Blank vs Cross-drilled vs Slotted brake rotors
 

Are the holes and slots really worth it/ make that noticeable difference? I've always just gone with blanks due to my previous knowledge and understanding about break rotors (decent write-upWHY Blank rotors are better than cross drilled and/or slotted - Honda-Tech) but I've seen members with cross-drilled/slotted rotors. It's come time for me to change my brakes and I've already orfered stainless steel lines and some Hawk pads but still have not ordered any rotors..

Any and all opinions wanted.... .

When I work the hot grid at Road America for all the big Porsche events and sprint races, I've never seen a single car without either slotted or cross-drilled rotors.

Blank rotors are completely adequate for street use, and they last longer. Drilled rotors tend to develop cracks radiating out from the holes. Don't know about slotted.

I think a lot of the cars you see on the street have drilled/slotted rotors because they "look cool" and their deployment is justified by vague claims of "better performance".

Dimpled rotors offer the advantage of cross-drilled while maintaining the structural rigidity of the rotors.

Slotted is just as effective but they shave your pad materials quicker than blank.

http://www.apexperformance.net/prod-2519.htm

http://www.apexperformance.net/cartg...mpledrotor.jpg

I prefer blank Zimmerman rotors but dimpled or slotted are probably fine. I see no performance advantage to cross-drilled but they do look cool.

I have driven blank, slotted, and drilled rotors on the track and I could notice a difference. I prefer the drilled rotors without a doubt. Does it really help me shave time off? Unknown; but I definitely like the feel of the drilled rotors. YMMV.

Drilled rotors will definitely crack out over time and the harder you use the brakes, the sooner this will happen. I replace my rotors with every pad change so the cracking isn't an issue for me but it is slightly more costly to do it this way (but worth it to me).

http://986forum.com/forums/general-discussions/43520-i-think-its-time-change-rotors.html

Thanks for the input guys. I think at this point I'll start looking into some slotted rotors.

I may be way off on this but are all drilled rotors actually drilled ? What I mean is I thought I read somewhere on the net or car forums that some " drilled " rotors actually have the holes cast in when the rotors are being made. Supposedly the cast in holes do not exhibit the hairline cracking like rotors where the holes are machined after casting the rotors. Anyone else heard/seen that ?

You are correct; rotors with the holes cast in (such as Porsche OEM rotors) are much less prone to cracking than aftermarket rotors with holes drilled in.

I had the pleasure of being at an event with a manufacturers rep. Casting with the hole does 2 things. It reduces machining time, and tool wear, while increasing the edge strength that improves resistance to edge cracking.

The hole idea of cross drilling is to improve heat transfer out of the disc pad and rotor. Heat radiates until it hits an edge and builds up there. The internal fin force air out the hole improving surface cooling. With out the cross drilled holes all you do is cool the core of the rotor. With the cross drilled hole you cool the core and the friction surface. If you've ever watched the thermal imaging of a solid rotor versus a Cross drilled rotor it is impressive how fast the edges of the holes get hot and how fast they cool back down. While the solid one just linger hot and gradually increase overall temperature with repeated braking. I saw a side by side thermal test for 3 minutes. Braking for 5 second cooling for 15 seconds designed to simulate track conditions. the solid rotor was over 150 degrees hotter at the end of 3 minutes with a 22% loose of braking force.

My opinion would be, If the car is a daily drive then use solid rotors. If you track the car at all use drilled or drilled and slotted rotors.

He also had some impressive test to fail video of, Solid rotors, forged then drilled, cast then drilled, and cast with the holes treated then drilled. Guess which one didn't have a catastrophic failure.

Send your new rotors out for cryogenic treatment. <$200.

While drilled (or cast hole) rotors do dissipate heat quicker, their true advantage is in gas control. Disc brake pads are held together by bonding resins which turn into gas vapor under the heat of hard braking, much the way water turns into steam under the same conditions. On a really fast moving race car, the gas generation (from resin or steam during wet sessions) can actually hold the pad off the rotor slightly during braking, reducing the overall braking effort. Holes, slots, or dimples give the gas a pathway to escape, dramatically improving pad contact and braking.

One of the most common comments you get from an owner experiencing drilled or slotted rotors for the first time is how much better the car seems to brake in the rain, when cooling is obviously not an issue.

You can also look for the newer "high carbon" front rotors, which are made from a different type of alloy with much harder properties. High carbon rotors can last nearly twice as long as conventional units.

But won't it be at the expense of an increased pad wear rate?

Last summer I replaced all 4 rotors and while they were under the min thickness limit, I could not find any evidence of cracking. Porsche knows brakes.

Not really, the rotors are not more aggressive in any way, just harder.

Hi all, long time since I've been here. One thing to consider with street driving that seems
to never show up is a solid rotor could in some cases get a layer of water under the pad
and prevent you from stopping. The slots or holes wipe away the layer of water under the pad
and clean it. This happened to me once driving through a puddle very slow and then shortly
after not being able to stop. Never make that mistake again.

I did a super cheap package off of ebay with the slotted, drilled, and cermic pads all for just over $200. They have been doing great for the past few thousand miles. No complaints.http://986forum.com/forums/uploads01...1401635706.jpg

Unless you are tracking the car or autoxing really hard, the type of rotors for the streets do not make that much difference imo. The pad material is most important. Hawks are good pads to the OP.

Like another poster said, for the rain, I always "pre-bed or pre-brake" a couple of seconds sooner than I normally would to wipe the layer of water off of the rotor/pads. Never had any issues with hard rain stopping.

Not really looking to go full track car or anything but I do intend on hitting the track a few times this summer since there are a couple close to me and an AutoX event as well.
I ended up picking up a set of black high carbon rotors for the front(since it sees most of the action) and some cross drilled/slotted for the rear(for looks :p). Another thing was I ended up not getting the HPS pads and instead ordered the Stoptech Performance pads(all around). A few friends of mine swear by them over HPS's so I thought I'd give them a try, and the $60 for each set that I saved contributed to the stainless steel lines.

I replaced my rotors and pads a few weeks ago and I admit I like the look of drilled rotors. I found these on Ebay:
Porsche Boxster 01-03 Zimmermann Drilled Cryogenic F+R eBay item number:170686225136
Zimmerman Z-coat rotors drilled by DRT and cryogenically treated for a little over $400. I thought it was a pretty fair deal, and so far they look and work great! I wasn't originally looking for cryogenically treated, but I figure the added strength may help reduce/eliminate any cracking. They have other listings for other years. Might be worth a look. Good luck! :cheers:

Sounds like a great setup! And very smart with the ss lines. That is one of the first things I do with all of my cars--->goodridge, I swear by these!:dance:

I have never seen proof of any mfg. with cast holes in the disc on mnay forums. Brembo also states that casting would have no service life benefit over drilled holes. Post #12 of this link has some interesting information.

Porsche Rotors

My question kinda falls into this thread so I'll revive it.

I have almost 100k on my car and it is probably due for some new rotors. I don't track my car. Actually, I don't really even beat it up too much. Guess I'm getting old. Anyway, I found these and they look really pretty. I have no issue with admitting that I want my brakes to perform, but I want them to be pretty too.

Brake Rotors Front Rear Kit Powersport Drilled Slotted Ceramic Pads BZ00140 | eBay

http://i896.photobucket.com/albums/a...pszykmp5n3.jpg

While I don't beat up my car, I don't want a piece of junk installed either. I guess my question is has anybody heard of these guys and are their parts any good? I looked online and haven't found anything specifically negative about this brand. Just a bunch of people complaining about drilled vs. slotted vs. blank.

I don't know about Powersport.
When I replaced mine I called Jason at Paragon. Great product and price.
8 track days so far and no problems.

Think solid, not blank.

The only cracked rotors i have had (twice) have been on solid/blank rotors. One on an Alfa which gained a significant crack from the outside egde to about an inch. the other on a Range Rover.

Solid, unvented discs/rotors dont dissipate heat so well and heavy driving can cause the rotor to distort. also can happen after heavy breaking and holding on the brake as the pad to rotor contact will give different heat dissipation to the rest of the rotor.

Personally , I would go with OEM or spec of better. The Boxster has cross drilled venting on the 3.2 and I've never had a complaint with the brakes or the braking pad and disc wear has been good too. I see no reason to adjust what works.

On the later range rovers, they are vented but slotted and cross drilled are not a good way to go as an off roader, they can trap dirct, grit and debris, scoring the rotor/surface and reducing braking effect. I had a BMW 325IC once that brakes were poor on, i changed them out for brembo cross drilled vented and slotted with a slightly softer pad it stopped on a dime and gave great hot performance.

there is no one size fits all on solid/blank/vented/cross drilled/ grooved it really depends on the car, but with brakes for road / hard road use, OEM spec does the trick. if it didn't they would be opening themselves up for all kinds of liability suits.

High Carbon rotors
 

I was looking at those, but they are not for the S model. I ran across this website saying that these rotors for the S model by the same company are High Carbon Rotors. Not sure about that?

1999-2008 Porsche 911 Brake Rotors - Centric 128.37034 - Centric Premium High Carbon OE Design Cross Drilled Brake Rotors

Of course you can get them cheaper on eBay, but no mention of them being High Carbon Rotors.

http://www.ebay.com/itm/Centric-Brake-Rotor-128-37034-/111047630513?hash=item19daf45eb1&vxp=mtr

I use these reasonably priced rotors ($64 front and $59 rear) and they work fine. Your choice of slotted/drilled or drilled only. They sell solid rotors for even less ($48 front and $53 rear).

1999 Porsche Boxster Street Series Cross Drilled Slotted Brake Rotors | Cquence.net

http://www.cquence.net/porsche-boxster-1999-oe-replacement-brake-rotors.html

I'm curious about this one. The listing states that it's only for a 2008 Boxster S and Cayman S, while everyone else show the rotors of a 2008 Boxster S are the same as 2003 Boxster S. What would be different on these rotors that they can only be used on a 2008 Boxster S?

Front Rear Kit Black Hart Drilled Slotted Brake Rotors Ceramic Pads C2553 | eBay

This seller states the rotors work on 2000 to 2008 Boxster S.

http://www.ebay.com/itm/Porsche-Boxster-S-Iron-00-08-Brake-Rotors-Ceramic-Pads-Front-Rear-/321733371984

Centric shows the same part number for both cars too.

http://www.centricparts.com/products/hcr

http://i57.tinypic.com/11wadkl.jpg
http://i57.tinypic.com/n3oyvr.jpg

I went ahead and pulled the trigger for those cheap ones. Year warranty for warping and they appear to have a lot more favorable ratings than negative. If they last me a year and then go to crap, then lesson learned (cheaply) and I'll be smarter about it next time. I didn't buy the kit with the pads through. I couldn't figure out who the manufacturer was for those so I'll pick those up locally or through Pelican. Guess I'll report back in in a few weeks with fancy pictures and then in a year to report on what I think of them.

Now I need to find that article about how to break in new pads/rotors.

The brakes I ordered just came in today. Front and rear drilled with ceramic pads. The set even came with new pins, clips and springs. I'm waiting on the new caliper bolts I ordered from ECS before I do the install. The rotors look to be good quality. I guess i'll find out after I install them. Total cost including shipping was $211. For that price I figured i could just put the old ones back on if they suck.

http://986forum.com/forums/uploads01...1429904001.jpg
http://986forum.com/forums/uploads01...1429904030.jpg
http://986forum.com/forums/uploads01...1429904056.jpg

Seems a shame to get them all dirty ! :D

about 75 miles without any hard/heavy braking.

Anyone know if there is weight difference from OEM rotors?

I will weight them when I do the brakes.

This was the article I remember.Instructions for bedding in your brakes

It doesn't say anything about ceramic pads specifically. Perhaps some more research will be necessary.

The brakes I purchased came with instructions for bedding the pads.