In my analysis of pump flow rates versus the intercooler pressure head it became clear that at higher flow rates the stock pump has restricted flow.\u00a0 In fact, instead of flowing 8 gallons per minute (gpm) it is probably flowing under 4 gpm.\u00a0 We could find a new source for a intercooler coolant pump that can flow 9 gpm against a 1.4 bar resistance; that would be ideal.\u00a0 However, there is a way to work with the parts we have to overcome this hurdle.<\/p>\n
Note that I don’t have a sophisticated model of the overall flow resistance, but that my conjecture is that the flow across the heat exchanger is around a 1 psi resistance, and that system resistance for the hoses etc is 0.4 psi.\u00a0 In my modeling a second front mounted heat exchanger is shown as another 1 psi of resistance.<\/p>\n
The stock intercooler coolant pump is a centrifugal pump.\u00a0 When two or more centrifugal pumps are placed in series, the resulting pump performance is obtained by adding their heads at a constant flow rate.\u00a0 [Ref: Engineering Toolbox<\/a>]<\/p>\n For our previous graphing this basically means if you put two pumps in series you ‘stack’ the two pumps’ flow versus pressure diagram on top of each other.<\/p>\n Using this insight, one way to overcome the pressure head presented by our intercooler system with the parts we know is to put 2 of the stock Bosch pumps in series in the flow.\u00a0 If that works well, how would 2 of the Jabsco Cyclone 50840-12 pumps work?\u00a0 Hmm, what if we put THREE Bosch pumps in series?\u00a0 What about the Cyclones?<\/p>\n Good questions.\u00a0 I wondered this also, so I continued with our previous graphs & calcs to do the analysis:<\/p>\n Multiple Intercooler Pumps in Series vs Intercooler Flow<\/p><\/div>\n Lots of complication, but let’s look at it.\u00a0 First, the light green line bottom left is the stock intercooler pump flow.\u00a0 Bottom left orange line is one cyclone pump.<\/p>\n See the light blue line that flows down from 1 bar and matches and doubles the green line flow line from one pump?\u00a0 That is the line for 2 stock intercooler pumps in series.\u00a0 The darker green line that runs down from 1.2 bar is for two Cyclone pumps in series.<\/p>\n What about 3 pumps?\u00a0 The purple line running down from 1.5 bar is 3 stock pumps in series.\u00a0 The yellow-green line running down from 1.8 bar is for 3 cyclone pumps in series.<\/p>\n What does all this mean?\u00a0 Here’s some tabular data:<\/p>\n This tells us that the flow rate through the system with 1 stock pump of 3.4 gpm goes up to 5.2 gpm if you add another pump, or 6.0 gpm with 3.<\/p>\n The system flow rate of a Cyclone goes from 4.7 gpm alone to 7.1 gpm with 2 or 8.9 gpm with 3.<\/p>\n Is more flow always better?\u00a0 Well, yes, up to a point.\u00a0 On the flow diagram I have summarized the heat transfer for each combination with the circles with letters in them.\u00a0 1B= one Bosch, 1C= one Cyclone, 2B= two Bosch, 2C=two Cyclone, 3B=3 Bosch, 3C= 3 Cyclone pumps in series on the line at the top of the flow diagram.\u00a0 That line they are all on is the heat transfer graph for the Laminova cores; it uses the right axis for its values, which are in kilowatts of heat transfer.\u00a0 In the table I have read off the approximate values from the graph.<\/p>\n What we see is that 2 Bosch (2B) pumps give us a 15% improvement in heat transfer, and 2 Cyclone pumps (2C) give a 24% improvement.\u00a0 Going to 3 pumps does improve it further but to a reduced degree.\u00a0 Adding 1 Bosch pump to the stock pump adds 15%; adding a 3rd only adds 6% more.\u00a0 Replacing the stock pump with 2 Cyclone pumps adds 24%; adding a 3rd Cyclone pump only adds 6% more.<\/p>\n My conclusion is that an optimal mix of expense versus reliability and complexity is to add a 2nd Bosch or replace the stock pump with 2 Cyclone pumps in series.\u00a0 That should give us the best bang for the buck improvement in flow and heat transfer relative to expense.<\/p>\n What is the safe pressure for the intercooler cooling system on the STS-V?\u00a0\u00a0 What PSI is the relief\/overflow cap set for?\u00a0 If it is set\u00a0 for 5 psi (0.3 bar) can the system function above that?\u00a0 Response<\/strong><\/em>:\u00a0 Because of the pressure drop across the Laminova cores at high flow rates there is a high pressure side of the system from the pump to the cores, and a low pressure side from the Laminova cores through the heat exchanger and the refill\/pressure relief back to the pump.\u00a0 The 5 psi relief won’t trigger unless the pressure in the system at THAT point is above 5 psi.<\/p>\n I like the additional front mounted intercooler idea. It seems a good way to add system coolant capacity and some additional cooling.\u00a0 Additional coolant capacity acts as a delaying function for changes in coolant temperature.\u00a0 Each of the Jabsco Cyclone pumps runs around $210; so 2 for $420.\u00a0 The front-mounted heat exchanger (FMHE) for under the bumper I have in mind\u00a0 is $179. It would take 5 hours of labor or so to remove and replace the front clip to install ($400).\u00a0 So for a total budget of $1,200 or so the overall intercooler cooling system could be 24% more effective.\u00a0 If you do the work yourself parts alone would be $600.<\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" Update: Although the info shown is relevant for 4 Laminova cores in series, the Cadillac design does not have 4 in series but rather has A-B in parallel and C-D in parallel flow.\u00a0 I caused some confusion in the way … Continue reading ![\"\"](\"http:\/\/docs.engineeringtoolbox.com\/documents\/636\/pump_serie.png\" "\\"Engineering")
<\/a><\/p>\n![\"\"](\"http:\/\/caddyinfo.com\/wordpress\/wp-content\/uploads\/2011\/07\/multipleintercoolerpumps-1024x684.png\" "\\"multipleintercoolerpumps\\"")
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\n <\/td>\n Liters\/Min<\/td>\n <\/td>\n Gallons\/Min<\/td>\n <\/td>\n Heat Xfer<\/td>\n <\/td>\n<\/tr>\n \n Pump<\/td>\n Core Only<\/td>\n System<\/td>\n Core only<\/td>\n System<\/td>\n KW<\/td>\n Delta<\/td>\n<\/tr>\n \n Bosch<\/td>\n 16<\/td>\n 13<\/td>\n 4.2<\/td>\n 3.4<\/td>\n 16.5<\/td>\n <\/td>\n<\/tr>\n \n Cyclone<\/td>\n 20<\/td>\n 18<\/td>\n 5.2<\/td>\n 4.7<\/td>\n 18.0<\/td>\n 9.1%<\/td>\n<\/tr>\n \n Bosch x2S<\/td>\n 21<\/td>\n 20<\/td>\n 5.5<\/td>\n 5.2<\/td>\n 19.0<\/td>\n 15.2%<\/td>\n<\/tr>\n \n Cyclone x2S<\/td>\n 29<\/td>\n 27<\/td>\n 7.6<\/td>\n 7.1<\/td>\n 20.5<\/td>\n 24.2%<\/td>\n<\/tr>\n \n Bosch x3S<\/td>\n 24.5<\/td>\n 23<\/td>\n 6.4<\/td>\n 6.0<\/td>\n 20.0<\/td>\n 21.2%<\/td>\n<\/tr>\n \n Cyclone x3S<\/td>\n 35<\/td>\n 34<\/td>\n 9.2<\/td>\n 8.9<\/td>\n 21.5<\/td>\n 30.3%<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Conclusion<\/h2>\n
Issue<\/h2>\n
Plans<\/h2>\n