Just had a conversation with Clyde this morning about rear pad wear on 350Zs. He was running our Panther XP up front and Panther Plus in the back. He said the front pads wore well but the rear pads wore out in a weekend. This is completely opposite of what I expected since
1) rear pads, generally speaking, do no wear as fast as front pads, and
2) Panther Plus, generally speaking, wears better than Panther XP.

We both think that the traction control system is causing excessive rear pad wear. Traction control engages the rear brakes to keep wheelspin down. I HIGHLY recommend traction control be turned off before a track session.

Also need to do more investigation to see if turning off traction control does or does not completely disable the system. I know on some of the newer BMWs you cannot completely disable traction control. It still intervenes when you get all tail-out stupid.

 

Hey Matt....

I have used your Panther Plus in the front Brembos and the Panther in the back Brembos and have had really good wear with them.

The Z has been to two high speed driving events on these pads. The fronts are a little chunked and worn down, but the rears are in fantastic shape.

I do run every run session with the traction control turned off.

Just my $0.02 worth.

Peter Haas

 

I agree with this, Matt. I ran every session of my event with the VDC/TCS turned off on my Touring 6MT and my stock, i.e., Nissan rear pads held up great with little wear. I do need to mention that the rear pads were NOT the OEM pads that came with the car, but a revision to the OEM pad that was replaced at about 10K miles.

 

Alrighty. This is good/important info. Mods may want to sticky it.

Traction control = fast rear pad wear.

 

I am at a loss now...

We had discussion about two weeks ago about the disproportionate pad wear on the track as couple more pointed out the rears are wearing faster, which was quite a bit of suprise as the Z is a front engine car with 53% (or was it 57%) front weight bias. It seems that the brakes may need to be rebalanced on the Zs (on some may be).

I am not sure how one can conclude that TCS has any effect on the break wear tho; I can somewhat understand VDC's effect but not on disproportionate wear.

 

It's been my experience with my Z06 that when running in Competition Driving mode (Traction control off, active handling on {same as VDC})the rears get a tonne more brake wear than with the system shut off. I only run that way on the track when just getting used to a new track or if it is really wet. Other than that, I shut it off. I run Panther Pluses on front and rear on the track and love them...

 

Some traction control systems engage the brake to reduce or elimitate a wheel from spinning. Go into a turn, romp on the gas, the computer senses the *** end coming around and automatically applies the brakes to keep this from happening. I can DEFINITELY see how the rear pads would wear quicker.

 

Matt,
I rant Panter+ on the front, Bobcats on the rear, always had VDC turned off, and my rears were gone in 2 days. I realize Bobcats are not Panter+ but this is what happened to me. As per our last discussion, I ordered XPs for the front and Panter+ rears. Should I get XPs in the rear as well?

 

P+ usually wears a little better than Panther XP, unless the operating temperature are very high (above 1000F). I can't imagine the rear rotors are seeing temps that high.

 

After testing a multitude of brake pads (no Carbotechs because I was testing for someone else and they weren't provided) on two 350Z track model (not my Z either) at a closed circuit race track, I found very even brake pad wear front to rear across every pad. Traction control/vehicle stability control was shut off for all the testing although I wanted to test the vsc/tcs (I've only got an Enthusiast model) and in one quick session (17 minutes according to the pit log) I found the vdc/tcs system to be garbage on the track. The system does a multitude of things from killing the engine power to randomly hitting individual brakes. In my best engineering judgement, this would kill a set of brake pads in the rear (since the rear seemed to be hit more).

Side note - after completing the testing, I'm glad that I only use Carbotech pads (I think I have 7 sets for my IT car in a variety of compounds and I still have a couple sets sitting around from my old car as well) on my cars at the track, the pads being tested were garbage.

Second side note - all my testing was done for a company and no results can be posted (including brands, compounds or results). Pad types tested though included street pads to race pads. My own personal generic assessments can be posted. I will reiterate though, no Carbotech pads were in the bunch (nor porterfield or Hawk which stricks me as odd as these big three brake compound manufactures I regard as some of the best).

I hope that my own assessment can help Matt and others troubleshoot the seemingly high pad wear on the rear of a 350Z. My personal opinion is that the 350Z has great brake distribution (credit suspension design, brake biasing and weight distribution to this) and should show fairly even pad wear front to rear. I can't imagine a car at the track with vdc/tcs turned off to get abnormely high rear brake pad wear. In no way will I claim to be absolutely right with only testing pads for 30-40 minutes but in my experience pad wear lifespan can be accurately predicted in this much time (within a certain statistical error).

 

I've been to:

2 Days at Laguna Seca
3 AutoX
14,000 miles

Car completely stock - no fluid change, no bleeding (other than factory). I did bed the pads as best I could when I first got the car, but it wasn't perfect.

All racing was done with TC/VDC off (and it really does turn it off).

My rear pads wore out a month or so ago, and my fronts have a little pad left, but not much.

In their stock form, the fronts are not only larger in area, but have 50% more usable thickness (9mm VS 6mm). I'm guessing that the main reason the rears are wearing fast is simply because they don't have as much thickness to play with.

-D'oh!

 

Here we are on the same issue we were a month ago D'oh

 

Hehe, yup.

It is definitely atypical, though (in general automotive repair, I mean).

When I first called the dealers to get new rear pads, they were all asking me what I had done to get them to wear out so fast.

Once even asked if I was doing E-brake skids all the time (he's probably one of the guys that does the PDI "E-brake" test on all the new cars).

At least the rears are cheap and easy to replace!

-D'oh!

 

Just want to throw my $0.02 into the discussion here. My rear pads wore out yesterday. I just did my 2nd track weekend with my Touring 6MT at BeaveRun. I ran at Mid-Ohio in April. Both weekends were using the original set of OE pads, 10K miles old now.

I ran 6 sessions at Mid-Ohio (~20 min each), all with VDC on. At BeaveRun I did two 25-min sessions with VDC on, then 1 with VDC off, during which I noticed the brakes were going. I ran twice more with VDC off, but I couldn't do my last session because I had barely any rear pads left, a 200 mile drive home, and not enough pocket change to invest in new rotors.

 

I have about 9000+ miles on my OEM pads, a weekend at VIR, and a weekend at Summit Point. (At Mid-Ohio, I swapped in a different pad)

All track weekends have had the VDC off, and brake pad wear has been even all around. I still have about 15-20% of my OEM pads left.

 

It's no surprise to me that the rear pads are wearing out so quickly. Have you seen how small they are?

The rate at which a pad wears has very little to do with the front/rear balance of the car's brakes. It has everything to do with the size of the rotors and the size of the pads. The lower the mass of the rotors, the higher the temperature (all else being equal) after a stop. And changing the surface area of a pad does not affect brake torque, but it certainly does affect the temperature of the pads.

Certain pads wear away very quickly when they exceed their maximum operating temperature. It is my belief that the microscopic size of these rear pads combined with the restrictive airflow caused by the stock rotor dust shield, which wraps almost completely around the poor rotor, is what is causing accelerated rear pad wear.

 

I think you hit the nail on the head. That is why I was questioning,in another thread, the logic behind brake upgrades with front-only.

As it turns out, front-only brake upgrades are not really improving braking on the track with repeated use significantly. The brake balance, and overall temp control are the most important aspects. Big brakes do help some but the keys - for the 350Z - are on the rear rotors, pads, brake lines, and fluid. In short, brake upgrades are not necessarily needed if you can manage to control heat dissipation with few inexpensive items

 

I agree with you. One shouldn't always go for the most expensive solution. Address the problems one step at a time. If you are having problems with the rear brakes, it is not necessary to install a rear big brake kit.

If you start with a 350Z that has stock brakes and run it at the track, it is likely that the first point of failure will be boiling of the brake fluid or fading of the pads in front. I'm basing this on the rotor temperature data from the December test of the two variants of stock 350Z brakes (Track and non-Track models) and the three StopTech brake kits (332mm front, 355mm front, and 355mm front/rear). The data may be seen in the table at the end of this page: http://www.zeckhausen.com/Testing_Brakes.htm

There was a 240 degree temperature difference between front and rear rotors after a series of 100 mph stops. This difference would probably grow even greater at track speeds since the energy converted to heat by the brakes goes up with the square of the velocity. For example, slowing a car from 120 mph to 104 mph generates the same amount of heat as stopping that car from 60 mph.

So, for a stock 350Z, the front brakes will give up the ghost first. We address this by installing a StopTech 332mm front kit and change nothing else. What happens next?

Since the driver can now continue braking much harder and deeper without fade, he will do so. As the session continues, the rear brakes will now start to get much hotter until they eventually experience pad fade, rapid pad wear, or fluid fade. Since the rear brakes would have never reached this point were the driver not able to brake much harder and deeper, it's not correct to say that the front brake kit gave him no benefit. He experienced rear brake problems, but only after running much harder than he was able to with the stock front brakes.

Next step is to address the problems in the rear. The no-brainer is to install a set of track pads to raise the temperature at which the pads will give up the ghost. Then we remove the rotor backing plate (dust shield) to improve cooling so that the car can brake harder and longer without reaching such high temperatures. And replacing the brake fluid with Motul 600 or Castrol SRF will take fluid fade out of the picture entirely.

With very little expense, it is possible to make the rear brakes last throughout an entire track event and the car is fully capable of braking much harder and much later than it was before. You don't need to spend $4495 on the 4-wheel brake kit to be competetive. In order to justify THAT upgrade, you'll have to factor in other benefits, such as easier pad changes, the same size pads at all four corners, and, of course, the stunning good looks of the brakes.

 

Well put Dave.

One thing we did not touch however is brake cooling. I believe that would be a very inexpensive and very effective way of keeping front temps under control and still be able to do 15-20 laps on a track (of course depending on the track) with the right pads, and (I'll use my vote on Castrol SRF ) and right fluid (specifically with the Track model's Brembo system).

Dave, do you know of a brake cooling kit on the market for the Z?

P.S. I cannot get to your web site.

 

When folks come to me and tell me they plan to go to the track and want a big brake kit, the first thing I ask them is if they have exhausted all other "conventional" means of improving the brakes. Very often, a novice can get by with stock brakes, and pads on their first track event because they are learning the driving line under the supervision of an instructor and not pushing the car very hard at all. I make sure they have fresh brake fluid and enough meat on the pads to survive the weekend. When they reach a skill level sufficient to cause pad fade, I get them to try a club race pad like Porterfield R4 or Pagid Orange. When that stops working for them (i.e., they get better and/or start using R compound tires) I have them remove backing plates, install ducts where possible, and move to full race pads like Hawk HT-10, Pagid Black, or Performance Friction 01. Eventually, all of that ceases to work and they end up going to a big brake kit. Many others just tell me they don't want to mess with all of that and they go straight to a BBK right away. But often, I am able to keep them going for a year or more on their stock brakes before they HAVE to make the jump to the more expensive solution. For folks with a budget, this allows them to spend that money where it belongs first: on driving or racing schools like Skip Barber, Bob Bondurant, Bertil Roos, Jim Russell, or Derek Daly.

It this time, I'm not aware of any ducting kits for the 350Z. The ideal kit would consist of a replacement backing plate that used a quick disconnect to attach a high-temp hose to duct air directly to the center of the rotor from an opening under the front bumper. You don't want to simply direct air to the inside face of the rotor, since this will result in differential cooling and added stress to the rotor as it tries to take on a cone shape. The quick disconnect would allow you to remove the hose for street driving, since it would limit the range of steering. On atrack, this is not a problem at all, but on the street it makes parallel parking a pain!