big brake idea?
06-05-2009, 09:07 PM
#46
Rennlist Member
06-05-2009, 09:08 PM
#47
Rennlist Member
Mark, I know you're views on the S4 rotors and calipers, but why do you suppose cars with a similar weight and less hp/tq as yours, say a GT3 have much larger rotors and calipers? I know you've put a lot of time and energy into making your setup work and that's great, but I wonder if it wouldn't have been better just to bite the bullet and put a more modern setup onto your racecar. I realise that replacement costs on components is higher too but you wouldn't have to worry about lack of choice on superior parts for the track either.
06-05-2009, 09:24 PM
#48
Rennlist Member
Thread Starter
If you look at professional race cars that have brakes to match their performance, my set up is almost identical to most all cars that have ever run a 1:37 out at laguna. the stoptech ST40 have the exact same pad and its positioned on a rotor the same size as I use now.
GT3 cup cars have more power to the wheels and are near 300lbs lighter than my current race car. their pad set up is as narrow, but very wide with the use of 6 piston caliper brakes. The F-40/F50 ferrari uses the simlar pad and caliper size to the S4 again, but on much larger 14" rotors. There is nothing wrong or lacking with the S4 calipers.
So, there are very few cars with similar HP /weight as I have with larger brakes. The ones that have larger brakes, the do not use a GTScaliper, but a caliper close to the S4, and most often, a 2 piece rotor. If I was to do anything brake mod wise, it would be to get the separate hat and rotor combo for the S4 calipers which are excellent calipers by any measurement. Again, why do you think the ST-40 Stoptech is such a popular set up for cars of my HP/weight ratio and overall weight?
Using a solid rotor is certainly a drawback in some ways, but the cost is very attractive vs making a custom hat assembly and works just as well.
If a good quality rotor that is less expensive is available and easy to modify with no sacrafices in safety, why not?
'Biting the bulllet" is what, near $1500 for the big reds, $1000 for custom hats and then about $50 more for the pads when its time to change them?
this is more than Half of my entire season racing budget!
mk
GT3 cup cars have more power to the wheels and are near 300lbs lighter than my current race car. their pad set up is as narrow, but very wide with the use of 6 piston caliper brakes. The F-40/F50 ferrari uses the simlar pad and caliper size to the S4 again, but on much larger 14" rotors. There is nothing wrong or lacking with the S4 calipers.
So, there are very few cars with similar HP /weight as I have with larger brakes. The ones that have larger brakes, the do not use a GTScaliper, but a caliper close to the S4, and most often, a 2 piece rotor. If I was to do anything brake mod wise, it would be to get the separate hat and rotor combo for the S4 calipers which are excellent calipers by any measurement. Again, why do you think the ST-40 Stoptech is such a popular set up for cars of my HP/weight ratio and overall weight?
Using a solid rotor is certainly a drawback in some ways, but the cost is very attractive vs making a custom hat assembly and works just as well.
If a good quality rotor that is less expensive is available and easy to modify with no sacrafices in safety, why not?
'Biting the bulllet" is what, near $1500 for the big reds, $1000 for custom hats and then about $50 more for the pads when its time to change them?
this is more than Half of my entire season racing budget!
mk
Mark, I know you're views on the S4 rotors and calipers, but why do you suppose cars with a similar weight and less hp/tq as yours, say a GT3 have much larger rotors and calipers? I know you've put a lot of time and energy into making your setup work and that's great, but I wonder if it wouldn't have been better just to bite the bullet and put a more modern setup onto your racecar. I realise that replacement costs on components is higher too but you wouldn't have to worry about lack of choice on superior parts for the track either.
06-05-2009, 09:26 PM
#49
Rennlist Member
Thread Starter
ill measure the run out on the current set up, drill the prototype holes by hand and measure them as well.
If I bought the rotors new, I would measure/copy the bolt circle and have them drilled by a machinist.
mk
If I bought the rotors new, I would measure/copy the bolt circle and have them drilled by a machinist.
mk
06-05-2009, 09:39 PM
#50
Captain Obvious
Super User
Super User
Don't drill it by hand!!!!! Take it to a machine shop and have them drill it out with an indexing table. They can propery devide the holes so they are exactly at the right location. One I had a rotor that had the holes out of center by 8 thousands of an inch (brand new Chineese made POS). The vibration that it gave out was as if the rim was severaly bent.
06-05-2009, 09:49 PM
#51
Rennlist Member
Thread Starter
im only drilling the prototype used rotor to see if the ID of the rotor clears the hub. If he rotors arehub centered, which I believe as well, they wont fit.
Ill see in the AM when i do the test
Ill see in the AM when i do the test
Don't drill it by hand!!!!! Take it to a machine shop and have them drill it out with an indexing table. They can propery devide the holes so they are exactly at the right location. One I had a rotor that had the holes out of center by 8 thousands of an inch (brand new Chineese made POS). The vibration that it gave out was as if the rim was severaly bent.
06-06-2009, 01:02 AM
#52
Rennlist Member
06-06-2009, 02:50 AM
#53
Rennlist Member
IMHO the poor venting is a deal-killer for a race car but, for the sake of argument it makes more sense to look up the bolt center spec than to try to measure it, and provide stud dimensions and tell him you want a slip fit.
Ideally if you want to switch to a cheaper rotor you would look for one that centers properly on the hub. One ugly solution if the rotor is too big is to cut the hub back and have a collar pressed on, with a step to keep it tight against the rotor. A better scenario is where the rotor hat is too narrow inside and you turn a couple mm off of the hub to make it fit.
06-06-2009, 03:54 AM
#54
Rennlist Member
If you look at professional race cars that have brakes to match their performance, my set up is almost identical to most all cars that have ever run a 1:37 out at laguna. the stoptech ST40 have the exact same pad and its positioned on a rotor the same size as I use now.
GT3 cup cars have more power to the wheels and are near 300lbs lighter than my current race car. their pad set up is as narrow, but very wide with the use of 6 piston caliper brakes. The F-40/F50 ferrari uses the simlar pad and caliper size to the S4 again, but on much larger 14" rotors. There is nothing wrong or lacking with the S4 calipers.
So, there are very few cars with similar HP /weight as I have with larger brakes. The ones that have larger brakes, the do not use a GTScaliper, but a caliper close to the S4, and most often, a 2 piece rotor. If I was to do anything brake mod wise, it would be to get the separate hat and rotor combo for the S4 calipers which are excellent calipers by any measurement. Again, why do you think the ST-40 Stoptech is such a popular set up for cars of my HP/weight ratio and overall weight?
Using a solid rotor is certainly a drawback in some ways, but the cost is very attractive vs making a custom hat assembly and works just as well.
If a good quality rotor that is less expensive is available and easy to modify with no sacrafices in safety, why not?
'Biting the bulllet" is what, near $1500 for the big reds, $1000 for custom hats and then about $50 more for the pads when its time to change them?
this is more than Half of my entire season racing budget!
mk
GT3 cup cars have more power to the wheels and are near 300lbs lighter than my current race car. their pad set up is as narrow, but very wide with the use of 6 piston caliper brakes. The F-40/F50 ferrari uses the simlar pad and caliper size to the S4 again, but on much larger 14" rotors. There is nothing wrong or lacking with the S4 calipers.
So, there are very few cars with similar HP /weight as I have with larger brakes. The ones that have larger brakes, the do not use a GTScaliper, but a caliper close to the S4, and most often, a 2 piece rotor. If I was to do anything brake mod wise, it would be to get the separate hat and rotor combo for the S4 calipers which are excellent calipers by any measurement. Again, why do you think the ST-40 Stoptech is such a popular set up for cars of my HP/weight ratio and overall weight?
Using a solid rotor is certainly a drawback in some ways, but the cost is very attractive vs making a custom hat assembly and works just as well.
If a good quality rotor that is less expensive is available and easy to modify with no sacrafices in safety, why not?
'Biting the bulllet" is what, near $1500 for the big reds, $1000 for custom hats and then about $50 more for the pads when its time to change them?
this is more than Half of my entire season racing budget!
mk
I get the budget thing. You somehow run on the smell of an oily rag and more power to you.
Ok let's do a hypothetical. Say someone gives you a blank cheque and says go update your brakes. Let's exclude C/F rotors for this exercise.
What would you buy?
06-06-2009, 05:44 AM
#55
Nordschleife Master
I was under the impression that zimmerman are the OE manufacturer for 928 brake rotors (at least for S4), and not just a regular "aftermarket" crowd?
Their discs are available as OEM (no holes) and cast-holed.
As for durability or quality, I have NFI being a non-expert and non-racer, but the pictures of Mark's Porsche 964TT rotors and the cracks in them are downright scary.
Not saying Anthony is wrong/right, just adding commentary for the sake of clarity on the "far less quality than the Porsche OE Manufacturer" comment.
Hilton.
Their discs are available as OEM (no holes) and cast-holed.
As for durability or quality, I have NFI being a non-expert and non-racer, but the pictures of Mark's Porsche 964TT rotors and the cracks in them are downright scary.
Not saying Anthony is wrong/right, just adding commentary for the sake of clarity on the "far less quality than the Porsche OE Manufacturer" comment.
Hilton.
mark,
I don't understand your fascination with zimmerman. Zimmerman is an aftermarket rotor and is far less quality than the Porsche OE manufacturer. I have seen their rotors fall apart under hard use and although they look the same the veining in the casting is not the same design and offers less air flow. We actually cut one of each apart for a brake demo. The zimmerman cut easily and the OE was much harder to cut. this might be why the have a tendency to groove more than the OE rotors. I was told but could be wrong that the holes are drilled not cast.
I don't understand your fascination with zimmerman. Zimmerman is an aftermarket rotor and is far less quality than the Porsche OE manufacturer. I have seen their rotors fall apart under hard use and although they look the same the veining in the casting is not the same design and offers less air flow. We actually cut one of each apart for a brake demo. The zimmerman cut easily and the OE was much harder to cut. this might be why the have a tendency to groove more than the OE rotors. I was told but could be wrong that the holes are drilled not cast.
06-06-2009, 10:26 AM
#56
Rennlist Member
Well the talk was that OEM rotors were 'seasoned' in such a way that proved superior to the Zimmerman ones.
06-06-2009, 12:33 PM
#57
Rennlist Member
Thread Starter
Did you forget that these cracked rotors, almost ready to fall apart, WERE O.E. porsche rotors??? (not Zimmermans) .
All the Zimmermans Ive used and abused have lasted half or almost full seasons before small little hairline cracks have made it to the edge. Im thinking that the Zimmermans are the better quality, not the Porsche OE which have failed in this instance.
All the Zimmermans Ive used and abused have lasted half or almost full seasons before small little hairline cracks have made it to the edge. Im thinking that the Zimmermans are the better quality, not the Porsche OE which have failed in this instance.
06-06-2009, 12:47 PM
#58
Rennlist Member
Thread Starter
Id go with Mark Andersons set up. 14" custom hat 2 piece rotors and Brembos to match (which are like the S4s). only because I know the system works. Now, the GT3 6 piston calipers use pads as narrow , but way longer (because of the 6 pot calipers) BUT, i dont know how the brake master cylinder would work with it. (un proven) So, it could cause more problems.
No as far as the GT3, they use a bigger brake package because they can, and its newer technology. the car is set up for being able to run 24hours races as well, so bigger in that sense is better. for 30min sprint races, its kind of over kill. I run as fast as one of the top pro drivers in a GT3 996. actually faster with less HP, so its not the brakes now is it? ( max Angelelli in a GT3 street car on DOTs at laguna seca ran a best time of 1:39.5. My average time since 2006 has always been 1:39.1 and with a peak of 1:38.8.)
So, im sure there are plenty of cars with larger and smaller brakes that run fast and safely at laguna. Just because the 996 GT3 has bigger brakes when it could safely run with smalller brakes, doesnt mean its the yard stick. again, look at much faster cars that are heavier that run at laguna. The majority run ST40 stoptechs and again, they are the same brakes as the 928S4 and these are pro teams that could go larger if they thought it was worth it. another point, is that if you dont get some of the pad temps high enough, they dont work as well. the mustang we run with has to drag its brakes to get them to work well at the proper temp at thunderhill!. Again, lots of factors. Proof is that with my HP and weight and times, the mix of brakes is working well. the only issue is finding a rotor now that doesnt falll apart.
mk
No as far as the GT3, they use a bigger brake package because they can, and its newer technology. the car is set up for being able to run 24hours races as well, so bigger in that sense is better. for 30min sprint races, its kind of over kill. I run as fast as one of the top pro drivers in a GT3 996. actually faster with less HP, so its not the brakes now is it?
( max Angelelli in a GT3 street car on DOTs at laguna seca ran a best time of 1:39.5. My average time since 2006 has always been 1:39.1 and with a peak of 1:38.8.)So, im sure there are plenty of cars with larger and smaller brakes that run fast and safely at laguna. Just because the 996 GT3 has bigger brakes when it could safely run with smalller brakes, doesnt mean its the yard stick. again, look at much faster cars that are heavier that run at laguna. The majority run ST40 stoptechs and again, they are the same brakes as the 928S4 and these are pro teams that could go larger if they thought it was worth it. another point, is that if you dont get some of the pad temps high enough, they dont work as well. the mustang we run with has to drag its brakes to get them to work well at the proper temp at thunderhill!
. Again, lots of factors. Proof is that with my HP and weight and times, the mix of brakes is working well. the only issue is finding a rotor now that doesnt falll apart. mk
Not sure what you make at the crank Mark but a 996 GT3 (non Cup) has about 380bhp. If they're lighter then all the more reason for them to have smaller brakes than you. Just saying.
I get the budget thing. You somehow run on the smell of an oily rag and more power to you.
Ok let's do a hypothetical. Say someone gives you a blank cheque and says go update your brakes. Let's exclude C/F rotors for this exercise.
What would you buy?
I get the budget thing. You somehow run on the smell of an oily rag and more power to you.
Ok let's do a hypothetical. Say someone gives you a blank cheque and says go update your brakes. Let's exclude C/F rotors for this exercise.
What would you buy?
06-06-2009, 12:54 PM
#59
Rennlist Member
Thread Starter
One of the main reasons is that the GT3 cup car now runs these brakes and rotors that has the capability of running near 5-8 seconds faster a lap. the GT3 has the same brakes as it is a marketing technique that the car would have the same stuff on it as the real race car, but set up for the street. as I mentioned, in some cases, bigger is not better. optimum brake pad temps are important for max braking effectiveness. larger brakes without the faster speeds could cause braking issues.
Mark, I know you're views on the S4 rotors and calipers, but why do you suppose cars with a similar weight and less hp/tq as yours, say a GT3 have much larger rotors and calipers? I know you've put a lot of time and energy into making your setup work and that's great, but I wonder if it wouldn't have been better just to bite the bullet and put a more modern setup onto your racecar. I realise that replacement costs on components is higher too but you wouldn't have to worry about lack of choice on superior parts for the track either.
