I've only been a MINI (2012 MCH) owner for a few months. Recently I had need to remove the upper 3-slat Grille. I was surprised to find that the whole piece was solid and provided essentially no air flow to the radiator at all. It's just a "Grille look-alike" not a real Grille at all. Now, this must work OK (probably flows enough air thru the bottom grille) most of the time but it kind of got me thinking if this might explain why the fan runs so often in hot weather.

Question ... Has anyone felt the need to attack their 3-slat grille with an electric drill to make the back look more like swiss cheese ? Seems like the additional airflow would help.

 

This may not help much with your question but, I had similar thoughts to you. I drove around with everything stock and watched my intake air temps (via scanguage). I then removed the grille and watched the temps on the same road with a 1 degree difference in ambient temps. The intake air temps remained relatively the same most of the time, but when flogging it on turns and boosting a bit, it did remain a few degrees lower.

Not really sure how the scoop helps with intake temps with the stock box on, with an AEM I see it making a big difference however.

Anyway, long story short, I plan to cut most of the slats out and put it back on. Looks too goofy without any grille on.

 

I sanded down the back of mine(with an angle grinder) to open the holes up. I posted a "how to" in the dorky cheapskate mods thread in the interior/exterior forum. If you have all the tools, it only costs you 30mins of time to do it right. (including gather said tools) Worth it in my opinion.

 

When I had a MC, I swapped in a MCS grille (or was it sold as a JCW?) for about $80. I liked the aesthetic change, and it was also an open grille.

I know it doesn't answer your question, but its another view point.

Have fun,
Mike

 

I'm pretty sure BMW did enough engineering and testing to make sure there'e enough air flow. Opening it up more increases drag, although probably not enough to be measurable at legal speeds.

 

Just like how BMW did enough engineering to understand how to make their cooling systems not fail every 60k? Or how they engineered an aux water pump that catches fire? Or an inferior timing chain guide, carbon buildup, or to a greater extent, massive rear subframe failure on early e46 models.

BMW is a great car company, but things get over looked and compromises are made to please the general public. It is foolish to think BMW makes the car 100% perfect.

Will the airflow be so much greater that engine and under bonnet temps are lowered substantially? I doubt it, but the stock system is clearly not ideal.

Anyway, to each their own. Have fun with your mini that's the most important part.