perforated grill block?
 

I'm new here, I was searching the net looking for information on posssibly using perforated sheet metal for a grille block on my 2001 Ford F150. To avoid overheating the truck during hot weather and towing I'm thinking of using this type of material which is 30% open. Any thoughts on whether this is worthwhile to do to reduce the air pocket in the grille?

Thanks
Rick

http://www.made-in-china.com/image/2...etal-Sheet.jpg

I have no idea is this instinct is correct or not, but I would say that perf metal is prolly less aero than an equivalent bit of solid metal with an open hole for the necessary cooling parts.

yes, I would go with a solid sheet of metal for places unused. Right now I've got a duct tape grille block over the part of the grille where the intake is, so now it draws in air from the engine bay, warming the engine faster and running it about 10 degrees warmer, since it's below freezing right now, this is good. But for the summer, I'll probably remove that and block the rest of the grille. perf probably would just restrict and harm more than help.

A perforated grille block will do no harm.

well that clears that up :D it was just a guess ^_^"

Perforated screens are velocity sensitive; at low speeds they let in about what you'd expect- say, a 30% open screen will let in 30% of what an unobstructed vent would- and at higher speeds they "close up" to the oncoming flow and appear to the air to be more "solid".

Without experimenting, I believe this is completely correct. Fluids have a tendency to adhere to a surface as they sheer off it. As you increase your speed there will be a build up of air around the surface of each hole's entrance that is an area of localized slow or stagnate air. So as you increase velocity, more air will be blocked from entering due to this.

So a perforated block would work good for some trucks then maybe? When you are going slow and hauling really heavy stuff it gets air flow. But when you are going fast on the highway it acts like a flat panel.

Sounds good to me :)

Well... in that scenario overheating sounds like a real possibility, but less so than with a solid grille block.

Some trucks achieve a similar result by using a thermostat to control the opening of the grille slats ahead of the radiator.
At low temperatures the grill opening is small and at higher temperatures the opening change to allow more airflow.

Rolls-Royce used the same principle as far back as the 1920's for the same reason.

Rick : Welcome to the place and and enjoy your stay.

Cheers , Pete.