Spring mounted Grill Block

[cfg83]

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

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[SVOboy]

Now have someone jog in front of the car on the highway and take pictures!

Really though, how will you know if it's working?

[Piwoslaw]

Originally Posted by SVOboy

Really though, how will you know if it's working?

Maybe some kind of one-way locking mechanism: once it lowers it stays there. Then you stop and see how far it closed at what speed and unlock it for another test. Of course, this locking device would be only be for testing.
Hmm, another option is to mount a pen on it and have and paper on the recieving end: if the wing closes, the pen makes a dot.
Then there's driving with a camera stuck to your bumper.

But the idea is simple, workable, and just plain AWSOME !!!!

[wagonman76]

You could tape some light gauge wire (light enough to not hinder the movement of the grille block, like maybe thin am/fm antenna wire) to both the spoiler and the grille block. Make sure the wires will easily touch when the grille block is closed. Maybe even use a small spring on one of the wires and tape the spring to the spoiler, like what is in the end of a battery case, that way the grille block won't have to be firmly bottomed out. Then run the wires to your dash, and connect them with an LED and appropriate size battery. The LED will come on when the grille block is closed.

[cfg83]

Hello -

Ok, you are giving me ideas. I do have a wireless mini-cam I can mount in the fog-light area on the side. I will see if I can make this work for definitive proof.

CarloSW2

[Deezler]

nice!

Does it really function as a full grill block though? Looks like it would block most of the lower grill, but then also extend below the bumper and perhaps create unnecessary drag there?

maybe you could take a picture while holding it in the "on" or down position so we can see what it does in action.

[cfg83]

Deezler -

Good point. I will take a picture and post it later tonight ...

[time passes]

Here it is :





It does extend below the based of the lower intake vent. This is also maximum extension. I think I am ok because I think the rest of the "undercarriage" (old timey word) is lower :



I won't change it until I know how much it moves.

Tonight on the freeway my IAT stayed a toasty 145 degrees F while my coolant stayed at ~195 degrees F. In the past on a night like this I would expect sub-130 IAT and 190 coolant temps, so I am pleased with what I am seeing.

CarloSW2

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[cfg83]

Hello -

Ok, I set up a webcam on the car :




This led to these pictures :


Notice the initial location of the spring and the license plate



As you can see in the picture, the spring is already very stretched out. Also, the license plate is "part" of the spring mechanism. It is only attached at the top, so it is being pulled in.



Here the spring is super-stretched out and the license plate cannot be seen.

Notes :

- The grill block works. It does "bounce" a little bit, but mostly in transition, not at steady-state speeds.

- The spring is too weak. I would rather have the spring hold it's own until the car gets over 40 MPH. This, however, will increase the risk of "bouncing" when the spring fights back.

- The license plate may need to be bolstered. I don't mind the license plate also "closing" the middle-section of the upper grill block, but I do want it to be more secure. There are only two plastic snap-in plugs at the moment.

- I need to make a YouTube of it in action. The first AVI I did was 900 MB, and I didn't get it with audio of me stating the MPH, so it was not postable.

Basically, it just needs tuning.

Me happy. Again.

CarloSW2

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[Daox]

Very nice! Glad to see it works.

[TestDrive]

Originally Posted by cfg83

- The grill block works. It does "bounce" a little bit, but mostly in transition, not at steady-state speeds.

- The spring is too weak. I would rather have the spring hold it's own until the car gets over 40 MPH. This, however, will increase the risk of "bouncing" when the spring fights back.

Go ahead and use a stronger spring but add magnets to reduce/eliminate bounce.