Pads to aggressive?

[vrinner]

I just put on a new set of Porterfield front rotors with their R4 race compound pads. After a couple of laps, when I get hard on the brakes, I get a really hard "chatter" in the front end.

Would this be a sign of the rotors getting too hot and warping?

After they cool down and I go out on the next session, they are fine for a couple of laps, then the same thing.

Any thoughts?

Thanks!

[svobud]

definitely due to heat...but more so, inadequate brakes. I bet if you slow down...your brakes would stop 'chatting' on you.

Could be your choice of Rotors (too small, poor quality, etc), brake fluid need changing, or inadequate cooling to the brakes.

Also - do you have S/S lines? Might want to think about getting them if you don't.

[SVOeric]

could be...

A lot of heating up problems with brakes can be with how you use them too...

You want to get into the brakes, and get out, riding them will only heat them up... now riding them doesn't mean keeping your foot on them all the time, it just means you have to wait til the last possible second before hitting the brakes, get down to speed quickly, and get out of the brakes.....

[vrinner]

They are Porterfield rotors OEM spec. I did not get the cryogenic (sp?) treatment. Non cross drilled and non slotted.

I have SS brake lines and just flushed the system with Motal 600 fluid.

Brakes are stock SVO brakes but I do have cooling ducts going to the rotors.

I am also waiting until the last second to brake then getting off of them.

I do believe it is the rotors. This is my second set of Porterfield rotors that I have had problems with. Porterfield is a local company that makes racing rotors and pads and their prices are pretty good. I can either try their cryogenic (again sp?) treated rotors that are supposed to be for racing or just go with another brand. Any suggestions...remember this car is only used for road racing.

Thanks!

[svobud]

Driving habits have little to do with it. You're going to drive hard and brake deep. That's the name of them game. Anyone who doesn't realize that will have a rude awakening.

Porterfield? never heard of them. What you need is higher quality material and .....

BIGGER

Stillen, Bembro, Baer .... or you do a swap to SN95 stuff and use the 13" brakes from a Cobra/Bullit.

[SVOPaul]

Originally posted by vrinner
They are Porterfield rotors OEM spec. I did not get the cryogenic (sp?) treatment. Non cross drilled and non slotted.

I have SS brake lines and just flushed the system with Motal 600 fluid.

Brakes are stock SVO brakes but I do have cooling ducts going to the rotors.


I do believe it is the rotors. This is my second set of Porterfield rotors that I have had problems with. Porterfield is a local company that makes racing rotors and pads and their prices are pretty good.

Thanks!

I've got news for you....Porterfield doesn't make their rotors...period....they are a local company to you, did you see a foundry out back for working with Cast Iron?...nope....there are only a few companies that produce rotors and they buy them from one of them....could be overseas, could be US made, it should be stamped on the rotors. As an example, do you think Walmart makes their own soup?, nope...it's repackaged....same thing there. I don't know porterfield(know the name, heard of them for pads but the same thing usually goes with pads...unless they can show you the manufacturing process of the pads via a shop tour, they are made for them by someone else).

You have good lines and good fluid.....also using brake ducts. You have a problem and I suspect it is either rotors or pad compound and cryogenically treated rotors are not going to change anything(it's marketing hype for the most part).
If you are shopping by price point, remember....you get what you pay for.

Does the brake pad compound contain material harder than the rotor surface?...probably...and that causes more heat and more wear on the rotors....

In the beginning of my open track driving, I experienced "chatter" and it was due to my braking too early and too long....simply because I was a newby and didn't know better...once I learned to brake late I never had the problem again......now you say you are breaking late, which leads it to a component issue if not a driver issue.

[vrinner]

I called Porterfield today and they said it could be just a bad break-in and I didn't do a good heat cycle to start with. Although I took it easy on my first session I guess I can take it even easier.

Their rotors are "American made" according to them. They do buy them from a domestic source. He even asked me to check the back of the rotor for the stamping and call him back.

Although I did not ask him if the manufacture their pads he did mention that their pads have less metal in them than the "Willwood" or "Brembo" race pads. He says as far as "racing" pads go, theirs are probably the least "aggressive". Take that for what it's worth.

He suggested I take the rotors to have them checked out to make sure they are not warped. He was also grasping at straws and said possibly when the heat builds up, some component on the brake calipers might be failing. Hell, I dont know, and either did he over the phone.

I bigger brake upgrade would be awsome but that would also require new wheels and tires right? My understanding is that I will need to go with 17" wheels to make bigger brakes fit.

Thanks for the help.

[vrinner]

Just as a followup...

I took the rotors and pads to Porterfield and found out that the rotors were slightly warped. Porterfield also GAVE me a new set or pads for all my troubles. I had the rotors turned and they were still within spec.

I broke in the new pads and rotors by driving the car around my neighborhood for about 30 minutes (you get strange looks from neighbors when driving around in a racecar with big numbers and stickers all over the car...but the kids love it )

I then ran a double regional Solo2 championship at Buttonwillow race track (they put gates and slolumns on the course to keep speeds down) and the brakes worked great. Although I did not have a good chance to build up alot of heat in the rotors, they did get a workout and seemed to be fine.

On a side note, I did get best time in class (C-Prepared) on both Saturday and Sunday) Because they have not yet tabulated the times, I'm not sure if I won first, but I am pretty sure that I didn't hit any cones on my fastest runs)

Next stop...Laguna Seca in November...

[CornerCarver]

Stupid question but did you burn them in "properly"? I forget where, but I remeber its a few 30-0 stops, then a few 60-0 stops of moderate pressure, then a cooling period, then some aggressize 60-0 stops then let them cool for 24 hours. Could just be the rotor company stating that. Again, I forget where I read it but it makes sense to "heat cycle" the rotors, similar to "green" race tires.

[vrinner]

Thats pretty much what I was doing by driving it around my neighborhood.

Porterfield said that they take their new pads and rotors out for a few very easy laps on the track, then park the car to let everything cool, then go out and race.

[KevinK]

Hi performance brakes require the proper burn in. Different types require different types of burn in. Wrong burn in can trash the parts. Honestly, I don't have any experience with anything better than normal stock type stuff. I suggest contacting someone who autocrosses who might have more experience.

[8T6 SVO]

Brake chattering

Vince, just an observation(I see your post about rear proportioning valve), but I've had high speed chattering from brakes caused by wrapping of the front rotors due to the rear brakes not working properly. Seems as though the rear brakes got too low to do any good, so when I stomped on the brakes, my fronts were doing all the work (I know they do most of the work anyway). Replaced the rear brakes, turned the rotors, and I was back in business.

[vrinner]

8T6 SVO...You are very observant.

I replaced my rear rotors and pads 3 events ago and have since replaced the front rotors 2 times. The rear rotors and pads are still like brand new! Not even a little wear on them. Fronts were probably overheating and warping due to them doing ALL of the work.

I am in the process of putting on a brake proportioning valve for the rears so I can get more pressure back there. I'll let you know how it turns out.

Thanks!

[drewkeen]

Originally posted by svobud
Driving habits have little to do with it. You're going to drive hard and brake deep. That's the name of them game. Anyone who doesn't realize that will have a rude awakening.

Porterfield? never heard of them. What you need is higher quality material and .....

BIGGER

Stillen, Bembro, Baer .... or you do a swap to SN95 stuff and use the 13" brakes from a Cobra/Bullit.

it you do get the 13"ers, you will need a 17" wheel or bigger, hence why the cobra has 17's, our spares look very funny because they have a 17" rim just so that you can clear the front brake. i'm just saying dont go do this swap and not buy wheels if you decide to do it.