Decided to test the idea of using home window screen material over the front Grill on my 99' civic during a road trip from Dallas to Denver. This was purposely a temporary mod so it was installed with Duct Tape!
The theory is that at low speeds or at a stop enough air can make it through the holes and retain cooling. At higher speeds the air cannot make it pass the screen and diverts around the bumper as a solid grill block would.
This drive was over night due to my 2 yr old son sleeping in the back seat. This ended up being a good thing since it was about 70 degrees leaving dallas and closer to 50 degrees in high elevation. I use a Ultra Gauge on my car and was closely watching the coolant temp. My normal is 183 degrees (+/- 3 degrees) almost the whole way i was running about 199-205 degrees with the screen installed so this deffinily blocked to much air flow.
I was seeing about 3mpg increase over my norm though..... My numbers are not great since i had my wife, son, + several hundred pounds of luggage for a weeks vacation on top of the climb up 4500 ft elevation change. = 43 mpg at 72 mph on cruise control.
For what its worth this mod seems to do what it should, but the screen mesh/size for a regular home window screen appears to be to tight and blocks to much air flow.
* Another thing to note: Blocked lots of bugs from splating on my radiator/ and ac condensor
