todinlaw

I have been on a pace of doing a DE every other week so far. I have been braking harder and deeper. My rotors are turning blue, its not totally even but I would say 80 of the drag surface is tuned color. I am assuming that this is expected. No micro cracks yet. I also see that some of the cooling holes in the rotors did clog up with brake dust, I just blasted it with the hose and it has cleaned it out. I still have the stock pads on the car. Any worries?

blake

I don't think this is a problem. I remember some old threads on this over on the 996GT3 boards a few years back. With my track car, I just inspect the rotors for cracks and also look at the "rings of Saturn" to locate any warping... I keep the cross-driller holes clear by using an air hose. Be sure to wear eye and mouth protection when doing that as it probably shouldnt be inhaled in a confined space... I always run the blower to cycle the air in my track garage...

UPDATE: Found the link I was looking for (needed to search for "bluish" rather than "blue")....
Have a read: https://rennlist.com/forums/showthre...ghlight=bluish

Reviewing this thread, 99% of the posts in this thread tend to feel it is okay.... except for Robin (Rennlist Name: "Nordschleife"). Here is his post:

"I believe that a series of extreme heat cycles can 'cook' the rotors. A strong blue hue is indicative of this. 'Cooked' rotors have undergone what might fairly be described as 'curing' or 'heat treatment'. In consequence, their behaviour under normal driving conditions is modified and their effective capacity for absorbing and releasingf heat is changed. It is hard to tell from the photograph because of the lighting, reflections and lack of some external colour reference. However, the cracks do not seem great. I would not dismiss your tech inspector's comments out of hand. My brake guy junks blued rotors faster than you can say 'HOW much?'
R+C"

As Robin works for Porsche in Stuttgart, many of us have grown to trust his word over the years...

-Blake

OldGuy

PCCBs or Iron?
If its iron its just your tempering the steel no biggie. if you see cracks start looking for the
bulletins on wear.

todinlaw

I just read the thread that Blake posted for me and it sounds as if its just the aftermath of the rotor getting real hot, but not a critical problem. they are iron rotors. I did not notice an brake fade. I just went out and took the pictures below.

blake

Frank - my rotors (iron) look EXACTLY like your picture... I'll be out at the track on Thursday and will take some pictures.. I don't think it is anything to worry about, and feel that Robin;s comments on that thread were directed towards Cup cars that encounter extremely high brake temps...

-Blake

AllanJ

My rotors looked a lot like that too after a hard day at the track. I got plenty of little cracks forming by the holes as well. After driving on the street, a track day in the rain and a Solosprint, the rotors aren't blue anymore. They're evenly polished and generally a little worn in the pad area (I can feel a ridge at the inner and outer edge of the rotors).

I ordered more today since these rotors will be toast very soon at the rate I'm going.

Cheers,

C.J. Ichiban

robin is far and away the most knowledgeable brake man I've ever encountered in my life. He hasn't posted on here since december nor has he responded to any of my emails so I wonder where he's at these days...

MJones

Blue Rotors...
Pretty normal IMO

When I AX'd my "S" it was a normal occurrence as well as the steel rotors of the Carreras at PDE.

blake

CJ - I'm worried about that as well. Robin is one hell of a resource. I hope all is okay with him...

-Blake

mjb

This is normal. Not sure what pads you're using but a change to race pads (pagid RS19/29, etc) will also help to better manage the heat generated by hard track driving.

Mateusz

I raced an STI last year with competition brembo rotors and after one of the sessions and some hard abuse, the rotors also turned blue. They also lost substantially on effectiveness and we had to change them to be able to compete. Our mechanics immediately said to dump them. I can't say if it was exactly the same phenomenon you encountered, nor whether this "cooking" process can have various degrees of seriousness affecting braking capacity of the rotors differently. Perhaps your rotors are not as badly affected as ours were at the time. I would simply exercise care and not push the brakes all the way until you are sure you know where their new limit is. There's nothing like discovering that your brakes have gone when approaching a hairpin. Good luck and be safe.

Kolbjorn S

I am certainly not a chemist but looked into this when I replaced the glaced blue flywheel on my 993. To my humble understanding it has to do with critical temperature: Each metal has its own critical temperature and when heated above this, for so to cool down slowly ("air-cooling"), a different crystal structure forms than the original one. Looking at it from an atomic level, basically molecules re-arrange, resulting in different light-absorption, reflecting a light which typically is blue.

How much this altering of structure affects strength / rigidity I really do not know. I replaced the flywheel to stay on the safe side.

todinlaw

Stock Pagid's. In one of my later run sessions my instructor commented that I had this heated up and working because we could smell allot of brake pad after heavy braking. I did turn some of my best times however. I never felt any pedal fade however.

930man

looks great to me!!!! using the brakes!

Bob Rouleau

Rotors turning blue show that you are braking hard and/or PSM is frequently invoked. No danger in the color. Youo will find premature cracking of the rotors because you are getting your rotors too hot. Street pads promote excess heat on the track. Get some track pads like the RS-19 or RS-29. You can use them on the street with no issues (but not in cold winter temps) and your braking and rotor life will be improved. If you have not changed to a high performance brake fluid, do so. ATE Super Blue,. Motul 600 Racing or the like will do fine.

Note to all, I deleted the reference in 315s post to a certain retailer who has been using Rennlist to promote his shop without being a sponsor. Since 315s refers to said retailer in the majority of his posts, I suspect that User 315s is associated with said shop and freeloading off Rennlist. That is likely why he is now banned.

Best,