Im sure most here know what a Grill Block is but for those who don't, I have included a description I got off of another thread by SVOboy.
The front grill block is on of the quickest, easiest, and cheapest ways to cut down on aerodynamic drag in your vehicle. While it doesn’t amount to much, it does make a difference, especially considering that a large amount of aerodynamic drag is caused by this opening. It’s best to leave it only partially blocked so that the radiator recieves some airflow, however, a large block is okay because radiators are typically larger than they need to be, and fuel economy drivers tend not to abuse their engines too heavily.
Many new cars, including certain Mercedes and Hondas use electronically controlled radiator shields that open/close depends on engine cooling requirements. Take a look at this Civic for an idea what this looks like:
I just made my Grill Block and while I was making it, I took some pics. So I figured, why not share my idea (though maybe not the best) of how I made my Grill Block. This Grill Block only cost me the price of the Coroplast. There werent any politcal signs or scrap I could get my hands on, still looking though. Ok, so here is what I came up with. Try not to judge me too harshly, as this is my first attempt.
I started with cutting out a template from cardboard:
I traced and cut it out on the Coroplast:
I then, added Great Stuff to the back of the Coro and let it set while hardening:
I cut slits into the Great Stuff to allow myself to push it onto my OEM grill:
I added a small strip of Coro, attached with Great Stuff to allow a zip-tie or whatever to be looped on each end:
Looped the zip-tie's on:
Pushed it onto the grill and zip-tied it to the slats.
Dont forget to cut a hole for airflow to your radiator.
Had to make the hole a little bigger after that last pic. It was 101F today and my radiator was not liking that. Will paint it flat black and maybe silicone the edges for a smoother/cleaner look, when i get time