: Those buying GM cross drilled rotors GB!



ssmith100
10-20-05, 11:23 PM
After having had my new cross drilled's for a while and checking out the factory CAD plating, I'm going to make a strong recomendation. Do yourself a favor and scuff down the rotor hat and outside fins with some sand paper and paint. I used VHT high temp silver which looks better than the plating. The problem with the plating is it just scratches off. I don't think the hats would make it three months before they starting rusting just like the facory rotors. It is time consuming to scuff, tape and paint them, but I think it will be worth it. Just my 2 cents.

Shane

51PHFTY
10-21-05, 12:11 AM
Thanks for the tip Shane. I wonder if powder coating would also work?


Marty

ssmith100
10-21-05, 12:31 AM
Power coating works great if you can find someone who knows what there doing. The rotors on my car right now are powder coated. They were done by a company called BrakesRUs. I wouldn't recommend them. The only nice thing about painting is that it can always be touched up. Small scratch, hit it with somes paint. If the powder coat starts to peel, no such luck.

Shane

LV_V
10-21-05, 07:13 AM
Rusting? My rotors only show slight rusting after washing the car. As soon as I hit the brakes a few times on the next drive the rust is completely gone. BUT I also live in a dry, arid climate.

1fstkde
10-21-05, 05:40 PM
Rusting? My rotors only show slight rusting after washing the car. As soon as I hit the brakes a few times on the next drive the rust is completely gone. BUT I also live in a dry, arid climate.
lv..do you get rust from spraying rim cleaner on your rims??? or just washing it?? because i notice that when i spray rim cleaner on my rims it gets on the rotors and the rust stains show up..but if i just wash it without the rim cleaner, nothing...just wondering if it happends to you??

LV_V
10-21-05, 05:46 PM
Pretty sure its just the water and soap on them. Here in Tucson we have very hard water, may add to the cause, but what do I know. Next time I wash my car I'll take some pics.

ssmith100
10-21-05, 06:27 PM
Not talking about the rotor surface itself. I'm talking about the actual hat of the rotor. Braking will take off surface rust of the rotor after washing or rain. The rust I'm talking about is on the hat and fins of the rotor.

Shane

pietroraimondi
10-21-05, 08:29 PM
The GM Brembo cross drilled rotors are the same economy gravity cast iron rotors that are standard equipment on the stock CTSV. There is NO tin-zinc plating, nor any Cad plating on the rotor hubs or the directional vanes which should act as a traditional rust inhibitor. The GM Brembo rotors (stock & accessory cross-drilled rotors) are simply painted and you already know the end result of that process.

A quality rotor should be treated with one of a number of plating rust inhibitor processes: on the low end; most rotors are either tin-zinc plated or cad plated. This process however wears off almost instantly in the rotors "fire-path" which is where the caliper contact pad area is. The fire-path does however "self-clean" once you begin braking. On higher end forged rotors; rather than using an electroplating process; the rotor receives a 3 hour copper and nickel chemical bath which provides a much harder and durable surface as a rust inhibitor and is much preferred in areas of the country that have higher salinity levels.

PneuBird
10-22-05, 04:39 AM
Soooooooooo Pie....what are you suggesting we do with our new drilled rotors?

pietroraimondi
10-22-05, 12:14 PM
I would not powder coat the rotor hub as the polyester agents in the powder coat will inhibit the rotor hub from "breathing" and ultimately act as a heat sink and defeat the purpose of allowing the rotors rear impeller to dissapate heat from the wheel bearings and ultimately through the directional vanes.

You can paint the rotor hubs. Yes it will flake and scratch and require touch up from time to time, but you will not have heat problems that would be associated with powder coating a one piece rotor.

What I would do is have the rotors media blasted to remove the factory paint from the entire rotors and then have them electroplated with tin-zinc. Cad is currently on the EPA "hot list" and will be gone from the scene by 2007 due to it's toxicity.

If you budget allows it; I would send them out for nickel bath plating versus nickel electro-plating. In a bath treatment; the rotors would receive a copper bath for two hours and a nickel bath for one hour.

The bath treatment will treat every part of the rotor internally that electroplating always seems to miss.

After plating the rotors, you can still paint the rotor hubs even over the nickel plating if you like that 2 piece look. With painting, you'll just have to touch them up maybe once or twice a year. But I would NOT powder coat the one piece rotor hubs under any circumstances.

There are some industrial powder coats that can be used on rotor hubs that will breath and not seal the bell-hub, however most local PC shops don't have access to it or have never heard of it as it is used in military applications. We do stock that particular type of powder coat material and it limited in color: green; blue, white, red and black.

Another option is that we can build a custom set of CTS-V cross drilled rotors for you in either a one piece configuration or two piece. Allot of clients have gone with the two piece rotors for the front and the one piece rotors for the rear. Our rotors are constucted of long grain ductile iron that are forged versus short grain gravity poured cast iron. The result is a much more durable rotor that is warranted against warping and cracking etc.

They are also thermal treated and cryogenically treated and can be tin-zinc plated, nickel-plated or nickel bathed

If you have any additional questions; let me know.

regards - Pete
Cadillac MotorSports, Ltd.

ssmith100
10-22-05, 07:06 PM
Painted my rotor hats and fins today with VHT aluminum high temp. They turned out great and will look very good on the car. Did a lot of prep work and taping. They will be installed this coming week.

Shane

urbanski
10-22-05, 07:11 PM
slide us some pics :)

ssmith100
10-22-05, 07:31 PM
I new I should have taken the pics first. In the two pics it is very difficult to tell the difference in color between the hat/ fins and the factory coating on the rotor. The hat will look a little darker. For those that elect to paint, the paint line on the hub will need to extend almost a 1/4" beyond the hub onto the actual face of the rotor. The reason being is the factory pad doesn't sweep the surface all the way to the edge of the hub. Once the pads are installed the pad will remove the slight edge of paint that might extend past the rotor surface. Hope that makes since. Hopefully the pics will show that. This was a very easy thing to do and will make a difference later. My hubs would have had to be painted anyway as when they were shipped they got scratched in the boxes.

CVP33
10-22-05, 09:06 PM
VERY NICE!:highfive:

pietroraimondi
11-15-06, 04:11 PM
I would be careful & exercise allot of caution with allot of the commercial wheel cleaners and there "overspray". Most all contain oxalic acid which is an excellent rust remover and will equally damage the mirror polishing and lacquer finish on your alloy wheel rims as well as any chrome plating on your wheel rims. In addition; I would caution the use of any high temperature paint on the hub portion of any one piece rotor. By doing so; you are in effect "sealing" the rotor hub and running the probable and substantial risk of having your rotor hub act as a "heat sink" and potentially damaging your wheel bearing and causing the rotor cheek to "cone".

BTW; technically speaking there is no such thing as rotor warpage. A rotor surface will "cone" from improper torquing; much like a tire will prematurely wear from not being balanced and I bet you've never seen a warped tire in your lifetime! The other factor that comes into play with rotor cheek "coning" is utilizing a brake caliper that is not rated for the application you are utilizing it for.

Caliper deflection; particularly the front OEM Brembo lug mounted 4 piston calipers are not designed nor are they intended for SCCA sanctioned "racing events". Using the front OEM Brembo CTS-V calipers for SCCA events will lead to rotor cheek coning and premature wear of the leading edges of the calipers pads. Why?....it's a 2 piece caliper that suffers from severe deflection under heavy braking.

This particular front OEM Brembo caliper should be replaced with a monobloc radial mount caliper in either a 4or 6 piston configuration for SCCA race sanctioned events. A 6 piston front caliper versus a 4 piston front caliper will give you more wear out of your front brake caliper pads particularly along the leading edges of the brake pads. These types of "monobloc calipers" are available from Brembo, Baer, Wilwood, AP Racing etc. These type of monobloc calipers typically start at about $1000 a piece plus the cost of the radial mounting brackets.

On a two piece rotor; the rotor hat itself should be either left bare or anodized. We anodize all of our rotor hats and now ceramic coat all of our rotor cheeks. The ceramic coating serves two purposes: first it helps lower the ambient temperature of the "fire path" of the rotor itself. The firepath is the area where the brake pads come into contact with the rotor surface under brake pedal pressure. Secondly; since it is impregnated with sterling silver; it is an excellent rust inhibitor in areas that are outside the firepath such as the internal vanes, etc.

Finally; the 4 piston factory Brembo rear brake OEM calipers are fine for just about any SCCA sanctioned event; and for the most part and as it has been said beforeby many others; for the most part the rear brakes are just along for the ride.

kgoch
11-15-06, 04:26 PM
I sprayed the hats of my drilled rotors with black VHT. I wanted the large rotor surface and calipers to show up better. The black holds up nice, but before I painted them black, I painted the silver VHT and they started to rust through in about six months.

pietroraimondi
11-20-06, 06:31 PM
With regard to the one piece rotors; do not paint them at all. The paint in effect will "seal the rotor hub" and turn it into a heat sink. Simply stated the rotor hubs will be hotter than a frying pan and you run the risk of rotor coning and cooking your wheel bearing.

If your budget prohibits 2 piece rotors where the rotor hubs or hats are constructed of anodized billet aluminum; what you are dealing with is trying to rust proof a ferrous piece of carbon cast iron.

The best product to use would be a hybrid epoxy based ceramic powder coating that in effect lowers the temperature of the wheel hub, acts as a rust inhibitor and increases the longevity of your wheel bearing.

Be cautious however as there are many different types of powder coating materials that are utilized for many different type of interior and exterior applications.

A can of VHT spray paint is not the simple answer to curing all of the potential problems with regard to one piece cast iron rotors. Professional plating, ceramic coating or hybrid based powder coating is your answer. We are able to provide all 3 types of applications.

bcholka
11-20-06, 08:33 PM
Pete,
I'd be interested in working with you on some new rotors.
Is your website down??
How can I get pricing/availability, etc??
Thanks,
Brian

V-Love
11-21-06, 01:55 AM
Pietro,
You sound like an engineer. It seems like if I'm going to go for the high end rotors I would need the new caliper set up too. What do you think of the stock brakes(well maintained) for 6-10 track days a year?

Dennisscars
11-21-06, 10:28 AM
Not my question but..
It depends... if you drive like your gonna win a big cash purse, you'll need bigger brakes and lots more. I have over 35 track days on stock rotors and pads (second set), but I'm pretty stringent on slow in, fast out. Only the light cars can sling shot in and out of a turn because our starter has more torque than their hamster motors. I'm finding that a smart driver makes better time than a crazy banzai driver. Alot of it depends on why you are on the track, for casual use this car rocks out of the box.

And I painted mine black..
http://www.cadillacfaq.com/faq/answers/img/chromewheels/chrome-wheels.jpg

StealthV
11-21-06, 01:00 PM
Thanks for digging up a thread over a year old. What was the purpose? $$$?

My rotors and calipers are painted for 2.5 years. DOOM AND GLOOM! We're all going to die. :)

zozmanCTS-V
11-25-06, 01:23 PM
I have Baer Eradispeeds for my Z06. I called Baer to see if they plan on producing Eradispeeds for the CTS-V. They are not in the future production schedule. So, I'm buying a set of GM drilled rotors and having them powdercoated. The stock solid rotors will be powdercoated also. I'll switch them out at the appropriate time. Those rotors look very good with the open faced type wheels available today. A friend of mine runs a powdercoating business. He regularly coats rotors. Never has had a rust, performance or customer return complaints. Heat build-up? :eek: That comes with tracking and you don't use drilled/slotted for tracking. Everyday use is not an issue. :thumbsup:

Randy