Holbert Brake upgrade project. Big red, without the red.
12-16-2008, 08:15 PM
#61
Three Wheelin'
hehe, sorry, but funny... i see here "metric" problems , just as we have it the other way around... the metric ones i can find around every corner, the inches types 
... o well, must order them or sometimes they even have them in stock ! 
sorry for the interruption, gentleman...
... o well, must order them or sometimes they even have them in stock ! sorry for the interruption, gentleman...
12-17-2008, 08:43 PM
#62
Rennlist Member
Thread Starter
Just got the brake rotors in today. It may seem like just a little on the spec, but these rotors are HUGE compared to the stock S4. there will be a huge advantage of heat disapating characteristics of the new rotor with a lot more space from the pad contact area to the Hub area. Plus, the Porsche OE 965 rotors are REAL nice . nicer than Zimmermans which ive been a fan of for years. they are coated to not rust in the hub and inside air vain area.
I have the spacers coming from a machine shop and Bolts from Jim Morton!
Now, all i have to do is some dremel work on the calipers. Ill see if i can do it as nice as the cnc machine did.
This could be one of the best braking upgrades of all time.
Ill post some pictures of the comparative rotors and pad match ups.
mk
I have the spacers coming from a machine shop and Bolts from Jim Morton!
Now, all i have to do is some dremel work on the calipers. Ill see if i can do it as nice as the cnc machine did.
This could be one of the best braking upgrades of all time.
Ill post some pictures of the comparative rotors and pad match ups.
mk
12-18-2008, 11:53 AM
#65
Rennlist Member
Thread Starter
No, that is not the case. In fact, again, the F50 set up is has an even greater area below the pad, as it's diameter is over 1" larger! AND, the pad is the same size as the S4 pad now. The ST40 SToptechs have the same appearance as this as well. 13" diameter rotor, S4 part numbered pad.
The zimmerman rotors Ive used for years slowly deveope rust on the areas of the rotor that are not in contact with the pad. Not an issue at all as it is as much of a factor as the rust that develops around the hub and right to the wear area now. guess if you were really concerned with appearance, you could mask off the bottom area of the rotor and paint it.
Its all about more leverage and more mass for getting rid of the heat. This does both.
mk
.
The zimmerman rotors Ive used for years slowly deveope rust on the areas of the rotor that are not in contact with the pad. Not an issue at all as it is as much of a factor as the rust that develops around the hub and right to the wear area now. guess if you were really concerned with appearance, you could mask off the bottom area of the rotor and paint it.
Its all about more leverage and more mass for getting rid of the heat. This does both.
mk
.
12-18-2008, 12:53 PM
#66
Nordschleife Master
Mark, I see all the micro cracking on your brake rotors, how do you think the 965 rotors will stand up against this and it there anything you (or anyone else for that matter) know of that can be done to prevent this on a drilled (non solid) rotor?
12-18-2008, 01:35 PM
#67
Rennlist Member
Thread Starter
To answer the question directly, i predict much less cracking to due the additional mass of the rotor and its position near the air flow. I think the mode of wear will still be cracking on the outside side only. the inner side never cracks, as it sees more air flow. the rotor in the picture is a worn out rotor but i keep the best ones for a spare in case of an emergency. when the cracks hit the outside edge, I change them. This season was very hard on the brakes, however, they did last the entire season (almost) i think i put the new ones on after the 2nd race last year. AND, they are still good for about 2 more weekends tops. (the ones on the car now are in the earlier picture on this thread). with the extra surface area and much better pads, I think there will be a reduction in cracking this season. the only thing that can be done to fight this is possibly the cryo process, but i doubt it, OR getting better venting to the hub area of the rotor for cooling. that surface sees no direct air flow, and that is the reason for the cracking. However, the rotors never are tossed for grooving, warping or wear limits. They are ONLY tossed due to cracking at the edges as that is the only reason I have been replaceing rotors.
Mk
Mk
Last edited by mark kibort; 12-19-2008 at 01:19 AM.
12-18-2008, 02:08 PM
#68
Race Director
MK
Nice......I look forward to the results when your done....... I'm lucky the widow already has GTS brakes with nearly new pagid oranges!!
It should be plenty of brakes for now, until I get more HP!
Nice......I look forward to the results when your done....... I'm lucky the widow already has GTS brakes with nearly new pagid oranges!!
It should be plenty of brakes for now, until I get more HP!
12-18-2008, 03:44 PM
#69
Rennlist Member
Thread Starter
I'm going to sell the used pagids. They have only the Thunderhill race, where i only did half the laps due to the alternator failure, and the mock race last month. 11mm pad thickness. All baked and ready to go. If anyone wants them, they are for sale, $85 free shipping! these are the pads shown in the first part of the thread. (normally $200+ ). If you are racing, the would be good for at least 2 more race weekends or if they are for the street, several years!
Let me know.
Mark
Let me know.
Mark
12-21-2008, 01:38 AM
#70
Rennlist Member
Thread Starter
The brake conversion is almost done. Just waiting for the final spacers.
The grinding of the calipers was much less than expected. There is a little ridge at the end of the calper area that needed that needs to be shaved down. Its pressing on the larger 965 rotor if it is just bolted on with the spacer. With the right sized spacer, and the ridge cut down with a simple dremel, it fits and has the same space as the stock S4 set up at the caliper edges.
Yes, Im using the cut off lug nuts for spacers, but i wont be driving very far with them! Glad i used them as i had to narrow down the thickness values for the final products so that the pads fit perfectly on the rotors.
mk
The grinding of the calipers was much less than expected. There is a little ridge at the end of the calper area that needed that needs to be shaved down. Its pressing on the larger 965 rotor if it is just bolted on with the spacer. With the right sized spacer, and the ridge cut down with a simple dremel, it fits and has the same space as the stock S4 set up at the caliper edges.
Yes, Im using the cut off lug nuts for spacers, but i wont be driving very far with them! Glad i used them as i had to narrow down the thickness values for the final products so that the pads fit perfectly on the rotors.
mk
12-21-2008, 03:36 AM
#71
Nordschleife Master
These will deform very very easily due to their shape, and when they do the bolts will back out almost immediately.
Until you have to proper spacers run the S4 rotors!!
as I dont want to hear about you on the news
12-21-2008, 04:07 AM
#72
Rennlist Member
Thread Starter
Don't try this at home.
Dont worry, its only going to tested for a mile or so. Plus Im leaving the other side the S4 rotor to see how much the extra braking torque pulls the car to one side.
mk
Dont worry, its only going to tested for a mile or so. Plus Im leaving the other side the S4 rotor to see how much the extra braking torque pulls the car to one side.
mk
Please tell me that this is a VERY POOR JOKE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
These will deform very very easily due to their shape, and when they do the bolts will back out almost immediately.
Until you have to proper spacers run the S4 rotors!!
as I dont want to hear about you on the news
These will deform very very easily due to their shape, and when they do the bolts will back out almost immediately.
Until you have to proper spacers run the S4 rotors!!
as I dont want to hear about you on the news
12-21-2008, 04:08 AM
#73
Nordschleife Master
Seriously i dont trust cut up lug nuts to hold my brakes on a little crappy 50 hp honda, let alone a 928, let alone let alone a 928 thats being raced.
The calipers look like they need to be torn down so why not just sell those calipers as a core rebuild, and buy the big blacks?
Im sure there is a method to his madness
The calipers look like they need to be torn down so why not just sell those calipers as a core rebuild, and buy the big blacks?
Im sure there is a method to his madness
Thanks.
Again, those cut up lug nuts are actually pretty good material, but no, they wont be the finished product. a larger piece to extend the contact patch to what is seen normally, will be used and probably a dense aluminum or steel washer will be used. (we are talking .35")
Those calipers are plenty. again, if you see the pads of some real fast pro racers, they are not much different. again, the S4 pad is almost identical to the F50 ferarri pad.
I dont know what the mode of failure of these brakes are, but i suspect it would be something like leaks or pulling to one side, under braking. Like most things on this car, it usually looks pretty good on the inside, but bad on the outside. when I bled the fluid, it always looks very clean, even after a good cooking
mk
Again, those cut up lug nuts are actually pretty good material, but no, they wont be the finished product. a larger piece to extend the contact patch to what is seen normally, will be used and probably a dense aluminum or steel washer will be used. (we are talking .35")
Those calipers are plenty. again, if you see the pads of some real fast pro racers, they are not much different. again, the S4 pad is almost identical to the F50 ferarri pad.
I dont know what the mode of failure of these brakes are, but i suspect it would be something like leaks or pulling to one side, under braking. Like most things on this car, it usually looks pretty good on the inside, but bad on the outside. when I bled the fluid, it always looks very clean, even after a good cooking
mk
Please tell me that this is a VERY POOR JOKE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
These will deform very very easily due to their shape, and when they do the bolts will back out almost immediately.
Until you have to proper spacers run the S4 rotors!!
as I dont want to hear about you on the news
These will deform very very easily due to their shape, and when they do the bolts will back out almost immediately.
Until you have to proper spacers run the S4 rotors!!
as I dont want to hear about you on the newsPLUS 1 MILLION
I dont think he likes to listen much, i think poor Mark has selective reading eyeballs or something.....
12-21-2008, 12:14 PM
#74
Rennlist Member
Thread Starter
Com'mon, I like that you guys care, but I listen to logic!
Those lug nut spacers have been trimmed to have two flat surfaces that are like washers, and with a little tightening torque, they are not going anywhere. I remember one time seeing hand tight lug nuts on a track session. I think one might have backed off a half of a turn! (still very dangerous, but its not like a loose nut will just spin right off)
The aluminun lug nut is very strong aluminum as well. It doesnt deform very easily. Plus, those bolts are 1/2" diameter and the threads go down ! Do you really think that the bolts will "immediately" back out? define imediately.
How much do you want to bet if i drive the car a mile the bolts will not be loosened a bit, let alone back out immediately?
So, reality check. Ive put the mock up system together. Ill probably drive down the road and make a few moderate stops and come back. If you think about it, there is really no possible way that the bolts will become untorqued, and then rotate the 20 turns needed to come off! plus, calipers make noise, a lot of noise when they start coming loose. This is not my daly driver, as all runs with the car to the store are test runs, complete with 60-100mph times!
(none of those until the real spacers come in)
I had left a caliper bolt loose on my 84 on the way to the track one time. by the time i got to san francisco, i noticed some clunking noise on braking. turns out the calipers were hanging by one bolt, as one fell out. I tightened the other one, and drove to oakland to the 911 dismantler where they had a 928 caliper bolt that they sold me. On to thunderhill for the race and DE.
Those lug nut spacers have been trimmed to have two flat surfaces that are like washers, and with a little tightening torque, they are not going anywhere. I remember one time seeing hand tight lug nuts on a track session. I think one might have backed off a half of a turn! (still very dangerous, but its not like a loose nut will just spin right off)
The aluminun lug nut is very strong aluminum as well. It doesnt deform very easily. Plus, those bolts are 1/2" diameter and the threads go down ! Do you really think that the bolts will "immediately" back out? define imediately.
How much do you want to bet if i drive the car a mile the bolts will not be loosened a bit, let alone back out immediately?
So, reality check. Ive put the mock up system together. Ill probably drive down the road and make a few moderate stops and come back. If you think about it, there is really no possible way that the bolts will become untorqued, and then rotate the 20 turns needed to come off! plus, calipers make noise, a lot of noise when they start coming loose. This is not my daly driver, as all runs with the car to the store are test runs, complete with 60-100mph times!
(none of those until the real spacers come in)
I had left a caliper bolt loose on my 84 on the way to the track one time. by the time i got to san francisco, i noticed some clunking noise on braking. turns out the calipers were hanging by one bolt, as one fell out. I tightened the other one, and drove to oakland to the 911 dismantler where they had a 928 caliper bolt that they sold me. On to thunderhill for the race and DE.
