Radiator Mist Cooling System

[Hobe]

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

[Geoff]

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

[Greg Roberts]

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.

[Geoff]

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.

[DrivingMissLazy]

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

[Dallas]

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

[El-Sonador]

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

[Buffalo SpaceShip]

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

[Geoff]

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.

[DrivingMissLazy]

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

[Ace]

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... LURKING[/glow]

[boogiethecat]

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!!

[ChuckMC8]

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

[DrivingMissLazy]

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

[Burgermeister]

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?)