Brake overheating on trackdays

[Wollemi]

ive just had to have discs and pads replaced on my 987.2 Boxster S after 5000 miles and 6 trackdays. The pads were crumbling due to overheating. To be fair the discs could have gone on for longer but they were a little warped.
Im looking for advice as to how to manage this, apart from not braking, and going faster round every corner. I will try that. I do know about cool down laps and not resting foot on brake and leaving the hand brake on. I usually only do one cool down lap; should I do more?
My car is still under Porsche warranty, my OPC have said that I could change pads but obviously other modifications are not allowed. Any thoughts on pads; as I am a mechanical incompetent I don’t want to have to change pads just for trackdays so would want something that I can full time.
It‘s been suggested that I monitor the temperature with a laser pyrometer but what is the safe operating temperature for the standard brakes and pads?
any advice gratefully received.

 

[MrDemon]

GT3 air ducts fit to aid air flow £25 and some mild better pads, fluid , if you are doing 5 or 6 then a geo with a bit more camber so you can corner faster so less braking needed
PSM off on this car also and sports mode on if you have it.

 

[Steve Brookes]

Six trackdays to do a set of pads on a 987 sounds good to me. Never got more than that on my Cayman R even when using Pagid RS29s.

As D says above if I hadn't turned off PSM the rear pads would have worn out before the fronts.

 

[carnaby35]

Hi Graham- Chris here??????
High speeds, relatively heavy car = lots of kinetic energy to get rid of via brakes turning it into heat therefore disks and pads are red hot.
Solution- lower speed approaching corners then fast out or a lighter car!!! (Or ceramic brakes?)

Have been up against a 996 C4 at Silverstone, (I also owned one at the time) and I was glued to his back bumper in the Lotus Elise. As I was pushing him he was trying hard but retired after two laps with smoking brakes. I carried on in the lotus for another 5or 6 laps, no problem with brakes whatsoever. (Standard pads, discs and no brake servo). The difference is that the Elise weighs about 750kg!!

Perhaps strip out all interior, radio, aircon, boot carpets and empty the ashtrays.????

 

[richardjjs1]

There is an interesting thread on Cayman about Drilled and/or Slotted Discs
Have just posted on it so it should be near the top

Talks about clearing out the crud in Drilled Discs and about corrosion on the rear of the Disc Well worth a read

 

[MrDemon]

Hi Graham- Chris here??????
High speeds, relatively heavy car = lots of kinetic energy to get rid of via brakes turning it into heat therefore disks and pads are red hot.
Solution- lower speed approaching corners then fast out or a lighter car!!! (Or ceramic brakes?)

slow in is not a cure (A it's slower and B you will have to brake more) , as one wants to play to the mid engine layout, so that's faster in than a 911 and higher corner speeds. 911's are slower in fast out as they have the traction.

the solution is cooling or bigger disks really, better pads will stop fade for an extra lap but will heat up the disks even more so not a cure , so one as to look at why, and it's all down to cooling, not fitting higher boiling point fluid and track pads, that's a bodge not a fix but it's the cheapest so thats what people do.

 

[carnaby35]

What I meant was ease off the throttle before the corner rather than get rid of excess speed by hammering the brakes. A trackday isn't a race so it is up to you, thrash the car and brakes to death and pay the price or drive smoothly with mechanical sympathy and conserve the car, brakes ( and money).
if it's all down to cooling then surely it is better not to have as much to cool!! We are talking trackdays here not racing with prize money at stake.????

 

[Brian_Innes]

[/quote]


slow in is not a cure (A it's slower and B you will have to brake more) , as one wants to play to the mid engine layout, so that's faster in than a 911 and higher corner speeds. 911's are slower in fast out as they have the traction.

the solution is cooling or bigger disks really, better pads will stop fade for an extra lap but will heat up the disks even more so not a cure , so one as to look at why, and it's all down to cooling, not fitting higher boiling point fluid and track pads, that's a bodge not a fix but it's the cheapest so thats what people do.

[/quote]


Couldn't have put it better myself David.

Regarding the issue of brake temps, I was also concerned about high brake temperatures on the 718 CS at my wet Knockhill session recently. On returning to the pits after some hot laps both the front and rear discs were showing temps of over 400 degrees! Not good. Even with PSM on Sport Plus setting, the PTV and PSM still intervenes frequently on a streaming wet track.......due to new tarmac being laid the day before, I didn't have the balls to switch off the PSM altogether on this particular day.

Spirited braking, combined with PSM and PTV will overheat the brakes in no time. As David says, better cooling is the main issue.

Brian

 

[carnaby35]

So if spirited braking etc quickly overheats the brakes coupled with the experience of the original poster and myself leaving the C4 behind at Silverstone with smoking brakes, does this mean then that standard Porsche brakes are not up to track work??

 

[Motorhead]

Graham,

If you're interested, I've just noticed that the GT3 cooling ducts are on sale at £2.72 each plus delivery on DESIGN 911UK (I've seen them elswhere for £33 for the pair..!). It may be worth checking the price at a Porsche Centre for comparison.

Jeff

 

[Brian_Innes]

The standard brakes on Porsches are designed for road use.

For the experienced motorsport driver on a track day, the brakes will need upgrading or extra cooling for regular high speed stops.

Current electronic interventions such as PSM and PTV also heat up the brakes even when the driver is not squeezing the brake pedal. This is particularly noticeable on wet, slippery track days such as I experienced recently at Knockhill.

It not all about simply stamping on the brakes.

Brian

 

[MrDemon]

So if spirited braking etc quickly overheats the brakes coupled with the experience of the original poster and myself leaving the C4 behind at Silverstone with smoking brakes, does this mean then that standard Porsche brakes are not up to track work??

Correct you have bought a road car not a cup racer, race cars are not that nice on the road I assure you nor are the pads they use, goto any forum in any make car , most people fit big brake kits and race pads.

GT cars have much larger disks and far better electronics to stop the brakes cutting in too soon.
but people still change out the disks and pads if you live on track.

i see people stay out far too long and come back into to pits with smoking blue disks.

issue is going slow on track days does not seem to happen, today’s track dayers seem to all want to be at 10/10ths

 

[carnaby35]

Exactly. That is why I mentioned slowing down before corners and not hammering the brakes hence keeping them cooler. Also mentioned, tongue in cheek, was reducing the weight of the car in order to reduce amount of kinetic energy that the brakes need to dissipate via heat.

Graham has certainly opened a can of worms here and he haven't even commented yet!!????

 

[Wollemi]

I don’t drive my car to the ragged edge, I go to track days to have a good time driving harder and faster than is sensible on the public road but I certainly don’t wish to risk damaging my very precious car!

The pads that were replaced due to crumbling were still at 8mm front, 7mm rear so not badly worn at all. The discs were not really bad, a local independent that I showed them to said they would have let them stay on for longer.

I have to admit that I hadn’t really considered the whole issue of PSM on or off before. I’ve always kept it on on the basis of if it’s working I probably need it - I’m not sure I trust my skills enough. If I binned the car with it off I would feel a chump. I suppose the rear pads being one millimetre worn than the front could well be due to PSM cutting in? No fancy stuff like PTV on my car.

Since track day driving for me isn't about chasing the fastest lap time - I have only done PCGB events where any time is strictly forbidden anyway so I have no idea as to my lap time anyway - i could ease of the gas at the end of a straight before going on the brakes?

It’s been really interesting to hear everyone's advice, what David (MrDemon) and Brian (BJ Innes) say about needing better cooling makes total sense. Fitting the GT3 cooling ducts sounds very sensible; what is involved in doing that please?

 

[Motorhead]

Graham,

See my post #10 above plus here's a simple DIY for fitting the GT3 ducts:

http://997parts.co.uk/por...t-997-gt3-brake-ducts/

Note that this is the site asking £33 for the pair..!

Jeff

 

[spyderman]

Can I just point out to those who repeatedly insist that you need to upgrade Porsche brakes to race on them that the BRSCC Porsche Championship has raced 986s for years using the standard callipers with better pads and race fluid. In fact after two seasons doing that I then raced a 987 for two seasons in Britcar (50 minute races) using standard callipers, Castrol fluid and Pagid’s admittedly very expensive but excellent RS29 endurance pads.

 

[MrDemon]

Can I just point out to those who repeatedly insist that you need to upgrade Porsche brakes to race on them that the BRSCC Porsche Championship has raced 986s for years using the standard callipers with better pads and race fluid. In fact after two seasons doing that I then raced a 987 for two seasons in Britcar (50 minute races) using standard callipers, Castrol fluid and Pagid’s admittedly very expensive but excellent RS29 endurance pads.

Not seen any one say you need bigger calipers, bigger disks though help loads with heat and quite cheap to do.
what weight was the race car ? And did it run slicks.

The thing is I have cars with bigger brakes and you can lap faster with a 6 pot 350mm set up over a 4 pot 319mm set up for sure In a car weighing 1400kg with driver On road tyres.

but I am sure standard calipers with a nice 340mm disk upgrade and rs29 would be ok That’s what I have on my R now. And what Andy races with with his Boxster race car.

 

[Wollemi]

Graham,

If you're interested, I've just noticed that the GT3 cooling ducts are on sale at £2.72 each plus delivery on DESIGN 911UK (I've seen them elswhere for £33 for the pair..!). It may be worth checking the price at a Porsche Centre for comparison.

Jeff

Thanks Jeff for that, Ive just ordered a pair from Design911UK. The helpful guy at the end of the phone couldn't really believe the price! Thanks also for the fitting guide.

Are there any disadvantages to having the GT3 ducts fitted? reduced ground clearance for example? I'm going to do the NC500 and then to Lewis & Harris - would it be better to delay fitting them until after that trip?

 

[Motorhead]

Yes, somewhat of a bargain Graham. I might even take a punt on them myself at that price..!

Since I've not fitted them I can't advise on potential reduced ground clearance, but when you get the new ducts you'll be able to offer them up to see if there's going to be a problem. Personally I wouldn't think so, and I can't see improved brake cooling as being a negative on your trip to the Highlands and Outer Isles. Even if the ducts do incur minor damage on some iffy roads, at that price you can replace them at minimum cost.

Sounds like a great trip - from personal experience I know you'll enjoy those Highland roads, and some friends had a very enjoyable trip to all the Outer Isles a few years ago. Just make sure that you've booked your ferries and accommodation..!

Jeff

 

[Brian_Innes]

Graham,

Think carefully before fitting the GT3 cooling ducts prior to your NC500 and Lewis-Harris islands tour. BTW I've done all of those, it's a great trip.

In my experience, the only ground clearance problems you may encounter is loading and unloading from the ferries. The Hebridean island's slipways are quite steep and depending on the tide at the time of loading/unloading, you need to be very careful at the point where the ferry ramp rests on the concrete slipway. Especially if there is a sea swell heaving the ship around. You will not usually encounter any ground clearance problems on the public roads of your intended route. Just remember to keep away from soft verges if you meet on-coming traffic at the designated Passing Places. Make sure the 4x4's go off the road to pass, not you.......

Enjoy the trip. It's a wonderful tour.

Brian