Slots/drills/dimples also help to prevent glazing of the pads by acting as a cheese grater and stealing your delicious asbestos.

 

hmmm wonder what those silly Porsche engineers were thinking?

 

You can't rely on Porsche engineering, they can't even put the engine in the right end of the car.

As for dust evacuation, most pads have slots cut at the centerline to aid that, and while it may build up, is it really a concern on a street driven car? An SUV at that? Even for race applications, i've found race cars with drilled/slotted brakes (except cars running drilled rotors in the rain) to be few and far between. Just my personal experience though.

 

I have also heard that modern pads do not need gas evacuation... but I have also heard that even race pads can overheat and still produce gas and "fade". It's just much harder and takes a lot more heat with modern non-organic mixed compounds. OEM style organics and organic/metallics (like EBC's green pads) can still fade at lower temps, but grab much better when cold which is why they are good for street driving. I've used EBC greens and found they were great for everyday driving in Michigan winters, but couldn't hold up to a summer track day. I use Hawk HPS now for street driving and HP+ for track days.

Even without much gassing problems anymore, I've still heard some companies claim cross drilling improves cooling. I just don't see it though since most of the cooling is down by centrifugal force pushing air through the cooling vanes in the middle of the disc. And the cross drilling does compromise the rotors metal structure unless they are properly temperature treated. My personal opinion is slotted only is best for performance because the slots clean glazed material off the pads so they always have a clean surface for better friction. Downside is more dust and faster pad wear. The OP won't be seeing any performance use of the brakes though which is why I said stick with oem.

 

you had me right up until the word "Armada"

Seriously - On an Armada = unless you are towing a large boat up and down mountains on a regular basis - don't bother.

On the track - with a car appropriate for the track - slotted or drilled rotors can also help reduce pad material build up. Not as much and issue with "gas evacuation" these days.

 

If your a hard driver this may be necessary unless your just doing it for looks. My Camaro had a serious glazing issue with the factory rotors and discs. So much so I had to run off the road one time at 100mph to avoid rear ending someone (anyone who attended Florirun 2008 can vouch for that), so to say that factory cars dont need upgrading is just horsecrap IF.....you drive the shit out it. I put drilled and slotted evolution discs on my car with hawk hps pads and it now stops on a dime regaurdless of how hot they are and how much I run the shit out of it. IMO the best thing you could do (is what I did) call hawk or some place similar and tell them why you want to upgrade and how you drive and they will recommend the best thing for you for example....I told them about Florirun 2008 and that my main issue was brake fade etc...
and that I wanted to put ceramic pads on my car and they said.......do not use ceramic pads in my case because I am overheating my brakes and ceramic does not dissipate
heat and they will hold the heat and the next time you brake all that heat will be applied to the rotor seriously increasing the chance for warping, they told me the hps composite pads were the best for my application. Ceramic is mostly for people that have show cars and dont want brake dust. I've had mine for almost a year now with no problems, no complaints and no more braking issues. To say factory cars dont need them seems crazy to me unless you got a 75-100k car that came with performance braking systems, most factory systems are inferior....IF.....you drive extremely hard or alot of long time driving where high heat is an issue.

I'm sure some people will will not agree with me and I'm not claiming to be the brake guru, this is just based on my personal experience, so don't get all bent

 

Your argument is a little flawed. You upgraded pads and rotors at the same time, so you can't really say the rotors helped at all. I'm willing to bet that if you have upgraded to the HPS pads and left OE rotors you would have seen a similar improvement in braking performance, if not the same increase altogether.

 

Actually the reason that porsche does it, continues to do it and has no issues is because... (pulled from a porsche forum)

1) The holes are cast in giving a dense boundary layer-type crystalline grain structure around the hole at the microscopic level as opposed to drilling which cuts holes in the existing grain pattern leaving open endgrains, etc, just begging for cracks.

2) The holes are only 1/2 the diameter of the holes in most drilled rotors. This reduces the stress concentration factor due to hole interaction which is a function (not linear) of hole diameters and the distance between them.

3) Since the holes are only 1/2 as big they remove only 1/4 as much surface area and mass from the rotor faces as a larger hole. Explained:

It increases effective pad area compared with larger holes. The larger the pad area the cooler they will run, all else being equal. If the same amount of heat is generated over a larger surface area it will result in a lower temperature for both surfaces.

It increases the mass the rotor has to absorb heat with. If the same amount of heat is put into a rotor with a larger mass, it will result in a lower temperature.

4) The holes are placed along the vanes, actually cutting into them giving the vane a "half moon" cut along its width. It effectively stops cracking on that side of the hole which makes it very difficult to get "hole to hole" cracks that go all the way through the face rotor

 

Every reason stated under number 3 points to blank rotors being more effective than a drilled one. Granted Porsche probably has one of the better drilled designs.

 

Understatement of the year. Bars of soap hold up better than EBC pads. A fresh set of EBCs (any color) won't last me a single day on the track.

That said, I do run them on my street Viper because I can get a gazillion miles out of the rotors. But the lack of stopping power is noticable on a heavy car like the Viper. Losing a couple hundred pounds would definitely help.