Belly Pan Louvers and Fan Shrouds

Has anyone ever seen a Dodge belly pan like this? It sure looks factory to me.



There has been debate as to how much good a belly pan does and whether or not is it a good idea to have a scoop or louvers.

My two cents on the louvers is that they allow very hot air to re-circulate when the van is stopped rather than suck in cool air through the grill. The upside to them is that once the van is underway they may provide more air to the radiator.





As you can see I had a custom shroud made for this aluminum radiator (note: an additional piece of sheetmetal was attached to the bottom of the shroud before installation). The bitch is that once I installed it with the new radiator, the engine overheats if I sat in traffic. Not fun when its in the high 90s and you're sitting in there with the heater on.

My friend blames the separate trans cooler and the fact that the inlet and outlets are on the same side of the radiator. I’m thinking that it’s the depth of shroud not allowing the air to exit off the ends of the fan blades. The factory shroud has an opening that is approximately the same size, but it doesn’t have the tunnel covering the fan blades.

What are our thoughts/theories? I don't want to cut down the shroud if it's no really the problem.

WHY NOT ADD A 2800CFM OR 3200CFM ELECTRIC FAN IN FRONT OF THE RADIATOR

Is that your belly pan? I think your lucky if so! I wonder if it would be more effective if the louvers were only in the front half, effectively still bringing in the cool air from the front... might keep the warmer air from the engine from recirulating underneath and within the fan's pull... I'm thinking if I do that, I might start with three rows of louvers in the first 12 inches.

Fan shroud... the flat corners concern me... maybe a dished shape would be better... maybe tack some gussets on the inner corners to round them off a little.

Also, your rad worries me... looks like the inlet and outlet are on the same side... isn't it possible that most of the coolant flow is on that side of the rad dropping straight down the side rather than circulating through the fins?

the bellypan is original the louvers are not, someone did a nice job on it though. i would check the rad like donivan65 said if it seems ok i would pop the freeze plugs to make sure the block is clean give it a good flush put new freeze plugs and look into one of those hi-performance waterpumps. im guessing the engine is stock?

My problem was the opposite.
I would stay cool all day long in traffic.
It was at speed on the freeway where I warmed up.
Without the bellypan the airflow just bypassed the radiator even with an upper shroud like the one you had made.
Since Early's have thier radiators up inside a tunnel with closed ends, that bellypan is critical in channeling airflow at speed.

First, as donivan65 says, check the temp side to side, you may be getting only half the benefit of that new core you had made.

Second, when doing the checking to the block, like benwah suggests, I would try removing the aftermarket shroud all together, but keeping the bellypan.

Then, adding an electric 'pusher' fan to the front if you have room, and modifications to the shroud as sasktrini suggests.

My bet is with donivan65, your only using half the core, because it's the flow of least resistance.
You may find a significant difference in side to side temps.
Even though, (or especially since) aluminum has generous temp conductivity, if you see any temp difference side to side, you should give that special consideration.

The engine is a 318 with an RV cam according to the previous owner. Beyond the fact that it has a 4 barrel Edlebrock carb/intake, I don't have a clue of what other alterations have been made. The thing didn't overheat with the stock radiator. Then I blew out the radiator in the parts van that I wanted to get going, so I transplanted the good one into the parts van.

Putting the upper radiator hose on the passenger side shouldn't be a big deal. I may have to move the heater hoses though.

Corey, I take it that you are referring to the bottom corners of the shroud being square? Bent triangle shaped gussets?

Don, I'll definitely do the surface temperature test. I wish I'd thought of that.

Mike, I'll also give the electric fan(s) strong consideration. I'm just concerned that if the fan fails or I have an electrical failure, I'll be SOL. I also have a separate trans cooler in front of the radiator right now. BTW - I really admire both your earlies, and also appreciate your service and the sacrifices you've made for our country.

Thanks Ben, Dave and everyone else for your help. I'll let you know what I find out next week.

I would think the louvers would hurt the cooling performance. The bellypan directs the air coming through the grille up into the radiator. The louvers would allow air just to pass through.

itruns wrote:
Corey, I take it that you are referring to the bottom corners of the shroud being square? Bent triangle shaped gussets?

The top corners arent so bad, but the bottom corners, a triangle shape of sorts to funnel the air flow towards the fan. It's hard to explain, but if you've seen demonstrations of how air swirls around in a pickup bed at highway speed, and the whole debate whether there is less drag with the tailgate up or down? I wonder if the same principle happens in the shroud's lower corners.

I'm a theory guy, no actual proof if it would improve it.

Something like this is what I believe Sas (Corey?) is refering to, though the size may not be exact to his idea.
The way I've blacked it out here (this size/placement), it seems that it might restrict the flow at the bottom-outside corners of the radiator.

Dang Mandos... you nailed it!


Does it make sense?

Looks good Dave. I think this will end up being the best cooled early around.

G-Man wrote:Nate as you know chevy belly pans have louvers and many put a air tunnel on theres and have only good luck. I would think after saying that a dodge should be no differant or only better. Then again this is only a guess on my part.

Actually I didn't know that..learn something new everyday. Many folks have put air tunnels in their Dodges as well to assist in cooling. Luckily I have never had an A-100 overheat without the tunnel, but that's with a completely refurbished cooling system mind you. The radiator shop that I deal with uses extra duty cores that have the capacity of a 4-row, but take up the same amount of room as a 2-row all with copper/brass construction.

sasktrini wrote:Dang Mandos... you nailed it!


Does it make sense?

It does make sense.
Any effort to channel air more efficiently, and avoid turbulence or constriction is better when it comes to cooling.

I'll be very interested to hear how the side to side temprature test comes out, since the flow of liquid is going to follow the line of least resistance.
Straight down the left side is going to be that line, and the right side of the radiator (looking at it from the engine to the radiator), is (currently) going to be mostly unused, I believe.
Swapping sides on the inlet, from the driver to the pax side, should more effectively use all of the radiator's core and capabilty.
Adding an electric (pusher) fan to the front, and making it thermostaticly controlled, is also something you should strongly consider.
Even if it never comes on after you make the inlet changes.
Redundancy in cooling is better than a 'facepalm moment' in the middle of the desert.
Much better!