Racing brake pad choices..... which one next?
#61
Former Vendor
Anyway make a two piece rotors with different offset is not a problem at all. We have more than 300 assemblies (combination of hat and disc), so once we know the offset, the two piece rotors can be made available in weeks.
A typical Porsche two piece rotor (380x34mm Cup Rotor):
Center Mount Design provides cold air circulation both inboard and outboard
Section Drawing Illustrates Convergent Vanes pump more air through the vanes than conventional curved vane and keep the disc cool.
#62
Rennlist Member
Thread Starter
I presume yours are retrofit correct, as I don't see any Porsche models are 350mm in size until 997 Turbo.
Anyway make a two piece rotors with different offset is not a problem at all. We have more than 300 assemblies (combination of hat and disc), so once we know the offset, the two piece rotors can be made available in weeks.
A typical Porsche two piece rotor (380x34mm Cup Rotor):
Center Mount Design provides cold air circulation both inboard and outboard
com/albums/cc379/wlin973/7cfd6d37-9b08-47d8-949d-f6b374032594_zps7f4a7f6a.jpg[/IMG][/URL]
Anyway make a two piece rotors with different offset is not a problem at all. We have more than 300 assemblies (combination of hat and disc), so once we know the offset, the two piece rotors can be made available in weeks.
A typical Porsche two piece rotor (380x34mm Cup Rotor):
Center Mount Design provides cold air circulation both inboard and outboard
com/albums/cc379/wlin973/7cfd6d37-9b08-47d8-949d-f6b374032594_zps7f4a7f6a.jpg[/IMG][/URL]
what would it cost? (rotors and hats)
what do the replacement rotors cost?
how do we get you the offset to be correct? rotor outer surface to wheel mounting surface measurement?
OH one other big issue is we need a centering ring or the rotor hat to have the right inner diameter, as the rotors are hubcentric. OR, we can use a centering ring as we did with scots 82 928 by using the cayenne rotors and a 5mm centering ring on the outer portion of the hub...... the set screws are not enough for centering
thanks
mk
#63
Former Vendor
The rotors im using now are the Porsche 964T rotors. same as the 928GTS. they are 322mm. *(12.7") I want to use the 350mm rotors (13.7" commonly called 14" ) as I think I can radius the calipers to fit. But, I need the hats to be made .
what would it cost? (rotors and hats)
what do the replacement rotors cost?
how do we get you the offset to be correct? rotor outer surface to wheel mounting surface measurement?
OH one other big issue is we need a centering ring or the rotor hat to have the right inner diameter, as the rotors are hubcentric. OR, we can use a centering ring as we did with scots 82 928 by using the cayenne rotors and a 5mm centering ring on the outer portion of the hub...... the set screws are not enough for centering
thanks
mk
what would it cost? (rotors and hats)
what do the replacement rotors cost?
how do we get you the offset to be correct? rotor outer surface to wheel mounting surface measurement?
OH one other big issue is we need a centering ring or the rotor hat to have the right inner diameter, as the rotors are hubcentric. OR, we can use a centering ring as we did with scots 82 928 by using the cayenne rotors and a 5mm centering ring on the outer portion of the hub...... the set screws are not enough for centering
thanks
mk
We are fully aware of the hub center/opening. Earlier models spindle are of side mount (caliper) and the hat is hubcentric, while the late models (996+) the hats are registered with the inner corner (157mm).
If we are to make this two piece rotors, the hat will be made correctly to fit 928 spindle just like OE so nothing to be concerned from your end.
Other than providing the two piece rotors, I would like to take a look on the spindle and calipers (Original I assume), so to ensure the retrofit-ability*.
You can get an idea of our 997 Turbo (350x34) two piece rotor price here, scroll down you will also see the replacement ring cost (price in pair):
http://www.racingbrake.com/Two-piece...-11-p/2179.htm
*Since this retrofit set up will re-use the stock caliper, being a stock rotor at 322mm I can't imagine if the rotor is thicker than 30mm, therefore you will not be able to fit 34mm rotor. But we have some other rotor rings with 30mm thickness.
Also need to be evaluated is there is enough space for an adapter that is required to bridge the OE caliper high enough to accommodate the larger rotor. My calculation: (350-322)/2=14mm ~1/2" which is unlikely possible.
#64
Rennlist Member
Thread Starter
Essentially you are looking for a rotor with combination of 928 hat with 350x34 disc.
We are fully aware of the hub center/opening. Earlier models spindle are of side mount (caliper) and the hat is hubcentric, while the late models (996+) the hats are registered with the inner corner (157mm).
If we are to make this two piece rotors, the hat will be made correctly to fit 928 spindle just like OE so nothing to be concerned from your end.
Other than providing the two piece rotors, I would like to take a look on the spindle and calipers (Original I assume), so to ensure the retrofit-ability*.
You can get an idea of our 997 Turbo (350x34) two piece rotor price here, scroll down you will also see the replacement ring cost (price in pair):
http://www.racingbrake.com/Two-piece...-11-p/2179.htm
*Since this retrofit set up will re-use the stock caliper, being a stock rotor at 322mm I can't imagine if the rotor is thicker than 30mm, therefore you will not be able to fit 34mm rotor. But we have some other rotor rings with 30mm thickness.
Also need to be evaluated is there is enough space for an adapter that is required to bridge the OE caliper high enough to accommodate the larger rotor. My calculation: (350-322)/2=14mm ~1/2" which is unlikely possible.
We are fully aware of the hub center/opening. Earlier models spindle are of side mount (caliper) and the hat is hubcentric, while the late models (996+) the hats are registered with the inner corner (157mm).
If we are to make this two piece rotors, the hat will be made correctly to fit 928 spindle just like OE so nothing to be concerned from your end.
Other than providing the two piece rotors, I would like to take a look on the spindle and calipers (Original I assume), so to ensure the retrofit-ability*.
You can get an idea of our 997 Turbo (350x34) two piece rotor price here, scroll down you will also see the replacement ring cost (price in pair):
http://www.racingbrake.com/Two-piece...-11-p/2179.htm
*Since this retrofit set up will re-use the stock caliper, being a stock rotor at 322mm I can't imagine if the rotor is thicker than 30mm, therefore you will not be able to fit 34mm rotor. But we have some other rotor rings with 30mm thickness.
Also need to be evaluated is there is enough space for an adapter that is required to bridge the OE caliper high enough to accommodate the larger rotor. My calculation: (350-322)/2=14mm ~1/2" which is unlikely possible.
the stock rotor is 32mm, and I wouldn't want to go thinner than that, but 34mm would work if the offset was the same. (1mm thicker on front and rear vs stock) (FYI. minimum value for post machine turning the stock rotor is 30mm)
#65
Former Vendor
If the caliper is of top mount then a 14mm spacer would work. What's your current bolt length, we have different length (45 - 125mm) of M12x1.5 caliper mounting bolts available.
Do you have a used rotor sample that we can barrow to measure the dimensions?. Once we determine the offset the 350x34 two piece rotor for direct mount to your 928 will be made available.
Do you have a used rotor sample that we can barrow to measure the dimensions?. Once we determine the offset the 350x34 two piece rotor for direct mount to your 928 will be made available.
#68
Rennlist Member
Thread Starter
Jeff, I still don't understand how grooving of the rotors is caused by my brake bias imbalance now. wouldn't it be that if I had more rear braking force, I still would want to run the fronts to the limit of the tires. the only difference it that I would be stopping faster. the force on the rotors via the calipers should be identical if I maxing out the capability of the tires grip under braking.
#70
Rennlist Member
Thread Starter
If you recall, you said I was "over working the fronts" now that I didn't take your advice and put the more grippy pads in the rear. (St41 or St43).
you cant over work a properly sized brake system. the tires should always be the limilt, especially for sprint races and new pads. the fact that they did groove and grooved the rotors in one session, not even running that fast, tells me they are too abrasive compared to the PFC 01 . maybe there is a stronger metallurgy in the two piece racing rotors? the fact that the pads are digging in , for similar stopping power, tells me something is wrong. you cant "over work the front brakes",. as I said, if you did have the correct bias, then the car would just stop faster, but I would always brake to the absolute limit of the system. if it cant handle it, I need to find a system that can.
you cant over work a properly sized brake system. the tires should always be the limilt, especially for sprint races and new pads. the fact that they did groove and grooved the rotors in one session, not even running that fast, tells me they are too abrasive compared to the PFC 01 . maybe there is a stronger metallurgy in the two piece racing rotors? the fact that the pads are digging in , for similar stopping power, tells me something is wrong. you cant "over work the front brakes",. as I said, if you did have the correct bias, then the car would just stop faster, but I would always brake to the absolute limit of the system. if it cant handle it, I need to find a system that can.
#71
Rennlist Member
Were they NEW rotors, or previous pad rotors.
You can easily overwork brake pads Mark, think about that some...you can overrun acceptable heat loads with a badly balanced system.
My objective advice across about 500 cars that I've been involed with, says that this is what happened, and well, you do admit it.
Ive -never- seen the Raybestos pads, groove rotors..I cant say why. I have seen people bake em to death in one weekend, but...it was always pretty much always a very fast car on sticky tires with no rear brakes to assist the fronts.
With adjustable bias you want 41/42 front/rear
W/O adjustable bias, you want 41/43 front/rear
NEVER re-use rotors between pad manufacturers.
And, as you know never use a turned rotor either.
..and I take that back on grooving, I have seen this on drilled rotors..with poor decision making in the drilling pattern where it can be really bad, or just odd.
A 2pc rotor design will cool a little more, but until you ask the *** of the car to do it's job in coordination with the front, it's throwing money away.
And..for ****s sake, never..ever..bed pads by smoking them out of the box and feeling like you did good unless the lady that took your money, told you to. Just run a moderate warm up session, and done.
I suggested that your bed in procedure was also going to likely cause problems as well.
You can easily overwork brake pads Mark, think about that some...you can overrun acceptable heat loads with a badly balanced system.
My objective advice across about 500 cars that I've been involed with, says that this is what happened, and well, you do admit it.
Ive -never- seen the Raybestos pads, groove rotors..I cant say why. I have seen people bake em to death in one weekend, but...it was always pretty much always a very fast car on sticky tires with no rear brakes to assist the fronts.
With adjustable bias you want 41/42 front/rear
W/O adjustable bias, you want 41/43 front/rear
NEVER re-use rotors between pad manufacturers.
And, as you know never use a turned rotor either.
..and I take that back on grooving, I have seen this on drilled rotors..with poor decision making in the drilling pattern where it can be really bad, or just odd.
A 2pc rotor design will cool a little more, but until you ask the *** of the car to do it's job in coordination with the front, it's throwing money away.
And..for ****s sake, never..ever..bed pads by smoking them out of the box and feeling like you did good unless the lady that took your money, told you to. Just run a moderate warm up session, and done.
I suggested that your bed in procedure was also going to likely cause problems as well.
#72
I'm running Carbotech pads up front, seems like the rear factory calipers and pads are perfect after removing another 40lbs.
The 330 cayenne centering rings fit the 350x34 cayenne rotors as well.
The 330 cayenne centering rings fit the 350x34 cayenne rotors as well.
#73
Rennlist Member
Thread Starter
Were they NEW rotors, or previous pad rotors.
You can easily overwork brake pads Mark, think about that some...you can overrun acceptable heat loads with a badly balanced system.
My objective advice across about 500 cars that I've been involed with, says that this is what happened, and well, you do admit it.
Ive -never- seen the Raybestos pads, groove rotors..I cant say why. I have seen people bake em to death in one weekend, but...it was always pretty much always a very fast car on sticky tires with no rear brakes to assist the fronts.
With adjustable bias you want 41/42 front/rear
W/O adjustable bias, you want 41/43 front/rear
NEVER re-use rotors between pad manufacturers.
And, as you know never use a turned rotor either.
..and I take that back on grooving, I have seen this on drilled rotors..with poor decision making in the drilling pattern where it can be really bad, or just odd.
A 2pc rotor design will cool a little more, but until you ask the *** of the car to do it's job in coordination with the front, it's throwing money away.
And..for ****s sake, never..ever..bed pads by smoking them out of the box and feeling like you did good unless the lady that took your money, told you to. Just run a moderate warm up session, and done.
I suggested that your bed in procedure was also going to likely cause problems as well.
You can easily overwork brake pads Mark, think about that some...you can overrun acceptable heat loads with a badly balanced system.
My objective advice across about 500 cars that I've been involed with, says that this is what happened, and well, you do admit it.
Ive -never- seen the Raybestos pads, groove rotors..I cant say why. I have seen people bake em to death in one weekend, but...it was always pretty much always a very fast car on sticky tires with no rear brakes to assist the fronts.
With adjustable bias you want 41/42 front/rear
W/O adjustable bias, you want 41/43 front/rear
NEVER re-use rotors between pad manufacturers.
And, as you know never use a turned rotor either.
..and I take that back on grooving, I have seen this on drilled rotors..with poor decision making in the drilling pattern where it can be really bad, or just odd.
A 2pc rotor design will cool a little more, but until you ask the *** of the car to do it's job in coordination with the front, it's throwing money away.
And..for ****s sake, never..ever..bed pads by smoking them out of the box and feeling like you did good unless the lady that took your money, told you to. Just run a moderate warm up session, and done.
I suggested that your bed in procedure was also going to likely cause problems as well.
I have no problem buying a set of more grippy pads in the rear, vs the pagid blacks now on the rear. but im still trying to understand how im over driving the front rotors. over such a short braking zone and time spent at threashold. these pads did what all others did. they failed and faded at the high heat area. I had to release pressure and re-brake to give them a breath. (literally) just to get slow enough to make a trail brake turn in to turn 2.
you talk about faster cars that are heavier using them (ST41) but you didn't answer the question. how many are using 13" rotors. even the ST40 stoptech system, uses 14" rotors, with my same pad size. 1" rotor diameter is huge. by the way, you also quote the CMCs running 6 seconds slower as being able to use them too (near 10 seconds slower at laguna) , but I also quoted my time with NO use of any brakes being near as fast. Again, I had no issues with brakes even in world challenge with the 320rwhp. that 10mph at the end of the straights is just proving too fast to slow down to turn in speed. you also mention faster cars that are heavier not having issues. This, can be for two obvious reasons. a lot more HP, (no where near the tax on the brakes, regardless of the weight of the car . a greater potential to run even faster . ) or much larger rotors in diameter.
Im not arguing with you . im trying to understand how to fix the issue, but I have a strong opinion that you might not be giving the credit to the smaller rotor being the issue, or the metallurgy being an issue with this ST41 pad
I think we are just concentrating too much heat in too small area of the rotor. That's my feeling.
see if you can give me the reasons why you think that I change the friction set up in the rear and all my problems go away. so, I'm not going to brake as hard with the fronts.? that makes no sense. I want to use every ability of the cars stopping ability. if I get better rear stopping power, then, guess what? the car slows even better . I'm still going to be at the limit. by the way with more stopping power , with the rears involved, you know even MORE weight would be shifted forward..... basic racing physics.
btw... why not use a turned rotor... my first experience with the 13" rotor mod was on a turned rotors and used the pagid blacks, which performed well. thunderhill turn 1, I couldn't get the turn in speed with the 12" rotors, but the 13s made it possible (same pads). turned rotors was the same as when I went to the brand new GTS 13 " rotor. what is the problem there? anyway, not to diverge.......... I really want to believe that a simple pad change will solve my issues, but this fade is enormous. ive driven fast cars , andersons as well.... braking points were near the same and the pedal, feel, was amazing, with absolultely no fade . Anderson was using the pagid blacks as well.
#74
Rennlist Member
Thread Starter
btw..... I do think that the two piece doesn't even have the heat disappation capabilities due to the much lower mass. sure , you save your hubs and wheel bearings, but getting all that heat out with a stock rotor coupled to the aluminum wheel, cant be all that bad. (sans the weight)
#75
Rennlist Member
2) You did it in breakin.
I wont say this again.
You broke down the binder doing something wrong, that IMHO is part of internet old wives tale for bedding brakes.
That white is _binder_ and you should be able to ride those thru a USEFUL friction peak temp of 1350, and then fade from there until the rotor is white.
But..like I said after you bedded them in , a few posts ago, and now visually absolutely confirmed..you cooked em from mile #1.
I don't haaave to drive with you, I'm not a racing expert. But I'd like to fancy myself a brake one with the compounds and use cases that I became very close to over a great # of years.
NEW pads, front and rear
NEW rotors, front and rear
Bed them during a FULL session warmup at moderate speeds and use
Then go have fun.
Do any of the above cheaply or wrong, and expect cheap wrong results.
Love ya..but you gotta find your way towards trying out new things, the way the people you are asking for help suggest you do them.
This guy with the 2pc rotors, if you don't do it his way, and get poor results again..he'll feel the same way. Im no rotor expert, other than I dont personally buy into the cryo stuff, drilling, or peeing on them in the back yard for a full summer to 'season them' (RX7 12b race theory)...
IMHO, a cracked rotor aint _that bad_ until the grease comes out of the bearings...THRU the rotor. Then you pit the car...grudgingly...