo... finally

 

[TX-2019-Black_GT]

There is a lot of interesting stuff on NACA ducts and how to get the most airflow through the duct in a forum i found a few years back. I have this saved in my bookmarks as I often refer back to it.
http://www.landracing.com/forum/index.php?topic=9912.165

The gist of it is NACA ducts are not able to move as much air as a forward facing duct, mainly because they are designed to allow air to move over the duct and create the least amount of drag at the expense of overall airflow. Most of the testing and design work for NACA ducts are for airplane use and are not really that effective at car speeds. Yes they will move some air but brake cooling requires a lot of air movement and air velocity to allow it to travel through a duct and then through the vane system of the rotor. NACA ducts require a flat area with enough surface area in front of the duct to allow a boundary area to form. They do not work well in turbulent air because they take air from the boundary layer and create vorticies to roll the air into the duct itself, with turbulent air around the duct the vorticies may not form and the duct is just a hole in the body work at that point. If you can not generate enough airflow to overcome the restriction at the rotor the air will stack up in the duct hose and eventually the duct opening, then it will stall and becoming useless.

If you do a downward facing NACA duct under the front belly pan I think you will likely need a scoop on the trailing edge of the NACA duct to force the air into the duct to achieve your cooling needs. Others have made ducts that pickup air from the front fascia without removing the driving lights, I would look into that method first and see if you can find a solution that would meet you needs.

I could be wrong but this is my understanding of how these NACA ducts function.

Dave

This is exactly what I was thinking - the main advantage of NACA ducts is low drag. They do not create a lot of airflow. A Scoop is what you want.

 

[Cobra Jet]

Update after running at Sebring this week. I kept the NACA ducts while ditching the hose routing (with all of its twists and turns that certainly restricted much of the airflow) and had the ducts direct airflow directly to Vorshlag air deflectors pushing the flow to the rotors. I also installed the minimal PP brake dust covers to allow more of the airflow access to the rotors.

Wow. What. A. Difference. At the VIR event referenced earlier in this thread, my front rotors/calipers initially read in the 215 degree range after the first session's cool down lap, then rising to 250-260 degrees after the last session cool down lap. This week at Sebring my highest temp reading was only 174 degrees! My EBC pads were too thin to survive another track day and I did not receive new track pads in time, so I was stuck using stock Ford pads - and they did not overheat.

NACA ducts + Steeda 2 piece rotors + Vorshlag deflectors + PP dust shields = Successful Fix!

What instrument or how are you measuring the temps at the rotors or ducting?

 

[GJarrett]

Just a simple laser thermometer gun pointed at the rotors, it has proven accurate in other applications. Even if not, I used the same one for all of the readings so the delta of temp difference still stands.

 

[ihasnostang]

https://www.mvpmotorsports.com/brembo/brembo-temperature-stickers/2516825

https://www.omega.com/en-us/tempera...sible-temperature-labels/tl-10/p/TL-10-290-10

could slap these on your calipers for peak temp

 

[Cobra Jet]

Just a simple laser thermometer gun pointed at the rotors, it has proven accurate in other applications. Even if not, I used the same one for all of the readings so the delta of temp difference still stands.

Ohhh… ok, I have one of those myself. I asked because I was wondering if you had some type of probe/instrument that was able to take temps and monitor in the cabin while on course.

 

[ihasnostang]

Ohhh… ok, I have one of those myself. I asked because I was wondering if you had some type of probe/instrument that was able to take temps and monitor in the cabin while on course.

i mean if you're feeling ambitious you could get one of these sensors and then get a little aurdino board/display. its just a 0-5v sensor

https://www.sens4speed.com/en/produ...nfkl-800degc-ir-brake-temperature-sensor.html

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