another DIY brake duct

[Scrappydoo]

OK, you are on your own.

Tiny bit of wee going down my pants from laughing.

Keep it up.

[alex.s]

Originally Posted by Scrappydoo

No, my point was that if you want to improve heat loss from the disks then why not remove the shrouds?

I thought about this a lot more and did some napkin math and I'm even more confused now. let me illustrate some points and make no clear conclusion.

1. the rotors obviously pump air.

2. the rotors pump a lot of air. doing napkin math, the ducts are about half the size they need to be in order to provide enough air to the rotors that there would be positive pressure before the entrance to the rotor at 80mph.

3. when the rotor is pumping, and the shroud is in place, the rotor pulls air from the area that is shrouded. that means it pulls air over the surface of the rotor, then pumps it back out through the inside. this should be substantially more air flow / cooler air over the back rotor surface than it would see simply spinning by itself in standing air that wasn't being pumped.

4. if you remove the shroud, it should improve the rotor's pumping effect, which should help cool the inside of the rotor a lot. but you lose some effect of the pump on cooling the back surface of the rotor. however you dramatically increase the back surface of the rotor's radiative cooling capability. another side effect of going without the shroud is that the air going into the center of the rotor is cooler.

5. because of 3 and 4, running without a shroud will cause a higher heat differental in the back rotor surface, but should cool the front rotor plate better and give more even cooling on one side of the rotor versus the other.

there might be some impact on rotor life regarding heat differential... it might be that one way is better than the other. i suspect cooling from only the center would be more prone to cracking but i'm not entirely sure if the difference between one side of the rotor to the other would really be that high that cooling only on the inside and decreasing cooling on the rotor surface would have much of an impact on cracking...


so now i have no idea if the shroud is beneficial or not. at least it helps keep the dust down?

starting to lean toward the idea that it should be minimal shrouding.

[alex.s]

Originally Posted by ApexEight

Any pics of how the hose was routed around the radiator?

[Jonsey]

That many bends is going to have an impact on the flow rate due to all the back pressure.

[Scrappydoo]

Originally Posted by Jonsey

That many bends is going to have an impact on the flow rate due to all the back pressure.

No back pressure. What from? Restricted flow maybe.

But not enough to make a gnats difference?

[alex.s]

Originally Posted by Scrappydoo

No back pressure. What from? Restricted flow maybe.

But not enough to make a gnats difference?

The bends cause a change in direction of the air. Body at rest stays at rest. Every action has equal opposite reaction. That means every change in direction requires energy. In other words the bends create a flow restriction. It's not massive but I would expect it to be at least 5 percent in my case

Sent from my Nexus 5X using Tapatalk

[Scrappydoo]

Originally Posted by alex.s

The bends cause a change in direction of the air. Body at rest stays at rest. Every action has equal opposite reaction. That means every change in direction requires energy. In other words the bends create a flow restriction. It's not massive but I would expect it to be at least 5 percent in my case

Sent from my Nexus 5X using Tapatalk

And you can lead a horse to water but a pencil must be lead.

[alex.s]

Originally Posted by Scrappydoo

And you can lead a horse to water but a pencil must be lead.

... what?

[Jonsey]

Bends in piping can create pretty significant reductions in flow, especially when that flow is not pressurized (the air flowing through is not pressurized or barely pressurized). Air will take the path of least resistance and if there is less resistance sliding sideways over the front of the bumper versus going though a long tube with numerous bends, it will take that path. I have only enough knowledge in this area from years of playing with aquarium piping and studying aerodynamics to get myself in trouble, but someone with more knowledge in fluid dynamics should chime in.

You might do some string testing to see if you are getting adequate flow.

I hope you are successful as routing on this car sucks and I am interested in doing something similar, I just have a feeling it won't be sufficient for heavy tracking by an advanced driver.

[Gunman]

Originally Posted by Scrappydoo

No, my point was that if you want to improve heat loss from the disks then why not remove the shrouds?

Shrouds do a lot, they 'shroud' heat from other areas, direct flow, even increase downforce if done right.

[stevesnj]

Originally Posted by wparsons

That doesn't actually help as much as you would think. Vented rotors are cooled much better by directing air into the center and letting it flow out through the vanes.

This is pretty much how it's done.