Technical
10 BASIC RULES OF CHARGECOOLING
1. Bigger is always better, regarding the core size, and the pre radiator size. As our cores are circular, even stepping up from a 4" diameter core to a 5" diameter core is roughly a 60% increase in core area, and internal water volume.
2. System design - Header tanks must be as high as possible, with the water level higher than the top of your chargecooler, and chargecooler cores should be as low as possible and below throttle body height. This helps with bleeding as any trapped air will rise to the top of the system, and the core being low will be less susceptible to air locks, and in the rare occurrence of a core failure, no water will get into your engine, but instead flow out of your intake.
3. Keep coolant pipe work as long and large diameter as possible, this adds more water volume to the system, aiding in cooling and prevents heat soak. 25mm diameter pipe work for instance has almost double the volume of 19mm.
4. Pre-radiators should be as large as possible, and a high quality aluminium design. We are trying to get medium water temps lower - try not to use automotive metal radiators, for instance motorbike radiators will not yeild great results... - they are fine in their intended role of maintaining say, 120c down to 80c, but insufficient in getting 40c down to 20c as a thin core aluminium design would.
5. Worried about 'heat soak'? Then use fan assistance to the pre-radiator. If you follow the points on this list you shouldn't have this issue anyway. Many people say, 'but my system heats up when standing still' - so would your car engine coolant system if you didn't run a fan, so why would you not fit one to a chargecooler system also ?
6. Pre-radiators, cores, and header tanks/fillers etc should always be polished, not painted black. Black is known for dissipating heat, we know this, but it is also equalled by its equal ability to absorb heat. Seeing as the components in a chargecooler system should always be cooler than the engine bay temperatures around them, having them black is going to make them hotter, instead of cooler. There are exceptions to this depending to where some installations have components located, but always bear this in mind..
7. Coolant - plain water, with the minimum amount of antifreeze required. No ethanol or methanols mixes required. Water has the highest specific heat capacity of all liquids (the amount of energy required to heat the liquid 1 degree), apart from ammonia and liquid hydrogen - but alas ammonia rots aluminium. We do not run our car engine cooling systems on ethanol, so why is this myth about putting it in chargecooler systems talked about? Fluids such as methanols dissipate heat via 'evaporation', due to the fact they have low boiling points. The lower the boiling point of a fluid, the less energy it can absorb, and as this is a 'closed' system, no evaporation would take place.
8. Bleeding - The most critical issue on any chargecooler system. Always use a header tank/filler, and it must ALWAYS be the highest point in any chargecooler system and the water level above the top of the chargecooler. Use a tank with an inlet an outlet at the BOTTOM of the tank. The air/water will flow in, the bubbles will rise up to the top of the tank, and the exiting water will leave already bled. Water inlet/outlets on the chargecooler should be facing as vertical as possible. Even pipe working should be routed logically. Air bubbles always want to go upwards, so having the piping routing downwards will not help...
9. Water flow - The cold water from the cool side of the radiator should be fed into the COLD side (ie throttle body side) of the chargecooler, and the hot water exiting the core should come out of the hot side (turbo side) of the chargecooler. This is a countercurrent design - the most efficient form of heat transfer across a medium.
9. System flow - Pre rad > cold water out > pump (at lowest point) > chargecooler > tank/filler > hot water back to pre radiator.
10. Pump - the pump should be fitted to the lowest point in the system, on the cold side (to assist longevity) and have decent flow AND pressure capability, and maintain it. Many pumps on the market claim 'high flow' but this drops off rapidly when they have any pressure behind it. Our unit is a tried and tested model, guaranteed and has had extensive testing and good for over 5 years of daily use....
CHARGECOOLING | TRUTHS & MYTHS
"Chargecoolers only work well until the water heats up..." MYTH...Now this is the biggest phalacy of chargecooler system myths, or simply brought about by people with poor installations. In a correctly designed chargecooler system, the whole point is, the water should always stay cool. That is the whole point of having a properly sized radiator, decent water volume and an efficient core. Think of it this way - you may have over 150 degrees Celsius of charge going through the chargecooler core, but this heat is being absorbed by water, which is four times more efficient at dissipating heat than air, known as 'Specific Heat Capacity'. As an experiment - fill a 'washing up bowl' of cold water, and plunge a scorching hot frying pan into it, until the pan is cool enough to touch (which will be a few seconds - hence why water is so good for cooling) - but likewise, now feel the temperature of the water in the bowl - you will hardly feel a significant difference from the original water temperature - even though it has absorbed all that heat - now lets imagine we can add an extra reservoir connected to that bowl, and a pump, with a radiator extracting any extra heat that was gained in the water, and what do you have? Cool water, always. Continuously....It would only heat up if you continuously plunged more red hot frying pans into it and the radiator system couldn't keep up...
Chargecooler systems are only as good as their complete system design.
If your water temps are rising, then either you have an undersized chargecooler for the amount of charge temps you are generating and it cannot cope - or your radiator selection/placement is insufficient for cooling, or your pump cannot move the water efficiently enough to the radiator, or air lock issues - All AVT chargecooler systems, when installed correctly will result in the chargecooler core ALWAYS being COLD to the touch - yes, not even warm, even after continuous full boost circuit work. Open the bonnet, feel the heat radiating off the engine - feel the chargecooler, it will not even be luke warm, it will actually be cold.
The other thing with water as a coolant, is you can have water temps varying 10-15 degrees, and it will minimally affect the charge temps, due to the way water works. Once again, with the red hot frying pan example, do you really think it will cool much slower if we plunged it into a bucket of water at 15 degrees versus a bucket of water at 5 degrees? It will cool within a few seconds, no matter what the temperature is, and cool much faster and better than air ever will.
"Chargecooler systems can heat up when sitting still..." MYTH...
True, but I don't know about you, but we don't really run much boost when we are sitting still, so the only place this heat build up can be from is placement of the core unit, or again, poor radiator selection, or non fan assistance, so that's not really a fault of 'chargecooler systems'. End of the day, if water is flowing around a correctly designed radiator and dissipating heat, then how should it be heating up? Do you realise how much energy is required to heat the water up in the first place? Take an engine block for example...When you start a car, the radiator is shut off from the main cooling system on start up. We have a solid metal engine block, with hundreds of combustion events over 500 degrees C happening every minute, and 100% of the water volume is flowing around inside the engine block/head - yet it still takes around 5-10 minutes for the water to get up to working temperature. Another example, a kettle - It has a few litres of water in it, and is being heated by element directly in the water, yet it takes 3-4 minutes to heat up with 3kw of energy going through it. ....so basically, if your chargecooler system water is heating up, with no boost going through the core, and with a radiator attached - then you seriously have a problem with your installation - either placement of the core, air lock issues (the main cause of overheating in any closed loop water system) or heat radiation towards your chargecooler radiator.
"Chargecooler systems weigh a lot..". MYTH...
For and againsts here - Our pre-radiator and chargecooler core will weigh a bit less than a decent sized FMIC system. The only extra weight is the pump, and inline filler and the few litres of coolant in the system, so the total weight difference is negligible. Some of the lesser chargecooler designs on the market rely on huge radiators and large boot mounted water tanks - so maybe this is where this comment has come from. The AVT/PWR units are efficient, compact and lightweight.
"Chargecoolers are not as good for circuit work as the water gets too hot..." MYTH...
Again, see point one and two - If your water is heating up too much, then look at your installation. If your car engine overheated by having a too small radiator, you wouldn't blame the engine, you would replace the radiator - so why do people think differently when it comes to chargecoolers?
In summary, a correctly designed chargecooler system will always outperform an air to air (FMIC) system. For drag use, it provides instant cool charge straight off the line, whereas an air-to-air unit will only start cooling once you have enough air speed going through the core. For drift racing, once again, a chargecooler system will cool for the high boost, but low speed use, and for circuit work, you will have stable, low temperatures constantly. Air to air systems are purely dependant on vehicle speed, chargecooler systems are not. The other benefits are ease of plumbing, no need for cutting bumpers, routing intake pipe work, or cutting bulkheads - and the systems can be moved from vehicle to vehicle. For decades, all high end performance sports have introduced water into forced induction system, due to its extra efficiency over air - drag racing, F1 Turbo, Indycar, WRC - Its just a far more technical system to perfect, but here at AVT we have the expertise to guide you in your installation to gain you the best results.
"If air is being used to cool the water, then we might as well use air in the first place" MYTH...
Now we know that water is FOUR times better at cooling than air, FACT. Now seeing that the heated charge air coming from your turbo is moving on average in a typical installation through your core (chargecooler or intercooler) at over 200 FEET PER SECOND, we need the best cooling medium working directly on it, which is water, FACT. You also have to note, this is not the same air cycling around and around the system getting cooler, this is continuous, new air, from the atmosphere, compressed by the turbo charger. Imagine how hard it is to cool air travelling at 200ft/sec at over 150 degrees C? This is a tough job, requiring the best cooling medium, at the fastest rate, thus water!. Again, remember how quick a bucket of water can cool a red hot frying pan, in comparison to how long it would take waving it around in air? Also, consider that we could plunge that frying pan in 20 degree water and it will be cold in a few seconds, yet you can bet you could stand in the -40c Arctic with that frying pan, waving it around in the air, and it will still take a few minutes to cool down....
On the flip side, the ambient air being used to cool the water on the chargecooler radiator has a much easier job. It has the job of cooling water by only say 20-30 degrees, and this is the same water cycling around the system. The other thing is chargecooler water temps are only marginally affected by outside ambient air temperatures, and even then, its also at a very slow rate. On an air to air system, if the ambient air temp rises, so does the charge temps, immediately. On a chargecooler system, this will also happen, but it takes a long time for that 5 degree ambient air increase to be able to raise the total water temperature 5 degrees.