cross drilled brake rotors in a street application is one of the most useless mod eveer. Solid face for maxximum brake useage.

 

As far as a useless mod, I guess we are all doing it,
Why change our wheels they are all round, who needs tinted windows it gets dark sooner or later , the stock stereo plays CDs , and my stock twins also boost.
It's all about a little extra and personalizing..

 

That´s something I would like to speak about. I mean OEM rotors for our babies are excellent w/o a doubt. But why do all, or say a lot, of high performance street cars have drilled rotors from the factory then? Just curious.
I mean even Mercedes do have it on all bigger cars in the meanwhile. Why should they do this if it´s worthless and cost more than a plain rotor?

Let´s discuss since I am also thinking of what to use next

 

They aren't drilled into the rotor, they are cast.

 

yeah the drilled is more for looks and for people who don't abuse their brakes too much

they also sell regular oem style rotors for 90 dollars for front and rear.

 

WTF ,, Heat for stopping , :nono: ..
Friction is required for stopping , The area the friction is applied to is also a factor. (bigger rotors more friction area) Heat is the byproduct of the friction. too much heat will cause the glazing. The main objective in a good braking system is to cool them as much as possible..
Too much heat will damage rotors (cross drill or not) drilled rotor may not be as strong ,but do keep tempatures down much better. For daily driving , they look good and work great..

 

Friction is required for stopping although larger rotors do create a larger friction area as long as the caliper/pad is sized up correctly...but most important of all larger rotors create a larger heatsink for the heat to be dispersed, in turn keeping your rotors cooler and glazing/fade to a minimum too.

 

I'll get those next... I have brembo cross drilled and hawk hps pads. They stop better then stock in my opinion. Fuck spending close to a thousand on stock rotors and pads.

 

i dont now were you are buying your OEM parts but i paid around 500 dollars for all new pads an rotors and new master and slave cylnder. Curt @ elmhurst toyota is the man!! :agreed:

 

I'd buy a set of those R1 concepts plain OE rotora and send them out for cryo-treating. That would be a great set-up...

 

Ok, fellas.
Let me summarize the aforementioned points in my (simplier words):
-Friction is the key for a good braking, right?
-As a result of friction heat is created. So far I am in the boat.
-Now the bigger the brake surface the greater the friction can be (take material components as given factors (metal for the disc, compounds for the pads)
-Saying this the heavier (and internally cooled) rotor can keep temps under control better.

All together logical until this point but this makes me think anyway:
Drilled rotors:
-Inside of the rotor, so in the cooling tubes (or whatever this is called in english) there must be heat getting captured.
-This heat could be evaded by creating a ventilation hole (drilled rotors) better than w/o. Or am I that wrong here.
Slotted rotors:
-No benefit for heat dissapation but I could imagine that this COULD BE helpful to clean the pads and remove dust from the contact area...

But back to drilled:
I would say that the reduced area in case of a drilled rotor is minor and so is the reduced weight. What is the weight of a rotor? 15lbs? More? I don´t see that the holes in there would reduce this by much, say maybe 1lb? If that makes a big difference in heat/fading in that particular application they are being used I guess the brakes are too weak anyway.

I see the point that for a lot of people this is just for looks. But, again, why do ALL sports car manufacturers utilizing this for years now if the rotors could crack or stop poorer than the same car w/o holes in the discs? And, for real, does anybody here have only a slight doubt that a Porsche, Merc. AMG, Z06 Corvettes etc. do brake bad?

But, again, this is a discussion and these were my thoughts.. Any comments? Just my 0.02

 

No benefit for heat dissapation but I could imagine that this COULD BE helpful to clean the pads and remove dust from the contact area...

sorry stopped listening after this. the slots are used to remove gases but i have no clue about how you got that clean off the pads statement.

put whatever u want on your car it doesnt matter to me. theres no reason to have drilled/slotted/ whatever rotors for the street. figgie was correct...it seems like people are just making stuff up to support their theories because ive never heard any of this stuff before.

 

so what would you recommend SJ

 

oem rotors and good quality pads

 

Stock rotors and calipers for any application other than a top shelf BBK like Brembo, StopTech, AP and GReddy/Alcon and, even then, if your rotors are not the Brembo cast iron 14-inch versions, (typically used by the others in drilled and slotted forms) or AP 14.2-inch rotor, you will not necessarily see enhanced braking performance. IMO, any replacement rotor for the OEM rotor, including (the now discontined) Brembos are inferior to the OEM rotor.

This is an area where guys continue to not fully appreciate just how good the OEM braking system is and, for looks or budget, or both, unknowingly diminish the braking performance of one of the best OEM braking systems ever.

Ken.

 

ken is right. its been top of the bunch for stopping power for years... recently a porsche beat the supra in stopping distance... there are not too many cars that can say they can do that... and here we are in cars that were built over 10 years ago...

 

Don't forget that the Supra brakes were superior compared to any sports car produced during the production years. IT was even superior to the Corvette. The OEM brakes and pads are not Mickey Mouse.

 

OK if the cross-drilled/slotted are just for looks on a street vehicle, what about those dimpled/slotted
rotors companies have been hawking? They obviously don't crack, have the same benefits as the
slotted variety plus they have that cross-drilled look.

 

Anyone ever see the DBA 5000 rotor?
It looked like a nice replacement rotor being a 2-piece. Then I saw the price of $400 per rotor

 

@SJ
So I can agree with you I also never ever had any problems with my OEM rotors braking from 180+ mls down to 50 because of jerks on the left lane of the Autobahn
Here one shot from Brembo´s FAQ section anyway
Why use drilled or slotted discs?
Drilling or slotting discs aids the disc in several ways:

The edges of the slots or holes continuously clean and refresh the pad surface as well as providing increased brake "bite". Additionally, they prevent gasses from collecting between the pad and disc interface.
The disc is lightened, thereby decreasing its rotational inertia.
Improved ventilation increases the disc's ability to shed heat, resulting in cooler operating temperatures

@all
For 90% of the people driving a MK IV the stock brakes are more than sufficient and in this case an upgrade is mostly a waste of money.
BBK is a good choice for those who do extensive track racing and experience fading with the stock system.

Rest is for looking

 

Well as promised, I'm reporting back with updates on these rotors.

So after about 1 month and 600 miles driving with these rotors, I am very happy with them. I just inspected them and no cracks or anything unusual at all. Not even any rust! And I've driven in the rain a few times and washed the car a few times. Braking performance is much better too and the brakes feel firm. This is probably because my oem rotors were very worn so these new ones is a world of difference.

However, most important is that there are no cracks or deformation in the rotor even after doing a few hard runs over 2 months and 800 miles. I included a picture of what mines looks like. Yes, I know that slotted/drilled rotors are not the best choice, but I liked the look of it and I drive pretty conservatively. I only drove hard a few times to test out the quality of the rotor.

In addition, the customer service there is very good as they are very polite and knowledgeable. The only thing that was bad was that it took 2 weeks to get the rotors in because they took about 3-5 days zinc coating them.

 

If that's the driver side rotor, you have it on backwards.....

 

Oh really? On the rotor is said "L" which I suppose meant Left and the oem rotor I took off that side also said Left. Thanks for the heads up.

 

ordered mine from them about a week and a half ago and they still have not shipped them out, I just ordered the stock non slotted/drilled rotors. I called last weeka dnthey said they would be out friday or mondays but still nothing. Hopefully I get some word from them soon.

 

Let me see the pic again?? Just want to be sure...

Don't feel bad. It might be me who is in error, or perhaps the rotors were labeled wrong. Generally, the outermost tip of the slot should be the 1st part of the slot to "cut" into the rotor.

Also, sometimes the cooling vanes are directional. Geez....it's often tough to tell.

 

Thanks, I'm gonna contact R1 Concepts and see what they have to say about it. So yes, either they mislabeled it or because it is a non-directional rotor, the side it is on doesn't matter.

 

Sounds good. As I said..post your pic up again, and see what everyone else thinks...

 

I'm sure you are right about the direction as I checked many other pictures of slotted/drilled rotors and they seem to go along what you said. I don't want anyone to get the impression that I'm not careful with installing so I will update again when the manufacturer confirms that either they mislabeled it or the direction of the rotor doesn't matter since it's a non directional rotor.

 

^^^^Who cares what everyone thinks. You don't even know these people...LOL At any rate, let us know how it turns out, OK??

 

I guess right now, the big question is. For NON DIRECTIONAL drilled/slotted rotors, does it matter which side the rotor is on?

 

Ok pic is back up. Phwew, I just contacted R1 Concepts and they say the way I have it is installed correctly.

After much researching, it seems like the direction of the rotor seems to matter only on directional vaned rotors such as on stoptechs, brembos, etc. That is why I guess people are so used to seeing the direction of the rotors the opposite way of how I have it. It's because that's how it's seen on more popular rotors and bbk's.

 

Think of the rotor as a centrifugal pump just like a water pump. You cant run a water pump backwards (ie: draw water from the outside diameter and pump it out the center, well you can with properly curved veins but it doesn't work as good as the other way). Directional rotors are designed to take the air from the center and pump it to the outside. Think of it like that and you will always be good.

BTW heres why you don't want to run drilled rotors, READ THIS look for the line "DRILLED VS SLOTTED ROTORS", about 3/4 of the way down. This entire site is an excellent read.

Would you drill holes in your water pump impeller? Yea I know a water pump impeller isn't designed to absorb and dicipate heat. But if its already designed to be a big pump, why would you drill holes in it and cause it to cavitate.

That being said, I think they look cooler too, but wont run them because slots accomplish the exact same task without reducing mass and creating stress risers, giving cracks plenty of places to start.

I have a lot of experience with racing brakes and lots of rotors without vent holes will develop cracks through out the entire braking surface from the extreme heat
cycles and teams on limited budgets will continue to run these extremely heat cycled rotors until these cracks make their way to the outside diameter of the rotor, thats when you run the risk of the rotor catastrophically failing.

That being said, if you are a conservative street driver you are probably fine. If you raced the car or did some time attacks or road course events you would quickly learn why not to run cross drilled rotors.

 

I have seen the same pattern on other rotors like the one above BUT I guess you just have to make sure they are all facing the same direction

 

I e-mailed brembo , thier responce was, Regardles which brand you choose , internal viens determine rotor desired rotation. vein curviture should be facing foward.

 

Nice, that's what I thought as well. So since the r1 concepts rotor are non directional vained, it should be good as long as all the rotors are facing the same direction.

This thread wasn't really meant to debate whether or not drilled/slotted rotors were beneficial or not. In my opinion, I don't think they benefit my performance, but I don't drive crazy on the street so I don't expect these rotors to crack anytime soon. I guess I just like the agressive look. Overall, for the money these are great rotors. However if you want significantly better than oem performance, probably a directionally vained rotor would be better imo.