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Discussion Starter #1 (Edited)
Hello,
The latest discussions about water-air intercoolers got me thinking: Water flow through the radiator (the coolest water in the system would be there) is controlled by the thermostat, which is constantly opening and closing. This will obviously cause the intercooler to lose efficiency intermittently. If the intercooler is plumbed across the heater lines, or other inlet/outlet from the block, the water flow is constant, but the temperature is much high higher than the water leaving the radiator, also decreasing intercooler performance.

So which one is it?

Also, my J300's radiator opening is rather modest, and if I went with a water to air intercooler, my smallish radiator would have to dissipage the heat from the engine AND from the air charge. I suppose this is not much different than having an air-air intercooler in front of the radiator, robbing it of some of its efficiency by heating the air going through it.

Any thoughts?

Thanks,
Mikel
 

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Ideally you want to run a seperate water radiator and pump circuit for an air-water intercooler.

That way you keep that water as close to ambient temp as possible.
 

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Intercooler mounts before the radiator, typically, therefore not afffected..
 

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A air after cooler is bettter than a water after cooler and that just because of the coolant temp.

a seprerate water system would be more effective than running into the engine cooling system.

Thanks
Scott
 

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Discussion Starter #5
A air after cooler is bettter than a water after cooler and that just because of the coolant temp.

a seprerate water system would be more effective than running into the engine cooling system.

Thanks
Scott
Sorry to sound like a broken record, but keep in mind that water is far more (heat) conductive than air. I wouldn't be surprised if a water-air intercooler running moderately hot water was as efficient or more than a similarly sized air-air one.
 

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Sorry to sound like a broken record, but keep in mind that water is far more (heat) conductive than air. I wouldn't be surprised if a water-air intercooler running moderately hot water was as efficient or more than a similarly sized air-air one.
It doesn't matter how efficient your air/water cooler is, if it's running water at 70 deg C from your radiator, then you can't cool air below 70 deg C.

If you're running a seperate system with water at say 25 deg C then you can strip a whole lot more heat out.
 

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Sorry to sound like a broken record, but keep in mind that water is far more (heat) conductive than air. I wouldn't be surprised if a water-air intercooler running moderately hot water was as efficient or more than a similarly sized air-air one.
You would be surprised how much a good air to air can do... I had a car with an aftermarket turbo setup @ a mild 6lbs of boost. On a humid 90 degree day if I was running the car hard the inlet side of the IC would be hot and the outlet would get icy condensation on the piping. Granted that is a differnt animal than a diesel it tells me a good air to air does the job...
 

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At 100 percent effeciency, an air to water will only cool down to the temperature of the water. Nothing is 100 percent. Air will cool to ambient temperature. Also, water holds heat 25 times better than air (not some backwoods estimate, physics). By this convention, the only time a water unit will outperform an air unit at driving speeds is until the coolant reaches a temperature greater than ambiant air.....which isnt long

Water units have their place and do good work. Stationary units, or vehicles that do not see much speed use them becuase they cannot get the airflow. If you have the room, an air will work more effiecently with a greater cooling drop.

Note water units as I am talking about are the ones plumbing into the same cooling lines, not a secondary. I have not done the math on them yet.
 

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also there is less room for air in the water/air cooler, so less turbo lag and better throttle response would be my guess. That said, they have been installing air/air for a long time, probably at near the same cost, so there is probably a reason versus water/air in Dodges, bread trucks, etc..
 

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More Aftercooler Theor-I-zin

air-to-air aftercooler will have little or no cooling capability in slow-stop & go traffic, water to air better in slow scenarios. Trail. Gotta keep air-to-air moving, I found this out on a 6.5TDA turned up. With a cummins, I can hardly get them to heat up, except with heavy load.:eek:

Engine temperature: My 4BT would not come up to operating temperature until about 50 MPH with my gearing. Electric fan needed only with full throttle scenarios. Yet to need high fan speed.

Based on these factors, and not-towing, expect little more than the Cummins OEM aftercooler to keep temps normal. Since my 4BT had no air cooling, and the 4BTA will have additional cooling...

I mean, really, these cummins are hard to keep temps up if stock.:rolleyes:

Exceptions projected for 120*F plus days, crossing the Rockies, towing heavy and over-stock fueling. :deadhorse:
Otherwise they'll run cold.

I don't like putting a baffle in front of my radiator for heat, but most of my diesels require this...
Guess I'm just not giving them enough fuel.:confused:

Wayne
 

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Aftercooler stuff

For those of you that are jumping up & down to put a air/water aftercooler on.. Im running a 4bta with the jwac setup on the intake, my exhaust gas temps went down when I stopped coolant flow through the unit. I intend to try converting to a self contained circulating system, but if this doesnt yield good results I will be going with air/air setup. Hope this helps. Also check the Yahoo group for more detail on my experiance with this subject.
Carl

1979 F-250 crew cab 4 x 4
4 bta
ZF S-42 5 speed
Borg Warner 1356 x-case
Dana 60 rear
Dana 44 front
3.55 gears
255/85R16 tires (33.5x10.5)
Hydroboost steering and brakes
Custom 40 gal. fuel tank
Much more later
 

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At 100 percent effeciency, an air to water will only cool down to the temperature of the water. Nothing is 100 percent. Air will cool to ambient temperature. Also, water holds heat 25 times better than air (not some backwoods estimate, physics). By this convention, the only time a water unit will outperform an air unit at driving speeds is until the coolant reaches a temperature greater than ambiant air.....which isnt long

Water units have their place and do good work. Stationary units, or vehicles that do not see much speed use them becuase they cannot get the airflow. If you have the room, an air will work more effiecently with a greater cooling drop.

Note water units as I am talking about are the ones plumbing into the same cooling lines, not a secondary. I have not done the math on them yet.
What you say is correct, but if the water in your water/air cooler starts to heat up, then you need a bigger radiator on the system.
IMO there won't be much size difference between the radiator in an air/water system and the intercooler in an air/air system.

The comments about an air/air cooler doing nothing at slow speed have a point, but in such situations an air/water will only help until the water heats.
To run any intercooler effectively at slow speed you need fans to shift air through them.

For me the deal maker on air/water is packaging. I just can't fit an air/air cooler in without serious surgery to the front of my truck.
Plus I already have the electric water pump, radiator and plumbing.
 
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