Thermostat with water tank?

[Jonny Hotnuts]

I have heard that the purpose of the thermostat is to increase pressure in the system and by increasing pressure the boiling point goes down 2 degrees per pound. By removing the thermostat the coolant will boil in the head causing hot spots and detonation.

I have also heard that the thermostats sole purpose is to maintain engine temperature. This allows the motor to come to temperature before coolant flows letting the motor get to the proper operating temperature sooner but also are coolant system restrictive and your motor cool more efficiently with out the thermostat especially if you are running a high flow/ low psi water pump.



So it is necessary to run a thermostat on the salt with a water tank?

-JH

[Count]

In our race cars at the superspeedways, the nose is all taped up, which would basically turn a radiator into a water tank.  I'm pretty certain we're not running any thermostats at all.  That being said, with my understanding of a thermostat, its to basically bring an engine up to temp. before cycling the water.  I would think the more water you can cycle in a closed tank the better.  I could be wrong about this and if I am let me know because this is something I'm interested in also.  Also, doesnt the radiator cap increase pressure in the radiator?  I'm assuming that however you seal your tank, pressure will increase in the tank due to the increase in heat.

[Stainless1]

JNuts,
Thermostats are for raising the motor to temp quickly, so your heater works before you travel too far and to eliminate condensation.  Some have them at Bonneville, some do not. That is a little like what oil works best, I suspect you will hear several sides to this question, here is ours  

We have always used a water tank, sometimes with a radiator, never with a thermostat.  We start every run with the water, oil and block 110 to 115 degrees F.  Tank holds about 5 gallons, when we warm the motor, about 8-10 cars back, we run until the oil or water hits 115.  There are several things designed into your motor that benefit from cooler oil.  Water temp after a run in the 200 ish range, we use a 10 lb cap.  
Yes the water has been hotter than 220 a time or two, when doing laps, but we change water for cooler, then cycle it a little to leach heat from the motor on those.  We use Top 1 Synthetic Oil.  



If you want your motor to run at 200 degrees for miles 1-5, run a thermostat, and carry enough water or a radiator capable of keeping it there.

[Harold Bettes]

Howdy All,

Because that the water temp is an indication of conditions on the backside of the combustion chamber (on the water coolant side) I would suggest to you that it might be worthwhile to try and target something about 160-170F for water temp. 

Relative temperature of the system water supply can be regulated by either flow control or temperature control which can be flow control when you use a thermostat for regulation. The total amount of water on board can be calculated once you decide what temperature you wish to control to (assuming you can closely guesstimate the engine power, use about 33% of that as an initial heat load).

On the other hand, oil temp should be perhaps targeted to be 190-200F in the pan or sump.

Regards to All,
HB2

[ddahlgren]

I don't think you would want to pressurize the tank unless a qualified welder for boilers..LOL and it would get big and heavy quick. And you sure do want to pressurize the cooling system to keep the air bubbles out. This has been discussed several times and the slick way to accomplish both things is to put a radiator in the water tank and run a thermostat at the engine and a pressure cap as well 26 lbs being a typical rating for a racing engine. This will keep the cooling capacity of the tank optimum and at the 5 mile mark the engine will be happy you thought of this and not used it up warming up the engine. Don't forget the expansion tank either along with a coolant recovery tak to go with it.. Another slick trick is to put a coil of steel tubing inside the dry sump tank if you have one and hook it up as though it was a heater core.. An instant oil heater and oil cooler depending on which one is the hotter/cooler of the two. If you are thinking electric water pump to gain 3 hp you might want to rethink that again as well. Those are the 8 second solutions and if you can get to the 5 in 8 seconds I have just become a big fan of yours..LOL Acftually if you get through the 5 in 8 seconds you have just become the fastest piston driven car in the world if you do it twice...
Dave

[Stainless1]

JNuts, forgot to add we use a water wetter type product to help water flow to the surfaces.... and the original engine water pump, it is a fairly efficient one.

[Jonny Hotnuts]

If you are thinking electric water pump to gain 3 hp you might want to rethink that again as well. Those are the 8 second solutions and if you can get to the 5 in 8 seconds I have just become a big fan of yours..LOL Acftually if you get through the 5 in 8 seconds you have just become the fastest piston driven car in the world if you do it twice...
Dave

We can not use the stock water pump because of chain routing. Last year we ran a stock busa radiator with 2 fans (only source of airflow) and a Meziere electric pump and it never got hot. This years motor is almost twice the hp of last years 1300cc motor, hopefully the increase of HP does not give us cooling problems.

Our class dictates that we must run a radiator, and will use on in conjunction with a 5-6 gallon tank.

I don't think you would want to pressurize the tank unless a qualified welder for boilers..LOL and it would get big and heavy quick. And you sure do want to pressurize the cooling system to keep the air bubbles out. This has been discussed several times and the slick way to accomplish both things is to put a radiator in the water tank and run a thermostat at the engine and a pressure cap as well 26 lbs being a typical rating for a racing engine

In truth “Turbo Rick” was the one who told me that he has a pre-pressurized system in the NT2. I may be mistaken by this but for some reason either he said (or I ascertained) that he uses pressurized coolant to pressurize the system and not air, keeping the system void of bubbles. I do remember he said the system was pressurized to 15 psi (30 degree higher water temp before boiling?) and was able to hold the pressure in the system until someone took off the cap a year later. I cant remember why (maybe he is using an electric pump as well) but for whatever reason he felt it was needed to have the system artificially pressurized.

After talking with Rick I contacted tech support @ Miziere about the fact that their pumps, while flowed like a garden hose, did not build the head pressure that a stock pump did. They explained that when water would heat up it would create its own pressure and this pressure would be dictated by the PSI of the cap and the overall temp of the coolant and a pre pressurized system would not be necessary. I don’t really know who really is correct (or more correct) regarding this.


I have decided to run without the thermostat. I will have plenty of water for the 1507cc motor AND a radiator with 2 fans (fans are thermostatically controlled).

At least our short course runs will be a good indicator on how well our cooling system will handle 2 more miles!

-JH

[4sfed]

After talking with Rick I contacted tech support @ Miziere about the fact that their pumps, while flowed like a garden hose, did not build the head pressure that a stock pump did. They explained that when water would heat up it would create its own pressure and this pressure would be dictated by the PSI of the cap and the overall temp of the coolant and a pre pressurized system would not be necessary. I don’t really know who really is correct (or more correct) regarding this.


I have decided to run without the thermostat. I will have plenty of water for the 1507cc motor AND a radiator with 2 fans (fans are thermostatically controlled).

-JH

If necessary to eliminate localized boiling, an engine-driven water pump combined with a flow restrictor in the coolant outlet can increase the pressure in the engine beyond the rating of the pressure cap.  The Indy Lights engines (stock block Buick) required 70 psi (not a misprint) coolant pressure in the heads, but the radiators were not capable of handling that much pressure . . . so a restrictor was installed in the engine outlet and a pump chosen that would supply the necessary flow and pressure.

-Jim