Ordered a set of Bobcats for the front (only) of my Z.

Matt @ Carbotech was VERY helpful with the entire process, and this is not meant to put the company or the product down, but is just my current opinion of the situation so far.

After going to my first track event on stock pads, I've worn them down a little bit, so with the Bobcats laying around, I've decided to put them on, and at the same time have my mechanic drain my brake fluid and fill it with some Valvoline Synpower Fluid, with a high boiling point.

The shop decided it'd be better to shave the rotors for the new pads, and so we did that. They put them on, and everything seemed fine. When I left the shop, I noticed the brakes were very... what's the word, weak. And I realized that this is probably because they are not yet bedded or broken in, so what I did is followed the break-in process and let the brakes cool off.

When I drove the car again, I was a bit disappointed because they felt weaker than the stock brakes. I then searched the board and decided to try Zeckhausen's "bedding-in brakes" instructions, where about 8 hard stops from 60-10 are to be done, after the brakes are warm. Notice that's (2) break-ins so far.

After doing so, like the instructions said the brakes had a noticeable smell to them (burned smell), which was fine. Now the braking improved a little bit, but it's still not up to par with the stock brakes. Every time I use them, I feel uncomfortable not knowing exactly when I'm going to stop at a certain speed or distance, unlike the stock brakes which bite hard, and let you know right away how much room you have to play with. These just seem to take it easy until you push hard, and then they still seem to bite not as hard as the stocks. So the end result is an upsetting lack of confidence with the brakes. And an "older car" feeling from cars with weaker brake systems..

Perhaps I've done something wrong.. maybe someone can suggest something ? I've read nothing but good things about the Bobcats.. but my results show otherwise. It also cost me $75 to shave the rotors and put these on, so it'd be a shame to spend ANOTHER $75 to put the stocks back on and have to shave the rotors yet again..

However, if there's nothing wrong with the installation or the break-in, then I'm disappointed at the results, and will probably need to talk to Matt about it. My goal wasn't to lose performance at the benefit of less brake dust.. but to keep or increase performance, with the same results. So, where's the bite?

 

Is the Babcat a street or a track pad? A lot of times, pads that are desinged to work at higher temps don't "bite" like stock pads during normal street use. They simply don't get up to temperature. My Hawk HP+'s are like that. They always have that weak feeling the first half lap or if I drive them on the street.

 

They are street pads. Carbotech's best street pads, according to them.

 

Well, I would love to see more input on this trend, cause I was thinking of purchasing the Bobcats soon. Don't want to lose any braking power, even if I do get less brake dust.

 

I have to agree the Bobcats just don't feel as solid as the stock pads, but the dust is so much less, I am not doing anything that would want me to have better performance so the dust wins out.

I have their Panther XP's for the track and they are very good.

 

Did you use Carbotech's recommended bedding procedure? Different pads need different methods of bedding in but honestly I wouldn't see that to cause a huge difference.

What about pedal feel. Are you sure there is no air in the system? Does the Z require DOT 5 fluid? I assume whatever DOT rating it requires is what you put in right?

 

Why did they shave the rotors? If they were not warped I wouldn't have touched them. In my experience using cut rotors is just trouble.

 

I've had them in the front Brembos for about a month and I am very happy with them. These grip much better than the OEM pads.

PeteH

 

Well,

Apparently the pads aren't as bad as it seemed. As per my newest thread, Dave Zeckhausen himself (of zeckhausen racing) has generously taken care of me, by professionally bleeding the brakes of air, and re-bedding the system. And he didn't even charge me. What a nice guy!

The car responds much better now, no mushy pedal, and performance is at least equal to stock. I'm going to drive around for a week before I decide whether I really dig the Bobcats.

Thanks for all the input guys!

-slay

 

The biggest problem with slay's brakes was that there was a bit more pedal travel than normal for the stock (non-Track Model) brakes. The shop who had installed the Carbotech Bobcat pads had failed to bleed the rear calipers and had not done a complete job on the front calipers. Their insistance on turning a perfectly good set of rotors was my first hint that the problem may not be with the choice of pads. Also, it's a good idea to completely bleed the brakes following any track event, particularly if the pedal travel has increased during or following the event.

With slay's help at the pedal, we went through and bled each caliper. There was a little air in both rears and another bubble came out of the left front caliper after I gave it a few solid whacks with a rubber mallet. This was enough to improve the pedal feel, although the bite on the pads still didn't feel terrific. I took the car out to my favorite bedding in area (low traffic, few cops, and plenty of straight sections) and we made two passes of about 6 stops (or slow-downs) because the wet roads made it harder to heat up the brakes. Then we cruised back to my place while the brakes cooled off.

Slay noticed an improvment in the friction level right away and the pedal was stiffer. These pads don't blow me away with their performance, but that's probably because the most recent 350Z I bedded in was equipped with StopTech 332mm front brakes and Performance Friction 01 track pads! I'll be interested to see how the Axxis Ultimate pads (on stock calipers) compare to the Bobcat pads.


Slay - enjoying his brakes again

He's got one of the funniest vanity plates I've seen in a while. If he gives me permission, I'll post a picture of it.

 

I had the Axxis Ultimates on and I think they are better in performance than the Bobcats, I took them off as I used them up on a track event, for which they were not well suited, now I use the Panther XP's, wow they are good for the track but not street.

I think I will stick with the Bobcats for the street just because of the dust factor and I wont be using them for any hard activity.

 

I totally agree. The Axxis Ultimates will fall down badly if taken above 1100 degrees F. On the street, you will never see those temperatures, but on the track you may and the Ultimate is particularly bad about putting uneven deposits on your rotors above that temperature. As a street and autocross pad, it is terrific.

 

Sure, go for it

 

OK guys! Here's slay's new vanity plate:

 

Hahahaha... nice plates!

I was wondering if anyone had any input on EBC pads. I've heard only good things about them so far and their green pads basically emit like barely any dust. Anyone have them on their Z's yet?

 

They tend to misbehave badly if taken beyond their MOT (Max operating temperature). The failure mode is uneven deposition of material on the rotors, leading to claims that "these pads warped my rotors!" In fact, the rotors aren't warped but have a thickness variation caused by this pad deposition problem. They are not a high quality pad, but they tend to be quieter than many and also emit less dust.

I like the Axxis Deluxe Plus as a better pad in the same category: low dust, low noise, low rotor wear. Much fewer problems than the EBC Greenstuff. The M5 guys like them so much, they've bought them all out! See: http://www.bmwm5.com/vbulletin/showt...threadid=28899

 

Hahaha, thanks for the new info. I'll definitely look into those pads you mentioned. I forgot to ask about the red pads instead of the green ones though. I knew the greens were basically just for daily drivers who wanted less work cleaning their brakes... but what about the red or yellow ones? Those are more racey and have higher operating temps, yes? I just hear people tell me they love their EBC pads and they aren't exactly slow drivers either. Maybe they don't know any better.

 

Yellow has a lower Cf than Green, even though it is marketed as their club race pad. It does survive to higher temperatures. I would not use this on the street. And for club racing, I would want something with a much higher Cf.

Red is marketed as their more agressive street pad. It has a very low friction level of 0.3 that slowly rises to 0.33 as you heat it up, so it's not going to feel like it has much bite, especially when cold. I would much prefer something with a Cf in the range of 0.4 to 0.45 such as Pagid Blue or Axxis Deluxe Plus. Greenstuff (the latest version) claims to have a Cf on the 0.45 range, but their propensity to deposit material unevenly makes me shy away from them. The common complaint is that, "they warped my rotors!" when, in fact, they just were overheated and left uneven layers of pad material on the rotors.

Brake torque is a function of three things: effective radius, clamping force, and Coefficient of Friction (Cf) of the pad. If you put a low Cf pad on the front, you are changing the front/rear braking bias of your car and moving it rearward. I wouldn't put a pad with a 0.3 Cf on the front unless you also put something with an equally low Cf on the rear. Typically, adding more front bias is safe, but adding more rear bias can lead to instability under hard braking, especially in the absense of a dynamic stabilty control system. The following chart, taken from a study of brake systems for the Audi S4 may help you visualize this:



As the bias is moved away from the "sweet spot" in the middle, stopping distances increase. And moving too far into rear bias results in an unstable platform.

 

I'd stay clear of the EBC. I've used both the red and green in the past. I completely destroyed the greens in one day at watkins glen, and that was in a 2500lb car! The reds were ok, but I'd go a different route. I liked the Porterfield R4's on the track, and R4s's for the street were pretty decent as well.

 

Ah, sorry for not replying sooner. I must've missed this thread. Thanks for the help on brake pads and I'll think of another alternative to EBC now.

Question though. If you were to get the Brembo big *** brakes in front and get like the stoptech big brake kit for the rear, would it still be too much front biased braking?