actually I think a thermostat tweek is in order to get it a little higher temp normally and to make sure it closes well. Takes about 4 miles to get up to temp plus it may run better a little hotter. A lot of times the idle is over 800 when I pop it in neutral and coast and it should be in the 650 range.
What did you cover the coroplast with? How did you attach this to the bumper?
I covered the coroplast with flat black paint.
First I had to make spacers to offset the grille block from the inset grille. I cut 21 2"x2" squares of coroplast, made 3 stacks of 7 pieces and put a 1 5/8" drywall screw through the center of each stack (cube). Then I drilled 3 holes in the center black plastic piece that goes horizontal from left to right. Then I screwed the coroplast squares to the center horizontal piece at the left, center and right sides. Then I placed the grille block in place against the three cubes and drove 3 more drywall screws through the grille block and into the cubes. I guess I will have to yank it off and take pictures. Not tonight. Somebody remind me tomorrow evening.
With the airflow on your summer intake port: a few questions (I'm really considering this).
The hole: does air enter the hole, or is it a port to exhaust the rad-A/C heat, or both? My concern is the flow of air. So, the air enters the port, but where does the air exit? As you mentioned, the engine is nearly sealed. I understand that around the hood the gap may provide some relief, but where does the incoming air go in bulk? Otherwise the pressure builds, and nothing happens, so the hole is basically as good as a flat piece of Cloroplast. I'm imagining a small opening, where the hood closes, near the wipers. It may not require cutting of sheetmetal, but rather manipulation of the rubber gasketing or running it into the screened area where water drains from the windshield. A fancy version could have a a one way valve (perhaps a rubber flapper like the the positive ventilation valve behind the trunk paneling to keep fresh air moving through the car, but keeps the rain/sand/dust out.) Just a thought about the whole heat rises thing.