w-20 brake cooling

[knebrdr]

I am thinking about water cooling the front brakes on a W-20. It would be used on long down hills only. I would probably inject the H2O from the inside out on the rotors immediately after/below the caliper. This has been done for years on racing semis around the world.
My thought is if I can control the rotor temp by starting the injection process early enough I may not cause the rotors to crack as occurs in racing situations. All input appreciated.
Randy
P,S. The system would be master switched, triggered off of the brakelight switch or an additional separate switch, and jetted as needed to control the water volume. Basically it would be set up similar to a nitrous system.

[knebrdr]

I am thinking about water cooling the front brakes on a W-20. It would be used on long down hills only. I would probably inject the H2O from the inside out on the rotors immediately after/below the caliper. This has been done for years on racing semis around the world.
My thought is if I can control the rotor temp by starting the injection process early enough I may not cause the rotors to crack as occurs in racing situations. All input appreciated.
Randy
P,S. The system would be master switched, triggered off of the brakelight switch or an additional separate switch, and jetted as needed to control the water volume. Basically it would be set up similar to a nitrous system.

[knebrdr]

I forgot to mention, the other approach would be to duct air directly to the rotor area and mist cool water into the duct, there by lowering the cooling air temp. Another race tested technique.
Randy

[DriVer]

Randy,

If you are needing to cool your calipers with water coming down a grade then you are operating your motorhome incorrectly.

Venting or cooling you calipers using ambient air isn't going to be a bad thing but I would suggest strongly that you not use water. You most likely will warp a rotor in a heartbeat.

Using select shifting I can descend any grade on a "US or State Highway" without over heating my brakes.

[knebrdr]

Driver,
This has nothing to do with operating the MH incorrectly. This is more of an intellectual excercise directed towards possibly stopping rotor cracking (from heat) by not allowing them to get into the danger zone much like using Nitous Oxide as an altitude compensator (not performance enhancer) in a non-turbo charged diesel application. If set up correctly it may be beneficial to rotor, pad and fluid life. Again this is not to allow more radical braking but to enhance normal vehicle operation.
Randy

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by knebrdr:
... Again this is not to allow more radical braking but to enhance normal vehicle operation. </div></BLOCKQUOTE>Randy, I have to commend you for pursuing a technology that would keep rotors cool under normal operation. Discussions among interested parties often fosters working solutions. Keep up the good work.

[knebrdr]

Well Driver,
Since it is just you and me participating I will fill you in on the plan. I located some 3" brake duct fans which will be manually controlled (heavy traffic & down hill) over a relay. I will then fit at least one misting nozzle in each duct pressurized by a 12v pump: master switched (temp or manual), relay controlled, triggered off of a separate switch tied to the brake pedal. Mister nozzles can be added if needed but I think the light mist created by one should be sufficient to drop air temp in a 3" duct approximately 20 degrees.
Parts acquisition will take a while since I am planning on keeping costs down (fans are $40.00/each) and will have to search multiple vendors for relays, tubing, etc.
Randy

[hwybnb]

I am open to suggestions because I have had three rotors with severe cracks but this sounds like a bad idea to me. Rapid cooling with the water mist is more likely to promote cracking than to prevent it. Aside from that no 3" fan that I know of is going to provide more air at highway speeds than you would get using ram air. My feeling is that the fan would impede air flow in the duct.

[knebrdr]

Bob,
This brake cooling system is not designed for highway speeds where modified brake cooling is not needed. This is for low speed, extended down hill situations. The fans are a race item normally used on short tracks. The mist is not to cool the rotors themselves but to cool the air in the duct and will be introduced at the bottom of a slight uphill loop (with drain hole) in an attempt to keep it off of the rotor. The design may change and allow the mist to exit at the end of the duct. This system is being set-up in an attempt to keep excessive heat from ever becoming a problem.
Randy

[dieselclacker]

knebrdr, IMHO you are working toward a problem that is non-existant. Read DriVers reply, you need to operate your motorhome differently if you are having heating problems with the brakes coming down grades, and in stop and go conditions. You have to anticipate conditions somewhat, and use the proper gear in the transmission. Don't rely on the motorhome brakes alone.

I do not doubt that you can effect brake cooling if enough time, effort, and money is applied, but is it really necessary?

Dieselclacker

[knebrdr]

diesel,
This is not because of an inability to operate a vehicle corrctly. This is an attempt to keep brake temperatures under control during normal downhill operation. At this point the projected cost is about $100.00 plus my design time and install labor. I am sure a lot more than this has been spent on decorative pieces, snake oil, and what not by members. Since I already stated this previously, please read all posts before repling.
Besides, even a short, twisty downhill similar to the road north out of Mariposa, Ca. when driven in low gear will add a substantial amount of heat to the rotors.
Randy
Randy

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by knebrdr:
This is an attempt to keep brake temperatures under control during normal downhill operation. </div></BLOCKQUOTE>Randy, Short of reinventing the wheel - please consider the use of the transmission grade brake OR select shifting. If you are sitting on the apex of a grade and select 2nd gear and proceed forward - I can guarantee you that you are not going to go down the hill with any appreciable speed unless you take a nose dive.

The rule is that you should go down a grade pretty much in the same gear as you would use to go up.

I don't believe that technology or any other purposeful means to introduce additional cooling will help improve performance. If you are to the point where you need to use a cooling device on a downhill grade then it is likely that your brakes are being used to slow the forward progress of the vehicle.

This practice will only cause inevitable brake damage and failure. That said, "If you don't use your brakes - you will not need to cool them."

Use the TGB or Select Shifting instead, this is a much better alternative.

[dieselclacker]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by knebrdr:
diesel,
This is not because of an inability to operate a vehicle corrctly. This is an attempt to keep brake temperatures under control during normal downhill operation. At this point the projected cost is about $100.00 plus my design time and install labor. I am sure a lot more than this has been spent on decorative pieces, snake oil, and what not by members. Since I already stated this previously, please read all posts before repling.
Besides, even a short, twisty downhill similar to the road north out of Mariposa, Ca. when driven in low gear will add a substantial amount of heat to the rotors.
Randy
Randy </div></BLOCKQUOTE>


Didn't mean to offend you Randy, as I said, just my opinion. And I did read and understand your previous posts. Go for your system if you think it is necessary, in my opinion it is not.

Dieselclacker

[knebrdr]

Sorry guys,
Did not mean to be rude.
This proposed modification is based on the fact that a factory brake pad / rotor combination is designed to work in a linear fashion from a cold temp (they will stop even when outside temps are below freezing) to their point of fade; 1000F or greater, I do not have the exact number on the WH combo. Now if the operating temp can be maintained at a more comfortable temperature on a long downhill, say 300 to 500F, the pad and rotor life will increase dramatically, stopping power will not be effected and the safety factor will increase. Heat is a direct indication of wear, therefore less heat, less wear, increased safety.
I would not do this if there was not a direct correlation between up front cost and overall brake part savings. The increased safety factor is just a by product.
Randy