lexuz125th

iTrader: (1)

Anybody Running Carbotech Racing Pads? I am currently running XP 12 front, XP 10 rear as recommended by Carbotech. However, I am having an issue where under rapid hard braking say from 100mph car goes out of line and nose dives to the right. When swapped back to OEM pads no such issue even braking from 140. Any possible reasons this might occur?

caymandive

iTrader: (2)

Did you bed them in properly?

lexuz125th

iTrader: (1)

I ordered them to be bedded in by carbotech, it was an option they provided. You think that might be the reason? If so that's on their part, and they should take care of the issue. Ill give them a call

flowrider

iTrader: (9)

^^^^I never heard of such an option?

Brake bedding allows the pads to mate with uneven surface of the rotors. Even new rotors have uneven surfaces that must be worn down to create as much surface as possible for the pads to come in contact with. As the brake pads bed in, they contour to fit every imperfection in the rotors.

So, the bedding process employs both the brake pads and the brake rotors. Can't do one without the other.

Lou

lexuz125th

iTrader: (1)

I would have to agree with you 100% on that!! Why would carbotech offer that option in the first place. I was also thinking if its possible for the cars brake balance to be off or something, maybe it's biting earlier on one side than the other. But that just would make sense, especially when I tried with OEM pads and car brakes on the dime without throwing the car out of line. It actually gets really scary at times, if going 140+ on a track and you brake hard, the cars front feels so unsteady like the car is about to loose control.

darbs242

iTrader: (5)

i have the same recommended set up and have never had a problem except for the front pads wearing out sooner than i would like

SpeedFreaksUSA

iTrader: (1)

There are two types of brake bedding:

The first type involves heating the actual pad material to the point where the resins and binding agents turn into a gas and "burn off". Most of the more aggressive pads that don't come burnished from the manufacturer will say in the bedding procedure to keep building heat until you feel the pad fade or "green fade". This fade is caused by the pads outgassing and some of that gas getting trapped between the pad and the rotor. This is what Carbotech means by the "pre-bedded" option, you still have to bed them with your rotors.

The other type involves bedding the pads to the rotor. This happens when you get the pads up to the temperature where the friction mechanism turns from abrasive to adherent. When they reach the temperature where they become adherent, they lay down a transfer layer of pad material on the rotor face which the pad works much better on compared the bare rotor face.

-Matt M.

ERDoc74

You know what... I had been running Carbotech XP 10's front and 8's rear for a couple of years but this year switched out to the more aggressive XP 12's front but left the 8's in the rear... with the previous setup I had no such issues like you are describing, but with the 12's (but also have new 2 piece front rotors from figs) I definitely noticed similiar "unsteady feeling" to the car and it getting a little "squirly" under heavy braking from high speeds... I was thinking maybe it was Front brake bias from such a difference in aggressiveness from front to rear pads 12's and 8's ... ? IDK.... ??? anybody have a clue? Mine were bedded in on an empty highway and also at the track btw...
any other ideas?

lexuz125th

iTrader: (1)

I think XP 12 front and XP 10 rear is too aggressive of a setup for this car, and Carbotech should not have recommended a setup that does not work properly with this car, and they should take these pads back and give the XP 10 front XP 8 rear free of charge. It's really dangerous, and can cause a serious accident. It cannot be the brake bias cause I put back my OEM pads, and it brakes on the dime with no hesitation.

lobuxracer

iTrader: (2)

I've run 12's and 10's at all my track events and not experienced this. Under hard braking uphill the rear gets light and wanders a little, but never enough to make me worried.

Sounds like you have other issues to address with your setup.

SpeedFreaksUSA

iTrader: (1)

Hello -

If you do not mind, can you assist by answering a few questions so one of us can help answer some questions or assist in resolving your concerns:

- Are you swapping track pads and street pads with the use of the same rotor?
- Does the pull occur immediately after you initiate the first braking run and is it repeatable, even when the pads are not fully at operating temperature? (this usually does not occur on the warm up lap)
- Are you using OEM brake lines?
- What brake fluid are you using?
- Have you checked your "hot" tire pressures after you came in from a session? Are they the same in the front two tires and the same in the rear?
- Did your OEM Rotors and Pads (or street pads that you used) have even wear when you removed them? (Check both pads for each caliper and let us know if you have any noticeable difference between the pads).

... I have further questions, but this would suffice for the first round. Please do post up when you have the chance.

To answer the question of a bias difference between using XP10 Front and XP10 Rear, XP12 Front and XP10 Rear, and finally XP12 Front and XP8 rear - regardless of the platform (given that we are talking Front Engine-Rear Drive cars here), it is very helpful if you can post up what tires you are using, what tread width, and (out of curiosity) what powertrain modifications (if adding hp and torque), as well as suspension/aero you may have. Ah.. and do include if you do not have the OEM calipers - ie. you now run a ST-60 BBK with stock rear calipers, etc.

Personally, I have run each of the aforementioned combinations on our test/track car (Brembo BBK Front, Stock Caliper Rear on a Honda S2000)- my biggest problem was when I overstepped the available tire forces at the front by having a very aggressive pad for my driving style (more so braking style, I guess) and the street compound I had chosen to run (engaging abs very easily). I backed down to XP10 in the front and found a great combo running the same pad in the rear. I should clarify that I have rear aero. My colleagues that run time attack professionally have the opinion that the RP2 or XP12 Front / XP8 Rear combo works best since they desire less less bite as they unload the rear- braking deep into most corners at the local tracks, namely Thunder Hill. In other words they prefer to control the trail braking with the lesser bite on the rear for the available traction (the traction being greatly reduced as weight transfers to the front in a hard braking entry on the average 255/40/17 street tire commonly run on the platform I refer to here).. and they have had great success doing so.

We'll try and help - will look forward to your inputs (PS.. thanks to Lou for pointing this thread out to me).

-Anish

SpeedFreaksUSA

iTrader: (1)

This sounds accurate, and a phenomena that is fairly common. Thank you for sharing sir!

lexuz125th

iTrader: (1)

I started running track with OEM pads and rotors, along with michelin pilot sport PS2 OEM tires. Car has a borla exhaust with no other mods. I never had an issue with braking, always stopped on the dime. However what would happen, is that the material OEM pads are made of is too soft causing them to let's say melt and destroy the rotor. This turned out to be a disaster, leading to the need of replacement of pads and rotors $$$$. So I called Carbotech and explained what was happening, and was recommended to use stock rotors with their pads. They also recommended that I swap pads in between track and daily driving. First time out on the track, I had brand new rotors and XP 12 front and XP10 rear, tire pressure was always maintained properly and had the issue of the car struggling really hard to stay in line under hard braking. Now I have Michelin pilot super sports, use the sane rotors and rotor surfaces are all smoothe, no imperfections noted. I tried stopping with OEM pads no issue at all, then swapped pads and the issue came back. Initially the first time i tracked the car everything including fluid was OEM. Then i used valvoline which exceeds dot 3 and 4. I do not see how that would affect the car making it go out of line ehen braking as it occurs at all times. Always get the pads warned up prior to driving or testing the brakes out. It seems as if too much bite at the front and not enough at the rear.

lobuxracer

iTrader: (2)

If the rear is moving around, it's too much in the back not too much in the front. Motorcycle road racers learn this lesson in brake bias very quickly - I learned it on approach to turn 11 at Sears Point on my Honda 500 Interceptor many years ago.

I run stock rotors with XP12 front and XP10 rear. My "home" track is Carolina Motorsports Park, one of the hardest braking tracks in the Southeast. I run Brembo LCF brake fluid for its very high dry boiling point and solid feel when at high temperatures. DOT 3 and DOT 4 have little to do with brake fluid performance except to say it meets a minimum standard. 3 is not better than 4 and vice versa (unless you have an ancient Triumph with Girling brakes, then you absolutely must have DOT 4). The thing that is MOST important with the fluid is be sure it is fresh from a sealed container - this is far more important than the brand at almost every track.

All the events I've done there were on Bridgestone RE050As. Cold pressure ended up at 32 psi, hot pressure was 44 psi (last track day). The rest of the car is bone stock down to the air filter.

Every time I swap from street pads to race pads (I was running Carbotech Bobcats for street) I used the first couple of laps to bed the race pads. They're very aggressive and remove the Bobcat material pretty quickly. I drive home to Atlanta with the race pads installed (except the last track day because my weekend ended with less than 1mm of pad in the front) and swap to street pads when I get home.

IMHO, initial bite on the 12's is unacceptable for street use. The wife definitely does not find the ride home much fun if there's traffic. If I were to change anything, I'd consider going to 8's in the rear because I can't change the bias to stop the rear end from moving around, and the two places at CMP where this is critical are both bad places to spin a car - not a lot of room for error.

What does "nose dives to the right" mean? Does the car rotate to the right? Have you swapped the pads from side to side and seen the issue move?

ERDoc74

As listed in my signature my Performance Mods are: PPE Headers, Joe Z I/E, aFe Pro Dry S Filter, BCR's with Swift 16/12K, Sikky sway, Tom's chassis bracing & shock tower bar, Figs: Mega arms, Toe/Rear upper links, bushings, 2-Piece rotors, Carbotech XP12/8, ISS RMI Scoops, TSW 18's/Nitto NT01's (275/35/18's)
Also using ATE racing Blue brake fluid...
when I have experience similiar situations as the OP, IIRC it seems as the front of the car seems to dart eraticly from side to side and not that the rear of the car "gets loose" and moves... I will pay better attention next time and report back.