Fan Shroud, To Weld or Not To Weld?

[Joel K]

Figure I’d pose this question. I am in the process of fabricating a fan shroud and haven’t decided how I will mount it. Looks like most builders simply weld it to the radiator and wondering if that is the recommended approach. I have dual brushless fans and they weigh 4.4 pounds each so figure the shroud with two fans will weight about 13 pounds. Wondering if that is too much weight and perhaps a better approach is to mount it on the side panels and floor of the front compartment and use weather stripping to seal it against the radiator vs. simply welding it to the radiator.

As always, appreciate everyone’s advice.

 

[Ken Roberts]

I would mount it independent of the radiator. That's how I plan to mount mine. Lower part of the shroud fastened to the floor and the top fastened to a rod or square tubing mounted at the top.

 

[Johan]

I welded 3 ears on top of the radiator and 2 at the bottom, you can see it on my build log #47.

 

[Scott]

I would do as Johan suggests and weld tabs to the radiator. I would then use foam to seal the shroud to the radiator and do your best to isolate the radiator from chassis vibrations.

 

[Johan]

I would do as Johan suggests and weld tabs to the radiator. I would then use foam to seal the shroud to the radiator and do your best to isolate the radiator from chassis vibrations.

Yea, ”tabs” is the word I was looking for, sorry for my Swenglish

 

[Terry Oxandale]

My tanks are on the sides of the core. This leaves a 14-16 gauge channel that borders the top and bottom of the core. My very simple shroud screws onto that channel with sheet-metal screws (4 top and bottom), to hold two 12" fans in place. For those times I track the car, it takes all of 10 minutes or less to unplug the fans and remove the shroud/fan combination. I've found that the high-speed track days have destroyed fans due to over-speed, hence the removal. So I only install the shroud for those hotter, city driving days with long red lights.

 

[Tim M]

I'm interested with your fan issue. Noticed your shroud has no 'bypass' openings...forcing all air to go thru the fans. I've seen on OEM applications where they have little flaps that open at higher air pressures (car velocity). The Camaro I'm working on has these all over the shroud - neat detail. I neglected to take an image before reinstallation - sorry.

 

[Terry Oxandale]

Tim, that could be a potential remedy for the over-speed on the track. Will need to think that over, vs the quick removal/reinstall. Considering that the radiator/shroud is essentially sealed to oncoming air, you're correct that there is no place for the air to go but to create additional DC power for the battery

 

[Howard Jones]

Have you tried to simply run the fans when on track? I would think that the normal powered fan speed is higher than the blown speed at nearly any speed seen on track. I run mine when on track because I believe that not running them causes a restriction to airflow through the radiator. Seams to work for me.

Cheap to try?

 

[Terry Oxandale]

I've never had a fan go bad until a track day, and then they just grenaded (split apart, even the outer ring, which created quite a mess), damaging a core, and of course needing two new fans. Not willing to risk that again. The fiber reinforcement was the only thing holding some of the piece together.