BCM Community

Mist Radiator Cooling System
I installed a mist cooling system on the radiator of my converted Eagle coach to resolve temporary overheating conditions, particularly when pulling long steep grades. I purchased the components at the local hardware store and total cost was probably less than $20.00. A Google search will give lots of ideas on this system.

The misters come in various ratings which are in Gallons per Hour I believe. Buy the misters that provide the MINIMUM water flow.

I used six misters total with two rows of three in each row. In addition to the misters you will need a few T connectors and some ¼ inch black tubing sold with the misters. I spaced the misters about 8 inches apart and the two rows about 12 inches apart. None of these dimensions are critical.

I used tye wraps to tie the tubing to a cross brace on the front of the radiator about two inches from the radiator coil. Use miniature tye wraps and also install them at each location where a T or mister is installed. The tubing tends to get hot and expands and the joints come apart. I used a tye wrap tensioning tool to pull them as tight as possible. Do not just plug the misters into the supply line. Use T connectors and short sections of hose. 

I connected the two ¼ inch runs together to a ½ inch section of tubing and run it forward to the fresh water tank area. I had previously installed a spare water pump as an emergency back up, so I just re-plumbed it slightly to feed the mister system instead of the coach. A remote switch with indicator light was installed on the dash to control the pump.

During testing I found that nothing was very critical about installation. I turned the misters so that they were pointing forward and about 120 degrees away from the radiator. This allowed the mist to disperse quite nicely outward and cover a larger area of the radiator. The engine should be running at a fast idle while making this adjustment.

As I have stated previously, the results of this system was simply amazing. Never again did I worry about outside temperatures or the size of the grade I had to climb. I never had to back off on the throttle or turn off my genset, which was plumbed thru the coach cooling system. I did try always to maintain a minimum of 1800 rpm while traveling the mountain passes.

I typically would wait until the coolant temperature reached about 200 degrees. And then turn on the mister. Within just a very few minutes the temperature would slowly start to drop and generally within 5-10 minutes it would be back at the 180 degree mark. At that time I knew that the complete cooling system was back down to 180 degrees or below, so I would turn it off and just continue monitoring the temperature.

I believe that I would have to use the system two or three times during the climb out of Death Valley on the way to Las Vegas. It really would not have mattered if I would have had to run it continuously as it consumed such a small amount of water. I could never detect any appreciable amount of water used while using this system.

It is definitely not a band aid system and I never saw any buildup of residue on the radiator during the 10+ years I used it. And I traveled well over 100,000 miles and made numerous trips thru the mountains where the use of it was required.

Sorry to be so long winded, but I so many persons have asked about this and I have made partial answers so many times that I decided to take the time and do it right for a change.
Richard

I once built a similar system around my air conditioner condenser at home.  It would spray water on the condenser whenever it ran.  It worked great and knocked the run amps down by about 40%.
The problem was that within a few months, the condenser was completely clogged up with calcium deposits.  My attempts to clean it with a mild acid (vinager) ruined the condenser.

I think that if I were to build such a system, I would have a dedicated tank with distilled water.

FWIW

Len

Quote from: Len Silva on May 25, 2006, 07:46:01 AM
I once built a similar system around my air conditioner condenser at home. It would spray water on the condenser whenever it ran. It worked great and knocked the run amps down by about 40%.
The problem was that within a few months, the condenser was completely clogged up with calcium deposits. My attempts to clean it with a mild acid (vinager) ruined the condenser.

I think that if I were to build such a system, I would have a dedicated tank with distilled water.

FWIW

Len

I was thinking the same thing Len.... May be a great added step in prevention and easy to incorporate and re-fill through the use of an old fire extinguisher, pressurized with air. - no pump needed
From what I have read here, the amount of water needed to mist the rads are very minimal and a fire extinguisher full may be enough for an average trip.

A good supply of Distilled water is always good to have on-board for Rad top-ups and battery top-ups anyways.

Does this make sense or not... Anyone...?

Steve

Great post, Richard! As long as we can keep a certain BNO poster from finding this and telling you that the "sky is falling", you'll do a lot of good helping folks cool their engines in marginal conditions.

My only question is what valve/solenoid did you use to control the flow. I've checked into inexpensive sprinkler control valves at the local Big Box that would seem perfect... but they run off of 24VAC current instead of DC. I found Grainger valves, but they're expensive and seem like overkill for the kind of flow and psi we're needing.

My runs up I-70 and over the Divide would be a lot less stressful for me (and my mill) with this setup!

Thanks again, Richard!
Brian Brown
Longmont, CO
4106-1175
4108-216

Quote from: SpaceShipBuffalo on May 25, 2006, 08:17:31 AM
Great post, Richard! As long as we can keep a certain BNO poster from finding this and telling you that the "sky is falling", you'll do a lot of good helping folks cool their engines in marginal conditions.

My only question is what valve/solenoid did you use to control the flow. I've checked into inexpensive sprinkler control valves at the local Big Box that would seem perfect... but they run off of 24VAC current instead of DC. I found Grainger valves, but they're expensive and seem like overkill for the kind of flow and psi we're needing.

My runs up I-70 and over the Divide would be a lot less stressful for me (and my mill) with this setup!

Thanks again, Richard!
Brian Brown

Longmont, CO
4106-1175
4108-216

I have found that 24 vac coils and relays work well on 12 vdc without overheating.  Can't explain the theory, but it seems to work.

Len

Quote from: SpaceShipBuffalo on May 25, 2006, 08:17:31 AM
Great post, Richard! As long as we can keep a certain BNO poster from finding this and telling you that the "sky is falling", you'll do a lot of good helping folks cool their engines in marginal conditions.

My only question is what valve/solenoid did you use to control the flow. I've checked into inexpensive sprinkler control valves at the local Big Box that would seem perfect... but they run off of 24VAC current instead of DC. I found Grainger valves, but they're expensive and seem like overkill for the kind of flow and psi we're needing.

My runs up I-70 and over the Divide would be a lot less stressful for me (and my mill) with this setup!

Thanks again, Richard!
Brian Brown
Longmont, CO
4106-1175
4108-216

Thanks Brian. I just turned the water pump on and off with a switch. The water pump was plumbed into the potable wter supply. The better/easier thing to do would be to use a solenoid off the existing potable water system. The thing is to find the prover 12 volt operating solenoid at a reasonable price.

Of course if you have an inverter running, then you could use a 120 volt solenoid. Come to think of it, I always had my genset running so I had 120 volts AC whether the inverter was on or not.
Richard

I found a 12v solenoid for a sprinkler system at Home Depot.  I plan on using it.

HTH,

Dug
75 MC8
Arcadia, FL

Richard, I see... you just used a different water pump for the mister. That could work!

I was thinking of installing a 24VDC solenoid (on the coach side elec.) to just open a valve from the tank under the bed in the back and the existing water pump would supply pressure to the mister until the valve closes.

I could mine eBay and pick whatever unit is cheaper. Or just buy a Toro sprinkler valve, supply it with 24VDC and see if it fries it.

Doug:
Was the 12v solenoid in the sprinkler stuff? Have you tested it on 12VDC. Most of the valves I've seen call for 24VAC

Thanks guys!
Brian

Richard, (Driving Misslazy)
Thanks for your support on this as I was going to do it no matter what after making my tank and all for my Eagle and by the looks of thing here on this post now I see that I was on the right track with the distilled water as well.  I have a dehumidifier that makes about 3 gallons a day, my tank is 29 gallons as explained on my web site.  I will be contacting you again after the framing is done here on my Eagle soon to get maybe a couple of photo's of your set up if possible.
I didn't believe I could be that far off in my thought of this.  Your success makes it worth while to put all the labor in making my tank.
Gary

OK, just in case any one needs a 24 volt d.c. solenoid, I have a supply of them, (Rainbird type), that will work just fine.  Can I say that on this board?  I won't post contact info in case I can't "advertise" them in this manner...
Dennis
HI YO SILVER! 

Great ideas.
Question; on a MC8 do I need two misters, one for each side, or just one?

Kent

I have a '67 MCI 5A w/ a 6v92 turbo and 5 speed auto. The rads are stock size and at sea leavel I have marginal cooling capabilities. Up here in the rockies it sucks. My rads have about 7000 btu capacity and the 6v92 can produce 12,000 btu. At temps over 75 I have to run the misters almost constantly. I hope to add two smaller rads to fix this issue. My first attempt failed, (due to their placement). Anyway I run 4 mist heads on each rad, spaced equally for full coverage. Each side is mounted to a pair of all-thread rods installed towards the outside of the rad compartments. I tried 1/2 gph heads but that isn't quite enough. I'm going to switch to 3/4 gph heads. They are hooked up to a sureflow pump w/ a lighted switch at the daash. no solenoids. The mist heads can be bought or ordered at any Ace hardware. I had trouble locating low flow heads. The original owner of my bus had two heads on each rad with 2.5 gph misters. I've had hot summer days where I used over 70 gal of water in one day. Also with that set up water would run out thus the change to smaller heads. Now with the 3/4 gph x 8= 6 gph total instead of 10 gph that I had.

I knew a guy who used a windshield washer unit out of an old junk car. It was cheep, easy, 12 volt, had a built in reservoir, and took up little space so it was easy to mount. I thought that the capacity was on the small side, but he claimed that he used such a small amount of water that it never ran dry.

Laryn

Quote from: Barn Owl on May 25, 2006, 10:44:54 PM
I knew a guy who used a windshield washer unit out of an old junk car. Laryn

Now thats some Busnuts smarts.

Don't reinvent the wheel, just find a new use for it! ;D

Cliff

Quote from: Floridacracker on May 26, 2006, 04:22:20 AM

Quote from: Barn Owl on May 25, 2006, 10:44:54 PM
I knew a guy who used a windshield washer unit out of an old junk car. Laryn

Now thats some Busnuts smarts.

Don't reinvent the wheel, just find a new use for it! ;D

Cliff

That made me think of those, like me, that are still on the Air wiper/washer system,
Could we just run a another line back to the rads off of the exsiting air washer system,
All the controls and wiring are up-front already.?

Steve

I can assure you that if you have to use a mist system to cool your motor you will over time plug your radeator with calcem. I have one at my shop now that is so pluged that a light will not shine through. Best to replace with a bigger unit to start with. The old Fram commercial, Pay me now or pay me later. Fred North Florida Bus Conversion

I bought the biggest (7 row) radiator I could get for my RTS (6V92TA-350HP), but had to install a radiator water spray system for pulling my 7-10,000lb. 20" trailer up the mountains.  I have a whole house water filter that I use when filling my water tanks and it seems to reduce the calcium levels in the water.  On my system I used a 5/8" industrial garden hose between the water supply line and the radiator, I then used a 24v Rain Bird on/off solenoid for full water flow, and 1/2" drip water system hose with 11 adjustabe sprayer set at the maximum output around the radiator.  I have it tied into the house water supply using the house water pump. 

Some people are saying "water misting system", mine is a full-ledged water sprayer!  I have a spring loaded toggle switch at the driver's area to operate the system and I give the radiator several blasts of water as I start climbing a  big grade.  Sonetimes I have to hold it quite a while, and If I don't start at the first sign of rising heat the engine will heat up faster than the sprayer can cool it off.  On my trips between N. California and my home in Arizona I have to climb several mountain ranges and I will use 125-150 gallons of water each way.  I have to stop and fill with water 3/4 of the way home.

So you can see I am having to drown the radiator to keep the engine cool pulling my trailer, and it works!  There is no way I could pull that trailer without the water sprayer, I would overheat and the automatic shutdown would come on.  On my first trip I didn't realize how much water I had used and I ran out climbing the last huge grade, my engine overheated, and I barely made the exit as my automatic overheat engine shutdown kicked in.

--Geoff

The trick on water misting systems is to design the system so that the fine mist evaporates before it wets the radiator. The idea is to drop the temperature of the cooling air 10-15 degrees via evaporative cooling. Second, but very important, you should use demineralized water to in these systems to avoid deposits on your fins. The more deposits you have, the less efficient your radiator will work this makes the problem worse.

To accomplish the task:
1. Use lower micron orifice sized nozzles with a higher pressure pump to allow ripping the water molecules into the smallest diameter. Smaller molecule spectrum allows faster evaporation.
2. Make certain that the nozzles are evernly spread in the airflow path with minimal overlap. Overlap causes merging of water droplets and reduces evaporation result.
3. Point the nozzles away from the radiator so that more time is allowed for evaporation.

Mist the air before it goes into the radiator?  Have you ever felt the air draw of a big diesel radiator fan at full throttle?  Along with the outside air flow from a moving vehicle?  It might mist when you are testing it but it is going to be drops when you are driving.  That is why I just drench the radiator-- it works.

Quote from: Geoff on May 27, 2006, 08:13:02 AM
Mist the air before it goes into the radiator?  Have you ever felt the air draw of a big diesel radiator fan at full throttle?  Along with the outside air flow from a moving vehicle?  It might mist when you are testing it but it is going to be drops when you are driving.  That is why I just drench the radiator-- it works.

Greg, my experience is that your comments are right on. Wish I could have said it this well.

It is kinda odd, but I never noted any buildup of mineral deposits on my radiator. Maybe because the water was already dry before it hit the radiator and all I had was cool air!!

Geoff, I found that my system seemed to work better when I pointed the misters almost straight out away from the radiator. Even at 1800 rpm it seemed like the water dispersed more across the radiator.

BTW, I might as well start another controversy, along with this. One of the busnuts (Gene from SC)  run a test a few years ago and determined fairly conclusively that the area directly outside the radiator on an Eagle was actually a low pressure area which was trying to pull air back wards thru the radiator. This was at highway speed of course. He installed several ribbons in the radiator vicinity and they stood straight out from the bus while traveling down the highway.
Richard

This is just my 2 cents worth, and it may not work into anything, but...
When I was logging as a young feller in Idaho and Montana, all our skidders and loaders and Cats had reverse fan blades on the engines, blowing outward through the radiator. This was to keep the radiator from clogging with dust and wood sawdust, (or so I was told). We never had a problem with overheat conditions except when there was an engine problem.
Why, if you have 2 radiators, couldn't you have one radiator pull air in and one push it out?
Or, with just one radiator, push the air out the left side and use vents on the right side to draw fresh air in?

This is just a question and not meant to start anything.

and By the way Richard, what are you still doing here? I thought the Divine Ms. L would have you well in hand today!

Dallas

So does that mean driving in the rain makes the bus run cooler...?

I didn't think about before to see if there was a difference.

It would make sense if it did... Has anyone actually noticed...?


Steve

Quote from: El Soñador™ on May 27, 2006, 10:02:13 AM
So does that mean driving in the rain makes the bus run cooler...?

Most definately, Steve. Two weekends ago while hauling our bus over the 7% grades and 10-11k feet passes of central-CO on I-70 we ran into a quick rain shower on one of the climbs. Temp dropped instantly from 190 to 180. This incident proved to me once and for all that mister systems work and are worth it.

Brian Brown
4108-216 w/ V730

Rain is a definite misting system that works.  It also works on patios.  However, on my bus we will continue to spray 'till the water runs out!!

BTW, my bus never overheats, even up the worst grades, unless I am pulling a trailer or vehicle.  A couple of weeks ago I pulled a 7,000 trailer loaded with 5,000 lbs. of steel building up 4,000 feet frpm Phoenix.  The temperature never got past 190 with the sprayer, and it was 101F that day.

Quote from: Geoff on May 27, 2006, 01:18:16 PM
Rain is a definite misting system that works.  It also works on patios.  However, on my bus we will continue to spray 'till the water runs out!!

BTW, my bus never overheats, even up the worst grades, unless I am pulling a trailer or vehicle.  A couple of weeks ago I pulled a 7,000 trailer loaded with 5,000 lbs. of steel building up 4,000 feet frpm Phoenix.  The temperature never got past 190 with the sprayer, and it was 101F that day.

Yea, but did you stay away from the red zone? LOL

Speaking of misters! Where IS Mr.MISTER MIESTER from San Diego anyway? Does he not frequent this BB anymore?

Come on Marc, we know your out there...[/glow]

Hey I'm here and Marc is not from San Diego (I hope)
I'm just lurking and agreeing with almost every post on this board...
quite not the same for BNO though... I give up over there!! :)

Gosh, this (misters) gets beaten to death here and on the other board at the same time.

I spoke with a helpful bus nut in the N.E. that had converted an MCI 8 to the 8V92. He did a neat trick, I think. IIRC he changed the ducting from the buses main heater core to exhaust to the outside of the bus. When he needs extra cooling, he turns on the heater blower and then he has an auxillary radiator.

Pretty cool

Quote from: Geoff on May 27, 2006, 08:13:02 AM
Mist the air before it goes into the radiator?  Have you ever felt the air draw of a big diesel radiator fan at full throttle?  Along with the outside air flow from a moving vehicle?  It might mist when you are testing it but it is going to be drops when you are driving.  That is why I just drench the radiator-- it works.

Geoff, I really wonder if flooding the radiator, instead of misting, is really that much more helpful.

I also towed a 25 ft trailer sometimes if I was not towing the Tahoe, and the extremely fine mist I had did a superb job of cooling the radiator under either condition. And the amount of water I used was minuscule. My overheating problem was so serious that while driving thru the plains of Texas I would occasionally have to use the mister to maintain engine temperature. (or slow down) LOL
Richard

Yes, Ace,  I'm here, and sometimes wonder why.

I was very clear that misters can help cooling, in marginal situations.  The specificity of my points are continuously ignored by some of my critics.  They chose to morph those points into general statements.

My ego isn't involved in this,  I seek to prevent the uninitiated from getting the impression that misters are a "cure all" which they aren't.

Y'all appear to be  focusing solely on the temp of the water out of the radiator when you should be focusing on the mass.  It's the temp of the  mass that bears on the ability to cool the engine. If you understand the definition of BTU,  it relates to the amount of energy necessary to raise a certain MASS of water 1 degree.    Taken to a ridculous extreme, even coolant dropped to 33 deg by a refrigeration system won't help the engine if coolant flow is restricted by a small radiator or a radiator plugged from poor maintenance.  Unless the product of lower temp times mass of mister-cooled water leaving the radiator exceeds  the product of "normal temp (non-mister) coolant" times the regular mass delivered through the engine, (max performance demand condition) the engine will overheat.

You gotta do the math and the only way a driver can tell if the "math" is working out (albeit indirectly) is by the simultaneous use of a pryometer and coolant sensor.

If engines couldn't locally overheat, then why do test engineers use multiple (typically individual - per cylinder) sensors on engines when developing the engine design?

Other than that, if my critics continue to morph my points, I refer those critics to Gen Honore, cuz you guys (critics) are stuck (on this point?)

Quote from: boogiethecat on May 27, 2006, 02:19:35 PM
Hey I'm here and Marc is not from San Diego (I hope)
I'm just lurking and agreeing with almost every post on this board...
quite not the same for BNO though... I give up over there!! :)

Amen! I couldn't have said it better! :) ;D 8)

Case in point - Geoff Smith.

He experienced an overheat condition while pulling a heavy trailer up a grade and misters cooled the engine down.

This is my first comment on Geoff and it's a positive one.

He is knowledgable and experienced.  He's reasonably certain that his cooling system and engine is in good order.  He knows what to look for and what to do if it's found.  He knows to watch the exhaust for over-fueling and he's a smart driver that will keep the engine RPMs up to ensure the maximum flow of coolant (MASS!!!!)  

The use of misters by such a converter is appropriate.

Now ask him if he'll repeat the situation  after blocking off 1/4 his radiator?  ( I don't think so!)

There's a possibility that one cylinder of his 6V92 engine may have compromised coolant flow.  Let's say it does for the sake of discussion.

As he starts to climb that grade again, that one cylinder will  get hot quicker than the other 5.   For awhile, the extra hot coolant coming off the one cylinder will be absorbed in the coolant of the other 5, raising the temp, but without the temp showing an overheat.  

The one cylinder can be near critical by the time Geoff sees the need to turn on the mister. This will drop the overall temp of the coolant, but by this time the coolant/metal interface isn't micro bubbles anymore, it can develop into macro bubbles and even the mister'cooled coolant can't get to the metal interface sufficient to cool it down.

I daresay that even Geoff could get "fooled" by this one, but he's one of the unlikely ones.

What would some of the converters who've so nicely detailed their "first trip" bringing a bus home, (the learning curve and numerous uncertainties) do if confronted with such a situation?   More likely than not, they'd do some serious detriment to their busses.

My comments have been directed soley to those individuals.


On Another Point - flood vs. spray.

Those parameters in the absence of distinguishing the dynamics of the heat exchange mechanism between "flood" or "spray" (evaporation) or anything else conceals the situation.

If a pure "flood" you'd have water to water conduction of heat.  What you would prefer to do is supply just enough water in such a way that it evaporates off the radiator core.  Evaporating water absorbs (takes away) much, much, much more heat than unevaporated water flow.

The goal would be to put enough water on the core but  just short of shifting from evaporation down to conduction.  The water evaporating after it is blown off the coolant tubes would waste the "opportunity" presented by the MASS of the water the misters are delivering.  

Geoff's flood approach is much more reasonable in AZ, (and might not fully be a flood if you could get a microscope on his coolant tube)  because of the high temps and low humidity.  In the MidWest and East in the summertime the 98% humidity pushing the "evaporation" method closer to "flood."  Anybody remember the term "Partial Pressure of Water" from their high school or college inorganic chemistry?  

Evaporation is the best -- Remember from high school physics --

Every gram of water that is vaporized removes one Calorie of heat

If you are flooding the radiator the water has to "absorb" the heat.

As the water evaporates it "dissipates" the heat a subtle but very important difference

NOW -- on another thread I wondered which will cause an error at the temp guage

The sending unit or the temp guage itself??

Sorry to hijack the thread but what are the thoughts on that


Melbo

I'm reading a lot of theory here and very little practical experience under real condtions.  I give actual experience and get back theory.  The people I know that have working radiator water sprayers use a lot of water, they may call them misters, but they are actually sprayers.  I strated with a small system using a windsheild washer pump and it did nothing, somebody on one of the boards said they had to hook their system up to the house water supply with a regular RV pump so I followed their advice and it works.  If one of you theorists want to set up their "misting" system and can honestly say it is possible to mist the air going into the radiator that is strong enough to pull your shirt off and it cools the engine I'm all ears.  I've heard enough theory.

--Geoff

Quote from: Geoff on May 30, 2006, 04:58:51 AM
I'm reading a lot of theory here and very little practical experience under real condtions.  I give actual experience and get back theory.  The people I know that have working radiator water sprayers use a lot of water, they may call them misters, but they are actually sprayers.  I strated with a small system using a windsheild washer pump and it did nothing, somebody on one of the boards said they had to hook their system up to the house water supply with a regular RV pump so I followed their advice and it works.  If one of you theorists want to set up their "misting" system and can honestly say it is possible to mist the air going into the radiator that is strong enough to pull your shirt off and it cools the engine I'm all ears.  I've heard enough theory.

--Geoff

Geoff, read all my posts. I have been there done that (BTDT) for 15 years and was 100% successful with a mist that never really got the radiator wet. At least as far as I could tell. Even sitting still with the engine at 1800 rpm, the radiator never appeared soaked.
Richard

Geoff
Your system is called "liquid-heat-exchanger" principle...liquid exchange heat or cool liquid system. However watering down radiator will reduce air-flow due to blockage or flooding air passage.

Mist-er is fine spray to cooled air before entering radiator air-fins. In so doing it shrink heated ambient air to carry more BTU with it.

After-all...ambient air is free & very light weight as compare to watering system such as old "one-lung-er" engine...no radiator but a large cast-iron tank to hold water. Even than it need running water flowing in from river whenever working steady hard load.

It hard to beat the prices of God's given air to cool our engine.

Which is most practical....carry a lot of water on hand or use less water to get the same job done?

I did mine like Richard setup (no-valve) but only one garden spray nozzle attach behind its grille of each of MCI-8 radiator's inlet.....it work to reduce about 5° F cooler in 195° F range. However Richard is better due to extra spray nozzles. MCI would be 3 spray nozzles per side to achieve greater cooling reserve.

FWIW

Sojourn for Christ, Jerry

Okay, I did a Google search to see what the GPM difference was between misters and sprayers and from what I gather you can get quite a bit of water through a mister.  What I am having difficulty with is believing that you are actually going to maintain a mist directly in front of a air sucking radiator at operating speeds without the mist turning into water drops. I am happy with my spray system, but I am going to turn the sprayer adjustments down as I know I am showering more than enough water at my radiator.  I wish I could look at someone who has a true mister system-- I have absolutely the highest regard for Richard and what he has to say so if he says a mister system worked for him, I believe it.  I just want to see one in action, you may change my mind yet.

--Geoff

Quote from: Geoff on May 30, 2006, 05:45:18 PM
Okay, I did a Google search to see what the GPM difference was between misters and sprayers and from what I gather you can get quite a bit of water through a mister.  What I am having difficulty with is believing that you are actually going to maintain a mist directly in front of a air sucking radiator at operating speeds without the mist turning into water drops. I am happy with my spray system, but I am going to turn the sprayer adjustments down as I know I am showering more than enough water at my radiator.  I wish I could look at someone who has a true mister system-- I have absolutely the highest regard for Richard and what he has to say so if he says a mister system worked for him, I believe it.  I just want to see one in action, you may change my mind yet.

--Geoff

There is a company in Las Vegas that installs mister systems on busses. I do not remember the name and I have never met them but I do recall a couple of people posting on the BNO board about them, and they were very happy. Maybe someone remembers?

I do not know why you think the mist would change into drops of water. Believe me, it justs disappears before it hits the radiator and that is a very short distance. The radiator does not appear wet. If you have seen the misters at the produce department of a large grocery store, that is the type of mister you need.

Richard

OK guys, need your opinion on mister parts.

Background:  my air to air radiator is very marginal on long pulls.  I tried to rig up a mister for the big passes on the way home and the "irrigation" sprayer parts at Home Depot just seemed very cheesy.  Indeed, the plastic delivery tube melted from the hot air going through the air to air radiator.  In addition, Richard mentions the issue with the tubing coming off the heads (I had that problem as well). 

So, I am looking for something more practical.  Take a look at:

http://www.plumbingsupply.com/misterscooldown.html

and see what you guys think.  It sure looks like a great way to mount the misters.  The stiff PVC tubing would assure that the misters are pointed in the right direction and the tubing would be easy to mount to the radiator with tie wraps (mister pointing away from the radiator).

If you guys think this is a good approach, what size head would you use.  I think I will mount 4 units for a heat exchanger that is 20 X 30 inches.  Right now I am leaning towards the .5 GPM units.

I will be using my extra water pump and have wired a push button on the dash to operate the pump as needed (long hills).

Jim, I do like the idea of using rigid PVC pipe on the radiator(s). I think it's much, much better than the drip system pipe. My only concern would be the plastic head of the misters on your link. I'd worry that they might not handle the heat very well too close to the rad. and engine heat. I read their FAQ about why they don't sell brass misters anymore, but I wonder if a threaded brass mister would handle the heat better.

Maybe it'd do fine, I dunno. Anyone else with an opinion?

Thanks for the link and PVC idea,
Brian Brown
4108-216

Geoff, I think you'll have to consider your climate to determine how much mist/water to throw into the rad. Whether its water droplets or mist, you want to get only enough into the air to raise the humidity but keep it from actually splashing a lot of liquid water onto the rad. Not only are you wasting prodigous quantities of water, but the science that everyone keeps mentioning is working against you. But... with the super-hot, super dry air in AZ, you'll still need quite a bit of water compared to someplace milder and more humid. There's probably some formula to help convert temp./desired humidity/required air flow into GPH... but just gettin' it close(r) would be good.

Bear in mind, I believe that your solution works, I just suspect it'd do even better w/o throwing all of that liquid right onto the rad. I also get what you're saying about the massive turbulence possibly keeping the mist from ever forming in the first place. Maybe some trial and error is in order... during a time when you're not pressed to get somewhere and can pull over and cool down as needed.

Something else that just crossed my mind... I've battled is cooling of my V730 in my 4108. When pulling those grades unlocked in 1st or 2nd, there's a massive amount of heat generated by the tranny, especially towing something. If you have a tranny cooler that uses engine coolant to cool it, it could well be dumping heat from the tranny into the engine cooling system.

My bus was converted from a coolant-cooler to an air cooler before I purchased it, and the P.O. said that the engine temps were easier to maintain afterwards. I recently had the cooler fan fuse blow and it seriously affected its cooling (obviously). When fixing it, I also added some holes in the side of my bus to provide freer, cooler air the tranny cooler, and it helped immensely. Since yours came stock with the V730, I doubt if its as much of an issue... but since the the coach was originally a transit, it probably wasn't engineered to pull long highway grades in AZ hauling up big trailers either.

I'm not necessarily saying your cooling issues are definately your tranny, but it could be contributing to the heat. I sure know mine likes to heat up on the climbs.

Anyways, just some random thoughts. Please keep us posted,
Brian Brown
Longmont, CO
4108-216

Gads, I'm posting like a madman on this topic...

Jim, I did find some other nozzles that look interesting. http://www.mistcooling.com/nozlles.htm They're brass 1/8" MIP fittings, and the one with the 160 degree spray angle looks especially promising for a rad. spray application.

Just some more ideas,
Brian Brown
Longmont, CO

What ever mist nozzle you use, make sure the water is filtered before going to the nozzle. It does not take much to plug one (or several) of these.  Jack

Well, I swore to myself that I was not going to post anything else, but I really have trouble keeping my mouth shut.

When I designed my system, the Internet was not available, so I had little choice other than the local hardware store.
The misters were extremely cheap and I started off with the smallest water flow rating they had. I never had to go bigger, but I do not recall what that gph rating was.

In construction, I installed a T in the 1/4 line, then about 1 inch of line and then the mister nozzle which was a 90 degree design. That construction allowed me to turn the mister any way I wanted to try and get the best performance. I ended up with the misters turned outward and forward to try and get the mist blowing away from the coach. Once the engine got up to speed it sucked the mist back and did a good job of dispersing the mist over a larger area.  If you use the drip mist tubing, make sure you tie wrap all the joints to keep them from coming apart due to heat expansion of the tubing.
Richard

I am making a post to this thread so that it comes up on top again.  DrDave posted a source of mister nozzxles and I thought folks should also see this excellent thread.

Aaaaaaauuuggghhh!

After you attended the "All you never wanted to know about Cooling Systems and were afraid to Ask" seminar?

What didn't I communicate?


Onward and Upward

Marc Bourget

Marc,

Did you ever find the water pump you are looking for???

Dale

No, I haven't.   I need to do further research.  I understand that there's a different rotation/configuration of one pump used to reverse the "standard" direction of coolant flow - from "block to heads" to from "heads to block".  The brief explanation was flow reversal, which I understood could be obtained from a LH engine, more particularly a LH marine engine.

Now have to dig deeper!

Thanks for asking

Marc,

Thought I was on to something, but it turned out a dead. :-\  It has to a marine application, I just haven't found it yet.

I'll keep looking as I am very interested in this idea. I believe "heads to block" could be interesting.

Dale

It's more than "interesting"  it is the best cooling config developed for the DD 2 strokes.  Used in Military applications.  I'll be working up the mods for my 8V92. 

The mods will go a long way towards remedying MCI's failure to design their cooling system to DD specs (if not eliminate it)

When I was having radiator cooling problems I set out to build a mister system which I did.  I found some brass misters at Home Depot that are used for porch mist systems.  I used 3/8 copper tubing to plumb them together...did this because I had to route the water from the rear half bath thru the engine compartment(Hot).  I have 5 misters.  Used a manual ball valve which one of the kids can turn on from the rear restroom.  Have not used it since I got a new radiator.  When I did use it, I did notice that some water that we took on left lots of deposits, most of which I could spray off before I left to get back on the road the next day.  On a typical day of driving I would use about 20-25 gallons of water.
Happy Trails,
Brent