Chargecooler Design & Comparisons


The reason why our tubular cooler is so efficient is it follows the basic simple physics that all air/water heat exchangers should follow. All chargecoolers should be of a 'countercurrent' design, which means that cold water from the pre-rad should be fed into the 'cold (outlet)' end of the chargecooler and the hot water that has absorbed all the charge heat comes out of the 'turbo (inlet) end of the unit. The reason for this is that the coldest water is keeping the coolest end of the CC cool, and the slightly warmed water at the hot end will not actually increase the temps at the 'hot end'. If the water flow is changed to a 'concurrent' design, so the cold water cools the hot end, then like wise, the water temps will heat up, and thus the 'cold' end of the charge cooler can not be any colder than the temperature of the ' heated ' water. Confused? For more information view the Wikipedia on heat exchanging.

Right, so now the basic physics are sorted, now you have to look at the physical design of the cooler. If you look at the top right pic of the internal core, you will see it looks very different to a traditional intercooler core. The core is a ONE PIECE aluminium extrusion, which means no welds, braized bars or ends, and thus is burst proof as there is no weak point to break on boost, or leak water into the core. Our CC cores have been tested to over 60psi in drag race use with zero failures.

You will also notice the core is 'segmented'. This is too allow the coolant to flow around the outside circumference of the core, down the middle of the fins and across the fins, so basically coolant can flow in all directions. This also means that air locks are less likely as they can not get stuck in a particular channel - Air lock problems are also relieved by having the coolant inlet and outlets at the very top of the core..

Flow wise, our cores are very efficient. The internal channels are very unrestrictive, and they have internal 'fingered' fins which add to the cooling capacity. The cores have a variety of inlet and outlet neck diameters from 2.5" right up to 4" for up to 2000bhp applications, but please note that the internal area of all the channels inside the core is always larger than the inlet/outlet diameters, to provide next to no pressure drops - Pressure drops figures are hard to take any proper data from as some cheap intercoolers have have very low figures simply down to the fact that they have very large internal channel areas but hence don't cool as well (a 3" diameter tube has zero pressure drop - doesn't make a very good intercooler though), but our cores are recording only 1-1.5 psi pressure drop at over 20psi of boost and over 400cfm of flow, whilst still maintaining excellent cooling ability, and superb recovery speed.

Circa 10-25 degrees above ambient in all conditions, with instant recovery time even under extended WOT periods when combined with our specific AVT/Bosch pump and rad/fan/tank...and of course, the quality of your installation.

Other designs of 'chargecoolers' on the market...

You will find that 99% of all other ‘chargecoolers’ on the market are just traditional ‘intercooler’ cores surrounded by a ‘water jacket’. The problem with this (as you can see in the pic on the right) is that they are made in ‘reverse’. If you look, the charge from your turbo is being blown through what is used in a normal intercooler to grab to cool ambient air, and the water is channels through the tiny bars which normally take the boosted charge.

The main problem with this is inefficiency. The bars on intercoolers are designed to be efficient for the boost, but all the tiny fins are not as they do not need to be (as its just moving air from outside the car going through it) So the main problem is, you are now trying to push say, 20psi of boost through tiny fins which are not designed for air flow as hence you get a very large pressure drop across the core.
The other problem is as the water flows through the small bars, there is hardly any coolant volume flowing so it heats up very quickly. On top of that, many of these CC designs use multiple cores stacked and welded together - As they are not aligned perfectly, the air flow is hindered more by turbulence and more pressure drops occur. On a bar of boost, figures of up to 7psi have been lost through restriction at high engine CFM levels.

Another main flaw, is as these are just intercooler cores, there is numerous points of attachment, such has braised bar ends, fins and welding. These are all weak points which can cause serious engine damage if they fail under boost, hence why many of these designs are only warranted to around 1 bar of boost maximum by their respective manufacturers. Even ignoring the obvious catastrophic issues of a total core failure, these internal cores in their original design can have pin hole leaks which are not a real issue in a traditional air to air intercooler setup. But once you surround them in a water jacket, then you have the issue of boost causing air locks in your water system. Air lock = no water flow = no chargecooling.

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These two pictures are of another popular design of CC unit, but is still basically an intercooler core with a water jacket surrounding it, still with the flaws of the boosted charge being blown through the restrictive fins. These cores have a very short distance from inlet to outlet, some only 2-3 inches, so the air passing though the core does not have a long time to cool. They misleadingly quote some very low pressure drop figures recorded for these units, but that is due to there is hardly any length of core being used. Often you see this type of design being used with very large coolant tanks (rear mounted) in order to gain efficiency, by flooding the cores with large amounts of water - but this is not required if the core was designed properly in the first place.

But THE main flaw is the water flow direction inside the core. If you look, the water inlet outlets are not on either end of the core (following the direction of the charge), but they are on the SIDE of the core.......? The flow is neither countercurrent or concurrent...

So, the boost is not being cooled as it goes ‘through’ the core, in fact, only one ‘side’ of the core has cool water on it, and the other side of the core has the warm water outlet! A completely illogical design of heat transfer, and hence the need for massive coolant tanks and very high output pumps in order to ‘flood’ the core in a hope to improve its cooling ability.

Another problem with side mounting the inlet/outlets is air lock problems. If the core is not perfectly level, then air bubbles can rise back to the end of the core with the lower fitting, and get trapped in the top corners. Adding to the fact that being an intercooler core inside, and that the water cannot flow between the channels, then air can be trapped inside a certain channel and difficult to eliminate.
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