Carbotech XP8/1521 Combo?

[NotYetLegend]

Hey guys, I am doing a brake job on my SS in a few weeks as I warped my rotors at a track outing this summer. I got oem rear rotors, R1 fronts, new DOT4 fluid (already have stainless lines), new caliper bolts and the Quantum brake duct kit.

I could not decide on pads until today. I previously have only used the OEM pads (which I love) and Porterfield R4 pads (which were on the car when I warped the rotors). The R4 pads were cheap (20% NASA discount on already cheap-ish pads) but only ok, insane squeal, ok modulation, the only thing I loved is I knew they weren't going to overheat and totally fail on me. They are shattered now with cracks all over the face of them, from just one track weekend, so I'm never using those again...

I ordered a full set front/rear of Carbotech 1521s (Bobcats) from Vengeance today. My thinking is that these will be excellent for the street/autocross. I will attempt a track weekend with them (counting on you Quantumn brake ducts ) and if it's just too limited I'll order a set of XP8s or 10s for the front axle only (to save $$$).

Is this even close to a good idea? Think it's dangerous to even attempt full track runs with the 1521s? Think it's safe to go XP8/10 on the front axle and 1521 on the rear?

Any real input would be very valuable to me. Thanks guys.

[White_SS/RS]

With 1521 on the rear I would go with XP8. The 10's would be too much of a split in performance IMO.

[NotYetLegend]

Originally Posted by White_SS/RS

With 1521 on the rear I would go with XP8. The 10's would be too much of a split in performance IMO.

Yup, probably a good call.

[NotYetLegend]

Quick update (not that anyone cares):

I installed the 1521s (Bobcats) this previous weekend with all new rotors, new RBF 600, and followed the bed-in procedure from Carbotech to a "T". The car sat overnight, took it to work in the morning, first thing I noticed was how fantastic the modulation was, I always liked the OEM pads but these have more feel and a little less initial bite, brakes seemed to be working at 100%.

Last night however my buddy with a '94 RX7 wanted to hit the backroads so I followed him. The 1521s? They last one stop, not kidding, one, and then fade into oblivion. ABS can barely be activated even once and after the first brake use the fade is downright dangerous. I would honestly say the performance is somewhere around 20% of the OEM pads. I have been driving this road for 11 years and the OEM pads never once faded on me back there, these didn't even make it to our favorite stretch of road before giving up (seriously, we were only about 5 minutes in).

This is all made worse by the fact that I installed Quantumn brake cooling ducts along with the pads and rotors. I could only muster to get the drivers side plumbed with the 4'-5' section of tubing provided with the kit but I thought it would be an interesting comparison to have the driver's side cooling operational and the passenger side not. The two front brakes faded at exactly the same time and inspection after parking showed absolutely no difference in brake temperature left to right. So much fail.

This whole job cost me close to $900 and all I have to show for it are brakes that are a shadow of their former selves. Do yourselves a favor and do not buy these pads, and if you do ABSOLUTELY NO TRACK DRIVING, not even autocross, you will crash.

[TBone]

How many times have you bled your brakes since installing your Dot 4 fluid? If you only did it the one time you MAY have some dot 3 left in the lines. Now that you have done some driving try another bleed to get all of the dot 3 out since some may have gotten stuck in the ABS module the first time. Just spit ballin' here.

I have been using the 1521's for a while, a couple of years, and I have not seen any fade in spirited driving on the street. IF I push them too hard on the highway they will get too warm though and I just need a couple miles to let them cool and then they are all good again. Keep in mind they are street brakes though, just sayin', not criticizing.

I started tracking with the 10/8 combo and they are a good learning combo. After I used up the 10's I moved up to the 12's for a while and they were very good too. Very easy on rotors but the trade off is you use up the pads.

Good luck on you track quest.

T.

[NotYetLegend]

Thanks TBone! that is all good information. I've had DOT4 in the car for about a year now and perhaps 3-4 bleeds but the ABS module may be causing issues as you stated. I obviously avoided ABS threshold during the bed-in procedure and since my final bleed was just before bed-in I suppose it is possible that some air or perhaps very old fluid made its way into the main brake lines the first time I hit ABS, this would explain my inability to reach ABS easily now.

I just ordered new brake fluid, currently don't have any, so I will have to wait until Friday before I can re-bleed and re-assess the situation.

Also good to hear that you are using the Bobcats on the street without issues. My original plan was to feel out the Bobcats abilities at the autocross this weekend and make a decision on pads for HPDE from there, you can imagine my surprise when I had massive fade after one stop from about 100mph down to 40mph! I was pissed to say the least and at a loss as I would not feel confident even autocrossing in an empty parking lot with my current braking performance.

Further, I purchased the pads from Vengeance so I sent them an email inquiring about swapping these pads out etc... They promptly forwarded my email to Carbotech and I'm sure they will be helpful in resolving the issue if it is not resolved by a new bleed.

Thank you for the support.

[White_SS/RS]

Did your pedal go soft, or was it still hard during this issue?

[NotYetLegend]

Its bottomed out but does take a lot of pressure to get there. So no, the pedal is not mush, but it does compress all the way to the bottom of its stroke. The brakes still engage pretty high up in the pedal travel even when too hot to lock a wheel.

[NotYetLegend]

Brake ducts will both be plumbed in Friday as well, hopefully this helps. The reason I didn't have enough ducting for both was I was sent a corvette kit instead of the camaro kit (with the camaro instructions however). The corvette kit only needs half as much ducting and no adapters for the top bolts on the dust shields/vents. Vendor fixed it all up however and should be good by Friday when I re-bleed.

[White_SS/RS]

Hmm, was curious about pedal feel since what you were describing was something similar that happend to me. I had a little air in the ABS system that wasn't noticeable until it cycled getting into the brakes hard. Afterwards I had less than great pedal feel even though the brakes engaged early in the travel. Let us know how it all goes.

[NotYetLegend]

Originally Posted by White_SS/RS

Hmm, was curious about pedal feel since what you were describing was something similar that happend to me. I had a little air in the ABS system that wasn't noticeable until it cycled getting into the brakes hard. Afterwards I had less than great pedal feel even though the brakes engaged early in the travel. Let us know how it all goes.

Yup, willdo. I suppose it is in my best interest to get the car out and do some hard stops into ABS before I re-bleed just to make sure it's cleared out. Going to be difficult considering the lack of stopping power currently but maybe I can find some puddles somewhere to lockup through.

[White_SS/RS]

Originally Posted by NotYetLegend

Yup, willdo. I suppose it is in my best interest to get the car out and do some hard stops into ABS before I re-bleed just to make sure it's cleared out. Going to be difficult considering the lack of stopping power currently but maybe I can find some puddles somewhere to lockup through.

Not saying that is your issue, just reminds me of mine. Anyway I don't think you have to go out and try and hit the ABS, I'm sure it's out by now if that was it.

[NotYetLegend]

Originally Posted by White_SS/RS

Not saying that is your issue, just reminds me of mine. Anyway I don't think you have to go out and try and hit the ABS, I'm sure it's out by now if that was it.

I have wondered if it's maybe worth bringing the car to the dealer once a year or so to have them do the fancy ABS bleed with the scanner tool? I usually bleed brakes after events however, I assume there was enough ABS activity at any given track day or autocross to pretty much clear them out. This may be something worth looking further into, I'll check it out.

[JusticePete]

Originally Posted by NotYetLegend

I have wondered if it's maybe worth bringing the car to the dealer once a year or so to have them do the fancy ABS bleed with the scanner tool? I usually bleed brakes after events however, I assume there was enough ABS activity at any given track day or autocross to pretty much clear them out. This may be something worth looking further into, I'll check it out.

If air found its way into the ABS pump the only way to clear it is with a Tech II doing a 2010 Corvette bleed. It cycles the pump to clear air and old fluid.

On the pad material the 1521 is only good up to 800 degrees. We have all seen the pictures of glowing rotors. This image puts numbers to the colors.



Match it up.



Looks like 1275 to me.

If you want to run Carbotech use their compound page and select a pad with a minimum of 1200 degree maximum operating temperature.

I have a strong preference for Cobalt Friction XR1 front and XR3 rear pads. They stop dead cold and your rotors will melt before you see fade.