Quote:
Originally Posted by Daox
A full grill block will be better than a partial any day. Just because it has to go under the car or around the car means nothing vs hitting tons of stuff going through the cooling system and engine bay.
But, yes you need to reconnect the fan.
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I disagree that a full block is better than partial any day or that grill blocks are universally better than air going through the grill.
The car and the airflow around it don't care whether there is turbulence under the hood. All that matters to the aerodynamics are
1- the resistance that air encounters when trying to enter the radiator. This is a factor of the restrictiveness of the radiator and the hardware behind it.
2- the way air flows over the grill if it doesn't go through.
3- the path of air as it comes out from underneath the car, the back end of the hood, or the wheel wells
If the resistance is high enough, it will be like a virtual grill block that some people attach behind the grill... If it's low enough, the grill would present a nice hole for airflow.
Now, on an angled surface like his upper grill, blocking that off would help, because it's easy to cut through air with a wedge. It would also have the benefit that the air coming up from the bumper would remain smooth, instead of being disturbed by the grill.
But blocking the lower grill under the bumper forces that air to move down or to the sides. The easiest path here is probably downward, especially for the center. That air would compress, go under the car, and be forced out the sides, possibly increasing drag. It could also be forced down and to the sides at an angle, into the tires.
The center of his grill is nearly vertical and flat. The car has to force this air toward the sides and downward. If he removes this, the sides will still help aerodynamics, and the small stream of air flowing through that opening would encounter less resistance proportionally. Also, the fan might be able to suck all the air it needs through the hole even if it is smaller than normal.