I still don't understand this grille block thing. The aero improvements have to come at a cost of decreased lifetime for anything rubber under the hood, at minimum.
Would it be smarter to hood vent
like this and then duct directly from the radiator to the vents with dryer tube? That way air's only obstructed by the radiator fins themselves, not by the whole engine/drivetrain/underbody/rear axle/etc.... and you're not heating up expensive parts needlessly?
Granted, I live in AZ where an engine's cooling system is pushed near capacity half the year. May not be such a concern up north... but I just don't like the idea of running organic compounds (like rubber hoses, belts, seals, plastics) hotter than necessary.[/QUOTE]
Ideally, the radiator flow would be all in smooth, tapered ducts, but there seems to be no room for them in most designs. Those exit vents are nice, but nowhere near the area needed to match the intake, let alone account for the increase in volume. The rubber bits might prefer their own moderate supply of fresh air. At the other extreme, parking lots in Fairbanks get llittered with "snow snakes" - fan belts that have just snapped from a cold start. I'd like to find a simple way to get a grille block to move along with the thermostat, or instead of it, as on the original Rolls Royce. Their famous grille is an imitation of "venetian blind" shutters.