Re: Johnson Intercooler Pump Cavitation?
Ok guys, I'll try to kill a lot of birds with one post here. A properly designed and operating liquid to air I/C system will allways be better than A2A, period. Yes on SyTy's they can be a pain in the ass to deal with etc. but like anything else in the hotrod world, if you want it you gotta work for it / modify to get it and you have to be smarter than the parts your trying to work with :tup: .
Air rises to the top (unless traped). I saw the petcock being mentioned, he has his brain power cap on!. If there is any air in the system, you can purge and fool around for days to get all the air out (I did!) untill I did the rubber hose change over and noticed that the return line to the upper I/C was on the lower port and the suction was on the top port, don't know if it was supposed to be that way from the factory or not but I have seen many that are. Configured like this, any air in the top of the upper I/C gets sucked in and will cause a never ending cavitation problem and I mean the Upper has to be full to the fill neck to be above the top of the upper port, think about it! Suction should be on the bottom, return should dump in from the top.
Any increase in volume / flow to the stock system will help. I have the Johnson pump, aux cooler in front of the radiator with a bleed petcock and no problems. Now I see several mentions of aux coolers, additional hoses and lines going to the rear of the truck etc. Keep in mind that this is just like a fuel system. Keep the hose runs as short as possible, bends and 90's to a minimum and do not go smalller that 3/4 in. fittings on a stock or aux. in front of the radiator. Larger fittings and hoses are required for longer runs or there will be a major flow decrease proportional to the restriction and overall hose / line length. Look a flow vs. pressure drop table and you will see what I mean. Larger / longer systems (in or under the bed / rear of vehicle) will require larger pumps, hoses and fittings. I would say that a Johnson or stock type replacement would be ok for a aux. cooler in front of the radiator but beyond that lager pumps will be required depending on the size of the system and yes hotrodding involves math so figure YOUR system specs. (most will very due to hose/fitting size and overall length due to routing and placement) and do your flow calculations and that will give you your pump flow requirments in G.P.H.
A2A is less to deal with if you just want to bolt on and go with little brain power involved but less maintenance, agreed and no argument from me. A2W will beat the A2A any day (if done correctly) so the choice is yours. We do I/C systems for the U.S. Navy and I will never use an A2A system on anything because I know what I can do with a liquid to air system.
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James Thomas
