Z WEAPON

Which 1 is better and why?.....

I am looking at the Brembo Gran Turismo 6 Piston Monoblock Kit!!

Thanx Steve

gonzalezfj

If you want these for track duty, forget about the cross-drilled rotors. They are for bling and will crack quickly under track usage.

Slotted are OK, plain are OK too.

Frank Gonzalez

Z WEAPON

Frank....why Just Plain ok?....

AU N EGL

Drilled rotors crack too fast and are 40 year old technology only kept around for marketing purposes as customers want them

Slotted rotors scrap glazed over pad material form brake pads that are too hot. again 40 year old technology to exceptional brake pad materials these days. If your brake pads glaze over from heat, your using the wrong brake pad.

still OK to use. but do eat brake pads faster.

solid side rotors provide more braking surface for the friction of the brake pad to the rotor.

Ever wonder how much braking friction a hole can make?


for normal street use D/S are fine. But not for performance braking.

Moss

Slotted rotors scrap glazed over pad material form brake pads that are too hot. again 40 year old technology to exceptional brake pad materials these days. If your brake pads glaze over from heat, your using the wrong brake pad.

QUOTE]

For those of us who drive different tracks and can't change pads for each individual track are we not better off with the slotted rotors?

AU N EGL

Maybe. however, you do bleed your brakes before each track event, which means you take each wheel off and inspect each rotor and set of brake pads.

Find your self one set or one brand or race pads and use those pads on all the tracks.

If you have a double duty car, they again you are taking each wheel off after a track event, changing back to street brake pads and rotors, plus bleeding your brakes again.

If you have slotted rotors those are fine. If you buying new rotors, then smooth sided rotors would be a better choice.

Good luck

vetdude

There have been numerous discussions on this. Try doing a Search using keyword "rotors".

vetdude

If just for the bling factor, I wonder why Porsche (arguably the best OEM braking systems in the world), Ferrari and other high-end sports cars use cross-drilled from the factory?

Katech_Zach

I believe Frank and Tom are right.

Cross-drilled - lighter (nominal) and to please the customers that just want them. We use cross-drilled on the ClubSport for marketing purposes because it fits the theme of light weight.

Slotted - I prefer slotted because it is less ricer-ish (my apologies to those who have cross drilled). And since my car is a multi-purpose vehicle wiping the brake pad is probably an advantage. I also don't like cross-drilled because I see so many of the production and cheaper aftermarket slotted rotors cracking between the holes. Brembo assures me that this is not a problem with their rotors (probably because there is a lot more material) and to date, they have yet to be proven wrong.


If you don't believe Frank, here is a picture.

Katech_Zach

..because it sells cars.

greendot

I agree, Is anybody making a plain rotor of the C6Z ? Direct replacement, not a 2 piece.
I got slotted because that was all that I could find at the time.

klasik-69

As is the case for the Corvette, Porsches and Ferraris are primarily used for the street, and cross drilled looks more "racy". Also, the better quality rotors, like Brembo, likely don't crack as the cheaper ones do.

I think the best argument made was from Au N Egl, how much braking does a hole make ? You have a way with words.

BEZ06

Yeah, me too - I got the slotted DBA 4000's because that was all I could find in a relatively cheap one piece rotor. They are $147 each from Tire Rack.

I've been looking for a plain rotor but can't find any. Of course even the plain or slotted rotors will crack just like drilled ones, but hopefully not as quickly.

Here's a picture of one of my DAB 4000's after some hard track braking:








You can see that it cracked right into that slot on the edge of the rotor (what DBA calls "wiper" slots).

Any hole or slot in the rotor creates a focus point for cracks to start developing.

Bob

greendot

That's what I got. I only run NCCC stuff so I don't have the continuous use of track days but thanks for the heads up to keep a close eye on these. I suspect that the hot soak of the NCCC high speed events is harder on brake fluid than on the rotors. DBA could easily delete that edge stress riser.
What pads do you run?

AU N EGL

ALL rotors crack. Some sooner then others.

Why do they crack? Normally rotors do not crack on the track from hard braking, they crack in the paddock after a very hard session of heavy braking.

in the Paddock? YES many times you can walk around a paddock and you may hear this unmistakable high pitched 'TING'. That is a rotor cracking.

How does this happen? Uneven cooling of the rotor. the part of the rotor that is next to the HOT brake pads, cools slower the the rotor that is exposed to the air. This cooling difference caused the iron to seperate and TING.

How to avoid this rotor cooling challenge? When you come of the track drive around the paddock a few minutes too help cool the rotors, the engine too. And if you get a chance, n. once you park your car, in 30-60 sec push your car, 1/2 a wheel rotation. This moves the part of the rotor that is still next to the HOT brake pads into cooler air.

I have seen even the TOP name rotors, Brembo, Alcon, StopTech, and Colman crack with in a few hot sessions on the track. Does not matter who makes the rotor. Rotors like brake pads, do need to or should be bedded prior to hard use.

StopTechs white paper on brake pad and rotor bedding is just about the best one out there.

***** footed brake bedding does not do the trick. or driving 500 miles easy does not work either.

BEZ06

I was running Hawk DTC-70 pads, and the crack occured in the last session of 3 days of hard running of almost 2 hours of track time each day.

At Daytona, after you turn into the infield there are only about 3 hard braking corners that come up pretty quickly one after another, but you only get up to 110 or 115 before braking down to cornering speeds of less than 60.

The big problem is that after heating the brakes up you leave the infield and they really cool down during your time blasting around the high banked oval around NASCAR T1/2 and up to 160+ before braking to 70 or so for the chicane on the back straight, then the brakes cool while you cruise around NASCAR T3/4 and get up to 170+ down the front straight before braking down to 50 or so for the first turn into the infield.

So....at Daytona the brakes get heated up a bunch, then they have some sort of extended cooling times before heating way up again. I'm sure that puts a lot of stress into them.

Bob

GMuffley

Exactly. People expect their high-end cars to look the part--cross-drilled rotors. Beyond that, I think it is safe to say that most Ferrari and P-car owners (or Z owners) will never experience cracked rotors from cross-drilling because the cars are not tracked.

Dirty Howie

I do this


DH

AU N EGL

Ever go to a Ferrari track event? Good events to go take your vette to. Lots of track time as all the Ferrari guys are standing around in their $3000 custom made Momo race suits LOOKING GOOD

but never hit the track.

AtlBlkZ06

I didnt know cooling was so important to the brakes. Thanks!

"