disc & pad wear rate & noises

disc & pad wear rate & noises

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veehexx

Original Poster:

118 posts

79 months

Tuesday 13th October 2020
quotequote all
I'm having some issues with brake wear with what i thought would be an ideal setup.
I'm using CL rc6e & girodisc 2peice discs. I've only seen good points with these two products so seemed ideal with all the research i did pre-purchase.

the rc6e's are annihilating the discs. i tired running them as a road pad last year pending an upcoming trackday which i wore 1/3rd of the disc in 6 weeks. iron filings all over my wheels too. I now swap them the day before/after a trackday to allow them to scrub the pad deposits on/off ready for track use & return to street pads.
based on that, i'd say rc6e's & giros have had about 7 weeks total together, 6wks before any track action, then 2-3 days of track use. giro's have seen maybe 12months/8k with OEM street pads. By feel & look at the wear ridge on the disc, i'd guestimate the disc is now around 75% worn but i'll get a proper measurement later to confirm.

Yesterday was Donington and by about mid/late morning i was getting terrible brake judder. Entire car shakes like ABS is always kicking in under braking.
i also notice a fair amount of loose dust around the wheels.
Coming into the paddock and on the drive home the front brakes feel & sound like it's metal on metal. They seemed to settle down (both metal on metal sensation & judder) between leaving the track and arriving home. based on the outer pads that have maybe 75% remaining it's definitely not worn pads.

Based on the experiences of others, i'm thinking theres something going on with the disc grooves & pads. I'll very likely be stripping the front end down later today and swapping disc&pads back to OEM in prep for winter, so will be taking a closer look to try to figure it out. I havent any real ideas or experience to go with on this so hoping one of you lot might be able to provide some insight.

Fonzey

2,175 posts

134 months

Tuesday 13th October 2020
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You may already know this but it's worth covering anyway, the Carbone Lorraine pads are fairly unique in that they don't rely on pad transfer for generating friction, they work instead by abrading the disk material - so though your wear does sound pretty high, it's a 'design feature' of the pads.

The benefit of this approach as you've found is that you can run a crappy/clean/quiet road pad most of the time, then simply lob the RC's in the day before the trackday without really needing to do any bedding in.

As for your wear/vibrations/etc - I've learned quite recently not to totally ignore odd sounds or sensation coming from the brakes. I've always subscribed to the "disks don't warp, it's pad deposits" line when people complain of vibrations but I was eating through pads like crazy quite recently - then finally the issue presented itself:



Obviously the disk had been somewhat out of shape before it cracked, but it had been acting like a cheese grater on my pads and made all sorts of horrible sounds/judders when applying partial pressure to the brakes.

I'd recommend whipping the lot off and giving everything a good check over. Make sure the disks are running true (also ruling out hub issues etc) and take it from there. Don't keep lobbing pads at it until a disk explodes like I did hehe


veehexx

Original Poster:

118 posts

79 months

Tuesday 13th October 2020
quotequote all
I know your points on CL pads needing no bedding in, but also assumed their not unique and they'd all be fairly similar for this segment.

pictures 1&2 are of left/passenger side disc. 3&4 are driver/right side. substantally more visual wear on the left disc and has almost completely wiped out the grooves on the back side.






while the pictures don't show it, disk surface is slightly cracked (crazing) but nothing abnormal for track use imo. certainly no full width cracks or anything major that could catastrophically fail. i'm going to have to remeasure them though. both discs had over 31mm left (32mm new, 30mm limit) but visually very different.

Ducting isnt really an option on the car and the best i've been able to do is enlarge the factory air re-directors. I've had definite heat issues in the past cooking 800C rated pads and this girodisc&CL combo is the only ones i havent knowingly cooked yet.
because of that, i'm dubious if changing pads again will help. RSL29's seem to be highly rated but only 700C max temp. depends how this thread goes will depend on what i do...i dont think it's heat related, but if i was 100% sure then i wouldn't be asking biggrin

veehexx

Original Poster:

118 posts

79 months

Tuesday 13th October 2020
quotequote all
worse than i thought. left disc is down to 30.52mm (30mm min; thats 75% done!), right is 31.2mm. darker spots seem to be pad deposits as you can tell the difference with finger.
i didnt think CL pads really did that; should self-clean. Plus they have something like 1100C max temp and i highly doubt i've hit that both down to not seeing issues elsewhere (calipers ok, fluid not boiled) and the look of the pads surface.

The Girodiscs have maybe 6months of use. Bought Aug'19, off the car for ~4months over winter, and the car hasnt been used that much since April either.

Am i right in thinking this is both a pad/disc combo (excessive disc wear) and heat (pad deposit evidence marks on the disc)?

E-bmw

9,976 posts

159 months

Tuesday 13th October 2020
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That is some ridiculous wear!

Give us some context/details on the car & its set-up.

Another_James

104 posts

159 months

Tuesday 13th October 2020
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I’m running RSL29’s on my FK8 type R and I’m pretty pleased with them although they haven’t lasted as long as I’d like. 3 track days and they have about 7mm left but no issues with deposits. I find the tyres go off before the brakes so I’m plenty happy with the performance. They are fine on the road as well if a little loud after a few weeks of light use. The OEM drilled discs have cracks coming from the drill holes so are going in the bin but haven’t worn excessively. I’ve now got the 2020 spec 2 piece discs in so will see how they do.

Edit to add I’m on Cup 2’s so not full on track tyres

veehexx

Original Poster:

118 posts

79 months

Tuesday 13th October 2020
quotequote all
2015 Civic typeR (FK2); 306hp, 1460kg
both a daily & track car with separate tyres (Nankang AR1) & pads for track use.

the car isn't ideal - dual axis suspension which is fairly bulky to stop torque steer and it being fwd it's impossible to get brake ducting piped in as your either battling the inner wheel & arch on fully lock, suspension components or driveshaft/steering arm. It's reliant on air redirectors to get air to the brakes. the factory air re-director has been increased.

my current thinking is relocate the washer bottle to the boot (currently behind fog light) which will then give me room for 140mm duct (+fog light size if i decide to remove) to pass through to the inner arch liner and get as much air as possible into the wheel well. no idea if it'll solve the issue but stands a better chance than the factory 130x150mm > 70-75% reduction.

veehexx

Original Poster:

118 posts

79 months

Tuesday 13th October 2020
quotequote all
Another_James said:
I’m running RSL29’s on my FK8 type R and I’m pretty pleased with them although they haven’t lasted as long as I’d like. 3 track days and they have about 7mm left but no issues with deposits. I find the tyres go off before the brakes so I’m plenty happy with the performance. They are fine on the road as well if a little loud after a few weeks of light use. The OEM drilled discs have cracks coming from the drill holes so are going in the bin but haven’t worn excessively. I’ve now got the 2020 spec 2 piece discs in so will see how they do.

Edit to add I’m on Cup 2’s so not full on track tyres
rsl29's are temping as my next set but with me seemingly overheating pads, i'm not sure i want to waste £330 for a set to try yet.
i had cup2's last year (19"). i'd say minimum for track use on this car. only reason i dropped them in favour of 18" AR1's was the cup2s struggling on the road in cooler wet days.

which track do you frequent? I've yet to go to any others than donington so could be we're comparing a lighter braking track to donny.

Another_James

104 posts

159 months

Tuesday 13th October 2020
quotequote all
Snet is my local and is hard on brakes but I’ve also been to donny and Cadwell this year.

I utterly destroyed a set of CL5+ pads and standard discs on my old FN2 at the donny GP circuit a couple of years ago so appreciate it has some big stops!

You should definitely branch out and experience some other tracks. Cadwell’s first 110+mph first corner uphill is an experience as are 4 wheel slides through the gooseneck. It’s also relatively easy going on brakes and tyres.

veehexx

Original Poster:

118 posts

79 months

Wednesday 14th October 2020
quotequote all
i am planning silverstone and hoped to get it in this year but it didnt turn out that way so have to be next year.

I'm back to thinking if i'll ever get this car sorted for track, should i call it and buy something else.
if i were to keep it, will 5" duct from bumper to wheel well with a large curved air redirector on inner arch to direct it to the back of hub. Its got to be better than the credit card sized hole for OE brake cooling. going to the Brembo 380x32 BBK (from 350x32) would cost £4.2k, force me to at least 19" wheels and likely have heat issues which'll still need ducting.

not sure if a bilge air blower would work. i've seen some do it on track cars (Stillen even make on for the R35) but inability to get close to the disc/caliper with ducting makes me wonder if it could work on the FK2R.

brillomaster

1,398 posts

177 months

Wednesday 14th October 2020
quotequote all
crikey, with that level of abuse i was thinking the car was going to be a 2tonne, 700hp BMW M5 or something, not a honda civic!

i've got to ask, how are you using the brakes? and how long are you out for?

my track car was a 1300kg, 230 bhp BMW Z4, and the bog standard discs, paired with some Performance Friction PF08 pads, was enough for 8 full trackdays, averaging 200miles a day.

it looks to me that both discs and pads are getting way way WAY too hot, and thus everything is then disintegrating.

E-bmw

9,976 posts

159 months

Wednesday 14th October 2020
quotequote all
^^^ My thoughts exactly, hence the question.

I have run similar cars (1180kg e36 328/1080kg r53) both with around 235/240 bhp on DS1.11/DSUno/RS29 pads & boggo aftermarket discs for years with nothing like those issues, both with & without additional cooling.

I would typically get a full year/6 - 10 track days without needing to change but would start the year afresh each time.

Never had any temperature/fade/wear issues with any of the above on the front.

veehexx

Original Poster:

118 posts

79 months

Wednesday 14th October 2020
quotequote all
brillomaster said:
crikey, with that level of abuse i was thinking the car was going to be a 2tonne, 700hp BMW M5 or something, not a honda civic!

i've got to ask, how are you using the brakes? and how long are you out for?

my track car was a 1300kg, 230 bhp BMW Z4, and the bog standard discs, paired with some Performance Friction PF08 pads, was enough for 8 full trackdays, averaging 200miles a day.

it looks to me that both discs and pads are getting way way WAY too hot, and thus everything is then disintegrating.
brake usage is hard. just off ABS kicking in. if/when ABS kicks in i back off a touch.
for those familiar with donington a drylap would be: redgate brake point is about a car length before the end of green pit lane exit tarmac, 100-110mph through crainers and hard on brakes about the end of the right side markings. starkeys to mcleans is brake just as you come out of starkeys in a straight line. brake approx half way up the increased incline into Coppice and exit there around 92-95. Esses would brake just after hump to avoid lockup. maybe a liftoff pre-hump depending on coppice exit.
This time was the GP circuit so while i was still trying to get a good point in melbourne i was braking too early (start of left rumble strip). Goddards brake point would be the start of right side rumble strip aiming to go deep and straighten early down for start/finish stretch.

while i have stopped video recording, i do have in car footage from june this year: https://www.youtube.com/watch?v=DQQyHYO6WMQ. looks like a lap cooldown on this video from 8-10minutes for brakes & oil.
same brakes & tyres, weather was 10c overcast (monday) vs a typical june 21c sunny.
i aim for 15-20mins max sessions. i seem to average 6-7 sessions per event. looks like i'm running 5-7 laps per session around 100mile on track.

seems everyone is saying heat, and it's a battle i keep loosing. seems the performance of the CL pads are hiding it when i'm in the car as the brake feel & power doesn't really suggest any problems (other than judder). Nor do the brakes feel or smell excessively hot when back in the pits.

i took a look at the car (yet again) and I'm pretty sure i can replace the OEM brake duct of 130x140 intake into a credit card size outlet with a redirector on the suspension, to a straight through 140mm duct (or substantially more if i remove fog lights) and maybe 1ft of a 90degree redirector on inner wing to push all that air towards the brakes & hub. Does mean moving the washer bottle to the boot but it's a small price to pay if it solves things. i also figure <£100 parts and a day of work to fabricate something.

Edited by veehexx on Wednesday 14th October 16:06

Applause

225 posts

162 months

Wednesday 14th October 2020
quotequote all
That is mental brake disc wear!

I run Giro Discs, coupled to RSL29 & previously RS5 (Very similar to RS29 but now discontinued)

Stopping power is very good, I have gone through 3 sets of pads and the Giros are nowhere near being done.

Car runs on Cup2's and weights circa 1425kg with fuel and driver.

RSL29's are expensive but so are Giro's and I would rather be replacing pads than discs. If you daily the car remove the RS29's and install for trackdays, they are usable on the road but they will squeal and not offer great bite from cold, but are perfectly ok to drive to and from circuit.

Also look at brake cooling, its often over looked but makes a big difference, does your car have brake ducts? How efficient are they? Can you retro fit?

Edited by Applause on Wednesday 14th October 22:03

veehexx

Original Poster:

118 posts

79 months

Thursday 15th October 2020
quotequote all
potential noise aside, could you use the RSL29's daily or are they too aggressive? i've seen the bedding process for them so rather not be doing that too often.
i did run cup2's before the AR1's and i'd say minimum tyre for the fk2r on track but were just too expensive (£250/ea fitted) and struggle in cold&wet conditions on the road. I shaved around 3secs from my donington national time between those tyres too.

i've got my orders in for cooling although probably wont get time to do it for a few weeks. washer bottle will be relocated to boot, and i'll be able to fit a 6" feed from bumper to the inner side of arch liner, with a big air re director mounted on inner wing. If that doesn't cool the brakes then i don't know what will.

glad the giros are are just over their limit. I'll get 1 more trackday with them next year and will be able to prove this brake cooling concept. assuming all good then I'll buy new rings and seriously consider the RSL29's. maybe sell the CL's or keep 'em as emergency track pads.

brillomaster

1,398 posts

177 months

Thursday 15th October 2020
quotequote all
perhaps a change of pads is required... try some Performance Friction pads maybe.

https://pfc.parts/motorsports/pfc-compounds/

as i say, i've used compound 08 with great success... says its an endurance pad perfectly happy at 800degrees C, or ive heard of people using 11 compound, which can still take very high temps.

their UK office is in banbury, contact them direct on UK Sales uksales@pfcbrakes.com


Humour

297 posts

158 months

Thursday 15th October 2020
quotequote all
Difficult to say for sure but it sounds like you are overheating the system and ending up with deposits on the disks which in turn give you vibration which later clears up with light road use. Had exactly this behaviour in my e36 track car in the early days on std. brakes bar the pads.

Added ducted cooling into the hub so air was forced through the disk vanes and that problem went away. Pad consumption was still high though. Brakes were ok and consistent for 10+ lap sessions with only 15 min break in pits

Moved up a disc size +10mm dia, same thickness and CL6 pads and consumption reduced but still highish. Brakes were excellent and consistent.

Moved up another disk size +35mm dia +3mm thickness, replaced 23yr old calipers for new, slightly bigger on the front and slightly bigger surface area pad. Yet to see the effect on track though frown

My reasoning for changes is as follows; 1) pads are expensive, 150-200ish per axle. 2) disks are oem (nothing fancy) and cheap at 70ish per axle. 3) bigger disks should provide more heatsoak capacity and in turn hopefully less pad wear in my use case and setup.

Im happy to sacrifice disks for pad life, even so, only the fronts apply and then they still seem usable after 3yrs and 3000+ TD miles. No complaints about CL pads other than price.

You can increase cooling, or increase disk size, then test but I would advise against using slotted or drilled disks, they add no benefit to you on track imo.

veehexx

Original Poster:

118 posts

79 months

Thursday 15th October 2020
quotequote all
Humour said:
Difficult to say for sure but it sounds like you are overheating the system and ending up with deposits on the disks which in turn give you vibration which later clears up with light road use. Had exactly this behaviour in my e36 track car in the early days on std. brakes bar the pads.

Added ducted cooling into the hub so air was forced through the disk vanes and that problem went away. Pad consumption was still high though. Brakes were ok and consistent for 10+ lap sessions with only 15 min break in pits

Moved up a disc size +10mm dia, same thickness and CL6 pads and consumption reduced but still highish. Brakes were excellent and consistent.

Moved up another disk size +35mm dia +3mm thickness, replaced 23yr old calipers for new, slightly bigger on the front and slightly bigger surface area pad. Yet to see the effect on track though frown

My reasoning for changes is as follows; 1) pads are expensive, 150-200ish per axle. 2) disks are oem (nothing fancy) and cheap at 70ish per axle. 3) bigger disks should provide more heatsoak capacity and in turn hopefully less pad wear in my use case and setup.

Im happy to sacrifice disks for pad life, even so, only the fronts apply and then they still seem usable after 3yrs and 3000+ TD miles. No complaints about CL pads other than price.

You can increase cooling, or increase disk size, then test but I would advise against using slotted or drilled disks, they add no benefit to you on track imo.
factory size is 350x32 discs & 4pot brembo. AP Racing have 355x32 upgrade with their radi-cal pro 5000R caliper. Brembo have a 6 pot 380x32 setup. Both are silly money for non-competitive use at £4.1k+ excluding pad choice. AP i doubt would give anything worth while with +5mm increase. 380mm would force me away from 18" track&winter tyres and into 19" territory so track wheels, tyre costs & tyre options play into that decision and likely see an easy £2k on top of the BBK. I haven't dismissed the idea but if it got to that stage then £6k would be better spent going down a different route.

the FK2/8 (fwiw same front pads as evo7-9 & scoobies) is similar costs as your pads; track pads start at £180. RSL29's are £330.
i've no interest in drilled discs, slotted seems to be the most common but plain discs perform the best from my online research. Just depends what girodisc (or compatible rings) offer with what replacement i go for. Thats a trackday & ducting test away though... I'll work on cooling and go from there.

Another_James

104 posts

159 months

Thursday 15th October 2020
quotequote all
veehexx said:
potential noise aside, could you use the RSL29's daily or are they too aggressive? i've seen the bedding process for them so rather not be doing that too often.
They are fine on the road apart from the squeal. I do bed them in again before track days or I get a bit of judder. Not the full procedure, just some big stops to get some material transfer.

Humour

297 posts

158 months

Thursday 15th October 2020
quotequote all
veehexx said:
factory size is 350x32 discs & 4pot brembo. AP Racing have 355x32 upgrade with their radi-cal pro 5000R caliper. Brembo have a 6 pot 380x32 setup. Both are silly money for non-competitive use at £4.1k+ excluding pad choice. AP i doubt would give anything worth while with +5mm increase. 380mm would force me away from 18" track&winter tyres and into 19" territory so track wheels, tyre costs & tyre options play into that decision and likely see an easy £2k on top of the BBK. I haven't dismissed the idea but if it got to that stage then £6k would be better spent going down a different route.

the FK2/8 (fwiw same front pads as evo7-9 & scoobies) is similar costs as your pads; track pads start at £180. RSL29's are £330.
i've no interest in drilled discs, slotted seems to be the most common but plain discs perform the best from my online research. Just depends what girodisc (or compatible rings) offer with what replacement i go for. Thats a trackday & ducting test away though... I'll work on cooling and go from there.
imo road calipers even brembo 4 pots are not designed for the type of abuse you can dish out on track particularly if you are running at 9/10~10/10ths all the time.

Dual purpose cars are convenient but for the hardcore TD'yer are too compromised both ways. Its the reason I have a dedicated TD car thats 90%+ racecar with as little compromise as I can afford to build into it and a nothing worth mentioning shopping trolley for daily duties to keep costs down to a minimum.

If ducted cooling doesnt prove successful for you, as you say it would make more sense to go alternative routes and I would suggest to consider instead to drop 4-6K on a pre-prepped TD car thats more suited to what you want to achieve on track. That kind of budget can get quite alot of used value and be recoverable at least 50% when you sell on. Given your knowledge, if you go that route go as low weight as possible as it means lighter on all consumables. A well prepped mx5 turbo or e36 328 would be my choice for that type of budget and wont be far shy of the FK2 laptimes with the exception they can do twice as many per session provided in good fettle.

Ive kept up with various FK2R and MegRS in the 300range running bigger tyre profiles than me an arguably stickier rubber on a track that favours more powerful cars in my 328 with 220hp with a 3.23 final drive and NS2R hard compound tyres. Only those with AR1/Mcup equipped rubber have consistently had the edge in my experience but of course its hard to compare drivers and their commitment. Ive exerienced enough range of test subjects however to know that a 328 and a decent mx5 turbo can punch well above their bhp/ton numbers would suggest.

Ultimately though, its about having fun and challenging yourself.

Good luck.