Hello -
(A moment of silence, please. Many zip ties were sacrificed to make this possible)
Like many of you, my car has a passive (doesn't move) grill block. That means it's a compromise between city and freeway driving. I also have an HAI, a Hot-Air-Intake. At city speeds this gets nice and toasty warm, but at highway speeds it typically gets cooler because of the increased air flow into the engine compartment. An active grill block could deal with this problem, but I don't want to spend a lot of time and effort on a control system that has a higher likelihood of failure. The main problem is I want an open grill block at city speeds and a "closed" grill block at freeway speeds. Right now I am trying this :
At city speeds, the coroplast "wing" stays in place. It is hinged in two places on the bottom and attached to the license plate via springs at the top. At highway speeds, these springs should stretch and close the lower radiator cooling vent. These springs are "C-7" springs that I got from OSH.
Here is a front view. The red lines show where the hinges are underneath the coroplast flap.
Close-up of the hinge. There are no holes drilled into the car. The diamond-grill is a rain gutter leaf protector that I used to slightly reduce the amount of air coming into the lower radiator cooling vent.
Close-up of springs.
Side view showing downward angle of flap. Sides of flap also bend down on the ends because the original coroplast had a bend to it. If you look closely, you will see a square piece of "packing sponge" that I am using to modulate the amount of air that gets into the upper cooling vent. As the weather heats up, that will probably be removed.
.........
A while back, Frank Lee pointed out that this could suffer from "wing flapping", but I think I have accidently used the right springs for the job. If they were too strong I am sure that there would be flapping. I need to have someone watch my car on the freeway, but I haven't gotten around to that yet. I keep waiting for a shiny-butt gas truck, but they seem to be hiding from me.
When I originally used it, I had a grill block (pipe insulation) on the upper radiator cooling vent. Everything was fine when I was driving on the city streets. When I got on the freeway, IAT and coolant temperatures immediately started to rise and wouldn't go down. I see this as proof that I am getting a "dynamic" grill block effect on the highway. I pulled off the freeway and removed the upper grill block. This is a compromise. Normally you want to have the grill block on the upper cooling vent, and the opening in the lower cooling vent. I am not too worried about this compromise because my car has the "below headlight" cooling vent style of the late 1980's/early 1990's.
In this current configuration, I am seeing hotter IAT temps at freeway speed, at least 10+ degrees F more than I used to see. My coolant temperature also is up from 190 to 193+ degrees F, which I can live with. I think that as the weather warms up, I will need to keep tweaking it to keep that car's cooling happy. But, it's zip tie mounted and therefore 100% removeable, so I have no worries.
CarloSW2
.