Radiator shroud question.

[baddawgcustoms]

Start off with driveline details. Running 307 view Chevy with very mild cam. Manual transmission so no trans heat in my radiator. I have a 16" SUPOSE to be 3000 cfm electric fan I'm using. Core is 18x18" 3 row aluminum radiator. I want to build an aluminum shroud but on the fence as to how deep to build it for best air flow all around the core. I'm thinking 1 1/2" but looking for other opinions. Thanks.

 

[WMG]

Seems like a lot of airflow for a 16" fan. Would think that you really could go with out a shroud with an electric fan. If it was mine I would make it deep enough to hide most of the fan if the fan is not a chrome one. JMHO

 

[baddawgcustoms]

Seems like a lot of airflow for a 16" fan. Would think that you really could go with out a shroud with an electric fan. If it was mine I would make it deep enough to hide most of the fan if the fan is not a chrome one. JMHO

Definitely NOT in the market for a plastic chrome fan!the shell I have is 5" and the radiator is 3" So I can hide most of it. Fan is 3 1/2. The radiator has 2 tabs on each side to mount a shroud to and I mainly just don't want the plastic tie dealeo to hold it to the rad. I'm just thinking if it it's too close it may interfere with air flow cruising down the road BUT I want to hide as much as I can and get the engine as close as I can. I'm have RPMs stretch body so I want the engine compartment small as possible to keep the car from looking to long. I may just make a bracket to hold the fan very close to the rad so I can hug the engine up tight.

 

[railroad]

A picture of your fan would really get you more advise. A shrouds first purpose is to direct or improve air flow through the rad.
If the blades have any depth on the outer edge and no surround frame, the shroud need to be somewhere in the neighborhood of a little over half the blade inside the outer edge of the shroud. Most elec fans have their own shrouds or mounting frame. Again a picture will help with the advise.
good luck,

 

[baddawgcustoms]

A picture of your fan would really get you more advise. A shrouds first purpose is to direct or improve air flow through the rad.
If the blades have any depth on the outer edge and no surround frame, the shroud need to be somewhere in the neighborhood of a little over half the blade inside the outer edge of the shroud. Most elec fans have their own shrouds or mounting frame. Again a picture will help with the advise.
good luck,

 

[baddawgcustoms]

This is the picture from my email receipt but won't be home for a few days to take a photo of it from the side. It's just a standard flush mount to the radiator fan, I just don't want to mount it that way. Planned on building a simple box style shroud sealed up against the radiator on the sides and about 1 1/2 deep, with the cutout just slightly off center toward the bottom. That way the motor is slightly under the water pump pulley, an I can move the engine up close to the radiator.

 

[baddawgcustoms]

A picture of your fan would really get you more advise. A shrouds first purpose is to direct or improve air flow through the rad.
If the blades have any depth on the outer edge and no surround frame, the shroud need to be somewhere in the neighborhood of a little over half the blade inside the outer edge of the shroud. Most elec fans have their own shrouds or mounting frame. Again a picture will help with the advise.
good luck,

Found this on jegs and it's basically what I plan to build. They range anywhere from 1/2 deep to 5 inches deep. Fan just mounts flat on back of shroud. My idea was to fit the shroud to fit the outer support of the rad, then split some vacuum line and put over the edges of the shroud to seal it up. That way the fan (in my feeble mind) Would have no choice but to pull air through the core.

 

[2old2fast]

I have no idea where you're at on you're build but before you build a shroud , make sure you have enough space between the water pump /radiator.... my fan mounts inside the "plate" & the plate is flat w/ the inside edge of the shell & it's still tight ... also , I wouldn't worry about sealing the edges , I have 1/4-3/8 gap all around & it cools in traffic on the hottest days just fine

 

[baddawgcustoms]

I have no idea where you're at on you're build but before you build a shroud , make sure you have enough space between the water pump /radiator.... my fan mounts inside the "plate" & the plate is flat w/ the inside edge of the shell & it's still tight ... also , I wouldn't worry about sealing the edges , I have 1/4-3/8 gap all around & it cools in traffic on the hottest days just fine

Thanks 2 old. Right now I have the body sitting on 2x4 wood frame(ripped down to 3") with the engine/tranny sitting in place and the radiator sitting up front. Steel is laying in the shop but I'm going to get placement of everything figured out, then setup a jig to build the frame, build the frame one last time with wood, crossmembers, k member kick and all, fit it one last time and then break out the metal saw. I know that's a lot of work, but when I'm done I'll know everything is right. That's why I'm going ahead and doing the shroud to see how far forward I can place the engine. The frame is tapered so in order to get it perfect I have to know where everything is going perfectly. (Or use the grinder to much!)

 

[old round fart]

If you are using a fiberglass shell, make the shell deep enough to hide the fan.

 

[baddawgcustoms]

If you are using a fiberglass shell, make the shell deep enough to hide the fan.

The T shell I have is 5", so it will cover all but 2" of it if I make my shroud 1/2". Wonder how it would look with 7" shell?? I think I have some black construction paper so I'll just have to tape 2 more inches on and see. I'll post some pics when I get home this weekend and get some opinions!

 

[railroad]

Sounds like you have things well in hand. I used the split vacuum line next to the rad and chrome door edge trim on the back edge on one of my round shrouds. I had to super glue the door trim on. I used black RTV on the vacuum hose. I chucked up a rubber washer on a screw, nut and fender washer in a drill press, with valve lapping compound and engine turned the alum on the outside before riveting the ends to make a circle. I would use one of the new round cleaning pads if I was going to do it again.

 

[jcunning]

I used that very shroud with a Spal fan. Trimmed down the shroud to fit the radiator, painted it black to match the fan and it has improved the cooling of the car 100%. Clearance is definitely a consideration. I have about 1/4 inch between the fan motor and the water pump pulley. Good luck.

 

[Hotrod46]

If your fan really moves that much air you shouldn't need a shroud. The fan you have is almost as big as the core now. I am currently cooling an OT car that has a 350/manual trans combo with a much smaller airflow fan. It's mounted directly to the the radiator and doesn't seem to effect cooling on the highway. Runs 180 all the time. That is when I remember to turn the fan on in traffic. I've got to get that auto temp switch installed!

Your shell will cover most of the fan if you mounted it to the rad. You could always try it and add the shroud later if you need it.

One thing to keep in mind is that while shrouds will improve airflow when the fan is running, they can impede flow at high speed. Some shrouds are equipped with flaps that open when on the highway and suck closed when the fan is running at low speed to combat this.

Your jetting and timing is just as important as your cooling system. The car I'm running had a 10 degree vacuum advance canister and the temp would creep up in traffic. I switched to a 20 degree canister and my heating problems went away. Both setups were with straight manifold vacuum, not ported. Interior temps went down too.

Mike