Surely if grooved and drilled discs were so bad.. porsche.. lambo.. Audi .. etc etc.. who spend MILLIONS designing cars each year why dont they use plain discs ?? It cant just be because they look good they must have a practical use.. 99% of cars which have big brakes have grooved discs..
Not bad at all - " Drilled Discs:
A common misconception is that the purpose of drilled discs is to promote cooling. This couldn't be further from the truth,
The real purpose is to reduce weight.Drilling can allow brake dust and gases to escape, but with modern brake pads, this usually isn't a problem. Choosing a drilled disc for that purpose doesn't make a whole lot of sense.
Many high performance cars like Porsche and Mercedes AMG come with drilled discs from the factory. For these cars, the drilling is mainly about the looks, just like bright red calipers. When people do serious high-performance driving on a trackdays, they usually swap to regular plain discs.
Drilled discs generally wear out brake pads faster and produce much more brake dust as a result.
Drilled discs have a shorter service-life than plain discs and tend to develop stress fissures/cracks over their lifetime "
