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BmacIL

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Squeaking and dust aside, the HP+ is still marginal at best as a street pad due to rapid rotor wear in street settings. Been there. Even XP12's don't beat the rotors up the way HP+'s do, not even close.


Norm
I've only had the experience driving and riding in a friend's Mazdaspeed 3 with DBA rotors and HP+. I'll let him know to check out XP12s. Thanks Norm.
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ZanarkO

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jdilissio

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Well I just got done running an AUTOX event today, stock 4 pots did great and had no issues what so ever. I wont be upgrading to 6 pots for a very long time as I dont think its really needed. A Road course would be different but I have a feeling they wont fade. Main issue are these crappy ass factory P zero all seasons. Horrible tire.
The Porterfields did great in HPDE at Lime Rock Yesterday. My instructor drives a 2003 Mustang and said how great the pads felt when he took me out the first two laps. His opinion has more validity than my inexperienced one. They held up great for the four 20 minute sessions. In the last 8 minutes of session #4, I had to adjust my brake point from #4 to #6 at the end of the front stretch as they got a little softer, but they were still very consistent with that adjustment, and they were consistent for me on every other turn at the track. I have so much to learn & master on driver skill that the mild brake fade at the very end were not that big a deal as I've got to get better on all the driver skills. Also- they are great on the street with not a bit of noise from the moment I installed them.
 

jdilissio

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GT Base brakes lead to greater pad tapering when tracking

While I spoke highly of the Porterfield pads after my spring HPDE day at Lime Rock Park, I had a very scary experience Nov 4th, 2017 at New Jersey Motorsports Park, but not due to the quality of the Porterfield product. At the end of my second HPDE session I suddenly lost almost all braking at the end of the straightaway, shot off turn one, and barely got the Mustang stopped three feet from the tire wall. It really shook me up, thinking of the thousands of dollars it almost cost me.

We pulled the brake pads, and they were greatly tapered. What really bothered me is that I had the car PA inspected the week before, and they reported I had 9/32" left on the pads. The tech looked at the pad on the car, saw 9/32" in the visible window, and never pulled the pad out to look at the entire pad. I was tracking on worn down pads but didn't know it.

I checked with David Zeckhausen from Zeckhausen Racing who sold me the pads and got this great answer for why my pads tapered so severely.

There's a fundamental design issue with the base GT (non-Brembo) front brakes. It's a 4-piston caliper with identically spaced 45.5mm pistons. That means it's prone to wearing pads at a taper.

A properly designed 4-piston caliper has a stagger between leading and trailing pistons, and 4mm is a typical amount. For example, 44/48mm would produce similar total clamping force (2% more), while reducing pad taper. The 4mm larger trailing pistons would apply more clamping force, holding the pad parallel to the rotor, rather than letting the leading edge nosedive into the rotor. It's similar in concept to putting more weight on your back fut, while surfing, to prevent the surfboard from digging into the water.

I'm guessing Ford had space constraints on the base calipers that preventing them from using pistons as large as 48mm diameter. The non-staggered 45.5mm piston design allows the caliper to be more compact. But you see the results.

There are two issues, really. The pad taper is one, but consumption rate is the overwhelming issue. Your car is powerful and fast enough that you're going through dual-use Porterfield R4-S pads in just a couple of track days. I would suggest continuing to use R4-S for street, but you need something capable of significantly higher temperatures, without being rapidly consumed.

The good news is Hawk has come out with a variety of race friction for your application. DTC-60 in front and back would be ideal. it's not, however, a dual-use pad. While you could drive to and from the track with them, you wouldn't find it very enjoyable to drive around every day on them.

See: https://www.zeckhausen. com/catalog/index.php?cPath= 11_90_6439_6441



I hope others might find this helpful to avoid the same dangerous potential problem. I think a driver can still track with the base brakes; he or she just needs to be checking the pads more often for tapering.
outside passenger pad.jpg
inside passenger pad top view.jpg
NASANE 11-04-17 HPDE 1 0019_1225x816_2134344_wm.jpg
 
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Optimum Performance

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While I spoke highly of the Porterfield pads after my spring HPDE day at Lime Rock Park, I had a very scary experience Nov 4th, 2017 at New Jersey Motorsports Park, but not due to the quality of the Porterfield product. At the end of my second HPDE session I suddenly lost almost all braking at the end of the straightaway, shot off turn one, and barely got the Mustang stopped three feet from the tire wall. It really shook me up, thinking of the thousands of dollars it almost cost me.

We pulled the brake pads, and they were greatly tapered. What really bothered me is that I had the car PA inspected the week before, and they reported I had 9/32" left on the pads. The tech looked at the pad on the car, saw 9/32" in the visible window, and never pulled the pad out to look at the entire pad. I was tracking on worn down pads but didn't know it.

I checked with David Zeckhausen from Zeckhausen Racing who sold me the pads and got this great answer for why my pads tapered so severely.

There's a fundamental design issue with the base GT (non-Brembo) front brakes. It's a 4-piston caliper with identically spaced 45.5mm pistons. That means it's prone to wearing pads at a taper.

A properly designed 4-piston caliper has a stagger between leading and trailing pistons, and 4mm is a typical amount. For example, 44/48mm would produce similar total clamping force (2% more), while reducing pad taper. The 4mm larger trailing pistons would apply more clamping force, holding the pad parallel to the rotor, rather than letting the leading edge nosedive into the rotor. It's similar in concept to putting more weight on your back fut, while surfing, to prevent the surfboard from digging into the water.

I'm guessing Ford had space constraints on the base calipers that preventing them from using pistons as large as 48mm diameter. The non-staggered 45.5mm piston design allows the caliper to be more compact. But you see the results.

There are two issues, really. The pad taper is one, but consumption rate is the overwhelming issue. Your car is powerful and fast enough that you're going through dual-use Porterfield R4-S pads in just a couple of track days. I would suggest continuing to use R4-S for street, but you need something capable of significantly higher temperatures, without being rapidly consumed.

The good news is Hawk has come out with a variety of race friction for your application. DTC-60 in front and back would be ideal. it's not, however, a dual-use pad. While you could drive to and from the track with them, you wouldn't find it very enjoyable to drive around every day on them.

See: https://www.zeckhausen. com/catalog/index.php?cPath= 11_90_6439_6441



I hope others might find this helpful to avoid the same dangerous potential problem. I think a driver can still track with the base brakes; he or she just needs to be checking the pads more often for tapering.
James is a great instructor if that is who you had. As far as your pad issue there is no such thing as a dual purpose pad. Run track pads on track. Looking at the glazing of your pads tells us that you greatly exceeded the temperature range of the compound and or had previous compound contamination. The taper also suggests that possibly the pad was hung up in the caliper but yes street calipers will taper a pad but it is usually caused by too much heat from the incorrect compound for the application. What tire do you run on your car? Size and Compound?
 

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z31maniac

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It seems like you learned a valuable, and thankfully not costly, lesson.

If you're going to track your car, don't rely on anyone else. You need to be inspecting brake pads, rotors, tires, hubs, etc, on your own, every time you go on track. Every time.

Not only is it your life you're caring for, it's all the other people as well.
 

jdilissio

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James is a great instructor if that is who you had. As far as your pad issue there is no such thing as a dual purpose pad. Run track pads on track. Looking at the glazing of your pads tells us that you greatly exceeded the temperature range of the compound and or had previous compound contamination. The taper also suggests that possibly the pad was hung up in the caliper but yes street calipers will taper a pad but it is usually caused by too much heat from the incorrect compound for the application. What tire do you run on your car? Size and Compound?
For the first day on the pads at Lime Rock, running the stock Pirellis. For the Nov 4th day, I had upgraded to Firestone Firehawk Indy 500 275/40R19. The grippier tire would have increased the load on the brakes & pads. Any opinions on how greatly the tire swap would have accelerated the brake pad heat & degradation?
 
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sigintel

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While I spoke highly of the Porterfield pads after my spring HPDE day at Lime Rock Park, I had a very scary experience Nov 4th, 2017 at New Jersey Motorsports Park, but not due to the quality of the Porterfield product. At the end of my second HPDE session I suddenly lost almost all braking at the end of the straightaway, shot off turn one, and barely got the Mustang stopped three feet from the tire wall. It really shook me up, thinking of the thousands of dollars it almost cost me.

We pulled the brake pads, and they were greatly tapered. What really bothered me is that I had the car PA inspected the week before, and they reported I had 9/32" left on the pads. The tech looked at the pad on the car, saw 9/32" in the visible window, and never pulled the pad out to look at the entire pad. I was tracking on worn down pads but didn't know it.

I checked with David Zeckhausen from Zeckhausen Racing who sold me the pads and got this great answer for why my pads tapered so severely.

There's a fundamental design issue with the base GT (non-Brembo) front brakes. It's a 4-piston caliper with identically spaced 45.5mm pistons. That means it's prone to wearing pads at a taper.

A properly designed 4-piston caliper has a stagger between leading and trailing pistons, and 4mm is a typical amount. For example, 44/48mm would produce similar total clamping force (2% more), while reducing pad taper. The 4mm larger trailing pistons would apply more clamping force, holding the pad parallel to the rotor, rather than letting the leading edge nosedive into the rotor. It's similar in concept to putting more weight on your back fut, while surfing, to prevent the surfboard from digging into the water.

I'm guessing Ford had space constraints on the base calipers that preventing them from using pistons as large as 48mm diameter. The non-staggered 45.5mm piston design allows the caliper to be more compact. But you see the results.

There are two issues, really. The pad taper is one, but consumption rate is the overwhelming issue. Your car is powerful and fast enough that you're going through dual-use Porterfield R4-S pads in just a couple of track days. I would suggest continuing to use R4-S for street, but you need something capable of significantly higher temperatures, without being rapidly consumed.

The good news is Hawk has come out with a variety of race friction for your application. DTC-60 in front and back would be ideal. it's not, however, a dual-use pad. While you could drive to and from the track with them, you wouldn't find it very enjoyable to drive around every day on them.

See: https://www.zeckhausen. com/catalog/index.php?cPath= 11_90_6439_6441



I hope others might find this helpful to avoid the same dangerous potential problem. I think a driver can still track with the base brakes; he or she just needs to be checking the pads more often for tapering.
Brake caliper/hub mounting ear flex.
Thermal effects on pistons and unequal brake force across pad.
I found higher temperature fluid decreased the difference in piston clamping from the "hot" to "cold" pair on each caliper.
After switching to SRF, still had assembly flex that would result in hot edges on pads appears likely due to caliper twist in relation to disc. uggg.
 

jdilissio

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Brake caliper/hub mounting ear flex.
Thermal effects on pistons and unequal brake force across pad.
I found higher temperature fluid decreased the difference in piston clamping from the "hot" to "cold" pair on each caliper.
After switching to SRF, still had assembly flex that would result in hot edges on pads appears likely due to caliper twist in relation to disc. uggg.
Can you tell me a little more about your experience that you commented on? I'd love to learn from your experience & description, but I could use some more details and clarification, as I'm a "layman" when it comes to car stuff & tracking.
 

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sigintel

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Can you tell me a little more about your experience that you commented on? I'd love to learn from your experience & description, but I could use some more details and clarification, as I'm a "layman" when it comes to car stuff & tracking.
It looked to me on both my base calipers that the caliper when loaded allowed a degree or more of twist/flex of the caliper/pads in relation to the rotor.
Imagine the caliper miss aligned with the rotor, the pads would wear uneven.
Now imagine the degree of miss alignment increases with load.
http://www.mustang6g.com/forums/showthread.php?p=1791171&highlight=twist#post1791171
The GT350 calipers and hub assembly look substantially stiffer in holding the caliper in alignment with rotor. I am not 100% that this is twist or some other dynamic issue and heating of the pistons/fluid/etc. Likely several issues going on.
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