CFM of C5/C6 Brake ducting?
10-21-2014, 01:02 PM
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CFM of C5/C6 Brake ducting?
Anyone have any idea how much air you actually get with the passive brake ducting in the C5 and/or C6? I have a widebody track 69 camaro and am roasting the brakes and looking for a ducting solution and may use some parts from a C5 or C6 as part of the solition.
Alternatively, I may use a 135 CFM fan from cool shirt to actively move air to the rotor.
Cheers,
Jason
Alternatively, I may use a 135 CFM fan from cool shirt to actively move air to the rotor.
Cheers,
Jason
10-21-2014, 02:15 PM
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Contact this company. Former GM couple that now supply the aftermarket with really good stuff. They can recommend exactly what you need.
http://www.detroitspeed.com/
http://www.detroitspeed.com/
10-22-2014, 12:25 PM
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The link in Anthony's post shows a leaf blower with a 126 mph outlet air flow that probably pushes more CFMs than a 135 CFM cool suit blower fan. I think if you calculate the cool suit blower outlet speed (assuming a 3 inch outlet) the speed of the air will be something like 31 mph. The C5 and C6 ducts on the market tend to have 4 inch duct inlets which narrow down to about a 3 inch diameter which is then flattened in the wheel well to provide wheel clearance. That flattened section along with a number of changes in direction restricts flow so actual air speed at the ducting outlet is probably more like 15 mph. Which means the you are losing half of your fan output.
I am not sure of the efficiency of the aero treatments ducting outside air into the C5/C6 ducts but the leaf blower example probably gives a good estimate of about 32% max. Which at any speeds above ~ 100 mph you will get more air flow by direct ducting of air from the duct inlet in front and above the air dam on a C6Z. It all depends on how much time is spent below 100 mph VS how much time above 100 which way is better.
If the fan is in direct line with outside air directed to the rotors it will tend to slow that air flow when the car is running at high speeds. I think if you use a fan it needs to be Y'd into the outside air ducting so the fan doesn't impede air flow.
If you can fabricate a 4 inch duct to connect a 4 inch 235 CFM Bilge Blower then you might be able to raise the trade off between direct outside air and blower supplied air into the 130 mph+ range which means that overall you would get better cooling using the blower no matter which track you are on. These are just some napkin type rough calculations and assumptions and there could be some errors in the assumptions so testing would be required to verify them.
Bill
I am not sure of the efficiency of the aero treatments ducting outside air into the C5/C6 ducts but the leaf blower example probably gives a good estimate of about 32% max. Which at any speeds above ~ 100 mph you will get more air flow by direct ducting of air from the duct inlet in front and above the air dam on a C6Z. It all depends on how much time is spent below 100 mph VS how much time above 100 which way is better.
If the fan is in direct line with outside air directed to the rotors it will tend to slow that air flow when the car is running at high speeds. I think if you use a fan it needs to be Y'd into the outside air ducting so the fan doesn't impede air flow.
If you can fabricate a 4 inch duct to connect a 4 inch 235 CFM Bilge Blower then you might be able to raise the trade off between direct outside air and blower supplied air into the 130 mph+ range which means that overall you would get better cooling using the blower no matter which track you are on. These are just some napkin type rough calculations and assumptions and there could be some errors in the assumptions so testing would be required to verify them.
Bill
Last edited by Bill Dearborn; 10-22-2014 at 12:43 PM.
10-22-2014, 12:38 PM
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The link in Anthony's post shows a leaf blower with a 126 mph outlet air flow that probably pushes more CFMs than a 135 CFM cool suit blower fan. I think if you calculate the cool suit blower outlet speed (assuming a 3 inch outlet) the speed of the air will be something like 31 mph. The C5 and C6 ducts on the market tend to have 4 inch duct inlets which narrow down to about a 3 inch diameter which is then flattened in the wheel well to provide wheel clearance. That flattened section along with a number of changes in direction restricts flow so actual air speed at the ducting outlet is probably more like 15 mph. Which means the you are losing half of your fan output.
I am not sure of the efficiency of the aero treatments ducting outside air into the C5/C6 ducts but the leaf blower example probably gives a good estimate of about 32% max. Which at any speeds above ~ 100 mph you will get more air flow by direct ducting of air from the duct inlet in front and above the air dam on a C6Z.
If the fan is in direct line with outside air directed to the rotors it will tend to slow that air flow when the car is running at high speeds. I think if you use a fan it needs to be Y'd into the outside air ducting so the fan doesn't impede air flow.
Bill
I am not sure of the efficiency of the aero treatments ducting outside air into the C5/C6 ducts but the leaf blower example probably gives a good estimate of about 32% max. Which at any speeds above ~ 100 mph you will get more air flow by direct ducting of air from the duct inlet in front and above the air dam on a C6Z.
If the fan is in direct line with outside air directed to the rotors it will tend to slow that air flow when the car is running at high speeds. I think if you use a fan it needs to be Y'd into the outside air ducting so the fan doesn't impede air flow.
Bill
My problem is packaging. The frame rails on the first gen are much wider than a C5/C6 so I actually rub wheel on the frame, so I have no room to get any duct outside the frame. I think my only option is to sandwich a hose between the upper control arm and frame.
What I'm thinking is that I'll attach two of the 235 CFM 4" on a rollcage reinforcement tube between the frame rails between the radiator and pulleys and then neck down to 2.5" and run that over the frame rail and under the upper control arm. TBD where/how I'll pick up the air
While it's not ideal versus clean, cool air, I have to think that even ~110 CFM (assuming 50% of ideal conditions) right on the inside of the rotor will help a lot more than 0 CFM.
Next question is how effective is the air if it's ~1" from the rotor versus a setup like the LG kit? AFAIK, noone makes a bracket/mount/duck like the LG kit for first gens, so I'll just have to deal with a hose safety wired to near the hub.
Thanks,
Jason