Hello, I would like some advice on brakes for my 997 turbo please. My last service was in October 2013 at Porsche. I had new front discs and pads and the brake fluid was changed. I was at a PCGB track day at Goodwood yesterday and felt the braking was poor expecially towards the end of the Lavant straight. This part of the circuit is fast ~ 140 mph, however I expected the brakes to cope more than they did; actual braking was weaker than I expected and there was some sponginess after the session. I imagine Porsche replaced the brake fluid with a standard Porsche approved fluid - does anyone know what this is and the DOT grade please. Additionally, does anyone have a comment about the pads that Porsche supply during a service? I have previously used a hydrophobic DOT 5 in my 964 RS with Mintek pads. Can anyone advise as to a good fluid and pads please for the 997 Turbo ? i dont really want to start upgrading the calipers unless pads and fluid don't give me better braking. I have the standard red calipers on the car. Many thanks. Duncan. PCGB member 1953.
Brakes on 997 Turbo
- Thread starter duncangould
- Start date
What size front disks does it have? I think most Porsche steel brakes are too small for track use.
Woodcote braking from circa 140 then immediately Chicane (85 down to 45) are quite hard on brakes and I have found road disks can get quite stressed after a few laps. Also the holes get clogged and again this does not help dissipation of the heat.
I ran Pagids on a Carrera GTS (1630kgs) and they were better than standard pads but wore the disks down faster (a set of fronts lasted 3 - 4 track days). The 200kg lighter Cayman has the same 330mm front disks as the heavier GTS and one set of fronts (with standard pads) has lasted 9 track days.
Woodcote braking from circa 140 then immediately Chicane (85 down to 45) are quite hard on brakes and I have found road disks can get quite stressed after a few laps. Also the holes get clogged and again this does not help dissipation of the heat.
I ran Pagids on a Carrera GTS (1630kgs) and they were better than standard pads but wore the disks down faster (a set of fronts lasted 3 - 4 track days). The 200kg lighter Cayman has the same 330mm front disks as the heavier GTS and one set of fronts (with standard pads) has lasted 9 track days.
Duncan,
Do you have a Gen 1 or Gen 2 car?
Gen 1 Turbos were under-braked IMO and need upgrading. Gen 2 Turbo brakes are better, but as Alan has said, a pad upgrade is really required for track day use.
However, before spending anything on upgrades, first verify your current set-up is working properly. Have the brakes recovered since the track day or is the pedal still spongy? A spongy pedal often indicates aeration in the hydraulic system, but may also be due to a flexing bulkhead, poor calliper alignment or defective master cylinder/servo system.
Is the pedal firm but the brakes lack retardation? This is usually due to glazing where heat has deposited pad material onto the face of the rotor. This is resolved by removing the road wheels and lightly facing up the rotors and friction pads with an abrasive.
TScaptain I know is a firm believer in PCCB's, but don't spend the huge sum upgrading to these. It's cheaper to do as I did and PX your car for a Turbo 'S' which has these fitted as standard! [
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Regards,
Clive.
Do you have a Gen 1 or Gen 2 car?
Gen 1 Turbos were under-braked IMO and need upgrading. Gen 2 Turbo brakes are better, but as Alan has said, a pad upgrade is really required for track day use.
However, before spending anything on upgrades, first verify your current set-up is working properly. Have the brakes recovered since the track day or is the pedal still spongy? A spongy pedal often indicates aeration in the hydraulic system, but may also be due to a flexing bulkhead, poor calliper alignment or defective master cylinder/servo system.
Is the pedal firm but the brakes lack retardation? This is usually due to glazing where heat has deposited pad material onto the face of the rotor. This is resolved by removing the road wheels and lightly facing up the rotors and friction pads with an abrasive.
TScaptain I know is a firm believer in PCCB's, but don't spend the huge sum upgrading to these. It's cheaper to do as I did and PX your car for a Turbo 'S' which has these fitted as standard! [
]Regards,
Clive.
Thank you for all the responses. The car is a gen I 997 turbo [manual], the sponginess has recovered so as mentioned the brake fluid may just have been topped up. I need to look at the Porsche invoice to see how much labour was apportioned to the brake work to see if it appears time was spent on bleeding the brakes. From memory the invoice charged for brake fluid but did not mentioned a brake bleed....... The discs are new and standard for the gen I turbo as of October last year and I have done 3 track days since then [2 at Goodwood which is fast] and they look fine. So firstly I think I must change the fluid to a DOT 5 [? or 4.5?] and also consider new pads. From the thread it sounds like Pagids destroy discs though. How do the gen II discs and braking gear differ from the gen I please? Many thanks, Duncan
I guess it's always going to be a bit of a trade off. If you want the pads to stop you then they may chew up the disc a bit faster. But I haven't found the Pagids to be unduly harsh. Some folk go away from the cross drilled discs so that you don't get the cracking problems.
Gen 2 discs are bigger. Still sounds like it may be a brake fluid boiling problem to me but, as Clive says, the Gen 2 brakes are better as standard.
Duncan,
OK. The sponginess was due to brake fade then, which indicates overheating. Gasses build up between the friction surfaces when hot and this reduces retardation. Topping up brake fluid has no effect on this - its level is lower because the pads have worn down a little.
There's no need to change the fluid as far as I can see because the fluid has not boiled, although you may wish to consider this if you decide to upgrade the pads as the heat range will then be higher.
Pagid pads are fine. They are probably kinder to rotors, since the metal content is low and metal in the friction material is a major factor in wear rates.
Gen 2 brakes have larger rotors and more calliper pistons to increase friction surfaces and the clamping effect.
Regards,
Clive.
OK. The sponginess was due to brake fade then, which indicates overheating. Gasses build up between the friction surfaces when hot and this reduces retardation. Topping up brake fluid has no effect on this - its level is lower because the pads have worn down a little.
There's no need to change the fluid as far as I can see because the fluid has not boiled, although you may wish to consider this if you decide to upgrade the pads as the heat range will then be higher.
Pagid pads are fine. They are probably kinder to rotors, since the metal content is low and metal in the friction material is a major factor in wear rates.
Gen 2 brakes have larger rotors and more calliper pistons to increase friction surfaces and the clamping effect.
Regards,
Clive.
The Porsche fluid isn't particularly good. I suggest you have it replaced with something far more suited to track use, such as Castrol SRF, especially as the car is quite heavy. Incidentally, don't read too much into DOT ratings. In theory DOT 5.1 fluid is rated higher but all race fluids are actually DOT 4.
Worth checking also that your front brake cooling ducts are still in place - they clip to the suspension arms and as they are quite low, its not unknown for them to be damaged or ripped off entirely. If one or both are missing, replacements direct from Porsche Reading aren't particularly expensive (unless you opt for the enormous 2-part GT2 ones).
Chris.
I don't think the fluid can be too bad. I assume it's the same stuff used in my Turbo S (fluid replaced annually). I've encountered pad fade in the PCCB's from extreme use, without any of the appreciable pedal fade that would occur if the fluid had overheated.
Worn pads are often a culprit since the thinner friction pad material reduces available heat-soak. So, if you're tracking regularly, I would recommend replacing the pads when down to around ½ worn.
Regards,
Clive.
Also try fitting the larger GT2 front brake cooling ducts which are only about £10 and just clip on.
Try GT3
Indeed they are Ralph. I have a set here and when we (as in PC and me) compared them to the OE it was hard to see how the GT3 ducts would produce significantly more cooling. The OE ducts spread the air over a larger area of the disc whereas the GT3 ones seem to be more "focussed" , if that is the right word, but are narrower. But maybe in practice they do as I seem to recall they use phrases like "more aggressive![]
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I fitted them on the advice of several track day regulars and I think it is a case of every little bit helps at the margin. On the GTS the extra "scooped" area was at the bottom edge.
Ah clip ons, happy days...
With cafe racer bikes in early 60's, I hasten to add.
With cafe racer bikes in early 60's, I hasten to add.
Chris_in_the_UK
New member
It will be very hard to see if there is any difference if they are still in the box!
ORIGINAL: tscaptain
I guess the only real way to tell is to take some temperature measurements with my IR temperature measuring thingy! Mine are still in the box the came in. Perhaps I should clip them on and try them![
Oh, they have been out of the box and very nearly on the car but I think it would be very hard to tell if there is any difference had I completed the task! The brakes aren't particularly shabby in the first place and the Pagids make them even better. If someone came up with some numbers, rather than just track day banter, which showed the GT3 ducts cool the brakes on a turbo considerably better then they would be on like a shot![]
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