Re: What fluids to use in A2W
"Although complex, the water based IC enjoys the one terrific advantage of the far greater (fourteenfold) heat transfer coefficient between water and aluminum than between air and aluminum... The focus of the problems on handeling the water is largely centered around rate of water flow, amount of water in the system, and the subsequent removal of heat from the water.
Water pumps. Easily the most usable pumps are 12-volt marine bilge pumps. These can be ganged in series or parallel, depending on pressure and flow capacity of the pumps. the fundamental should not be overlooked that the more water circulated, the greater the IC efficency. consider a water flow rate of 10 gallons per minute a reasonable minimum...
Coolant Water is by far the best cooling medium, Glycol and other anitfreeze materials degrade the ability of water to transport heat and should be used only in quantities required to prevent freezing and corrosion. Essentially, put the same ratio of water and antifreeze into the IC that is used in the enigne cooling system.
Reservoirs. The size of the reservoir is of prime importance to the efficiency of the water-based IC. Consider that most applications of boost will only last a few seconds -say, 15 as a high average. Then it is reasonable to be sure in this interval that any given piece of water will not see the IC unit twice. A pump capability of 10 gallons per minute will move 2.5 gallons in 15 seconds; thus, the ideal size of the resercoir here is 2.5 gallons. Unreasonably large, obviously, but the pint is made that the bigger the reservoir, the greater the time until the water takes it's second lap through the IC. It is ot too difficult to see that as a larger reservoir is used, the need for a front cooler devreases. Consider that the greater the mass of water, the greater the Thermal Inertia.
Front cooler. The front cooler is the least important part of the IC system, as it is doing most of it's work when the vehicle is not operating under boost. At the start of aboost run, the entier system will be at apprtximately ambient temperature. As boost rises, heating the water in the main core, this heated water must get to the front core before it has any temperature difference with to drive the heat out. This timje dealy can be as long as 7 or 8 seconds, depending on the size of the reservoir. That amount of time is typical of a boost application. It is clear, then, that the front cooler will do most of its work after the boost run. Since the temperature difference between the water and the front core is small compared to the temperature difference between the boost charge and the water, the time required to cool the water down is much greater than the timre required to heat it up. This is another reason for running the twaer pumps all the time. The front core dows not need to be as big as it may seem at first glance, because the relative CFM rates through the two cores will usually be havily biased towards the front cooler. For example, a forward velocity of just 60 MPH could potentially put 5280 CF through a cooler of 1 square foot area. Surely it is another case of bigger is better, but not really enough better to get carried away with huge front coolers"
--Taken from "Maximum Boost, Designing, testing and installing turbo charger systems" By Corkey Bell
Now this basic idea I've read in several books, and find it most amusing that our trucks completely lack a resiervour, and have a wimpy 2-3 GMP pump which adds up to a piss poor IC system. I've added a 4 gallon resivour in the bed and a 12.5 gpm bilge pump to my system, wrapped the IC in heat blankiet, and using the stock CCHE with a scoop, and 3/4" lines through out the whole system my IAT's stay a ROCK STEADY 20-25 degrees above ambiant through out the entire run... take it for what it's worth.
