DIY Removable Grill Block - 1994 Honda Del Sol Si - Fuel Economy, Hypermiling, EcoModding News and Forum

Shortie771 · 07-06-2012, 01:07 AM

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

Nimrod · 07-06-2012, 07:11 PM

Hi Shortie,
you are doing much the same thing that I am about to start on, on my 2012 Ford F-150 truck. The truck has an open area (about 100 sq. in) below the bumper that I want to initially block off while I start blocking off small portions of the upper grill areas that are open to the radiator, and watch the UG display of the coolant temperature swings in this hot summer weather.

When I find out how much (if any) of the open areas I can block off in the upper grill and still keep things sufficiently cooled, I want to then close up the upper grill as much as possible per those results, and build a moveable/controllable shutter that will partially/fully block the lower opening when possible at highway speeds, and still keep the coolant temps under control.

Shortie771 · 07-07-2012, 01:03 AM

Glad to hear your looking for improvement and on a 2012 at that. Mine ended up covering about 200 sq. in, if I did that math right. Good luck with your grill, would like to see how that goes for you. Only took me about 2 hours if you dont include the waiting time for the Great Stuff to harden.

Yes DEFINITELY watch those coolant temps. I drove to work with mine (35 miles) with no hole in the block as a test. Got pretty warm at 50+mph, was happy to hit a red light. After work i cut a hole in because it was MUCH hotter (101F) in the afternoon. That worked well for a little bit, but i soon realized that i needed to make that larger. So i pulled over in a nice shady spot and cut the hole larger... Thank you drywall saw.

Shortie771 · 07-07-2012, 11:54 PM

Had to cut the hole even larger today after I noticed my temps going up (even with it being a cooler/more windy day), but hey at least now it is symmetrical

CigaR007 · 07-08-2012, 02:33 PM

You can also try ducting some of the incoming air as to redirect it towards the radiator.

Shortie771 · 07-08-2012, 04:39 PM

Quote:

Originally Posted by CigaR007

You can also try ducting some of the incoming air as to redirect it towards the radiator.

I thought about that but there really isn't much space between the radiator and the bumper for ducting. Also I wasn't sure on how to duct it. Regardless I guess it is a little late for that since I have already cut it larger, unless I make another block.

Shortie771 · 07-10-2012, 02:04 PM

Ok so even after cutting the other side to let some extra air in, my car is still getting hot at highway speeds. D*** you Texas weather!! So I am looking at ducting the opening that is away from my radiator. Does anybody have ideas on how to get that air to my radiator, without putting holes in my car?