elecric rad fan
 

hi all i am running very tight for room was wondering if one can get by without a shroud???? If i need a shroud all i could have is about one inch deep shroud and think it might hinder more than help. thanks in advance for your replies

Re: elecric rad fan
 

Running the long water pump set up on a 454 left enough room to change the belt and that's about it. I ended up with a Spal "pusher" mounted in front of the radiator.

Re: elecric rad fan
 

fun fact, most electric fans have a shroud. that extra shroud you see guys using that covers the whole back of the radiator is a great way to always have your fan running, it limits about 40% of the airflow through the rad, forcing it through the fan shroud. sometimes those extra shrouds have holes in them with flaps to let motive air through the rad out.


there are two types of electric fans, though. pushers usually are much more open so they dont block airflow into the rad. I have a pusher fan that would be dangerous as a puller, a real finger chopping good time. pullers usually have more webbing/probe covering, because pullers are much more efficient.

anyway, long story short, you dont need that box thing a lot of guys use.

Re: elecric rad fan
 

It looks like you are even more tight for space for a fan than I am.

I think I can run a fan on the water pump pulley but am thinking seriously about mounting a pusher on the top half of the radiator as the mechanical fan only covers the lower half of the radiator.

My 98 BMW 528 has a pusher that kicks on when the ac is on that flat moves some air. It also has a mechanical fan. I've thought about getting one of those pushers for mine.

Re: elecric rad fan
 

I agree with your assessment that an improperly-designed shroud can hinder more than help. Because their opening is smaller than the frontal area of the radiator, shrouds restrict airflow at speed.

Re: elecric rad fan
 

what are you running for a fan?

Re: elecric rad fan
 

hi Orge i am in the building phase and just want some input, without a shroud i have enough room but not realy enough room for a shroud.

Re: elecric rad fan
 

if you don't have a fan yet, no need to look for a shroud
with a mechanical fan shroud adds no extra space
if you have room for a fan, you need a shroud
some electric fans zip tie to the radiator, but you lose cooling efficiency without the shroud
my truk has an electric fan, the shroud adds about an inch to the depth

that's why i asked: what are you running for a fan?

Re: elecric rad fan
 

sorry buddy, but the fan in your picture has a shroud, and I dont mean that box its bolted to.

a "fan shroud" makes a fan a ducted fan, thats the purpose of it on a mechanical fan also, making it efficiently pull air through the rad. there is a specific ratio for the blade tip to the shroud. all that box does is make sure all the air entering the radiator will exit through the fan opening, which is unnecessary.

the radiator has fins that point straight back, in the corners your box will BLOCK airflow unless the fan is on and pulling air through itself

those types of shrouds can actually make a truck run hotter and the fan run longer. if they were deeper, and the fan opening larger,the air could gently turn and exit, but an inch off the core and perpendicular to the flow will make it turbulent and will trap air.

I ran a CFD (computational fluid dynamics) lab for a retail fan company, you might have some of the products we designed in your house right now!

Re: elecric rad fan
 

i don't care if you have a phd in fan shroud.
we still need to know what he has planned for a fan to recommend a shroud

truk did a 3200 mile power tour in 105°+ temps without any heat issues
i'd say the shroud/fan combo works as intended

Re: elecric rad fan
 

i didnt say it wouldnt work. I said it would run the fan more often than needed. the only way for air to get out when the fan is off is through the fan hole. I also said electric fans already have shrouds, you have added a second.

if it were deeper, it would be better for the airflow. if it were angled to direct the air, it would be better for the airflow. as it is, it doesnt work well for airflow.

Re: elecric rad fan
 

would you guys agree that no shroud on the hyw would be better and a shroud in slow city traffic wold be better. i have the shroud built but is so tight basicly o clearence. think i will put fan in and see how it cools

Re: elecric rad fan
 

i think I have been explaining this badly so I will try again.

a fan shroud is typically used on a mechanical fan that is either always turning (directly bolted to the water pump) or it can have a thermo switch to freewheel when its not really needed. even freewheeling though, it will pull air through the shroud. so the shroud is made to cover the whole back of the radiator because the fan will always be turning, never completely stopped.

a fan shroud for a mechanical fan is designed to have a precise distance to the blade edge and a precise pitch of the blade to pull the most air through the rad.

an electric fan does not have any mechanical drive, when its off its off and because of the angle of the blades the air flow moving through the rad wont turn the blades fast enough to pull any stalled air in the shroud out (if it did it would be a perpetual machine and we would all have them powering our homes). an electric fan DOES have a shroud in the sense that the blade to shroud distance is that precision distance like I mentioned, making it efficient.

the 1" box type shroud is based on what you need for a mechanical fan, and when they use them on factory cars with electric fans they shape the shroud so that air flows out the fan hole efficiently.

now your question asks if it is better for sitting still or on the highway? definitely sitting still. but for that purpose, an electrical fan fastened right to the rad will do almost the exact same job, it has a shroud on it to be efficient. when you are on the highway the electric fan probably wont be running either with or without that extra box shroud. it will run more often with the extra shroud, as the box shroud and fan structure will inhibit the airflow. remember that the radiator does the job of removing heat from the coolant via the fins on the tubing, a fan helps that process by removing the heat from around the fins more quickly. moving through the air (driving the truck) does this too.

so in my opinion, the extra is not needed. its certainly going to work with it installed, but it will also work without it installed too as long as the fan is installed tight to the rad with no gaps.

Re: elecric rad fan
 

are you dense? we don't know what fan you plan to run. work with us here

Re: elecric rad fan
 

If you have a good radiator and a high quality fan , like SPAL it should be fine without a shroud. I removed my shroud and my truck runs cooler.


Just be sure to avoid cheap fans and avoid a pusher fan if possible.

I have one of these and it works great
https://www.spalusa.com/products/fan...2ffans%2f16%2f

Re: elecric rad fan
 

orge thanks for the compliment. as i said in my first post its an electric fan 16 inch. what i was asking is what guys think is better a shroud or not and the shroud can only be 1inch thick . Dont know what else you want to know

Re: elecric rad fan
 

jweb thanks for the info those are the comments i wanted to hear so your cooler without a shroud. i guess you had enough info to reply. Thanks

Re: elecric rad fan
 

I have very limited space and my shroud was only about 3/4" deep. I'm no expert but I think a shallow shroud hurts more than it helps. There's no good way for it to direct air, it will just restrict flow.

Re: elecric rad fan
 

jweb thats what i thought also