Brake Cooling - Overheated rotors?

[V10 ICBM]

Hi - I just loaded on a new set of 2-piece stoptech rotors - very good - BUT - i am staring to notice tiny cracks in the rotor - likely from heat - they seem small - but i am driving a stock 2000 GTS, stock tires, 4-wheel stoptech upgrade, PFC 01 pads.

Is this common if i do not have ducts or deflectors? Is this truly an overheat issue? Also I notice shudder after a while which seems to be related to intensity of use - ie perfect stoping and brake feel for several laps - then - - the dreaded shudder - Perhaps this the result of overheating the rotor and my theory: DE-bedding of the pad material due to overheat?

Any help could save me money - thanks

 

[SingleMalt]

Yeah! You know how FEW Viper owners have problems like this. Good to see your car's getting used. First thing I'd look into is brake material. I think most people on the track are using Brakeman #3, Pagid Blacks, or Pagid Orange (a less abrasive compound I believe -- but more for street/mild track use); they seem to be good compounds for higher temp situations. I'd prefer the Pagids due to brake feel.

Are you seeing any 'blueing' of the rotor surface, or just hairline cracks? Are the rotors standard, slotted, or drilled?

Mike

 

[Janni]

PFC 01's are a great pad. If you like the feel of that pad, the BM#3s will feel like you need too much force applied. They are very progressive, but not as high temp and have a shorter life. Both are pretty gentle on rotors. Sensitive brakers may feel a little bit of shudder with slotted rotors. Alternatively, heating them up can start to warp them slightly if they "grow" at different rates. Cooling should help this - it's always a good idea - the Viper holds a LOT of heat inside the front wheel well area.

The hairline cracking you see on the rotors is COMPLETELY NORMAL. It's surface checking and just keep an eye on it. When a crack starts to make it's way to the inner or outer edge of the sweep area, then it's time to replace the rings.

 

[Tom F&L GoR]

Janni; the PFC's are very progressive, but not as high temp and have shorter life or the B#3s are very progressive, but not as high temp.... thanks.

 

[V10 ICBM]

Thanks for that advice - yes - usedto use the BM#3s, but decided to switch to PFC01's - i thought it would give me more pad life (I swap new pads at 1/2) and i heard had a more aggressive initial bite - I believe they are giving me that performance.

My only real issue is that re-curring shudder - which - I think is just too high heat - thereby affecting the bedding.

I love these pads AND these brakes - to be honest I am hanging with and even pushing the guys in GT3's and twin turbos here at Mosport - into turn 2 and through 3 and into 4 with this big lug of a car (nick name is Bruce (nemo fame) through 5a,5b, and 5c - which is pretty good considering overall mass.

To be honest - never had more fun - just want to sort this out - would recommend the PFC01 over BM#3 if you are driving pretty hard. they also work fine on the street with no less brake tham BM#3's - but they take the heat better (ie wear slower) and and really hit hard earlier.

FYI - I have slotted rotors and drive about 4-5 full tanks per open day (ie 400-500km (240-300miles) at mosport -

Note: You all should be very proud at how stout and consistent our cars are - all the GT3's, Z06's, race cars regularly pit out to cool off (ie red tranny light) while we (GTS steel grey and bumble bee ACR) go non-stop, to empty and again and again tank after tank untl 9am-12 1:30-5pm. Just utterly impressive - not sure the reliability of the GT3's (which i like and pull me up to turn 8) will be like our cars.

2000 GTS Steel Grey.

If I can just get a consistent pad feel (no shudder)

 

[SingleMalt]

Based on your input and seeing that they're Stoptechs, I would call them up and ask the pros. They are very helpful and have years of experience diagnosing braking issues.

Good luck and HAVE FUN!

Mike

 

[luc]

You have brake material on your rotors. What you think is warped rotors may be your previous braking material that is scorched on the rotors, thus giving you the shuddering under braking. This can happen when you switch brands of brake pads. PFCbrakes do not react well to other brake material on the rotors. Call Matt Weiss @ Stop Tech and he will give you the procedure to get the material off the rotors. I believe he will recommend a Hawk brake pad that is very abrasive when cold that will help clean the rotors.
Good Luck.

 

[V10 ICBM]

Hi Luc - Nope the rotors were replaced new with new PFC01's.

Spoke with MATT - seems only 2 options - try to keep the PFC's cool (3 stops 60-40mph cold) to try to scrub off the material - attempt 20 cycles with cool rotors and pads each time. If that fails - try hawk blues.

Hopefully that will clear it. It's a little frustrating as the BM3's had no such issues - i can only think that PFC01's are just more finicky to bed in - perhaps I am too slowwww.