Water spray cooling

[Karaya]

Hi All,

I actually started this thread in the the 911 / 930 Turbo & Super Charging Forum because that's where the search engine took me when I looked for "water injection" and I was prompted by some of the guys there to put it here and seek further opinions. If you guys live in a nice cold climate...you can stop here.

Here in the tropics we race in really blistering heat conditions where the ambient temps can reach 40+ degress C at noon in summer. I used the basic aquamist system (still have it in a box and waiting to find another home for it) and I could run flat out for the 12 lap sprint race. But if the race was longer then I'd have to back off and short shift to let the temps come back down like when I did my last 4 hour enduro. I am all for WMI!

I then installed a home made sprayer using spray nozzles bought from a garden supply store and used a windshield spray pump, a big one from the headlight sprayer of an old Montero salvaged from a junk yard hooked up to an old speed controller set on hi, and sprayed water onto the intercooler and radiator. That improved the engine cooling a lot. I noticed it stopped the heat soak and pegged the temp needle to a very acceptable level and found out that I could run flat out until I run out of water and using a 3 gallon tank of water... was about a bit more than an hour of revving to the redline racing on a hot summer day.

On my 911 which is air cooled (non-turbo) I was wondering what if...I installed a misting/sprayer system to the oil coolers and also to the engine shroud after the fan? The one for the engine would have to be a really fine atomized spray. Tap a nozzle or 2, one for each side, somewhere after the engine driven fan. You would command the spray/mist via a switch when you see your temps rising. Anybody done this yet? Would doing so shock cool the cylinders? As usual your thoughts and suggestions would be appreciated.

Note that I am not going to be racing my 911 seriously as I have another car for that. I'll track it some but just for fun. Mostly it'll be a daily driver/tourer. My brother has a nice 88 911 and always complains about driving in hot 3rd world traffic...engine gets hot...AC (a must have here) starts to struggle...and I therefore am looking for ways to help keep the car cool. I already have the fender mounted aux cooler and fan for the engine compartment.

Karaya

[Grady Clay]

Karaya,

Here is the thread with all the numbers.

Water vapor cooled 911 - the Rubbermaid Solution

Best,
Grady

[Karaya]

Wow! Thanks Grady!

Now I know it's been done and it's safe and with plenty of benefit.

Still use your system or have you modified/improved it any?

Karaya

[Wil Ferch]

Grady has a lot of experience in such systems.....but in my line of work that also touches on industrial, plant level cooling systems, this is like spraying water on a finned, dry-bulb style heat exchanger to make use of evaporative cooling effects. Sure....effective, but I would think also prone to condensing all manner of stuff on on the outside finned surfaces and causing crud to collect or clog the fins over time. Comments?

[Grady Clay]

Wil,

No, everything stays clean and rust-free. The water evaporates off the hot engine when you park.

We first started using it on the engine dyno in 1975 with a then-new 930 Turbo.

After 35 years using it, I have never seen any issue with this.

The few more picky that I use distilled water – not necessary IMHO unless you have mineral deposits from very ‘hard’ water.

Best,
Grady

[Karaya]

Wil,

I will have to agree with you. I have not sprayed/misted water onto a 911 yet but I intend to do so. I have been spraying onto radiators and intercoolers for years. In my humid, hot, and dusty enivironment, I do have to wash those parts out occasionally...about twice or thrice a year but the benefits outweigh the hassle.

Karaya

[ClickClickBoom]

Hey,
I have a buddy who is a crew chief for an unlimited Reno air race team. He decided that the cooling drag on the Hawker Sea Fury was slowing them down. He decided to use the latent heat ofi vaporization to their advantage. He faired all the oil cooler openings down to minimal openings and created misters around the oil coolers. He said they carried about 50 gallons of water to cool the radiators. He also said the decreasing weight allowed performance to increase as the water was consumed. I noticed a barely discernible contrail behind the plane in flight at the races. His planes finished 1-2 that year.
Every plane he crew chiefs on is a front runner.
Eric

[Wil Ferch]

I'm telllin' ya....I respect Grady....but any evaporative water cooling on an external finned heat exchanger can collect dust, cottonwood....anything...simply call it "fouling" . It was a big problem with any ACHX ( air-cooled-heat exchanger....aka "fin/fan") industrial cooler we installed anywhere in the country. I don't know how an air-cooled Porsche engine can avoid "ingesting" whatever air-fouling we have in the air. I mean....air filters for our engines get dirty....right?

In this case, I need to give the nod to Karaya's observations that it does happen, and when this "stuff" dries out on the cylinder finned surfaces, there has to be at least a microscopic layer of condensed material that wasn't there before. In time it will coat and cause loss of heat-transfer capability.

[Grady Clay]

I agree that it is necessary to keep cooling fins clean and free from obstructions that might limit
air flow or material that can inhibit heat transfer to the air.


Our cars actually are designed to drive in the rain.
Some even race in the rain.




One morning at breakfast, Valentin Schaffer, Bruce Anderson, another (Helmut Flegl?)
and I discussed the ‘Rubbermaid Solution’ via ‘paper napkin engineering’.
Schaffer went away with the napkin.
Some time later he packed the 917/30’s intercoolers with crushed ice.
The ‘meltwater’ was directed into the engine fan.

Two phase changes later …
… Mark Donahue set the “Closed Course” speed record at 221.120 mph.

I can’t say for sure that I contributed to this but ….

Best,
Grady

[Wil Ferch]

Grady...maybe you did, don't sell yourself short. You know..."the forest before the trees" syndrome.

And also true....sure cars race in the rain, and just like my ACHX example, we did this because there was an "immediate" benefit of doing so...just like race cars get an immediate benefit in doing so. I'm saying that continued wetting/drying will cause a long term film layer to form , that ( when forced to run as "air-cooled-only" later)...will make that form of air-cooling less efficient than it was before, when the surfaces were cleaner.

No argument....ya gotta pick your poison. At high altitudes where the air is thin...or in racing when every ounce of extra hp or reliability is important, I'm sure an external water spray has definate advantages.

[rnln]

At first I thought I got a good size proj for near future, but the more I read, the more I got confused. Now, I am completely blank :lol:
So, regarding oil temp, will Grady mist (spraying right at the fan pulley) will reduce oil temp?

[T77911S]

my big idea was to use the AC system to cool the air for a turbo. instead air cooling air as with an intercooler, air is pulled through an evaporator and into the engine. the HP gains would have to overcome the loss of running a compressor, but think how cold the air could be. of course the evap would be mounted where the intercooler was. it could also be smaller. i dont know how much the evap would restrict air flow either.

i also thought about water sprayed on brake rotors for cooling.

[Wil Ferch]

Bottom line.....spraying water in a finned air cooled cylinder....or even on brakes, works during the time that is performed. There is a great amount of evaporative cooling affect not possible with air alone, and it is very effective. The question is longer term particle deposition and "fouling" of these same surfaces.

[lindy 911]

Use distilled water?

Lindy

[T77911S]

i was thinking hot rotors cold water= warping.

[Wil Ferch]

Water has been used by many racing cars.....warping is avoided or minimized... if you use proper amount ( not too much) and proper spray pattern ( nozzle diffusers). Also....try to hit both sides of the rotor....not only one side.

World Champion Rally cars even have water-jacketed ( cooled) calipers with their own water pumps and radiators !!

Fouling is not all calcium hard water fouling that can be avoided by using demineralized water...some fouling will still exist because of what's in the "air"...see my engine intake air filter comment above.

[911pcars]

Latent heat of vaporization depends on the phase-change from a liquid to a vapor to absorb heat. It's not water spray cooling. For this to work effectively and not waste water (8 lbs/gal.), droplet size should be small enough to evaporate and absorb heat before arriving at the oil/trans. cooler, brake rotor, engine compartment, etc.

For brakes, it's recommended to use air ducting to direct air to the desired location, then place misting nozzles in/near the air intake. In most applications, provide sufficient space to allow full evaporation over the widest area. Here's a front brake duct on the Paul Gentilozzi TransAm Championship Jag from a few years ago.



and our pump assembly:


Sherwood
Seine Systems

[Steve@Rennsport]

Originally Posted by 911pcars

Latent heat of vaporization depends on the phase-change from a liquid to a vapor to absorb heat. It's not water spray cooling. For this to work effectively and not waste water (8 lbs/gal.), droplet size should be small enough to evaporate and absorb heat before arriving at the oil/trans. cooler, brake rotor, engine compartment, etc.

Sherwood
Seine Systems

Precisely! Thats why Grady's "Rubbermaid Solution" won't cause any corrosion/dirt/contamination issues beyond anything normal provided its done properly.

[Wil Ferch]

Steve....however no one brought up corrosion as a problem.... ?????

[Steve@Rennsport]

Originally Posted by Wil Ferch

Steve....however no one brought up corrosion as a problem.... ?????

See above,....