Surely this restricts airflow towards the air intake

 

So why block it up

Probably some emissions/drag reduction effort 

Quite common now to close most of the grill to improve aero performance.

It makes quite a significant difference on the drag of the car & I guess with fancy cooling systems & a good performance fan it is enough keep the engine temperature Under control at least in the European markets.

I suppose it also helps warmup the engine.

 

BMW & some other manufacturers experimented with a grill shutter which could close at high speed & open when the engine become hot or at low speed.

I guess the cost & complexity versus a better fan didnt make sense as I dont know many new cars which have this now.

Ford's Active Grille Shutter does that.

A balance between looks and aerodynamic efficiency and warm up speed. Who likes the look of cars with just a slot air intake and no grille? Not me. A Jaguar E type is the exception, maybe the current Fiat 500. Ford Sierra springs to mind as being grill-less and less attractive than a Mondeo. A number have had body colour intake surrounds.

Dragging an old thread up from the depths:

 

Having recently done the intake mod to open up both sides of the intake it got me thinking whether a bit of modding would help this blocked grill.  Maybe some holes drilled in line with the intake?  Or even a dremel to remove some of the blockage altogether?  I noticed that the honeycombe grille has no blockage.  I don't want to remove the blockage completely as I'm sure some engineers somewhere have worked out that the cooling system is happy as is.

 

Anyone?

3 minutes ago, MarkyG82 said:

Dragging an old thread up from the depths:

 

Having recently done the intake mod to open up both sides of the intake it got me thinking whether a bit of modding would help this blocked grill.  Maybe some holes drilled in line with the intake?  Or even a dremel to remove some of the blockage altogether?  I noticed that the honeycombe grille has no blockage.  I don't want to remove the blockage completely as I'm sure some engineers somewhere have worked out that the cooling system is happy as is.

 

Anyone?

If the engine doesn't need any extra cooling/airflow then the unnecessary parts of the grille will be blocked up to stop air entering the engine bay with two negative effects - increasing the CdA (drag) and allowing more air to exit under the car affecting high speed stability.

5 minutes ago, PetrolDave said:

If the engine doesn't need any extra cooling/airflow then the unnecessary parts of the grille will be blocked up to stop air entering the engine bay with two negative effects - increasing the CdA (drag) and allowing more air to exit under the car affecting high speed stability.

 

I'm a little confused now.  Please excuse if I have misunderstood your meaning.  I was under the impression that the blockage was to reduce the drag and also to try to send more air over the top?  The way you worded it makes it sound the other way.

 

Also, if I did mod it in any way it would be a modest increase in airflow directly towards the intake so very little would be flowing into the bay.

Tempting though it is to start opening up the grill Petrol Dave is right IMO, air flow into the engine bay exits under the car, airflow over the top is a smoother flow and creates downforce. Direct airflow into the filter risks water being sucked in at worst, and far more grit, dust, insects etc at best. I've had a cold air feed to a big K&N on a V6 and IMO it made next to no difference, probably just countered the heat soak. 

 

BTW I like seeing old threads resurrected rather than a new one started covering the same ground, just my 2p worth. 

There is also snow and moisture ingress to consider. In snowy weather, it doesn’t take long for snowflakes to enter the air intake and clog the air filter solid. Too much moisture entering and saturating the air filter will also restrict air flow. The  standard grille acts as a first line baffle plate to reduce this.