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ELA
Suzuka


Joined: 30 Aug 2011
Posts: 1168
Location: Nurburgring Doorstep


PostPosted: Thu Dec 17, 2015 11:57 am    Post subject: Reply with quote

NXI20 wrote:
PF are good discs but I'd be amazed if you saved even 500g per disc over standard.


I've contacted the manufacturer, I'll let you know how much they weigh when they respond Thumb
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Stuart
General
General


Joined: 16 Sep 2007
Posts: 5036
Location: Waterworld

2004 Porsche 996 GT3 Mk2

PostPosted: Thu Dec 17, 2015 1:25 pm    Post subject: Reply with quote

I contacted PF when I was looking for new fronts on my '02 C2.

Their answer at the time:
Quote:

-----Original Message-----
From: Stuart
To: aspinformation@aol.com
Sent: Tue, 5 Jan 2010 11:12
Subject: RE: Performance Friction 2 piece rotars for Porsche 996 C2
Thanks Alyn,

That’s heavier than stock discs at 9kg each. Looks like weight will have to come from somewhere else.

Many thanks,

Stuart

________________________________________
From: aspinformation@aol.com [mailto:aspinformation@aol.com]
Sent: 05 January 2010 10:50
To: Stuart
Subject: Re: Performance Friction 2 piece rotars for Porsche 996 C2

The 318.067.87/88 disc assemblies are 9.2kg each, the hats for these are made from cast iron not the usual aluminium

cheers, alyn
www.asperformance.com
0191-4103770



-----Original Message-----
From: Stuart
To: info@asptrading.co.uk
Sent: Mon, 4 Jan 2010 16:39
Subject: Performance Friction 2 piece rotars for Porsche 996 C2
Hi,

I’m looking at purchasing a set of Performance Friction Direct Drive Discs for a Porsche 996 C2 from you. Do you have any weight information per disc? I’m trying to reduce weight and this is fairly crucial info…

Many thanks,

Stuart


I went with Girodisc in the end and was very happy, here's my write up http://911uk.com/viewtopic.php?t=51688&start=0&postdays=0&postorder=asc&highlight=disc+weight

Now I'm running Alcons and will be calling Nick/Uber9s very soon for my second set.

Thumb
 
  
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NXI20
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Joined: 02 Feb 2008
Posts: 3234
Location: South Bucks

2004 Porsche 996 GT3 Mk2

PostPosted: Thu Dec 17, 2015 1:36 pm    Post subject: Reply with quote

But you've got a proper track car now Stuart (and you track it), so Alcons are the obvious choice Thumb
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Nick
Need Alcon discs or Pagid pads? https://uber9s.com

2004 GT3 CS in Atlas Grey with too many mods to list!
1995 993 GT2 recreation in Polar Silver
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Sustanon400
Spa-Francorchamps


Joined: 10 Jun 2011
Posts: 263



PostPosted: Thu Dec 17, 2015 1:38 pm    Post subject: Reply with quote

I'll be needed front discs and pads for my 2004 996 turbo very soon, what options do you have ?
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Stuart
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General


Joined: 16 Sep 2007
Posts: 5036
Location: Waterworld

2004 Porsche 996 GT3 Mk2

PostPosted: Thu Dec 17, 2015 1:38 pm    Post subject: Reply with quote

NXI20 wrote:
But you've got a proper track car now Stuart (and you track it), so Alcons are the obvious choice Thumb


shhhh, don't tell anyone... GT's are for polishing, not driving...
 
  
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NXI20
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Joined: 02 Feb 2008
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Location: South Bucks

2004 Porsche 996 GT3 Mk2

PostPosted: Thu Dec 17, 2015 1:54 pm    Post subject: Reply with quote

Sustanon400 wrote:
I'll be needed front discs and pads for my 2004 996 turbo very soon, what options do you have ?


Do you already have 6-pot callipers on the car?

We can do the Alcon 362mm discs & bells for the 996 Turbo for £1339.99 inc VAT

You do need the 6-pots to make that disc work; if you don't have them we can source callipers for less money than Porsche will charge.

We always recommend Pagid RS29 pads for use with Alcon discs.

PM me or use our contact form if you need more details:

https://uber9s.com/contact/
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Need Alcon discs or Pagid pads? https://uber9s.com

2004 GT3 CS in Atlas Grey with too many mods to list!
1995 993 GT2 recreation in Polar Silver
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spyderman
Suzuka


Joined: 26 Jul 2009
Posts: 1094
Location: near Milton Keynes


PostPosted: Thu Dec 17, 2015 10:09 pm    Post subject: Reply with quote

Nick - can you supply RS29 pads in other sizes - 987 3.2 for example? We've been using them on race Boxsters in endurance for a few seasons and love them.

Chris.
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NXI20
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Joined: 02 Feb 2008
Posts: 3234
Location: South Bucks

2004 Porsche 996 GT3 Mk2

PostPosted: Thu Dec 17, 2015 10:16 pm    Post subject: Reply with quote

spyderman wrote:
Nick - can you supply RS29 pads in other sizes - 987 3.2 for example? We've been using them on race Boxsters in endurance for a few seasons and love them.

Chris.


Of course; give me the Pagid part number & an indication of how many sets you'd want & I'll PM you with a decent price.
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Nick
Need Alcon discs or Pagid pads? https://uber9s.com

2004 GT3 CS in Atlas Grey with too many mods to list!
1995 993 GT2 recreation in Polar Silver
2010 GT3 CS in Riviera Blue Smile
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Stuart Mackay
Monza


Joined: 29 Apr 2013
Posts: 171
Location: Swaffham, Norfolk and Good


PostPosted: Sun Dec 04, 2016 4:18 pm    Post subject: Reply with quote

Wanted to say thanks to Nick for the totally impartial advice in trying to convert my Race Brembo RSR discs to fit on the GT3.

In the end, I was so impressed with the impressive technical advice and support, that I decided to buy a complete set of 380mm/360mm Alcons/RS29s (with spacers/bolts to adapt the existing calipers to the larger brakes) from him, all of which were delivered at lightning speed.

Finally, and within ten days of starting discussing the upgrade with him, the car is now at Fearnesport being converted.

Tremendous service, guys...one stop shopping, most impressed and confidence inspiring to someone who hasn't been involved in this type of conversion in the past.
Highly recommended to anyone thinking of upgrading to floating discs from the crack prone OEM Porsche discs!
thumbsup thumbsup thumbsup
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NXI20
Approved Trader


Joined: 02 Feb 2008
Posts: 3234
Location: South Bucks

2004 Porsche 996 GT3 Mk2

PostPosted: Sun Dec 04, 2016 4:32 pm    Post subject: Reply with quote

Thumb Glad you're pleased Stuart. Sorry we couldn't make the RSR discs work for you but the Alcons are just as good & replacement rotors will be easier to get hold of.

Come back & tell everyone how impressive the brake upgrade is once you've got some miles on them Grin
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Need Alcon discs or Pagid pads? https://uber9s.com

2004 GT3 CS in Atlas Grey with too many mods to list!
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Stuart Mackay
Monza


Joined: 29 Apr 2013
Posts: 171
Location: Swaffham, Norfolk and Good


PostPosted: Thu Dec 22, 2016 8:13 pm    Post subject: Reply with quote

Wow, is all I can say, thanks to Nick from Uber 9S https://uber9s.com/997-gt-gen-1/ and Matt from Fearnsport http://www.fearnsport.co.uk/

A great job, well done, the 380mm fronts and 360mm rear brakes/ Pagid RS29s have a vastly improved feel and potentially will stand the car on its nose now, confidence inspiring stuff and thanks for making a great car even better! thumbsup thumbsup thumbsup
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Stuart Mackay
Monza


Joined: 29 Apr 2013
Posts: 171
Location: Swaffham, Norfolk and Good


PostPosted: Thu Dec 22, 2016 8:31 pm    Post subject: Reply with quote

360 mm rears
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IMI A
Österreich


Joined: 02 Aug 2014
Posts: 997
Location: United Kingdom


PostPosted: Fri Dec 23, 2016 11:02 am    Post subject: Reply with quote

on a 997.1 turbo with steels does increasing disc size from 350mm to 380mm at front improve braking performance? I find the steel oem set up with 350mm very good indeed.

Easy enough to increase size with adapter kits but will the adapter kit not just add weight and complexity ?
 
  
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NXI20
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Joined: 02 Feb 2008
Posts: 3234
Location: South Bucks

2004 Porsche 996 GT3 Mk2

PostPosted: Fri Dec 23, 2016 11:34 am    Post subject: Reply with quote

IMI A wrote:
on a 997.1 turbo with steels does increasing disc size from 350mm to 380mm at front improve braking performance? I find the steel oem set up with 350mm very good indeed.

Easy enough to increase size with adapter kits but will the adapter kit not just add weight and complexity ?


In 2 words: Yes & No

In detail:

Increasing the disc diameter increases retardation because for the same brake pedal pressure you have greater angular force. To some extent it also reduces the amount of heat the brakes need to absorb per square centimeter because of the greater surface area. This is why PCCB brakes are of a larger diameter than the equivalent steel brakes on each model, steel being less impacted by high rotor temperatures than the construction of ceramic disc chosen by Porsche.

Increased weight & complexity? Spacers & longer bolts are hardly "increasing complexity"; as for weight I'd estimate that it adds less than 20 grams per side. The discs themselves are about 11Kg so they will add a bit of weight over the 350mm OEM ones but the extra isn't really noticeable, particularly if you compensate with lighter wheels. The OEM wheels are very heavy.
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Need Alcon discs or Pagid pads? https://uber9s.com

2004 GT3 CS in Atlas Grey with too many mods to list!
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Disco
Estoril


Joined: 13 May 2008
Posts: 3643
Location: Hertfordshire

2010 Porsche 997 GT3

PostPosted: Fri Dec 23, 2016 1:41 pm    Post subject: Reply with quote

NXI20 wrote:
The discs themselves are about 11Kg so they will add a bit of weight over the 350mm OEM ones but the extra isn't really noticeable, particularly if you compensate with lighter wheels. The OEM wheels are very heavy.


You might want to check that - I don't have the numbers to hand, but I believe that the OEM 350mm disk on the 6 piston 997.1 setup is actually still a little bit heavier than even the 380mm Alcon (due to being a single lump of iron rather than a rotor floating on an alloy hat)?
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Black 996 GT3 Mk2 - Gone, but will never be forgotten
 
  
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IMI A
Österreich


Joined: 02 Aug 2014
Posts: 997
Location: United Kingdom


PostPosted: Fri Dec 23, 2016 5:02 pm    Post subject: Reply with quote

NXI20 wrote:
IMI A wrote:
on a 997.1 turbo with steels does increasing disc size from 350mm to 380mm at front improve braking performance? I find the steel oem set up with 350mm very good indeed.

Easy enough to increase size with adapter kits but will the adapter kit not just add weight and complexity ?


In 2 words: Yes & No

In detail:

Increasing the disc diameter increases retardation because for the same brake pedal pressure you have greater angular force. To some extent it also reduces the amount of heat the brakes need to absorb per square centimeter because of the greater surface area. This is why PCCB brakes are of a larger diameter than the equivalent steel brakes on each model, steel being less impacted by high rotor temperatures than the construction of ceramic disc chosen by Porsche.

Increased weight & complexity? Spacers & longer bolts are hardly "increasing complexity"; as for weight I'd estimate that it adds less than 20 grams per side. The discs themselves are about 11Kg so they will add a bit of weight over the 350mm OEM ones but the extra isn't really noticeable, particularly if you compensate with lighter wheels. The OEM wheels are very heavy.


Thanks for this. Would retardation not be virtually exactly the same as the surface area the brake pad grips onto is exactly the same i.e. is limited by the size of the pad? Then I suppose it depends on the performance of the tyres? Still not sure which way to go on this. Confused
 
  
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NXI20
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Joined: 02 Feb 2008
Posts: 3234
Location: South Bucks

2004 Porsche 996 GT3 Mk2

PostPosted: Fri Dec 23, 2016 7:42 pm    Post subject: Reply with quote

IMI A wrote:
Thanks for this. Would retardation not be virtually exactly the same as the surface area the brake pad grips onto is exactly the same i.e. is limited by the size of the pad? Then I suppose it depends on the performance of the tyres? Still not sure which way to go on this. Confused


Think of it like applying torque to a bolt. The longer the lever the easier it is to apply a particular torque. It works the same on brakes. Yes, the pad area does ultimately limit the clamping force that can be applied but if you increase the disc diameter you can apply less force per square centimetre to achieve the same torque. This makes threshold braking easier to modulate & also allows you to load up the nose more progressively so that you maximise the grip under brakes of the front tyres.

Go & do a test drive of a 991 Turbo on PCCBs (410mm discs) to see what I mean.
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Need Alcon discs or Pagid pads? https://uber9s.com

2004 GT3 CS in Atlas Grey with too many mods to list!
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Stuart Mackay
Monza


Joined: 29 Apr 2013
Posts: 171
Location: Swaffham, Norfolk and Good


PostPosted: Sat Dec 24, 2016 3:47 pm    Post subject: Reply with quote

NXI20 wrote:
IMI A wrote:
Thanks for this. Would retardation not be virtually exactly the same as the surface area the brake pad grips onto is exactly the same i.e. is limited by the size of the pad? Then I suppose it depends on the performance of the tyres? Still not sure which way to go on this. Confused


Think of it like applying torque to a bolt. The longer the lever the easier it is to apply a particular torque. It works the same on brakes. Yes, the pad area does ultimately limit the clamping force that can be applied but if you increase the disc diameter you can apply less force per square centimetre to achieve the same torque. This makes threshold braking easier to modulate & also allows you to load up the nose more progressively so that you maximise the grip under brakes of the front tyres.

Go & do a test drive of a 991 Turbo on PCCBs (410mm discs) to see what I mean.


The Physics are exactly as Nick describes, the Maths are as follows;

Torque = Force x Distance. The Units are Newton.Metres or lbsf. Feet

Therefore, for the same braking force applied by the Caliper/Pad, increasing the radius (or diameter of disc) will increase the Braking Torque applied to the wheel.

If we take 100 Newtons Brake Force (approx 10kg of brake friction) then for:

1) a 350mm diameter disc, The Brake Torque = 100 N x 0.175m = 17.5 Nm

2) for a 380 mm diameter disc, The Brake Torque = 100 N x 0.190m = 19 Nm

The 380mm will therefore allow 1.5 Nm more Torque to be applied for the same braking effort/ pedal pressure than for the same braking effort applied to a 350mm disc.

This represents a 8.5% increase in braking torque applied by a 380mm disc vs 350mm for the same pedal pressure.

(the difference in radii of the discs also gives the same percentage increase also).

Which in reality, either, will allow more braking torque (force x increased distance/disc radius) to be applied which equates to a shorter stopping distance OR reduced heat generation by the pad/caliper due to reduced torque (8,5% less) being needed to apply the same braking torque (reduced force x increased distance/radius) as that required for a 350mm disc.

Hope that wasnt a too complicated Applied Maths explanation?!? Floor Question
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Senoj
Zolder


Joined: 23 Jan 2006
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Location: Sussex


PostPosted: Sat Dec 24, 2016 4:08 pm    Post subject: Reply with quote

Nice upgrade Stuart. I would say that those bridgestone's may be a significant limiting factor now though. Question
 
  
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IMI A
Österreich


Joined: 02 Aug 2014
Posts: 997
Location: United Kingdom


PostPosted: Sat Dec 24, 2016 7:24 pm    Post subject: Reply with quote

Stuart Mackay wrote:
NXI20 wrote:
IMI A wrote:
Thanks for this. Would retardation not be virtually exactly the same as the surface area the brake pad grips onto is exactly the same i.e. is limited by the size of the pad? Then I suppose it depends on the performance of the tyres? Still not sure which way to go on this. Confused


Think of it like applying torque to a bolt. The longer the lever the easier it is to apply a particular torque. It works the same on brakes. Yes, the pad area does ultimately limit the clamping force that can be applied but if you increase the disc diameter you can apply less force per square centimetre to achieve the same torque. This makes threshold braking easier to modulate & also allows you to load up the nose more progressively so that you maximise the grip under brakes of the front tyres.

Go & do a test drive of a 991 Turbo on PCCBs (410mm discs) to see what I mean.


The Physics are exactly as Nick describes, the Maths are as follows;

Torque = Force x Distance. The Units are Newton.Metres or lbsf. Feet

Therefore, for the same braking force applied by the Caliper/Pad, increasing the radius (or diameter of disc) will increase the Braking Torque applied to the wheel.

If we take 100 Newtons Brake Force (approx 10kg of brake friction) then for:

1) a 350mm diameter disc, The Brake Torque = 100 N x 0.175m = 17.5 Nm

2) for a 380 mm diameter disc, The Brake Torque = 100 N x 0.190m = 19 Nm

The 380mm will therefore allow 1.5 Nm more Torque to be applied for the same braking effort/ pedal pressure than for the same braking effort applied to a 350mm disc.

This represents a 8.5% increase in braking torque applied by a 380mm disc vs 350mm for the same pedal pressure.

(the difference in radii of the discs also gives the same percentage increase also).

Which in reality, either, will allow more braking torque (force x increased distance/disc radius) to be applied which equates to a shorter stopping distance OR reduced heat generation by the pad/caliper due to reduced torque (8,5% less) being needed to apply the same braking torque (reduced force x increased distance/radius) as that required for a 350mm disc.

Hope that wasnt a too complicated Applied Maths explanation?!? Floor Question


Hmmm interesting formula. Still doesn't fully compute to my mind.

I don't profess to be an expert but the amount of force applied to both a 380mm rotor and a 350mm rotor should be exactly the same if you use exactly the same size caliper and brake pad?

In fact logic tells you that through giroscopic effect i.e. weight of the heavier 380mm rotor perhaps becomes even heavier when spinning hence the 380mm rotor may need more force to stop it than say for example a lighter 350mm rotor if using exactly the same caliper and pads. The larger rotor may also be more prone to warping through heat compared to a lighter 350 mm with less mass depending on the design of the rotors if not heat cycled properly. The Porsche OEM rotors for example with holes in both 380mm and 350mm are very prone to cracks and warping slightly if you used for a few trackdays. Looks awful but they still seem to work well.

I've spent a reasonable amount of time behind the wheel of a 991 turbo S and yes the brakes are amazing. The size of the calipers and pads are also as massive as the huge ceramic rotors.
 
  
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