997 GT3 Help Please
Discussion
28 laps of Castle Combe resulted in 3mm loss of front brake pad. 16mm to 13mm. The car didn't want to stop without great fuss from the ABS and a horribly dead pedal, all around the circuit.
Three weeks later at the same circuit and over a similar distance and weather conditions (cold and dry) the pad wear was zero! Not measurable.
If anything it was driven harder the second time and I swallowed harder when the pedal froze up the hill into Quarry lap after lap. As I am still here the car obviously stopped but it is very very scarey.
Please explain all that to me.The two other 997 GT3's were about on the same pace but I was unable to discuss this with the other drivers for unrelated reasons.
NB. There was no pad material offset on the disks.
The OPC has no idea.
Three weeks later at the same circuit and over a similar distance and weather conditions (cold and dry) the pad wear was zero! Not measurable.
If anything it was driven harder the second time and I swallowed harder when the pedal froze up the hill into Quarry lap after lap. As I am still here the car obviously stopped but it is very very scarey.
Please explain all that to me.The two other 997 GT3's were about on the same pace but I was unable to discuss this with the other drivers for unrelated reasons.
NB. There was no pad material offset on the disks.
The OPC has no idea.
Youngman said:
28 laps of Castle Combe resulted in 3mm loss of front brake pad. 16mm to 13mm. The car didn't want to stop without great fuss from the ABS and a horribly dead pedal, all around the circuit.
Three weeks later at the same circuit and over a similar distance and weather conditions (cold and dry) the pad wear was zero! Not measurable.
If anything it was driven harder the second time and I swallowed harder when the pedal froze up the hill into Quarry lap after lap. As I am still here the car obviously stopped but it is very very scarey.
Please explain all that to me.The two other 997 GT3's were about on the same pace but I was unable to discuss this with the other drivers for unrelated reasons.
NB. There was no pad material offset on the disks.
The OPC has no idea.
Three weeks later at the same circuit and over a similar distance and weather conditions (cold and dry) the pad wear was zero! Not measurable.
If anything it was driven harder the second time and I swallowed harder when the pedal froze up the hill into Quarry lap after lap. As I am still here the car obviously stopped but it is very very scarey.
Please explain all that to me.The two other 997 GT3's were about on the same pace but I was unable to discuss this with the other drivers for unrelated reasons.
NB. There was no pad material offset on the disks.
The OPC has no idea.
Did you have the sport button on ??
The ABS will cut in earlier when it is 'off'
Assume you have steels ??, everyone has said how good they are, so can't understand it tbh...
Upgrade the fluid to Castrol SRF, this will help keep a firm pedal for longer.
Were the brakes properly run in for your 1st time on track ?
G.
Yes I had the Sport button on and the pedal was too hard for my taste, so brake fluid was ( I guess) not a problem.( Car is new/700miles).
Did I bed the brakes in properly ?- now that may be the question. The car was delivered in February and without being anti-social I suppose that I was very gentle with the whole thing. It is possible that I didn't bed them enough before the first track day and that they have glazed.
Still doesn't explain the differential in wear from 3mm to zero.( Or does it) They have been through the smokey stage on the first track day and I assumed, through previous experience, that what once might have been glazed no longer was!
Thanks very much for your input, please keep it up because I can't believe it should be like this!
Did I bed the brakes in properly ?- now that may be the question. The car was delivered in February and without being anti-social I suppose that I was very gentle with the whole thing. It is possible that I didn't bed them enough before the first track day and that they have glazed.
Still doesn't explain the differential in wear from 3mm to zero.( Or does it) They have been through the smokey stage on the first track day and I assumed, through previous experience, that what once might have been glazed no longer was!
Thanks very much for your input, please keep it up because I can't believe it should be like this!
glenn mcmenamin said:
Youngman said:
28 laps of Castle Combe resulted in 3mm loss of front brake pad. 16mm to 13mm. The car didn't want to stop without great fuss from the ABS and a horribly dead pedal, all around the circuit.
Three weeks later at the same circuit and over a similar distance and weather conditions (cold and dry) the pad wear was zero! Not measurable.
If anything it was driven harder the second time and I swallowed harder when the pedal froze up the hill into Quarry lap after lap. As I am still here the car obviously stopped but it is very very scarey.
Please explain all that to me.The two other 997 GT3's were about on the same pace but I was unable to discuss this with the other drivers for unrelated reasons.
NB. There was no pad material offset on the disks.
The OPC has no idea.
Three weeks later at the same circuit and over a similar distance and weather conditions (cold and dry) the pad wear was zero! Not measurable.
If anything it was driven harder the second time and I swallowed harder when the pedal froze up the hill into Quarry lap after lap. As I am still here the car obviously stopped but it is very very scarey.
Please explain all that to me.The two other 997 GT3's were about on the same pace but I was unable to discuss this with the other drivers for unrelated reasons.
NB. There was no pad material offset on the disks.
The OPC has no idea.
Did you have the sport button on ??
The ABS will cut in earlier when it is 'off'
Assume you have steels ??, everyone has said how good they are, so can't understand it tbh...
Upgrade the fluid to Castrol SRF, this will help keep a firm pedal for longer.
Were the brakes properly run in for your 1st time on track ?
G.
The ABS function is not affected by the Sport button - The Sport button changes the dynamics of PSM - not available on GT3 (TC optional).
Pad wear will always be faster as the brakes bed in, however if the pads have been overheated then they will harden and become less effective, reducing wear rate.
What tyres are you running?
If the tyres are the 'Ultra High Performance' option then braking grip may have been compromised by the ambient temp. (Porsche recommends reducing speeds during cold and or wet conditions - i know, there's always a compromise!!) and maybe the relative 'greenness' of the circuit at this time of year??
The usual Sport tyres from Michelin (Pilot Sport) and Pirelli (P Zero Rosso) have now been approved for GT3 / GT3 RS as of January 2007.
Quarry Rise is a point at 'Coombe where grip is low as the cars' weight is pitched up, do the brakes feel strange all the time, or just at this point?
Which OPC did you seek advice from?
Best Regards
Jon
I think it quite likely that the pads were not properly bedded in before the first track day. IMO during the early part of the track day activity the brakes may have been operating with 'abrasive friction'. During this time significant pad and disk wear can take place. As the track activity progresses the pads will have been bedded in and the wear will be significantly reduced as 'adhesive friction' starts to take over.
There is a really good article here that explains the science and how bedding brakes should be done. It is a much more vicious process than I ever imagined.
Off topic:
BTW were you at Combe on Saturday and if so which GT3 - I hope not the white one? I had a brilliant first track day of the year (Velvet Red 930 LE) and was surprised (and delighted) that the 997 GT3s and RS got through the noise test on a 'quite' day. Bodes well for when mine arrives in 3 weeks time as Combe is my 'local'.
There is a really good article here that explains the science and how bedding brakes should be done. It is a much more vicious process than I ever imagined.
Off topic:
BTW were you at Combe on Saturday and if so which GT3 - I hope not the white one? I had a brilliant first track day of the year (Velvet Red 930 LE) and was surprised (and delighted) that the 997 GT3s and RS got through the noise test on a 'quite' day. Bodes well for when mine arrives in 3 weeks time as Combe is my 'local'.
pope said:
glenn mcmenamin said:
Youngman said:
28 laps of Castle Combe resulted in 3mm loss of front brake pad. 16mm to 13mm. The car didn't want to stop without great fuss from the ABS and a horribly dead pedal, all around the circuit.
Three weeks later at the same circuit and over a similar distance and weather conditions (cold and dry) the pad wear was zero! Not measurable.
If anything it was driven harder the second time and I swallowed harder when the pedal froze up the hill into Quarry lap after lap. As I am still here the car obviously stopped but it is very very scarey.
Please explain all that to me.The two other 997 GT3's were about on the same pace but I was unable to discuss this with the other drivers for unrelated reasons.
NB. There was no pad material offset on the disks.
The OPC has no idea.
Three weeks later at the same circuit and over a similar distance and weather conditions (cold and dry) the pad wear was zero! Not measurable.
If anything it was driven harder the second time and I swallowed harder when the pedal froze up the hill into Quarry lap after lap. As I am still here the car obviously stopped but it is very very scarey.
Please explain all that to me.The two other 997 GT3's were about on the same pace but I was unable to discuss this with the other drivers for unrelated reasons.
NB. There was no pad material offset on the disks.
The OPC has no idea.
Did you have the sport button on ??
The ABS will cut in earlier when it is 'off'
Assume you have steels ??, everyone has said how good they are, so can't understand it tbh...
Upgrade the fluid to Castrol SRF, this will help keep a firm pedal for longer.
Were the brakes properly run in for your 1st time on track ?
G.
The ABS function is not affected by the Sport button - The Sport button changes the dynamics of PSM - not available on GT3 (TC optional).
Best Regards
Jon
Well this is what i have been told by the instructors of both the 997 GT3 experience days i have been on !!
I think everything points to ineffective/less than 'aggressive', bedding in.
As for Combe, the car was poor on the brakes everywhere - same problem; very dull pedal and premature ALB. Avon Rise(?)remains the most memorable experience though!
My OPC is very helpful but obviously not motorsport oriented. They are doing their best but IMO not supported by Porsche Customer Services and certainly have no contact with Porsche Motorsport, who choose to be invisable.
I drove my car home but was saddened by the accident. I don't know the guys involved and felt it best to let them have their space after the event because I have been in their shoes over the years.Wounds & licking come to mind.
As for Combe, the car was poor on the brakes everywhere - same problem; very dull pedal and premature ALB. Avon Rise(?)remains the most memorable experience though!
My OPC is very helpful but obviously not motorsport oriented. They are doing their best but IMO not supported by Porsche Customer Services and certainly have no contact with Porsche Motorsport, who choose to be invisable.
I drove my car home but was saddened by the accident. I don't know the guys involved and felt it best to let them have their space after the event because I have been in their shoes over the years.Wounds & licking come to mind.
Youngman, I have the answer!
The abs threshold is set very low on the new GT3 so it cuts in very early making the pedal feel like mush. It's due our friends in the US suing all and sundry. The cup car has the same brakes but the parameters are different so they feel and brake beautifully. The (PCCB) brakes on my, 997 GT3, are frankly woeful and I am desparately trying to change the set up but sadly it requires a new ECU from the cup car which leaves out other stuff you need. Can't see an easy fix solutuion.
Initial pad wear is simply down to bedding it. Discs and pads are relatively ruff when new so wear quickly. Once bedded they don't wear as quick.
Hope that helps.
If anyone can help with the ECU issue let me know as it totally spoils what is a great track car.
The abs threshold is set very low on the new GT3 so it cuts in very early making the pedal feel like mush. It's due our friends in the US suing all and sundry. The cup car has the same brakes but the parameters are different so they feel and brake beautifully. The (PCCB) brakes on my, 997 GT3, are frankly woeful and I am desparately trying to change the set up but sadly it requires a new ECU from the cup car which leaves out other stuff you need. Can't see an easy fix solutuion.
Initial pad wear is simply down to bedding it. Discs and pads are relatively ruff when new so wear quickly. Once bedded they don't wear as quick.
Hope that helps.
If anyone can help with the ECU issue let me know as it totally spoils what is a great track car.
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