Radiator in tank sizing question

[awelker]

I am looking into converting my Flathead Ford V8 powered bellytank to a radiator in a tank cooling system. Currently I have two 6" x 16" radiators with small electric fans (about 600cfm each) which proved to only barely keep it cool for 3 miles. Also the current setup has 2 Aerospace Components electric water pumps that each feed one radiator and one bank of the engine.

Space is limited and I have come up with enough room for a tank that would hold about 11 gallons and have a radiator with a 7" X 13" core dimension sitting horizontally in the bottom of the tank. I can calculate the amount of Btu's the 11 gallons would absorb from and ice mix to a partial boil off which I think will be sufficient, but would that size radiator in the tank be large enough to dump the heat from the engine water to the cooling tank water quick enough? Also, I would be switching to one inline electric water pump from Stewart and adding thermostats to the outlet side of the cylinder heads.

Looking for what some others have done and how it has worked out for them, any real world experience is appreciated.  To do this I need to relocate alot of stuff and I want to be sure it is a move in the right direction.

Andy

[SPARKY]

Andy, I forgot to turn the pump on one time with 900 HP for 2+ miles at B'vill --my exit eng temps were 220 with 9 gallons of water and no ice with a closed radiator system with a 28# cap.  yes the water in the box was boiling violenty as the boil temp at B'vill that day was 194  we now turn the pump on when we close the canopy.

[38flattie]

Andy, I run a system real close to what you describe, right down to the Stewart water pump and a thermostat-I run both heads into one thermostat, then return to the tank.

It sure works great on the Caddy flathead, so I'm sure it will work great on yours!

[Sumner]

Is the 11 gallons the total water you are using or is that what is in the tank surrounding the radiator and you are going to pump into that tank from another source?

I made...



...a radiator in a box for Hooley's Stude and we were very happy with how it worked but we are pumping water continuous through the box from a 30 gallon tank in the car.  With the electric pump we are using for that we are only exchanging the water from the larger tank about 1 time during the run.  Of course our combination is making much more heat from the motor than yours so the radiator and cooling water to the tank could probably be quite a bit less.

If you are only using the 11 gallons in the tank with the radiator sitting at the bottom and no circulation that might worry me.  Although in theory you might not need other water and circulation as the hot water would keep rising to the top.  I still think I'd want some circulation that is moving water through the core of the radiator in the box.  Have you seen others with no circulation?  Sparky has it but Buddy do you?

We are using a 2 pass radiator and passing the cooling water through it twice also.  A belt driven pump on the engine for the coolant water from the engine to the radiator.

The radiator in water vs. air is very efficient.



Here is a link to the rad-in-a-box I made.....

http://purplesagetradingpost.com/sumner/Hooley%202013/13%20-%20construction%20menu.html

.... you will find it down the page a ways,

Sum

[38flattie]

Sum, I don't have circulation in the box, but I do add ice.

I'm using a Ron Davis, 23x4x3.5 thick radiator.

[Sumner]

Sum, I don't have circulation in the box, but I do add ice.

I'm using a Ron Davis, 23x4x3.5 thick radiator.

Do you have a picture of the finished box that has the radiator in it?  Thanks,

Sum

[awelker]

Well, I'm definitely not making 900 hp, I'd need 3 more engines to come close...  But the flathead does put alot of heat into the water.

The 11 gallons would be all I would have, no circulation in the box, no other room for additional water storage.  Already need to relocate fire bottles and build a fuel tank, no more room left.

Buddy, how much water do you have in your box?  If you start with ice how warm does your box water get after a run, any boiling?

Sumner, I considered boxing in my existing radiators and circulating though them from another tank, but if I keep those radiators I can't relocate my fire bottles and would only be able to carry about 5 gallons of water for circulation over the radiators.  I like your setup, just wish I had some more room.

Radiator in water is very efficient, considered doing a chassis dyno test with existing radiators dipped in some open water tubs.

[38flattie]

Sum, I don't have circulation in the box, but I do add ice.

I'm using a Ron Davis, 23x4x3.5 thick radiator.

Do you have a picture of the finished box that has the radiator in it?  Thanks,

Sum

Here you go Sum! If you notice, I run 2 radiator caps. The top cap is the return, and bottom the feed. The dual caps make 'burping' the engine very easy.

The electric pump to the left of the box feeds the mechanical H2O pump on the back of my dry sump.

Well, I'm definitely not making 900 hp, I'd need 3 more engines to come close...  But the flathead does put alot of heat into the water.

The 11 gallons would be all I would have, no circulation in the box, no other room for additional water storage.  Already need to relocate fire bottles and build a fuel tank, no more room left.

Buddy, how much water do you have in your box?  If you start with ice how warm does your box water get after a run, any boiling?

Sumner, I considered boxing in my existing radiators and circulating though them from another tank, but if I keep those radiators I can't relocate my fire bottles and would only be able to carry about 5 gallons of water for circulation over the radiators.  I like your setup, just wish I had some more room.

Radiator in water is very efficient, considered doing a chassis dyno test with existing radiators dipped in some open water tubs.

I have a 20 gallon tank, but could go smaller, if I didn't need it for ballest. The ice melts, but the water in the box stays cool to the touch-I'd guess 70-80 degrees. I'm also probably putting out about 700 HP at the moment, so I'm very hasppy with the setup!

[saltwheels262]

these radiators in boxes, dual caps, external
water tanks and whatnot ~~ very genius .

bf

[kiwi belly tank]

Flathead Henry engines need a bunch of cooling just because the exhaust ports wrap around the cylinders. Don't skimp when you build a system for it. Too much cooling isn't a problem.
  Sid.

[Sumner]

.... considered doing a chassis dyno test with existing radiators dipped in some open water tubs....

If you can do that it would tell you a lot.

Buddy thanks for the pictures.  Also there are pictures of Sparky's old rad-in-a-box here...

http://purplesagetradingpost.com/sumner/Hooley%202013/13%20-%20hooley-construction-2013-13.html

Ours was made to go in a specific location, in the fender well next to the engine.  Helps to get ballast forward on the car.  The 28 gallon intercooler ice water tank is in the fender well on the other side and also helps to get ballast forward on the car.  With a carefully made tank you can get quite a bit of water storage in an area that is fairly unusable for something else.

Sum

[Tman]

Andy, did you make Speedweek this year? I was looking for you guys in my brief trip. This is a great thread, I am doing the rad in a tank as well. I copied Skips setup in his roadster in the build diaries.


http://www.landracing.com/forum/index.php/topic,6794.0.html

[Rex Schimmer]

Andy,
The "radiator in a box" style cooling system really has only one advantage over having a closed coolant system with a pressurized container, you don't have to build a container for the cooling water that has to operate at your engines cooling system pressure, that pressure is taken by the radiator that is in the box. The "box" system, if done correctly, does add additional complexity and size to the cooling system as you will need an additional water pump to circulate the water in the box through the radiator along with having a water pump to circulate the actual cooling water through the engine/radiator system. As you can see from the pictures of Buddy's system and the system that Sum built for Hooley's Studi they are not small. When Hooley was running a supercharged small block Chevy they ran a pressurized closed system using a 15 or 20 gallon air bottle that carried the cooling water and that was on an engine that made at least 800-900 horse power. I would think that for you going with a closed system would be the best approach. I feel that one of the biggest mistakes made in cooling systems is improper selection of the engine water pump capacity. The rule of thumb that works is: 10 gallons per minute per 100 horse power (thanks to Stu Van Dyne, Van Dyne Engineering for this information) . In your case your flatty may make around 200 horse power so 20 gpm is what you would need BUT this does not mean you can go to the Summit or Jegs catalog and just buy one of their 20 gpm electric pumps because the 20 gpm has to be at the pressure drop that is required to make 20 gpm actually flow through your engine and these pumps are rated at 20 gpm at zero pressure on the outlet. If you look at Buddy's system he has a pretty stout mechanically driven water pump that probably is capable of pumping 70-80 gpm of water through his engine at the pressure required to over come the pressure drop of going through both the engine and the "radiator in a box" system. So knowing the actual output flow of your water pump at your systems back pressure based upon the flow rate is very important and most of the electric pumps you can buy will not provide you with this information. If you go with an electric pump and the manufacture cannot or will not provide you with the flow vs. out put pressure capabilities of their pump than I would start by buying a pump that is at least 2-3 times your required flow rate and remember that the 10 gpm/100 hp rule is a minimum so if you have more flow than that the system will only work better. Water flow through your engine and the radiator needs to be turbulent to be efficient.

The other recommendation that I would have is to use a BMW 320 I three way thermostat. These are really cheap, about $20, and what they allow you to do is to have full pump volume water flow through the engine while the engine is warming up as opposed to "normal" thermostats that "lock" the water in the engine until their set temperature is reached and then open which can cause temperature fluctuations. Also adding some ice to the water will provide additional cooling capacity as ice requires additional energy to do the phase conversion from ice to water.

Rex

[manta22]

Andy;

Most of the unlimited air racers at Reno use a "total loss" cooling system with a heat exchanger. The engine coolant is circulated through a tank filled with water and some methanol at atmospheric pressure. The pressurized engine coolant is hot enough to boil off the tank's contents, which are allowed to vent overboard. No radiator drag!

Regards, Neil  Tucson, AZ

[awelker]

Andy, did you make Speedweek this year? I was looking for you guys in my brief trip. This is a great thread, I am doing the rad in a tank as well. I copied Skips setup in his roadster in the build diaries.


http://www.landracing.com/forum/index.php/topic,6794.0.html

Did not make it to Speedweek this year, was a little burned out after last year, mentally, physically, and financially.  Plus finishing our house remodel had been on hold for a few years making this happen.  But slowly trying to work out my upgrade list that I have been pondering for a year.

Rex, thanks for the input.  Currently I have two electric water pumps which are rated at 37 gal/min each, I don't have any pressure/flow info but in the realm of your suggestion.  The one thing I still like about the radiator in a box scenario is the boil off "safety net" heat dissipation that you won't get from a simple closed system.  The closed system may handle my current horsepower output but I am trying to accommodate future engine changes.

I'm working on layouts of a few possibilities given all the ideas suggested.  Not necessarily the conventional "radiator in a box" but some differently packaged water to water heat exchangers.

More to come, thanks for all the suggestions.

Andy