RRS/RR Supercharged grills have holes all over them in basically the same pattern. I slapped the side I had drilled in front of a fan and it was night/day vs the other side.

Also where the holes are the air is being directed back in a > shape, so even "if" the air bounces around right after the holes it is still getting channeled back thru the > and into the radiator.

 

correct me if I am wrong, the super charged rovers also have vents on the front exterior panels. My assumption is this is to allow hot air to escape, hence, increasing the air flow in the engine bay. I bring this up because I would be concerned that the decrease in intake air flow is not offset by the exhausting of the hot air.

 

Not sure on the vents on functionality on a RRS, but a Saudi Grill on a 99-02 is basically a grill without a center section, so if the flow was to be effected then in theory a Saudi Grill would not work.

 

We may need someone in thermodynamics to make the call on this...not discounting the Saudi Grill allows more airflow across the radiator and hence that increase airflow will push the hot air out maybe below the engine.

What I am thinking is that less airflow across the radiator requires increase in exhausting the hot air and maybe that is why there are vents on the RRS. I have no background on this and more than willing to concede the thought.

Just tossing it out there.

 

While I'm no expert in thermodynamics, but two degrees in engineering are making me think that it shouldn't matter much. The airflow over the radiator is what matters most. Since the radiator is in the front of the engine bay, the air in front of the radiator will be around the ambient air temp; the air behind the radiator will be roughly the temperature of the air in the bay. If more air is passing through the front grill to the radiator at ambient air temp, then it should cool better because more open grill area will help force more ambient air through the radiator.

The RRS exit vents would help and make it easier for the hot air to leave. (I honestly thought they we're fake until now) by creating a channel where the hot air would experience a laminar flow pattern and exit the bay, which is ideal. I don't think that a lack of exit with more flow will create a turbulent effect that is any worse than what is already there.

If you think that this will be operating at speeds of 40+ mph and the Discovery is quite high off the ground, most of the air probably flows out underneath. Changes in air pressure at the underhood temperature versus the ambient will not have an appreciable effect compared to the force of the air blowing through the motor at speed.

I'm willing to bet that the side vents on the RRS are more for looks and because it has a big engine squashed into a very small bay. I have an family member with an LR4 and it's so tight around that engine you can't even get your hand down there. After the air goes through the radiator it hits a brick wall of plastic. Solution: side vents.

My 2 cents...