R brakes advice

[fun meter]

Hi,

I took my R on its first track day yesterday. All went well, impressed witht he car. The only issue is I now have juddering on any moderate or heavy brake application or once a bit of heat gets into the brakes.

Car has done 10,000+ miles, and the speed and braking intensity was increased through the day as my confidence with the car grew. Also, I carried out cool down laps and didnt apply the brakes when off track (DSG - Neutral, engine off, Park gear). Generally, I done 20minute sessions.
The brakes faded slightly towards end of 4th session (which was a session with an instructor, in which I pushed the car quite hard), but they didnt disappear. But, on my next run out I had a juddering / rumble on braking but performance was fine, but after another quick session seemed to get worse. Finally, the last session I felt the braking performance dimminish quite a bit and decided to call it a day.

The juddering is what I imagine could be described as "warped discs", but Im more likely suspecting that the pad material has started to break down and desposit on the discs? Additionnaly, as the performance seemed to dimmish progressively, it was as if the material was on its way out.
Normal driving is fine, but I obviously need to get something sorted as I dont like the issue with every day driving, and I will inveitably be doing more track days this year.

Can anyone offer any advice or experience on upgrading the R brakes?

My options as I see it are:
1. Buy decent quality discs and some harder wearing pads
2. Buy a big brake kit and swap the whole lot over (keeping the old set for when I sell the car in future)

Obviously, I dont want to compramise every day use or invalidate my whole warranty (I can accept invalidating brake warranity if I fit non OEM parts).

Many thanks

[Macman]

You did turn off ESP right? I'm sure the instructor would've said otherwise as it puts the brakes in over use for best traction.
Also what miles has it done and due new disks/pads?

[fun meter]

I left ESP on as the conditions where patchy and it was first track day in the R. The ESP didnt come on much, only a handful of times when the back moved around under heavy breaking and if one corner lifts slightly.

At the start of track day, had about 10,100 miles. Discs and pads where in good condition. Like new, hadn't been given any abuse.

Many thanks

[Macman]

XDS doesn't light up the ESP dash but it can brake a lot at speedy corners thus there's your over heat issue and the reason the new ESP button (2012 but can update 2011 also) now switches it off altogether. The icon now says "ESP Off".
It's this that makes it feel smooth with less feedback on the steering because the loss of traction is not there in the first place.
I'd rather not try in my own road car but love to learn the flick turn and lift-off over steer on a rental
These ways you don't brake!

[fun meter]

Interesting..., thank you. Mine is MY12 with the "ESP Off" light. I'll have to disable it next time. The cumulative heat of the heavy braking and XDS must have been too much. Brands Hatch Indy circuit doesnt give the brakes much of a chance to dissapate heat.

With the ESP off, do you find the brakes hold up better after heavy use? If this is the case, I may consider replacement discs and a set of Tarox Strada pads front and rear.

Cheers for the help

[Macman]

Track Dayers have upgraded the already larger ones. But is the juddering still there now?
When I tried a Launch Control it went into a spin and the ESP braked it several times per second.
It felt like I'd got a flat so I crawled back home. That feeling that I could be damaging my tyre and 19" alloys if it was flat

BTW how well was the DSG in deciding when you could lay down the power to exit bends? Did you find you had to know rather than see the exit before flooring?

Also did you try left foot braking whilst keeping power up? It doesn't work on D mode for the roads as at lower revs it just changes down and I daren't try Sport doing it on the roads either.

[James321]

It's possible you have pad material stuck to the disc, his would show up more when the disc and pads are warm where a warped disc would usually be obvious all the time.

To clear the material, take the car up to motorway speed and brake firmly (not enough to make the ABS cut in) do this 3 times allowing a good run for the pads to cool a little in between heavy braking. If it is pad material then it will clear from the disc surface and the brakes will feel normal again, if it continues then. It could well be time for new discs and pads.

[cyman]

ive done a couple of track days in mine already. never had any probs but after 6 or 7 fast laps the brakes do start to fade.

some simple rules to follow.

do a warm up lap to get heat into everything before really pushing it
do a cool down lap at the end of the session to dissipate heat build up
never apply the handbrake when parking up after a session as this will warp the discs
wait 20 -30 mins between sessions so everything cools down
if you feel the brakes fading then slow down and let it all cool down again its norm a sign to end that session. if you keep going it will only glaze the pads which can cause judder and decrease braking efficiency.

if you want to carry out some upgrades just fit a set of braided hoses this will improve peddle feel over standard when really hot.
change brake pads to a fast road/track day pad something like ferodo ds2500 spec
if you still want a little more you can go for a high boiling point racing brake fluid like motul rbf600
then you are onto larger amounts of money with replacing discs to a slotted type this will improve pad efficiency and decrease the glazing that high temp can cause.

if you do all of the above and still aren't happy then look at a big brake conversion but tbh the r already has 345mm front discs which are more than enough for fast track day fun.

hope this helps

[Chungster]

Fun meter - if you want to play on track get some proper brakes on the car.



They are so worth it!

[Chungster]

Or can get u a set of these for £1500

Brembo GT Senior 4 pots with 370mm discs

[wigit]

I do keep looking at these brembos, the 370mm Stasis Alcons were just immense, so good I'd warn anyone about to drive it, those APs are bloody lovely too, floating discs FTW

I think the disc size on the R is the red herring, it's the calipers that let the side down, AP discs are actually smaller, in reality the Porsche Boxter caliper upgrade on 312s have more stopping power

[James321]

What do you guys think of the VWR brake kit? It seems reasonable money for a kit that contains everything you need to convert to a 6 piston caliper, or is there anohter kit on the market for similar money that you would recommend.

I'm looking at reducing unsprung weight as well as improve on braking.

[fun meter]

Many thanks for the replies.

I've tried some moderate-heavy braking to see if the any pad material clears, but no joy. Im going to jack the front up and have a look at the brakes tomorrow. Either way, they are going to need replacing as the issue remains.

Chungster - what AP kit do you have on yours? I've been looking at the CP7068-1000 Forumla Brake Kit, which I believe is a 4 pot with 355x32mm slotted discs. From what I've seen its just over £1500. Im going to give AP a call and check its the right kit, but I have the 19" VW wheels which should be big enough (i think), and whether this is suitable for every day use. Was there much involved in fitting?

[wigit]

VWR kit is engineered by Caparo and uses an AP pad size so plenty of choice, kit does not have floating discs (all be it i believe there is work in progress by a third party), very good set up and toyed with it recently, I'd still look at AP or Alcon

[Chungster]

Many thanks for the replies.

I've tried some moderate-heavy braking to see if the any pad material clears, but no joy. Im going to jack the front up and have a look at the brakes tomorrow. Either way, they are going to need replacing as the issue remains.

Chungster - what AP kit do you have on yours? I've been looking at the CP7068-1000 Forumla Brake Kit, which I believe is a 4 pot with 355x32mm slotted discs. From what I've seen its just over £1500. Im going to give AP a call and check its the right kit, but I have the 19" VW wheels which should be big enough (i think), and whether this is suitable for every day use. Was there much involved in fitting?

Mine is the CP5200 4 pot kit with 330mm discs. fantastic on the road and track.

6 pots are overkill IMO but £1500 is avoid price if it's the right kit for the car

[cyman]

ive read most of the posts on here and im not sure why there is a big push to replace the front brakes on the R with a £1500 kit.

ive only had mine 4 months and have already done 2 track days and the one thing I can say is I have never found the front brakes lacking in power to slow the car up. yes there are some issues with heat build up after say 8 laps of flat out driving but at present I am running standard pads,discs,fluid and flexi hoses so that is what I would expect. some may say you aren't driving quick enough but my last car I built over 6 years and was a 500bhp track day rx7 with everything upgraded inc 8 pot 356mm front brake setup and larger rears aswell and im used to doing 6 track days a year and I rag the arse off my cars on track no matter what. at the last day I was on the arse of many faster cars and had a real nice run against a noble (he couldn't drop me which I did laugh about) the one thing that I could do with most cars is get closer to them on the brakes, through the corners and under initial acceleration so excuse me but I do find it a little confusing when everyone is saying drop the front brakes for track days.

im well aware of the advantages of bigger brakes when higher speeds and higher grip levels are concerned but unless you are stripping out the R and going uprated suspension (coilovers,arb etc) with track day only tyres and pushing for 350bhp it just seems to me that its more about be able to say you have ap,brembo or an r8 conversion than it is about actual performance increases.

please if I am completely wrong about this point me in the direction of some comparison tests or track day enthusiasts that went the normal route of pads,braided hoses and maybe discs and fluid that found they were not a sufficient improvement in performance.

[fun meter]

The main issue has to be the lack of heat dissipation after consecutive laps. Once I had pushed the car really hard for a 20min session I think the damage was done, and the braking performance suffered from that point on.

1. A set of tarox sport Japan discs (fronts) and tarox strada pads (front and rear) is best part of £500, goodridge brake hoses just under £100. Fluid isn't much. This would probably be ample for me, but its not guaranteed.

2. A AP set would be thick end of £2000. But would almost certainly solve the issue. More stopping power, less weight and looks great. Resale value is good too.

I'm contemplating either option to be honest. The last thing I want is the problem to occur again having spent ££.

Many thanks

[cyman]

I wouldnt change the discs first off tbh. Pads and flexi lines should improve your heat issues massively as the pads will be designed to work in a higher heat range and the fexis will take out the loss of peddle feel as they wont expand as thefluid gets hot. You can basicly spend 300 quid to do this easily.

One thing though if you want your road car to last you should only be doing 15-20 mins max flat out laps at a time on track anyway or at least do several cool down runs in the middle and then stop and let everything cool down. Otherwise you will get heat build up in everything under the bonnet that and risk other issues manifesting.
Heat soak can effect everything from oil temps.water temps.inlet temp that will reduce performance massively and justgenerally put all componants in the upper ranges of what they are designed to take.

Unless your loaded of course and dont mind if it breaks on you

[fun meter]

I would go that route with just pads and lines, but with the vibrations I get when braking is making me suspect discs have suffered. But I'm going to have them checked out before I buy anything.

I tend to build up speed every time I go on a track session, I'd hate to be one of those people who spins it it on first corner of out lap. it's easy to get carried away, but I'm pretty good at sticking with time out and use traffic build up as opportunity to ease off. 0.5c at brands last week, which kept everything cool. I like the DSG and mid range power this car has, still be very quick with out always hitting 6k rpm, and gear changes are effortless.

Many thanks for the advice will keep this topic updated

[Rev 555]

The other advantage of getting a good brake kit is the saving of unsprung weight. My AP racing set up weighs 10.2 kgs per corner (disc and caliper combined). Stock R brakes are over 20kgs a set. That's a huge advantage. Combined with a good set of pads and brake fluid you will out brake the competition who are on OEM set ups every time. Pronvided of course you are a decent steerer.

If you are doing regular track days and plan to modify your motor for a bit more go its also worthwhile getting your DSG remapped. On the track I drive my car on manual mode, the DSG remap I have in the car has a new red line of 7100 and the car will not up shift at red line. Its like driving the car as a manual race car where you can bounce off the rev limiter and keep the revs up without the DSG upshifting.