Double Intercooler Discussion

I have built a lot of Dbl ICs and have strived to re engineer them to perform better. I have sold a lot of ICs with a shroud and threaded inserts to bolt on a 8" fan to. This seemed to be the best way to pull air through the double cores. Pretty much like the radiator on your car having a shroud to allow it to pull air through the radiator. The ICs have been ran on Dynos and ACT temps were claimed to drop. Performance seemed to be proven on numerious club members cars. As of late I have followed threads where some members (members I have a lot of respect for) have stated that they feel the shroud is a bad idea due to
(1) The fan blocks the natural flow of air at higher speeds
(2) The fans lack capacity to move enough air to cool the cores and there for the air charge down.

My question to you all is. Is the shroud a option that improves performance or hinders performance?

My second question is should the tubes and fins be painted or stripped of paint and left bare for better heat transfer?

In the pictures below I build a custom IC for a guy who wanted something a little diffrent. He wanted no shroud, bare fins & tubes and a better flowing outlet tank. How he plans to attach the fan, should he install one would be up to him.

The whole point of his thread is I will build Intecoolers that work for you guys but what is the consensus here as to what works best? What are everyones thoughts?

Ken

I am very happy with my Double IC, which does not have painted fins or a fan shroud.
I used a Mr. Gasket Replacement Fan Mounting Kit MRG-1994 to mount my fan.

One day I hope to afford one of these from you Ken they are very nice, but it seems like if you did paint the fins it would slow some air flow though the core itself, I would think that would help but yet Ford painted the stock ic...


Jerry

I have heard that black paint tends to improve the heat transfer. But I don't know for sure.

My thinking would be that any coating on the cooling fins would delay the cooling effect of the air at least. Would it delay it long enough to show in a quarter mile run?????? Maybe anodizing the fins would be a better option but probably more expensive. One thing for sure and certain though is Ken does some fine, fine work, and its pretty too.

This is what I understand on the subject of paint and shrouds.

Paint:
Black attracts heat white reflects it. There is a reason why auto manufactures paint the engine block black and its to help draw the heat out of the engine. As far as being efficient on an IC only testing will tell

Fan Shroud:
If you take the fan shroud off and an older car with a mechanical fan that vehicle has a higher tendency towards over heating. A shrouds purpose is to help the fan draw air from the total surface of the "heat exchanger". Even factory and high quality, vehicle specific, after market electric fans have shrouds to help the fan draw air from the total surface. Now, shroud design could more than likely raise or reduce the total effectiveness of the fan so it has to built properly.

Hock said:

This is what I understand on the subject of paint and shrouds.

Paint:
Black attracts heat white reflects it.

Click to expand...

I believe this only matters when comes to sunlight or another similar source.

This should hopefully explain the black paint better.

http://www.offroaders.com/tech/paint-it-black.htm

While black certainly dissipates heat better than any other color, any coating at all also provides an insulating effect. Any coating is going to interfere with the heat transfer from aluminum to air.

To demonstrate this effect, touch a plain aluminum radiator on a car that is running at operating temperature. Now touch one that is coated. Or - Touch a polished SC top after a hard run, now touch one with a coating on it....

In each case the actual temperature recorded by a contact probe will be roughly the same, but you'll burn your hand a lot quicker on the bare aluminum. Bare aluminum = highest heat transfer rate.

If I were to guess I'd say the most likely reason Ford painted the IC in the first place has to do with corrosion protection and/or cosmetics.

They make special coatings that actually help in heat transfer..And you need something to protect the bare metal from oxidizing

One reason engine blocks are often painted black is because doing so helps conceal oil leaks. Also, I have heard that in the case of a radiator that painting a copper/brass core reduces thermal conductivity. The only reason that traditional copper/brass radiators were painted was to keep them from turning green. I would assume that painting aluminum would also reduce its ability to dissipate heat but I'm not positive.

Now for what it's worth I have no complaints regarding my double IC.

DamonSlowpokeBaumann said:

They make special coatings that actually help in heat transfer..And you need something to protect the bare metal from oxidizing

Click to expand...

Is that like the coating that makes James Bonds Aston disappear? Seriously, what compounds have better heat transfer capability than bare aluminum? I'm just curious, because I might want to get some.

Hock said:

This is what I understand on the subject of paint and shrouds.

Paint:
Black attracts heat white reflects it. There is a reason why auto manufactures paint the engine block black and its to help draw the heat out of the engine. As far as being efficient on an IC only testing will tell

Fan Shroud:
If you take the fan shroud off and an older car with a mechanical fan that vehicle has a higher tendency towards over heating. A shrouds purpose is to help the fan draw air from the total surface of the "heat exchanger". Even factory and high quality, vehicle specific, after market electric fans have shrouds to help the fan draw air from the total surface. Now, shroud design could more than likely raise or reduce the total effectiveness of the fan so it has to built properly.

Click to expand...

You are correct with a fan shroud, but.... the fan has to have the capacity to do the job effectively, and it has to be able to outflow what could effectively be the air being forced through when the car is traveling. Fact is, an 8" fan does not move alot of air.

Because of that and the only way for air to go through the DIC is through the fan on the shroud, it severly becomes a restriction even at low speeds. If the shroud isn't in place, then the whole intercooler can flow air and not have the restriction of the fan while travelling, and you will get a bit of flow with the fan when the car is stopped.

Look at it this way. The EEC shuts off the cooling fan when the car hits 47mph. This way the air can flow through the rad without the fan restricting it. Now look at much that fan can flow compared to the little 8" and I think you can get the idea.

Fraser

A note. I believe the fins on the IC are aluminum, thus there is little point in painting to avoid corrosion. Aluminum oxidizes almost immediately and this natural oxidation, while doesn't look pretty, does a good job of protecting the surface.

My guess is due to the fin density on a doubled intercooler, the pressure differential required to move air from one side to the other is significant. I would use a shroud simply because it would be necessary to create a concentrated pressure differential. Otherwise it'll be too localized and air flow across the whole core will be limited. I'd build a shroud that can seal tight to the back of the intercooler and then also had some flaps on it a the top and bottom. The flaps could be thin rubber panels that once you're going down the road and air pressure in front of the intercooler overwhelms the fan, the panels could open up and allow the air through.

I.e. something like this done for a cobra intercooler

I've thought of that idea about the flaps as well, but never really figured out how to pull it off.

Fraser

Hock said:

This should hopefully explain the black paint better.

http://www.offroaders.com/tech/paint-it-black.htm

Click to expand...

I'm not sure I agree with this...notice the comment from the article:

"The effect won't be much, and might not even be noticeable unless closely monitored, but it is a fact."

Even if it is true, it seems that it is negligible for what we're talking about.

Dave - try pure copper for a semi-affordable answer.

http://en.wikipedia.org/wiki/List_of_thermal_conductivities

I think the bare core will indeed cool more efficiently, simply because of the lack of a layer of insulation - like Dave mentioned.

I built my own shroud on one of your DIC's. The only difficulty was the lack of clearance to the steering pump pulley with a fan attached. I think it was only allowed for 1/2 to 3/4 inches. That might be a bit of a restriction in the outer corners but not overall. Smaller double fans would allow more clearance but still might be lower CFM.

There isn't a lot of air movement under the hood to begin with and it gets worse with lowering springs. Combine that with any sc overdrive, the stock condenser, the location of the wiper fluid bottle on 94/95's and push/pull fans on the rad/condenser and a fan on the IC is an absolute necessity.

So, if the choice is between running a fan without a shroud to running a fan with a shroud, my gut instincts say shroud. I have no data to back that up.

The one thing I do know, being in HVAC business, is that 90% of the air movement of a propeller fan is on the outer 10% of the blades (maybe 80/20 or something like that, but you get the idea). If the fan is mounted flush mounted to the fins, it would only draw air on the circumference of the blades.

Tod

I do have actual numbers and comparisons, but I'm not going to repeat myself in this thread since there seems to be some doubter's.

Fraser

would it be possible to put 2 smaller fans on there? if there is any worth using.

or maybe

has anyone tried to use a pusher fan on the front side of a dbl ic

other wise i agree you need a shroud but some how need to figure out a better setup with high cfm fan or more fans.

If you want to go crazy serious, make a shroud, then hook a hose/duct onto it to pull air into an area where you can attach a much larger ducted fan that can move 3000cfm or more to create a huge vacuum. Similar to what is being used by road race cars for cooling brakes or for their ducted multiple radiators.