martifers Posted September 23, 2011 Share Posted September 23, 2011 I know some turbo petrol production cars are water-air charge cooled but I don't know of any diesels. I assume there are a number of reasons for this including diesels spending more time on boost thus the cooling requirements maybe greater and/or the costs being greater than standard air-air intercooler cooling systems. I don't know. Has anyone water-air charge cooled a diesel recently? I was thinking of doing it to with my Td5 Challenge truck when off season maintenance begins. My main driver for doing this is being able to move the winch backwards to reduce winch overhang (along with sending the radiator to the rear) and theoretically being able to increase 'low vehicle speed' cooling efficiency over a ‘comparable’ Intercooler. A turbo lag reduction could alternatively be seen due to being able to utilise a smaller cooling system when charge cooling than air intercooling to get the same heat dissipation. A problem I can see in the future would be fitting a VNT at a later date, the extra heat this would add to charge (always being on boost) and the subsequent effect on affective cooling or the size of the charge cooling system required to see a benefit over intercooling. Does anyone have any firsthand experience on the set up, the sizes / flow / radiator capacity required for charge cooling and more importantly when it becomes a benefit over intercooling? Unfortunately I do not have the knowledge to answer the following questions thus I am hoping that some of you bestowed with bigger brains than my own might be able to impart your knowledge. A few questions..... 1: What volume / flow rate charge cooling system would you require to get the same cooling characteristics of a standard intercooler at idle/low speed? With the heat capacities of; Air: 1.0035 J/(g.K) and Water: 4.1813 J/(g.K) I would have thought the charge cooling system could be considerably smaller. 2: What efficiency gap would exist between the systems when travelling at road speeds if the charge cooling was set up (to reduce packaging) to mimic low speed intercooler cooling efficiency. 3: What volume / flow rate charge cooling system would you require to get the same cooling characteristics as a standard intercooler at high road speed / large air flow? How far could you go? What do you think?? Tom Quote Link to comment Share on other sites More sharing options...
fozsug Posted September 23, 2011 Share Posted September 23, 2011 http://www.enginebasics.com/Advanced%20Engine%20Tuning/Water%20vs%20Air%20Intercooler.html Stick to air to air Quote Link to comment Share on other sites More sharing options...
martifers Posted September 23, 2011 Author Share Posted September 23, 2011 Cheers for link foz. However only reason not to try just from that is heat soak. Something not considered, though would like to know more about it's affect. Quote Link to comment Share on other sites More sharing options...
Team Idris Posted September 23, 2011 Share Posted September 23, 2011 Heat soak argument is arse. It only applies to undersized charge coolers. I've just been sourcing flat bed coolers to cool V16 Perkins gas engines, which have charge coolers either side of the engine and run at full power constantly The charge cooler is great for the Td5, as the turbo and inlet manifold are on different sides of the engine, so the charge cooler fits nicely on the front of the engine. The turbo lag is reduced with a charge cooler. A full width intercooler puts heat load on the rad, so the charge cooler is an opotunity to get rid of the heat somewhere else. A charge cooler is smaller because one of the fluids has a much bigger j/kg.K than the other, as you guessed. A cubic meter of air weighs 1kg, and a litre of water weighs 1kg, so the real gain is in the density of gas vs liquid. The charge cooler is slower to 'saturate' which means the benefit of cold system lasts longer. It's acts like a bigger thermal capacitor than an intercooler. Who uses them? Charge coolers are great on supercharged V8's, as they slip nicely into the inlet manifold. Anyone with a turbo or supercharged rear engine, as the charge air temperature can be passed to the front. (done parts for a porsche and a Lotus) Anyone who wants less lag but still wants a low temperature charge. Draw backs; Double handling the heat in two fluids does mean the charge temperature will be slightly higher on average, by maybe 3-5 degrees. You're in R&D territory with the Td5 charge cooler Quote Link to comment Share on other sites More sharing options...
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