Topic: Brake Ducting Q: Add Duct Fans or Not?
We have a heavy car at 3300 lb with driver and at our last race, one of our drivers boiled the fluid during a yellow. This is despite having 13" rotors and cobra calipers (biggest bolt on options for a 95 tbird). He had to pump twice to slow down. We measured a temp of 580F on the disc after he pitted.
FIX 1: upgrade the fluid from ATE Super Blue (dry temp 536F) to Motul RBF 600 (594F) right before the next race. This will clearly help.
FIX 2: I built some ducting that dumps air from a front bumper hole straight onto the rotor. I made this by fiberglassing in some ducts into two holes in the bumper cover and then welding two metal tabs onto some scrap 3" tubing. Ducting is RV sewer hose from Walmart. Interesting and satisfying project.
I'm now thinking that while fix #2 should lower disc temps at speed by forcing air onto the rotors at speed, it might not have the same effect under caution because of the reduced vehicle speed.
Q: Should I now consider adding two bilge pump fans (130CFM for ~$20 each) inline with the ducts or potentially as a separate duct?
PROS: would force more air during cautions onto the rotors... Arguably when we need it most.
CONS: fans themselves could/would be airflow obstructions when the car is moving at speed. See pic of how much of the inside of the tube is blocked by the fan.
Will the pros of active cooling outweigh the cons? This is what I'd like advice about.
I'm clearly over thinking this problem but this is the fun of Lemons for me. The cost and fab time don't bother me; I just want some advice if the added complication of the fan ducts (either inline with my existing new ducts or mounted on a second bracket aimed at the caliper) is worth it. A second bracket is added complication and imo one more thing that can fall into the track. If I go with inline mounting, I could probably secure the fans more securely on the inside of the fender.
Existing ducts and brackets I just made
We have a heavy car at 3300 lb with driver and at our last race, one of our drivers boiled the fluid during a yellow. This is despite having 13" rotors and cobra calipers (biggest bolt on option for a third). He had to pump twice to slow down. We measured a temp of 580F on the disc after he pitted.
FIX 1: upgrade the fluid from ATE Super Blue (dry temp 536F) to Motul RBF 600 (594F) right before the next race. This will help.
FIX 2: I built some ducting that dumps air from a front bumper hole straight onto the rotor. I made this by fiberglassing in some ducts into two holes in the bumper cover and then welding two metal tabs onto some scrap 3" tubing. Ducting is RV sewer hose from Walmart. Interesting and satisfying project.
I'm now thinking that while fix #2 should lower disc temps at speed by forcing air onto the rotors at speed, it might not have the same effect under caution because of the reduced vehicle speed.
Q: should I consider adding two bilge pump fans (130CFM for ~$20 each) inline with the ducts or potentially as a separate duct?
PROS: would force more air during cautions onto the rotors... Arguably when we need it most.
CONS: fans themselves could/would be airflow obstructions when the car is moving at speed?
Will the pros of active cooling outweigh the cons? This is what I'd like advice about.
I'm clearly over thinking this problem but this is the fun of Lemons for me. The cost and fab time don't bother me; I just want some advice if the added complication of the fan ducts (either inline with my existing new ducts or mounted on a second bracket aimed at the caliper) is worth it. A second bracket is added complication and imo one more thing that can fall into the track. If I go with inline mounting, I could probably secure the fans more securely on the inside of the fender.
Existing ducts and bracketry I just made
Duct fans I'm considering
https://www.walmart.com/ip/Attwood-Turb … t/14150765
Thanks in advance.
Regards,
-g
2017 Sears Pointless Organizer’s Choice
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