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Porsche Brands Hatch


Joined: 31 Dec 2002 Posts: 13050 Location: Nürburgring Nordschleife
2003 Porsche 996 GT3 Mk2
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Posted: Thu Nov 15, 2007 9:36 pm Post subject: 996 GT3 & RS Brake Upgrade
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Time that I need to replace my entire brake system, the rears are approaching their end, although the front bells on the Alcon Brake discs are knackered so I need to change the lot :shock: which means new discs and pads.
I also need to change all of the front calliper seals as the track days the car has been thgrough means that the rubbers on the inside of the calipers have worn away. I am also fitting GT2 rear brake ducts, to see how they fare.
So I've taken a few pics to add as a Bigger Brake DIY thread, or si the plan hopefully. The attached is what I have got which is an excellent brake upgrade for a 996 GT3.
The rears appear to be off a 996 Turbo at 330mm, so out of interest what was the OEM front and rear brake sizes for a Mk2 GT3 ?
Front Brakes
362mm Alcon Front Discs
Pagid Yellow RS29 Pads
Rear Brakes
330mm Porsche Discs
Pagid Yellow RS29 Pads
Brake Fluid
Castrol SRF
Brake Ducts
Front - Cup
Rear - GT2
1st up The front discs & pads are being changes and the rear brake ducts fitted, with pictures to follow.
Note - Every bolt, washer and screw was also replaced.
I decided not to get them done at the same time as all the parts cost just shy of £2500 (which does make one go weak at the knees) but this lot should last well into 2009!
Doing it step by step saves a few pennies but gives me a chance to give everything a good going over and the rears have a bit more life left in them, so will be done in a months time.
So here are the main parts, those 362mm Alcon's are large and then some, at 14" how time have changed, I remember my 1st car a VW Golf running on mere 14" wheels, which were still large back then ! _________________ Porsche on Youtube!
964 Project Car
996 MK2 GT3 CS Manthey
993 Targa
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Ricky Bobby Trainee

Joined: 23 May 2007 Posts: 96 Location: Gloucester
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Posted: Thu Nov 15, 2007 9:44 pm Post subject:
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I will keep looking at how you get on Sundeep, maybe something I will get done! Are you doing all the work yourself, I would'nt like to change things inside me calliper. :shock: _________________ white & red
911 GT3 RS
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PolarExpress Loser
Joined: 03 Mar 2005 Posts: 4487 Location: Prison
2000 Porsche 996 GT3 Mk1
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Posted: Thu Nov 15, 2007 9:47 pm Post subject:
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OEM front brake discs for Mk2: 350mm
OEM rear brake discus for Mk2 (same as Mk1): 330mm
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Ricky Bobby Trainee

Joined: 23 May 2007 Posts: 96 Location: Gloucester
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Posted: Thu Nov 15, 2007 9:51 pm Post subject:
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Should I think about RS29's? How much better are they than OEM? And what is the costings (inc fittling). _________________ white & red
911 GT3 RS
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Jeff Indianapolis

Joined: 30 Aug 2007 Posts: 2382 Location: Chavley South South
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Posted: Thu Nov 15, 2007 9:56 pm Post subject:
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Ricky Bobby wrote: | I will keep looking at how you get on Sundeep, maybe something I will get done! Are you doing all the work yourself, I would'nt like to change things inside me calliper. :shock: |
I've rebuilt three sets of 4 piston calipers. Simple simon stuff REALLY!
The rebuild kits come with the rubber grease necessary. There is a seal around the piston you replace then the dust cover. That it all there is to do with it ASSUMING you haven't actually damaged a cylinder. If you have no brake problems when you do it then more than likely you will have no wear. You can simply pop all pistons, clean, replace seal, replace dust cover, done.
You would be quite surprised just how easy it really is. Yes, you could get ***** and measure bores and cylinders but seriously, no one will do this. Really believe me, unless the bore is scored, nothing more than a freshen up gets done.
As I've said I've done three sets of Nissan GTR callipers and one of those was on my car for a long time without fault.
Cheers, _________________ Jeff
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PolarExpress Loser
Joined: 03 Mar 2005 Posts: 4487 Location: Prison
2000 Porsche 996 GT3 Mk1
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Posted: Thu Nov 15, 2007 10:01 pm Post subject:
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Ricky Bobby wrote: | Should I think about RS29's? How much better are they than OEM? And what is the costings (inc fittling). |
RS29s are an endurance race pad - the same pad used by Porsche and other race teams at Le Mans. One set of pads can last them the entire 24hrs!
I think it depends on how you use your car: if it spends time on track, you will find a massive improvement with RS29s. If you use it on the road, RS29s don't work as well at low temps and they will never get into their optimum operating temperature. However they are perfectly fine on the road apart from the squealing if the pads become unbedded.
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Porsche Brands Hatch


Joined: 31 Dec 2002 Posts: 13050 Location: Nürburgring Nordschleife
2003 Porsche 996 GT3 Mk2
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Posted: Thu Nov 15, 2007 10:07 pm Post subject:
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the biggest change is going away fron the noisy Floating Alcon 350mm discs to Fixed 362mm discs.
As for those who have been for a ride in my car in the last few months, they would agree it has been noisy !
Now without any floating disc noise, I'm hearing every other noise in the car ! _________________ Porsche on Youtube!
964 Project Car
996 MK2 GT3 CS Manthey
993 Targa
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Daniel Donnington


Joined: 02 Feb 2005 Posts: 11919 Location: Not where I want to be!
2000 Porsche 996 GT3 Mk1
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Posted: Thu Nov 15, 2007 10:13 pm Post subject:
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Sundeep wrote: | the biggest change is going away fron the noisy Floating Alcon 350mm discs to Fixed 362mm discs.
As for those who have been for a ride in my car in the last few months, they would agree it has been noisy !
Now without any floating disc noise, I'm hearing every other noise in the car ! |
Is that Carpet mat still moving about !!!!!  _________________ *Current - GT3 996.1 Clubsport (Manthey K400)
EX VR993 - C4
EX 993 - C2
EX GT3 996.1
EX Cayman 3.4 S 987.1
EX Megane R26R #36.
EX Cayman R
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Jeff Indianapolis

Joined: 30 Aug 2007 Posts: 2382 Location: Chavley South South
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Posted: Thu Nov 15, 2007 10:16 pm Post subject:
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Floating Alcons? Do you mean your bells were worn so were moving around? Otherwise I can't understand the difference between what you had and what you have other than the size difference? _________________ Jeff
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PolarExpress Loser
Joined: 03 Mar 2005 Posts: 4487 Location: Prison
2000 Porsche 996 GT3 Mk1
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Posted: Thu Nov 15, 2007 10:21 pm Post subject:
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Sundeep wrote: | the biggest change is going away fron the noisy Floating Alcon 350mm discs to Fixed 362mm discs.
As for those who have been for a ride in my car in the last few months, they would agree it has been noisy !
Now without any floating disc noise, I'm hearing every other noise in the car ! |
Sundeep - you've got it all mixed up!
You used to have the old Generation 1 350mm Alcons which did not have the spring mounted bobbins of the Generation 2 Alcons, hence the Gen1s were noisy.
The Generation 2 Alcons are not fixed... they are a floating design but they employ spring bobbins which result in them being silent.
The bonus is that the Gen2 Alcons are larger in diameter at 362mm. The Gen1 Alcons were the same size as the OEM discs at 350mm.
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Jeff Indianapolis

Joined: 30 Aug 2007 Posts: 2382 Location: Chavley South South
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Posted: Thu Nov 15, 2007 10:27 pm Post subject:
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PolarExpress wrote: | Sundeep wrote: | the biggest change is going away fron the noisy Floating Alcon 350mm discs to Fixed 362mm discs.
As for those who have been for a ride in my car in the last few months, they would agree it has been noisy !
Now without any floating disc noise, I'm hearing every other noise in the car ! |
Sundeep - you've got it all mixed up!
You used to have the old Generation 1 350mm Alcons which did not have the spring mounted bobbins of the Generation 2 Alcons, hence the Gen1s were noisy.
The Generation 2 Alcons are not fixed... they are a floating design but they employ spring bobbins which result in them being silent.
The bonus is that the Gen2 Alcons are larger in diameter at 362mm. The Gen1 Alcons were the same size as the OEM discs at 350mm. |
That makes more sense. _________________ Jeff
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Porsche Brands Hatch


Joined: 31 Dec 2002 Posts: 13050 Location: Nürburgring Nordschleife
2003 Porsche 996 GT3 Mk2
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Posted: Thu Nov 15, 2007 11:20 pm Post subject:
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PolarExpress wrote: |
Sundeep - you've got it all mixed up!
You used to have the old Generation 1 350mm Alcons which did not have the spring mounted bobbins of the Generation 2 Alcons, hence the Gen1s were noisy.
The Generation 2 Alcons are not fixed... they are a floating design but they employ spring bobbins which result in them being silent.
The bonus is that the Gen2 Alcons are larger in diameter at 362mm. The Gen1 Alcons were the same size as the OEM discs at 350mm. |
OK, I'll got with that reply
All I know the lack of noise is wierd ! _________________ Porsche on Youtube!
964 Project Car
996 MK2 GT3 CS Manthey
993 Targa
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PolarExpress Loser
Joined: 03 Mar 2005 Posts: 4487 Location: Prison
2000 Porsche 996 GT3 Mk1
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Posted: Thu Nov 15, 2007 11:25 pm Post subject:
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Sundeep wrote: | PolarExpress wrote: |
Sundeep - you've got it all mixed up!
You used to have the old Generation 1 350mm Alcons which did not have the spring mounted bobbins of the Generation 2 Alcons, hence the Gen1s were noisy.
The Generation 2 Alcons are not fixed... they are a floating design but they employ spring bobbins which result in them being silent.
The bonus is that the Gen2 Alcons are larger in diameter at 362mm. The Gen1 Alcons were the same size as the OEM discs at 350mm. |
OK, I'll got with that reply
All I know the lack of noise is wierd ! |
No worries my young jedi... with time learn you will!
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Carrera4S Loser

Joined: 16 Oct 2006 Posts: 3039
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Posted: Fri Nov 16, 2007 12:02 am Post subject:
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What's the advantage of 362mm discs when the pad area is identical? Do you get a ridge on the inner or outer part of the disc as they wear?
I'm only asking as I'm going with PFC discs on the front when the disc are knackered, I already have the bells so it seems a shame to waste them
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Porsche Brands Hatch


Joined: 31 Dec 2002 Posts: 13050 Location: Nürburgring Nordschleife
2003 Porsche 996 GT3 Mk2
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Posted: Fri Nov 16, 2007 12:06 am Post subject:
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Damian wrote: | What's the advantage of 362mm discs when the pad area is identical? Do you get a ridge on the inner or outer part of the disc as they wear?
I'm only asking as I'm going with PFC discs on the front when the disc are knackered, I already have the bells so it seems a shame to waste them  |
My Padawan learner will be along to answer that one, but they do make a slight difference, although then tyre limits come into it but isn't there a point when an 8 pot calliper can be used ?
Did have a look at PFC pads as they are a bargain verses the PAGID. _________________ Porsche on Youtube!
964 Project Car
996 MK2 GT3 CS Manthey
993 Targa
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PolarExpress Loser
Joined: 03 Mar 2005 Posts: 4487 Location: Prison
2000 Porsche 996 GT3 Mk1
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Posted: Fri Nov 16, 2007 12:16 am Post subject:
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Damian wrote: | What's the advantage of 362mm discs when the pad area is identical? Do you get a ridge on the inner or outer part of the disc as they wear?
I'm only asking as I'm going with PFC discs on the front when the disc are knackered, I already have the bells so it seems a shame to waste them  |
The 362mm radius is 6mm longer than the 350mm. So with a larger radius, the same size brake pads can apply a greater brake leverage force. The centripetal [negative] acceleration must be greater given the increase of radius since the actual perpendicular/circumferal brake pressure/frictional force is a constant with the same pad area and brake calipers.
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Carrera4S Loser

Joined: 16 Oct 2006 Posts: 3039
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Posted: Fri Nov 16, 2007 12:20 am Post subject:
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PolarExpress wrote: | Damian wrote: | What's the advantage of 362mm discs when the pad area is identical? Do you get a ridge on the inner or outer part of the disc as they wear?
I'm only asking as I'm going with PFC discs on the front when the disc are knackered, I already have the bells so it seems a shame to waste them  |
The 362mm radius is 6mm longer than the 350mm. So with a larger radius, the same size brake pads can apply a greater brake leverage force. |
That would only happen if the calipers were moved out the 6mm to offset this. This explains the longer caliper bolts and 'washers' needed. So you still waste 6mm on the inside
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PolarExpress Loser
Joined: 03 Mar 2005 Posts: 4487 Location: Prison
2000 Porsche 996 GT3 Mk1
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Posted: Fri Nov 16, 2007 12:22 am Post subject:
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Damian wrote: | PolarExpress wrote: | Damian wrote: | What's the advantage of 362mm discs when the pad area is identical? Do you get a ridge on the inner or outer part of the disc as they wear?
I'm only asking as I'm going with PFC discs on the front when the disc are knackered, I already have the bells so it seems a shame to waste them  |
The 362mm radius is 6mm longer than the 350mm. So with a larger radius, the same size brake pads can apply a greater brake leverage force. |
That would only happen if the calipers were moved out the 6mm to offset this. This explains the longer caliper bolts and 'washers' needed. So you still waste 6mm on the inside  |
Yep. Better to use 6mm on the outside than 6mm on the inside.
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Carrera4S Loser

Joined: 16 Oct 2006 Posts: 3039
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Posted: Fri Nov 16, 2007 12:27 am Post subject:
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PolarExpress wrote: | Damian wrote: | PolarExpress wrote: | Damian wrote: | What's the advantage of 362mm discs when the pad area is identical? Do you get a ridge on the inner or outer part of the disc as they wear?
I'm only asking as I'm going with PFC discs on the front when the disc are knackered, I already have the bells so it seems a shame to waste them  |
The 362mm radius is 6mm longer than the 350mm. So with a larger radius, the same size brake pads can apply a greater brake leverage force. |
That would only happen if the calipers were moved out the 6mm to offset this. This explains the longer caliper bolts and 'washers' needed. So you still waste 6mm on the inside  |
Yep. Better to use 6mm on the outside than 6mm on the inside. |
Very true. I bet someone will come along to calculate the pedal pressure difference needed for a 350mm disc to be retarded the same as a 362mm given the same pad size with the 6mm offset
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PolarExpress Loser
Joined: 03 Mar 2005 Posts: 4487 Location: Prison
2000 Porsche 996 GT3 Mk1
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Posted: Fri Nov 16, 2007 12:39 am Post subject:
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I'm guessing that since hydraulic pressure is a constant, the change in pressure is a constant relationship to whatever the increase in acceleration rate is of the larger disc being retarded! (something over 6mm squared!)
Someone pass me another Guinness
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