Okay all you M5 mavens, pros, aficionados, experts, etc...
What are the benefits/drawbacks with slotted rotors vs. drilled rotors?? I see on Dinan's website that they offer kit upgrades for the M5 that are have both slotted and drilled rotors...is one better for track usage??
What you want with any rotor and pad is to get rid of the hot gasses as quickly as possible. Some people drill, some slot, some do both. Some think random drills work, other have patterns.
There is really no HUGE benefit to one over the other. Drilled works well, but can ge more brittle and may crack. They also get clogged fast. Slots work well and crack less, but some think the gassses cant esacpe fast enough and the rotor retains more heat. I can make pros and cons for each.
Bottom line is that they look cool.
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What you want with any rotor and pad is to get rid of the hot gasses as quickly as possible. Some people drill, some slot, some do both. Some think random drills work, other have patterns.
There is really no HUGE benefit to one over the other. Drilled works well, but can get more brittle and may crack. They also get clogged fast. Slots work well and crack less, but some think the gasses cant escape fast enough and the rotor retains more heat. I can make pros and cons for each.
Bottom line is that they look cool.
Agreed!!! The slotted/drilled rotors DO look great!!!
I always thought that you wanted more surface area to dispense the heat and by drilling you compensate surface area compared to slotted. I believe slotted is used by F1 and nascar but I could be wrong
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Just make a note, the least surface area you take away from a rotor the more stopping surface it has....Now with that said, if you can't shed heat away from a rotor and pad the more brake fade you will have (this is with convential brake parts). with some brake systems you have little brake till you get them HOT, ie ceramic/carbon fiber...but for the stock or slightly modified M5's out there the stock rotors are fine, may just need pads....BUT if you need to LOOK COOL, the flashier the better.....and pay through the nose too.
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As many have said, there are pros and cons for both, but the pros/cons are fairly minor details. I ended up putting slotted on my M3 and the M5 is stock. I chose slotted because they clog up less often and are easier to clean when they do clog. The M3 sees the track occasionally and I was experiencing brake fade with the stock brakes. This is the only time when slotted/drilled rotors will make any noticeable difference. They're not needed for street use other than to look cool.
Just in case anyone is interested in where the drilled discs can crack.
If you are very hard on your brakes you will eventually get hairline cracks radiating from the drilled holes which is exasperated by the holes getting clogged.
This happened to my brothers cosworth with a BBK many years ago, he just kept replacing the discs. No idea why he didn't buy slotted
Obviously different pads may reduce the holes getting clogged in the first place which would help.
Never had an issue with clogged holes with stock discs / pad combo even on a track.
If you are going to seriously abuse your brakes, go with slotted discs.
The brake discs will loose most of the heat through the viens that radiate out from the centre to the edge in the middle of the disc, so I don't believe there is much difference in heat performance between the slotted and drilled.
Another plus for the slotted disc is that they are supposed to improve the initial bite, though I've never swapped discs on a car with the same set-up so have no idea if this is true.
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