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Cayman CompetitionAuto Cross, Club Racing, DE, this is the place to discuss the Cayman on the track
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I was at a track day on Friday, and during the first run group the brake pad wear warning message came on ('07 CS). I brought the car in, and noticed that my left front pads had very little material left (the right front was in better shape--this track is very hard on the left sided tires, so likely brakes as well). In any case, I parked the car (I didn't have extra pads). When I started it to drive it home, the message had cleared (these are the stock original pads). I thought these sensors, once the circuit was broken, were broken.
Any thoughts? I was wondering if the sensor got hot enough to increase the resistance enough to make the computer think it was worn through?
1. Whoever teched your car let you down. You shouldn't start a track event with less than 50% brake material. Heat dissipation decreases greatly which increases the likelihood of brake fade, melted pads or loss of brakes (all bad things). It's a good habit to periodically check the pads yourself during the track day. it's easy with most Cayman wheels and it is an important safety factor.
2. Side to side brake wear should be about equal absent a brake problem, or perhaps significant PSM intervention (although that's usually the rear brakes) regardless of a track that's harder on the tires on one side.
3. The sensors employ a normally closed ground circuit that is physically broken when the rotor cuts through the sensor body. That happens when the pad is very thin (far too worn for safe track use), but may initially cause an intermittent brake warning light much like moving a blown out light bulb may cause the fliment to temporarily close an otherwise broken connection. In addition, applying the brakes may also temporarily turn off the light as the rotor closes the connection. A little more wear and the light is on until the sensor is replaced or the sensor wires are sliced together, as is done by many track drivers.
PSM - Porsche Stability Management
While it can’t overcome the laws of physics, the revolutionary Porsche Stability Management (PSM) system does lend an added degree of balance and control to the Cayman’s mid-engine driving dynamics, inspiring surefooted confidence in corners and extreme situations.
A standard feature on the Cayman and Cayman S, PSM continuously monitors steering input, road speed, yaw velocity and lateral acceleration to calculate the actual direction of travel. If the car begins to steer off line, PSM instantly intervenes with precision brake inputs on individual wheels to help bring the car back onto the driver’s intended path.
If braking alone isn’t enough to correct the vehicle’s cornering line, PSM then calls on the Cayman’s engine management system, adjusting engine output as needed to help stabilize handling. PSM can also compensate in an instant for mid-corner changes in load resulting from deceleration or braking. When Sport mode is selected with the optional Sport Chrono Package, PSM’s threshold for intervention is raised, allowing for greater driver involvement. If you prefer driving without automatic PSM assistance, the system can be set to standby at any time. In this case, it will only intervene under heavy braking, where both front wheels exceed the ABS threshold.
For all of its technical ability, PSM goes virtually unnoticed in everyday driving situations, preserving the Cayman’s natural agility.
Good info. The pads looked fine at the start of the day (by eyeball, about 50% of the pad was left). I'm swapping brakes on my track car (BMW M3) all of the time so I understand the concepts.
PSM was switched off (though I understand it is never really off, except in a GT2). As the Cayman understeers and given the track, I would have expected the other side to have been worn more (if front) or the rears as you suggested. Any other thoughts as to the significantly differential wear?
I would like to just replace the pads myself--at that time I can mic the rotor thickness (which I would think would still be fine) just to check. The problem would be if I have an issue (which would be a warranty thing) the P-car dealer (from my understanding of other posts here) will want to replace the pads and rotors (which gives me two things I don't want--new rotors and factory pads).
Thanks--Scott
PSM - Porsche Stability Management
While it can’t overcome the laws of physics, the revolutionary Porsche Stability Management (PSM) system does lend an added degree of balance and control to the Cayman’s mid-engine driving dynamics, inspiring surefooted confidence in corners and extreme situations.
A standard feature on the Cayman and Cayman S, PSM continuously monitors steering input, road speed, yaw velocity and lateral acceleration to calculate the actual direction of travel. If the car begins to steer off line, PSM instantly intervenes with precision brake inputs on individual wheels to help bring the car back onto the driver’s intended path.
If braking alone isn’t enough to correct the vehicle’s cornering line, PSM then calls on the Cayman’s engine management system, adjusting engine output as needed to help stabilize handling. PSM can also compensate in an instant for mid-corner changes in load resulting from deceleration or braking. When Sport mode is selected with the optional Sport Chrono Package, PSM’s threshold for intervention is raised, allowing for greater driver involvement. If you prefer driving without automatic PSM assistance, the system can be set to standby at any time. In this case, it will only intervene under heavy braking, where both front wheels exceed the ABS threshold.
For all of its technical ability, PSM goes virtually unnoticed in everyday driving situations, preserving the Cayman’s natural agility.
Scott
If you had that much pad to start and ended at the wear sensor I assume you're running hard on the oem pads. I had a similar experience where my oem pads overheated and melted away rather quicly, but I also had fade, a soft pedal and increased travel. Pagid yellows was the cure.
Assuming all your hard braking is in a straight line, track configuration should have a minimal effect on pad wear. If PSM was off we can rule that out as a factor (and it was unlikely for the front anyway). You may have a sticky caliper piston or similar mechanical issue. As a start, I'd go for a 15-20 min drive and bring the car to an easy stop. Feel the wheels or calipers (or measure rotor temps w/an infrared) - both fronts should be about the same temp. If the left front is much hotter you may have a pad hanging up against the rotor.
PSM - Porsche Stability Management
While it can’t overcome the laws of physics, the revolutionary Porsche Stability Management (PSM) system does lend an added degree of balance and control to the Cayman’s mid-engine driving dynamics, inspiring surefooted confidence in corners and extreme situations.
A standard feature on the Cayman and Cayman S, PSM continuously monitors steering input, road speed, yaw velocity and lateral acceleration to calculate the actual direction of travel. If the car begins to steer off line, PSM instantly intervenes with precision brake inputs on individual wheels to help bring the car back onto the driver’s intended path.
If braking alone isn’t enough to correct the vehicle’s cornering line, PSM then calls on the Cayman’s engine management system, adjusting engine output as needed to help stabilize handling. PSM can also compensate in an instant for mid-corner changes in load resulting from deceleration or braking. When Sport mode is selected with the optional Sport Chrono Package, PSM’s threshold for intervention is raised, allowing for greater driver involvement. If you prefer driving without automatic PSM assistance, the system can be set to standby at any time. In this case, it will only intervene under heavy braking, where both front wheels exceed the ABS threshold.
For all of its technical ability, PSM goes virtually unnoticed in everyday driving situations, preserving the Cayman’s natural agility.
Indeed, if you drive hard, you'll get at most two track days out of the stock pads. Note that when the light comes on, you are at about 1/4 pad left (maybe a little less).
I also use Pagid Yellows for track duty. They are so much better and last a very long time.
__________________
97 Turbo | 06 Boxster S | 06 Cayman S (sold)
Update: I pulled the front wheels off to look at the pads. These are all guestimate measurements based on my measuring the pad backing plate thickness at about 5 mm. The right front pads are equal in material left, and have about 8-9 mm of friction material remaining.
On the left front caliper, the outside pad has about 2-3mm of material remaining, while the inside pad has about 9-10mm of material.
Given the differential wear on 1 caliper, I am going to have the dealer take a look at at.
Given the differential wear on 1 caliper, I am going to have the dealer take a look at at.
Something must be wrong with that 1 side. Perhaps a piston or rubber seal was damaged during a pad change keeping that pad in contact with the rotor. Please post the dealer's findings.
Update--just spoke with the service department. They confirmed uneven pad wear--they did not say it was out of spec (they didn't say that there was a spec) but they did agree it was not normal. They checked the caliper and found no issues. The checked rotor runout (normal) and thickness (still acceptable, but slightly less compared to the right front).
They insist that the driver front brakes and rotor will wear the fastest, because it is the closest to the master cylinder (while I can see this on a theoretical basis, I find it hard to imagine that it is a practical thing).
They have decided that it might be a defective pad, and offered to warranty them. I declined, as I am putting aftermarket pads in. I guess the story is therefore unfinished, but I will be following the wear patterns of the new pads closely.
They insist that the driver front brakes and rotor will wear the fastest, because it is the closest to the master cylinder
We hear some dumb things from service writers and this is right up there. The front rotors and pads do wear faster than the rears (in all cars) not because of proximity to the MC, but because of weight transfer when braking which shifts weight to the front wheels causing them to do most of the car's braking. That's why front brakes are generally larger than the rears. That's why there are proportioning valves to keep the rears from locking up as their load is reduced. That's why many cars had, and perhaps a few still have, disc brakes up front, but cheaper drum brakes at the rear.
However, the important thing is they recognized that grossly unequal side to side front pad wear IS abnormal. Why not have the dealer replace the pads (should do all 4 fronts)? At least you'll get a new set of oems which may come in handy down the road. You could just get the box from them to (in theory) install yourself.
We hear some dumb things from service writers and this is right up there. The front rotors and pads do wear faster than the rears (in all cars) not because of proximity to the MC, but because of weight transfer when braking which shifts weight to the front wheels causing them to do most of the car's braking. That's why front brakes are generally larger than the rears. That's why there are proportioning valves to keep the rears from locking up as their load is reduced. That's why many cars had, and perhaps a few still have, disc brakes up front, but cheaper drum brakes at the rear.
However, the important thing is they recognized that grossly unequal side to side front pad wear IS abnormal. Why not have the dealer replace the pads (should do all 4 fronts)? At least you'll get a new set of oems which may come in handy down the road. You could just get the box from them to (in theory) install yourself.
Dan--I think maybe I wasn't clear enough in my comments. I never got the sense that the service guy was ignoring all the things you mentioned. His point was, all other things being equal, a longer hydraulic tubing run does cause a theoretically greater loss. So, assuming straight stops on a even surface, the left front brake should experience some fractionally greater wear. He was quick to admit, thought, that even given this what I experienced was not normal.
I told them I was replacing the pads anyway and didn't need the stocks. My current issue (having said that) is that my replacement pads aren't here yet, and I was planning on taking the car on a road trip this week. I may ask if they'll provide the warrantied pads (and I'll do the labor) and/or split the costs of the pads with them (which I don't have to do, but it might smooth things out).
Until 
