Soft pedal after installing titanium brake shims?
03-10-2020 | 10:15 AM
#16
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They are from you 
Thanks for the great deal on all the goodies! I put on the brake duct scoops last night for the rear brakes from that thread, I accidentally trimmed off more on the top since it looked like they could possibly contact the outer CV boot if the duct got pushed back, and that part just redirected air to the back of the wheel carrier (which I guess any cooling is good ) and I am going to get another bleed with my son tonight and I think I will be good to go. 
Thanks for the great deal on all the goodies! I put on the brake duct scoops last night for the rear brakes from that thread, I accidentally trimmed off more on the top since it looked like they could possibly contact the outer CV boot if the duct got pushed back, and that part just redirected air to the back of the wheel carrier (which I guess any cooling is good ) and I am going to get another bleed with my son tonight and I think I will be good to go. Hi Steve,
I don't remember if I sold you the shims, but I've never had a problem like you described. Something's definitely strange. I've used 2 separate Ti shim sets on 3 different 987s.
For some of the other comments, I never measured and studied temps with and without to see if the shims were definitely helpful. Odd since I own an IR gun and regularly used to measure rotor, caliper, pad, wheel, etc., temps after sessions. I just figured they couldn't hurt and may help.
IIRC, my front temps were always higher than rears by 100-200 *F with PSM turned off (not fully). Also, caliper temps were roughly 200+ *F lower than rotor temps.
I don't use shims and haven't done much measuring on the GT3 because (A) I've only tracked it a couple of times, and (B) GT3 is over-braked. Well... thinking more about racing I guess "B" isn't really true... I guess a more accurate statement should be that GT3 isn't as under-braked as 987.
Ha. Interesting where the link leads to.... Brings back memories.
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I don't remember if I sold you the shims, but I've never had a problem like you described. Something's definitely strange. I've used 2 separate Ti shim sets on 3 different 987s.
For some of the other comments, I never measured and studied temps with and without to see if the shims were definitely helpful. Odd since I own an IR gun and regularly used to measure rotor, caliper, pad, wheel, etc., temps after sessions. I just figured they couldn't hurt and may help.
IIRC, my front temps were always higher than rears by 100-200 *F with PSM turned off (not fully). Also, caliper temps were roughly 200+ *F lower than rotor temps.
I don't use shims and haven't done much measuring on the GT3 because (A) I've only tracked it a couple of times, and (B) GT3 is over-braked. Well... thinking more about racing I guess "B" isn't really true... I guess a more accurate statement should be that GT3 isn't as under-braked as 987.
Ha. Interesting where the link leads to....
Brings back memories..
03-11-2020 | 02:28 PM
#17
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To partially close the loop on this, I pulled the shims out last night, and it turns out that a couple of the front shims have a slight 1-2mm of bow in them, which I believe was acting like a spring and pushing the piston back into the caliper. I've got an email out to hardbrakes.com to see what may have happened but I am thinking I got some debris in between the shim and pad backing plate that caused them to bend. I haven't had a chance to take the car out for a test drive but I believe I have identified the issue.
03-13-2020 | 04:38 PM
#21
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To partially close the loop on this, I pulled the shims out last night, and it turns out that a couple of the front shims have a slight 1-2mm of bow in them, which I believe was acting like a spring and pushing the piston back into the caliper. I've got an email out to hardbrakes.com to see what may have happened but I am thinking I got some debris in between the shim and pad backing plate that caused them to bend. I haven't had a chance to take the car out for a test drive but I believe I have identified the issue.
03-16-2020 | 12:08 PM
#22
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hah! i had a big long post typed out about the backing plates on brake pads not being smooth, as they were designed to be pushed by two pistons and not by a uniform flat surface, and that irregularities in either the pad or the shim could result in odd pedal feel. then i thought meh and deleted it.
Also, I would not be surprised to find out that the shims were nice and flat when installed and the heat from braking with the slim cross section caused them to bow. The pistons getting pushed back was also going to be my first thought as I was reading this.
We did a lot of research and field work while we were developing the pucks that we sell to replace the ceramic discs for the GT3 calipers. We researched and then bench tested about 30 different materials before selecting the one that we did. And, Titanium was not selected, although tested.
To give you an idea, here is the thermal conductivity of a few materials:
Carbon steel 26 -37 BTU/ hr-ft-f
Stainless steel 8
Pure titanium 12
Now, Titanium alloys do much better than pure titanium, but in our bench tests, grade 2 and grade 5 did only about as good as stainless steel.
Thanks
Ed
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03-16-2020 | 06:29 PM
#23
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