Minimum % open area for a radiator screen

[JohnK]

I've been kicking around different ideas for radiator screens for a while. I was planning to use the Nomex honeycomb screen that several others have used, and in fact bought one and have it sitting in the garage. However, I'm also planning to use Mike Everson's radiator surround piece and would prefer a mesh-style screen that can lay flat on the radiator and the radiator surround can sit on top of it rather than having to trim the nomex honeycomb screen to fit inside the radiator surround.

In looking at what's available through McMaster, there are all sorts of woven mesh and perforated screens. Personally, I prefer the look of a perforated screen over a woven mesh screen, and would like to go with stainless steel. In narrowing it down to those criteria, this is the one with the largest open area:

https://www.mcmaster.com/9358T59-9358T591/

It's an 18 gauge stainless screen with 0.1562" diameter holes, for an open area of 64%. My concern is whether this is enough open area to provide sufficient cooling. A backup option would be something like this:

https://www.mcmaster.com/92725T5-92725T23/

This has an open area of 79% but looks a bit less protective than the other one and is not stainless steel so would need to be painted or powder coated (thereby somewhat reducing the hole size slightly).

Has anyone here used something similar to either of these, and what was your experience. FWIW - I'm running a gen2 coyote, which are known to run cool. I also have a Maradyne PWM fan controller installed, which can vary the fan speed based on load. With no radiator protection installed and the car idling in the garage for a while on a hot day I've never heard the fan run any higher than 50% speed.

[GoDadGo]

I'm running this grill mesh (Black) and it only lets 62% of the airflow through and I've had NO issues with overheating.

https://www.customcargrills.com/proddetail.asp?prod=Perf_GT

I wanted a finished street version look; however, I didn't want the grill to be a focal point on the car.

https://youtu.be/9WEe6-wdNtA

Good Luck & You've Got This!

[JohnK]

Ah, that's great - thank you! That's good peace of mind.

[Chopper]

One thing that will help a lot is to buy or make a panel to cover the gap between the body and the top of the radiator (if you have not already). This will force more air through the radiator. Breeze sells a pre-made piece. I know it's not an answer to the original question, but if you're trying to maximize what airflow you do get, this will help a lot.

[JohnK]

Thanks - yes, already have that piece.

[GoDadGo]

Ah, that's great - thank you! That's good peace of mind.

> Remember that all engines are different.
> I'm running an Iron Dart SHP Block that is bored to 4.030".
> That block can safely be bored to 4.165" so the thick walls make difference.
> It is likely the main factor as to why my engine runs cooler than I had anticipated.

Your Coyote Engine Is So Far Over My Head That I've Got No Clue Regarding Cooling It!

[J R Jones]

John, 64% is troubling.
In either case consider the structure of the mesh.
With an impact, will projectile irregularity poke through the mesh?
Will the mesh yield to impact and damage the core it is protecting?

It may be advisable to space the mesh forward from the cooling core for impact adsorption.
My sense is flow through the mesh is improved when it is spaced away from the cooling core.
jim

[J R Jones]

John, I anticipated that you would agree or disagree, but crickets. I have been thinking about this and have another observation about laying the mesh on the core.
The cooling core is a mesh, a thick one, with an open area for flow.
Rather than assume a core "open area" number let's just use your first mesh as an example.
It is 64%, and if you stack two against one another, the result is 32%, twice the mesh.
If you space them apart, 64% then through 64%, the result is 64% of 64% or 41%

As NAZ (I miss him) has pointed out previously, the front of your cooling core is more effective than the aft of your core because of the flow % and the adsorbed heat. SO, surface area is more effective than core thickness. Take advantage of it.
jim

[JohnK]

Hey Jim. Sorry, I didn't intend to ignore your input. I've picked up a piece of the aforementioned SS mesh and have been contemplating various mounting solutions but have been busy with other things and haven't spent too much time on this.

Rather than turning this into a math problem, I'm going to trust my gut. The perforated screen looks to me to be pretty open. "Open enough," in my opinion. I'm going to come up with a way to mount it that spaces it away from the radiator a bit in a way that cushions it from the radiator to avoid transferring the shock of rock impacts to the radiator directly, and see how that works. The good news is that this isn't one of those "gotta get it right the first time, or else..." decisions. If I observe that the car is running too warm for my liking, I can always remove it and come up with a different solution.