Crossdrilled rotors?

[steevil]

I have a set of new factory rotors that will be cross drilled and slotted. They will then be cadmium plated.

The person doing it will be using a CNC machine.

Cost is going to be $50 CAN per rotor.

Any thoughts on this? I know that cracking may be an issue and that they can not be turned after this. Anything else I should know?

He tells me tht cross-drilled AND slotted is the best.

thanks.

 

[twr]

Honestly, Cross drilled takes away from braking performance. It removes material reducing the heat dissapation of the rotor and also removes contact area for the pads to grip.

Slotted rotors allow the gas generated under heavy braking a place to go. But with the newer bonding agents that are used in todays brake pads, not much if any gas is generated.

More often than not, most people the go slotted and cross drilled are after the look more than any type of performance gain. Sure some of the exotics have them but have you ever seen a true race car with them??

 

[steevil]

good points. Appreciate the info.

 

[ChrisR]

I agree, I have heard neither is really a performace gain. But don't get me wrong, the look pretty sweet.

Do you think slotting negative affects? Or has any performance loss?

 

[yamahaSHO]

I have slotted rotors from PowerSlot. I don't see anything detracting from braking. The slots don't take too much surface area away and they don't crack like cross drilled. I like the fact they let gasses, water, and dust vent out very easily. I did not do it for the look, I did like the fact they were plated so they did not rust where the pads do not contact.

 

[LOUDSHO92]

I had a new set of stok rotors for my 92 cross drilled because I could do it for fairly cheap. I have not noticed anything taken away from the breaking. I have not warped them or cracked them yet and I do some heavy breaking every now and then. I do like them though.
One thing about heat transfer which breaks rely on, the more surface area you have, the more heat will get disipated. I dont know how much of an advantage cross drilling offers but just something to think about.

 

[SHO24V6]

crossdrilled should be for show cars only I think
thumbs_u

 

[noSHO]

Yes I have advice. Don't cross drill stock rotors. Rotors that come cross drilled are specially treated/designed (I think it depends on the manufacturer how EXACTLY the handle the process) to strengthen to metal for the cross drilling. If you cross drill a stock rotor you will weaken the metal and greatly increase the chances that the rotor will crack due to heat stress. IF there is a performance gain to be had, it is far outweighed by the increased chances of cracking your rotor and any risks that come along with that. I'd stay away from it.

 

[BlackOnBlackATX]

cross drilling is more for watershedding than anything else. and as said before its not a good idea unless the rotors are treated for it (i.e. forging or cryo treatments) just because it can cause premature cracking (not always but its a possibility) but slotting is not a bad idea at all. you could even slot your brake pad, one line down the middle (if it didnt already come like that). slotting pads is a technique used not only in the race industry but i find that some auto stores are even selling their pads preslotted. let us know how it turns out.


ps - if anyone is curious, my friend has a twin turbo 300zx, and he said the difference between his stock and cross drilled rotors was night and day. i can vouch for this myself. the car stops much much smoother and quicker. but also keep in mind he payed around $100 a rotor i believe, maybe a little more. just food for though.

<small>[ March 18, 2003, 07:41 AM: Message edited by: BlackOnBlackATX ]</small>

 

[Dave Kegel]

Yeah, but they do look cool.

Seriously, I just got them because they were fairly inexpensive (~$165). I believe this was less than stock Cobra rotors would have been at a local auto parts store.

Dave Kegel

 

[kaoticSHO]

I have cross-drilled rotors on the blown car and they do "look" cool. I went with gas-slotted on Opal.

I don't have any empirical evidence either way. I would like to know if one or the other is easier on the pads.

 

[noSHO]

The thing about drilled rotors releasing trapped gases is somewhat of a misnomer, somewhat. The only way you release gases is if you have them there in the first place, and not all pads create gases. Typically race-type and some high performance pads release gases when heated, but I'm not sure on the state of CF pads. So kaotic, if you have regular or mildly agressive pads, there probably isn't much difference. What you might gain is probably equaled out by a loss in contact SA, but yes, they look cool. Even with a small probability of having a rotor crack (and there is no real way to know what the probability is either way until someone does a good scientific test, ie not a ricer test in Honda Tuner), I don't think that's something most people would want to risk. Besides, IMHO, cross-drilled are sort of a "last touch" type of thing. Look at Kegel's and kaotic's cars, they're beautiful. Personally, I have a few other things to fix before I start spending money on nice looking rotors.

 

[steevil]

I am basically at that point. I have pretty much done all I can (within financial reason).
The rotors do look cool and that was part of it. Hopefully It will help with my chronic warping problem.

My wheels have huge voids so the rotor is highly visible. The cadmium plating will take care of the rust problem to I hope.

 

[noSHO]

steevil:
I am basically at that point. I have pretty much done all I can (within financial reason).
The rotors do look cool and that was part of it. Hopefully It will help with my chronic warping problem.

My wheels have huge voids so the rotor is highly visible. The cadmium plating will take care of the rust problem to I hope.

Have you upgraded your brakes yet? If you're on a bigger set of brakes and you're getting warping you might want to look into that. Yikes. eek! What kind of wheels do you have?

 

[steevil]

I have priced out the bigger brakes and it is quite frankly out of my budget.

I would prefer to go to the 96 SHO brakes but finding one at a wrecker is virtually impossible.

Pricing it out at Ford was almost $1900 (CAN) and for that price I would prefer the Baer upgrade.

Which brings a second problem. After a Baer upgrade, I would hate to have to wait 2 weeks to get brake pads, especially if I am in the middle of nowhere.

I have the discontinued TSW "Blades" in 17"

Forgive the chevy pic, coulnd't find a pic unmounted

<small>[ March 19, 2003, 01:54 PM: Message edited by: steevil ]</small>

 

[Dave Kegel]

FWIW, the 13" brake upgrade cost me under $600. I paid $218 for the PBR calipers (with brackets) from http://diskbrakesrus.com ,$162 for the rotors off of EBAY, and $100 for used '94-'95 hubs at a local junkyard. $60 for stainless steel brake lines (all four), and $25 to have the rotors drilled for the Taurus bolt pattern.

So it can be done relatively cheaply if you've already got 17" wheels

Oh, and brake pads are readily available at any AutoParts store. Just ask for pads from a '94 - '99 Cobra.

Dave Kegel

<small>[ March 19, 2003, 02:34 PM: Message edited by: Dave Kegel ]</small>