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Discussion Starter #1
The acchilies heal of this truck seems to be coolant temps while towing heavy or towing up long hills. GDE I believe it was you guys that informed us of why. The CAC sits in front of the radiator partially blocking it.

So what is the solution? Are you guys working on anything? Seems like a bigger or more efficient radiator might help.

I think there is a market for a solution to this problem.

What say you?
 

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The main issue is that all of the heat rejected by the charge-air cooler is immediately dumped into the radiator. Instead of exchanging heat with "ambient" air, you're cooling the engine coolant with air at 80-90C (assuming max power running up a grade).

In order to keep the engine cool in these conditions, you need to either: 1) pull more air thru the cooling stack (have mechanical fan on the engine), or 2) push "cool" ambient air thru the radiator instead of heated air from the CAC.

To solve this, the preferred approach would be to move the CAC down out of the air flow path of the radiator. Another option is to create a diverter off the backside of the CAC to deflect it's air down under the rad.
The second option is the easiest to implement since it requires the least amount of vehicle modifications.

Moving the CAC down means also farther away from the engine. This in turns will increase the induction volume since the pipes would be longer (induction volume = volume of CAC plus all piping between the turbo compressor outlet and the intake manifold inlet). Since the induction system volume is proportional to the turbo lag, and considering that the DS diesel's turbo has rotational dynamics which can be measured with a sundial, increasing the system volume is directionally incorrect from an engineering perspective.

We have a lot of ideas on what to do, it's a bit harder to plan the time to build something to test out west before the summer heat starts fading. Fortunately there are still a few months left.

The CAC itself on the DS is very good in stock form, capable to remove in excess of 100-110°C (with inlet temps of 160-190°C).

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Another thing to consider is the huge impact on cooling system air flow given by the grille itself.

If you want max trailer tow performance, you need one of these two grilles on your truck (they are the Laramie Longhorn and Tradesman/SLT grilles):
View attachment 8443 View attachment 8444


These two grilles restrict air flow horribly, and could be best utilized as a garage decoration or otherwise placed close to your garbage can (they are the Laramie & Sport/Big Horn grilles):
View attachment 8445 View attachment 8446
 

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I believe that there are companies that have, or will build, heavy duty radiators. I always replaced the radiators on my off road trucks soon after purchasing them. Since I don't tow or do any off road work anymore, the stock radiator may do. However, I am surprised at how well it does work, being such a puny thing.
 

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GDE- thank you for posting all of the info you post. When you get a min could you repost those pics?
 

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Discussion Starter #6
GDE thanks very much for all the feedback. A diverter certainly sounds like a straightforward and simple solution. Easy to do comparative testing too. I for one am hoping you bring one to market and make a fortune selling 100s of them :D

Top, I believe we have the Hemi radiator on our trucks. I could be mistaken but thought that item carried over unchanged.
 

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GDE , your grill pics aren't working. Can you repost ?
 

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What do all of you see for coolant temps. I do not recall mine getting overly hot. Guess I will have to pay closer attention to that, :confused:
 

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In case the grille pics aren't working, here they are again.

The good grilles to have for air flow - the Tradesman/SLT "Honeycomb" or the Laramie Longhorn's "Wire Mesh":
09-2013-ram-1500-crew-fd.jpg 2013-Ram-1500-front-grill-view.jpg


These are the grilles to stay away from if you're doing any kind of strenuous towing - the Big Horn/Lone Star "Sport Grille" and the Laramie's "Billet":
2013-Ram-1500-chrome-hex-foil-grille-insert2-1024x640.jpg 2013-Ram-1500-chrome-horizontal-grille-insert2-1024x640.jpg



For comparison sake, towing at "over" GCW (around 14800-15000lbs, depending on fuel load) the Wire Mesh grille goes up Davis Dam (the J2807 testing hill) about 15kph faster and reaches the summit of the grade 1min faster than the same truck but with the "Sport" grille installed.
 

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The radiator on the diesel is roughly the same surface area and thickness of the hemi, but the ED actually has a higher fin density. This translates into more surface area available for cooling.

The ED's rad and cooling fan are sized appropriately assuming that you're pushing ambient air thru the rad, not air at 80°C.


The Hemi's clear advantage is the mechanical fan which becomes a hurricane under the hood during the trailer tow, and not having an intercooler. I've seen a Hemi truck go up Davis Dam towing the same trailer as an EcoDiesel and do the grade roughly 20mph faster.
 

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You guys are a wealth of information. Thank you so much .... I find this kind of stuff intriging. I have an SLT but with the Bighorn Pkg so I have the slat type grill (non-prefered). Although I get dramatic rises in oil temps when towing steep grades on hot days, I don't see the coolant temps getting to those scary levels ..... relative to normal running temps that is.
 

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Folks all I can say is that Matt n Keith are really good people to deal with they have been helping me with an issue and they won't steer anybody wrong they work with real numbers not guessing numbers that's the way it should be IMOP Thanks GDE for all your help!!!!
 

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I can't remember how much space is around the CAC and radiator, but it there a chance of fitting in an additional small high flow auxiliary electric fan somewhere in there to help?
 

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Discussion Starter #15
Man you are a wealth of information!

If the ED coolant cooling issue could be overcome or significantly reduced this would get it up the Davis much quicker wouldn’t it?

My truck is a serious beast towing up hill in 5th. The problem is coolant temps quickly sky rocket. If the truck had the ability to maintain coolant temps while in 5th what would the next limiting factor be?

I really don’t care about racing up the mountain. I just don’t want to hit the defueling limit. It’s a helpless feeling and puts undo stress on the motor. Plus maintaining 55-60 is much less of an impedance upon all the other vehicles on the road.
 

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In my sports cars for track days here in TX I have ran these typical Water Wetter products that I guess just improve heat transfer of the radiator. They were good for some noticable temp drops in that application. No turbos or intercoolers however in my case.

Just a thought.

GDE, doesn't a lower EGR duty cycle result in less coolant temp rise because you are not cooling exhaust gas with the radiator fluid as often?
 

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I don't tow but I haul a lightweight slide in camper in my Outdoorsman. During the last trip driving across hot desert doing some steady climbs I saw coolant temps as high as 233-235 but I could always get it to go down by 10 degrees very quickly by easing off a bit on the accelerator.

Do people think there are any problems with coolant temps this high?

PS - The grill is another reason for the Outdoorsman - one of the "good ones".
 

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The radiator on the diesel is roughly the same surface area and thickness of the hemi, but the ED actually has a higher fin density. This translates into more surface area available for cooling.

The ED's rad and cooling fan are sized appropriately assuming that you're pushing ambient air thru the rad, not air at 80°C.


The Hemi's clear advantage is the mechanical fan which becomes a hurricane under the hood during the trailer tow, and not having an intercooler. I've seen a Hemi truck go up Davis Dam towing the same trailer as an EcoDiesel and do the grade roughly 20mph faster.
The ED has a mechanical fan as well, which is also as loud as a Hurricane when operating at full speed. I had a defective thermal management unit on my transmission which caused it to overheat. When the fan came on the tranny temp kept on rising (no circulation) and the coolant would drop like a stone. If I recall the fan had at least three speeds, might be a feature opportunity for you if you could adjust the coolant temperature level that engaged the fan?
 

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The radiator on the diesel is roughly the same surface area and thickness of the hemi, but the ED actually has a higher fin density. This translates into more surface area available for cooling.

The ED's rad and cooling fan are sized appropriately assuming that you're pushing ambient air thru the rad, not air at 80°C.


The Hemi's clear advantage is the mechanical fan which becomes a hurricane under the hood during the trailer tow, and not having an intercooler. I've seen a Hemi truck go up Davis Dam towing the same trailer as an EcoDiesel and do the grade roughly 20mph faster.
The ED has a mechanical fan as well, which is also as loud as a Hurricane when operating at full speed. I had a defective thermal management unit on my transmission which caused it to overheat constantly. When the fan came on the tranny temp kept on rising (poor circulation to the cooler) but the rad coolant would drop like a stone. If I recall the fan had at least three speeds, might be a feature opportunity for you if you could adjust the coolant temperature level that engaged the fan?
 

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might be a feature opportunity for you if you could adjust the coolant temperature level that engaged the fan?
GDE already did.

Improved cooling fan control

Fan will now run for a certain amount of time after shut-down to cool down the engine and exhaust system
Activates if either the regen is still active when the engine is shut off, or if the exhaust temps are above a prescribed limit
Earlier activation based on coolant temp while driving to keep engine and oil cooler
 
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