Exotic Brake Cooling Ideas

dunk · 05-06-2009, 01:46 PM

I'm bouncing around the idea of planning a 2gph water injection nozzle in each brake duct. I've found some examples of this done with success on racecars in the past, however have seen very little current data. I'm willing to be the lab rat here.

Any thoughts from NASIOC?

-Duncan

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STi-MAN · 05-06-2009, 01:56 PM

you need more cooling?

Homemade WRX · 05-06-2009, 02:15 PM

I say go for it!!

Are you planning to trigger flow demand based off of current from a brake line pressure sensor? It could be variable and progressive.

How did you come up with 2GPH flowrate per brake (assuming just the fronts)?

Frank A · 05-06-2009, 02:17 PM

did you already consider a fan? Someone suggested that those "electric turbochargers" use model jet airplane engines. I looked into them and you can get over 850 scfm from medium-large units that fit in a 3" tube. They don't build pressure very well and bigger units require too much power to justify as a supplemental turbocharger, but that should be more air than typically flows in brake duct hose at >70 mph. Could do some math...

Frank

FunkRider · 05-06-2009, 02:31 PM

I've never done a water cooled brake system but I would imagine you'll only see a worth while benefit from injecting water into the rotor hat area or inject into an airstream the feeds into the rotor hat area.

STi-MAN · 05-06-2009, 02:32 PM

Quote:

Originally Posted by Frank A

did you already consider a fan? Someone suggested that those "electric turbochargers" use model jet airplane engines. I looked into them and you can get over 850 scfm from medium-large units that fit in a 3" tube. They don't build pressure very well and bigger units require too much power to justify as a supplemental turbocharger, but that should be more air than typically flows in brake duct hose at >70 mph. Could do some math...

Frank

he already has a fan on there.. hahah thats why i asked if he needs more cooling.

rexspeedworthy · 05-06-2009, 02:34 PM

When you are not racing, you can adjust the nozzles to spray your tires with soap water, and do AWD burnouts without fear of breaking your shizz.

generalee69 · 05-06-2009, 02:49 PM

My only theoretical concern would be if the mist/air temp is too cold, you might do some warping damaging due to the rapid change in temp. I'm thinking going from glowing red rotors to spraying them down with a garden hose as an extreme example...

dunk · 05-06-2009, 03:07 PM

Quote:

Originally Posted by generalee69

My only theoretical concern would be if the mist/air temp is too cold, you might do some warping damaging due to the rapid change in temp. I'm thinking going from glowing red rotors to spraying them down with a garden hose as an extreme example...

I did the basic math and at rotor temps over a 1000 degrees the water will be steam long before it touches the rotor face.

-Duncan

dunk · 05-06-2009, 03:09 PM

Quote:

Originally Posted by Homemade WRX

I say go for it!!

Are you planning to trigger flow demand based off of current from a brake line pressure sensor? It could be variable and progressive.

How did you come up with 2GPH flowrate per brake (assuming just the fronts)?

I picked 2gph out of a hat. It seemed a reasonable size based on the flowrate and tank sizes needed to sustain 45 minutes of operation. I'm going to dig through the Trackmate data and see how many minutes of braking I do per x driving time. I'll use Summit Main for a data point since it's the worse out of all the tracks I drive.

I was going to use a simple on/off using the brake switch to keep the cost and complexity down.

-Duncan

dunk · 05-06-2009, 03:11 PM

Quote:

Originally Posted by STi-MAN

you need more cooling?

Wouldn't hurt. My rotor temps are still hotter than I'd like. Before the next track day at a minimum I'm going to .

Remove the fans from the primary ducts (restriction at speed)

Hook them back up to the lower RCE ducts (currently not hooked to hose)

This shold give me both a low and high speed system.

Doing the water injection would be cheap using parts from Mcmaster and I just thought it would be interesting to compare how well it works.

-Duncan

Turn in Concepts · 05-06-2009, 03:49 PM

Hey Dunk,

I did some research on this a while ago. You need the nozzles to be fairly close to the beginning of the ductwork as opposed to right next to the rotors.

-Clint

dunk · 05-06-2009, 05:45 PM

Quote:

Originally Posted by Turn in Concepts

Hey Dunk,

I did some research on this a while ago. You need the nozzles to be fairly close to the beginning of the ductwork as opposed to right next to the rotors.

-Clint

Clint,

Return my call when you get a chance.

-Duncan

Mr_Snips · 05-06-2009, 07:31 PM

Well, they do this alot in the big semi truck racing down under. But i know for awhile (maybe they still do) WRC cars had watercooled calipers as in water flowed through them.

There was some talk awhile ago and some people brought about the hypothesis of steam forming under the pads and causing loss of braking power.

drdabbles · 05-06-2009, 08:42 PM

Quick temp fluctuations have different effects on different materials. Also, different brake compounds work more effectively at different temperatures. So, finding a pad that can handle quick thermal cycling and do its job effectively.

Good luck and let us know how it works.

misterwaterfallin · 05-06-2009, 08:56 PM

Quote:

Originally Posted by rexspeedworthy

When you are not racing, you can adjust the nozzles to spray your tires with soap water, and do AWD burnouts without fear of breaking your shizz.

this.
needs to happen

Token-Negro · 05-06-2009, 08:58 PM

Why not go to the 4" fans with the 3" reducer?

dunk · 05-06-2009, 09:09 PM

Quote:

Originally Posted by Token-Negro

Why not go to the 4" fans with the 3" reducer?

You're no fun.

I don't have the room to package it all in front of the brake duct inlet. I'm debating putting the 3" fan parallel to the main duct, with a y junction into the main pipe. This would probably involve the least fabrication.

-Duncan

wallyman424 · 05-06-2009, 09:42 PM

Duncan, why are you having so many brake cooling problems? How much does your car weigh? How big are your rotors? What pads do you use?

I figure our cars can't be too far off on weight and top speed, and I have no problems with brake fade.

Chris_Lee · 05-06-2009, 09:55 PM

Quote:

Originally Posted by Turn in Concepts

Hey Dunk,

I did some research on this a while ago. You need the nozzles to be fairly close to the beginning of the ductwork as opposed to right next to the rotors.

-Clint

This would make sense. Applying some sort of cooling fluid directly to the surfaces of the caliper or rotor could cause the metal to expand and contract to fast and to much This could cause the metal to crack. This is a really good idea though. You've got to post some pics when you work out the details. I wonder if there is way to use a flexible bladder?

Mr_Snips · 05-06-2009, 10:03 PM

why not just have a small nozzle spray something like C02 on it?

boost junkie · 05-06-2009, 10:33 PM

Quote:

Originally Posted by wallyman424

Duncan, why are you having so many brake cooling problems? How much does your car weigh? How big are your rotors? What pads do you use?

I figure our cars can't be too far off on weight and top speed, and I have no problems with brake fade.

Problem is subarus are very front heavy so the front brakes do most of the work. I've gone through countless brake setups up front, including several sets of rotors, a couple different calipers, and a ton of pads. I still have my stock rear rotors and calipers (5 years old) and they are completely fine.

dunk · 05-06-2009, 10:42 PM

Quote:

Originally Posted by wallyman424

Duncan, why are you having so many brake cooling problems? How much does your car weigh? How big are your rotors? What pads do you use?

I figure our cars can't be too far off on weight and top speed, and I have no problems with brake fade.

As Dan said, Subaru's are tough on brakes.

Car weights 3250 - race weight
Rotors are 13.3x1.26.
58% of the weight is on the front of the car.

It's not a fade issues as the brakes hold up fine. I'm just going through front rotors a lot quicker than I'd like. VIR is not so bad, but Summit Main kills them.

-Duncan

dunk · 05-06-2009, 10:43 PM

Quote:

Originally Posted by boost junkie

Problem is subarus are very front heavy so the front brakes do most of the work. I've gone through countless brake setups up front, including several sets of rotors, a couple different calipers, and a ton of pads. I still have my stock rear rotors and calipers (5 years old) and they are completely fine.

I've had the same set of race pads in the rear for about 6 events now. I've never replaced the rear rotors.

I'm on the fourth front caliper setup.

-Duncan

Frank A · 05-07-2009, 12:10 AM

I want to see the water injection too, buuut, have you considered switching to one of the newer ceramic-based pads like the Ferodo DS2.11's? I understand the ceramic-based stuff is gentler on rotors. Since you say the rotor temps aren't too high, you may have room to switch to a softer pad. How hot is "not too hot"?

If you're running stoptech's you could switch to the 355mm rotor, assuming you use 18" wheels...

Frank

05-06-2009, 01:46 PM	#1
dunk Scooby Guru Member#: 15359 Join Date: Feb 2002 Chapter/Region: MAIC Location: Monterey, CA	Exotic Brake Cooling Ideas I'm bouncing around the idea of planning a 2gph water injection nozzle in each brake duct. I've found some examples of this done with success on racecars in the past, however have seen very little current data. I'm willing to be the lab rat here. Any thoughts from NASIOC? -Duncan * Registered users of the site do not see these ads.

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05-06-2009, 01:56 PM	#2
STi-MAN Scooby Guru Member#: 70252 Join Date: Sep 2004 Vehicle: 05 STI blue	you need more cooling?

05-06-2009, 02:15 PM	#3
Homemade WRX Scooby Guru Member#: 33782 Join Date: Mar 2003 Chapter/Region: MAIC Location: 3MI Racing LLC Vehicle: 96 bastard child search FIRST, then PM!!!	I say go for it!! Are you planning to trigger flow demand based off of current from a brake line pressure sensor? It could be variable and progressive. How did you come up with 2GPH flowrate per brake (assuming just the fronts)?

05-06-2009, 02:17 PM	#4
Frank A Scooby Specialist Member#: 49979 Join Date: Dec 2003 Chapter/Region: MAIC Location: MD, US Vehicle: 11 dgm wrx hatch 08 black TA STI	did you already consider a fan? Someone suggested that those "electric turbochargers" use model jet airplane engines. I looked into them and you can get over 850 scfm from medium-large units that fit in a 3" tube. They don't build pressure very well and bigger units require too much power to justify as a supplemental turbocharger, but that should be more air than typically flows in brake duct hose at >70 mph. Could do some math... Frank

05-06-2009, 02:31 PM	#5
FunkRider Scooby Specialist Member#: 195055 Join Date: Nov 2008 Chapter/Region: E. Canada Location: Southern Ontario Vehicle: 2002 WRX PSM	I've never done a water cooled brake system but I would imagine you'll only see a worth while benefit from injecting water into the rotor hat area or inject into an airstream the feeds into the rotor hat area.

05-06-2009, 02:34 PM	#7
rexspeedworthy Scooby Specialist Member#: 26965 Join Date: Oct 2002 Chapter/Region: MWSOC Location: Independence, KY Vehicle: 2011 WRX DarkGray	When you are not racing, you can adjust the nozzles to spray your tires with soap water, and do AWD burnouts without fear of breaking your shizz.

05-06-2009, 02:49 PM	#8
generalee69 Scooby Specialist Member#: 106470 Join Date: Jan 2006 Chapter/Region: NWIC Location: Kent WA Vehicle: 2004 STI ICSCC #9 www.ClintonRacing.com	My only theoretical concern would be if the mist/air temp is too cold, you might do some warping damaging due to the rapid change in temp. I'm thinking going from glowing red rotors to spraying them down with a garden hose as an extreme example...

05-06-2009, 03:49 PM	#12
Turn in Concepts NASIOC Vendor Member#: 93646 Join Date: Aug 2005 Chapter/Region: MWSOC Vehicle: Many Track Records Let us help you go fast!	Hey Dunk, I did some research on this a while ago. You need the nozzles to be fairly close to the beginning of the ductwork as opposed to right next to the rotors. -Clint

05-06-2009, 07:31 PM	#14
Mr_Snips Scooby Specialist Member#: 152117 Join Date: Jun 2007 Chapter/Region: SCIC Location: Hills Have Eyes Vehicle: 2012 Ford F150 ECO White	Well, they do this alot in the big semi truck racing down under. But i know for awhile (maybe they still do) WRC cars had watercooled calipers as in water flowed through them. There was some talk awhile ago and some people brought about the hypothesis of steam forming under the pads and causing loss of braking power.

05-06-2009, 08:42 PM	#15
drdabbles Scooby Newbie Member#: 110229 Join Date: Mar 2006 Chapter/Region: NESIC Location: Manchester, NH Vehicle: 2004 WRX STi Java Black	Quick temp fluctuations have different effects on different materials. Also, different brake compounds work more effectively at different temperatures. So, finding a pad that can handle quick thermal cycling and do its job effectively. Good luck and let us know how it works.

05-06-2009, 08:58 PM	#17
Token-Negro Scooby Specialist Member#: 81659 Join Date: Feb 2005 Chapter/Region: NWIC Location: Sammamish Vehicle: 2010 Fozzy XT Ice Silver Metallic	Why not go to the 4" fans with the 3" reducer?

05-06-2009, 09:42 PM	#19
wallyman424 Scooby Specialist Member#: 60357 Join Date: Apr 2004 Chapter/Region: South East Location: Charleston, SC Vehicle: #17 NASA ST2 Z06 my wang > your wang.	Duncan, why are you having so many brake cooling problems? How much does your car weigh? How big are your rotors? What pads do you use? I figure our cars can't be too far off on weight and top speed, and I have no problems with brake fade.

05-06-2009, 10:03 PM	#21
Mr_Snips Scooby Specialist Member#: 152117 Join Date: Jun 2007 Chapter/Region: SCIC Location: Hills Have Eyes Vehicle: 2012 Ford F150 ECO White	why not just have a small nozzle spray something like C02 on it?

05-07-2009, 12:10 AM	#25
Frank A Scooby Specialist Member#: 49979 Join Date: Dec 2003 Chapter/Region: MAIC Location: MD, US Vehicle: 11 dgm wrx hatch 08 black TA STI	I want to see the water injection too, buuut, have you considered switching to one of the newer ceramic-based pads like the Ferodo DS2.11's? I understand the ceramic-based stuff is gentler on rotors. Since you say the rotor temps aren't too high, you may have room to switch to a softer pad. How hot is "not too hot"? If you're running stoptech's you could switch to the 355mm rotor, assuming you use 18" wheels... Frank