CL RC6 or RC8?

[JB21]

Currently running RC5+ on Brembo HC discs and r888 tyres and find the pads totally lacking, good initial bite when warm going into a braking zone but really tail off mid-end zone and in long zones are pretty much none existent in the last 20% of a zone when hot, they also seem to be very inconsistent over say 5 hot laps where sometimes the initial bite is even weak, this does not inspire confidence at all for me and I need something with more consistency and more coefficient though the whole of the braking zone.

Was thinking RC6 as these have a coefficient of 5 start-mid range and seem to work better at higher temps (see below) whereas the RC5+ have a coefficient of just over 4 mid range but tail of towards the end which explains the above. Then you have the RC8 which have a coefficient of a tad over 6, but not sure if these would be to much on a light Clio?

Preferably I would like a pad that I can get to the limits of the r888s, the RC5+ there's no chance of a lock up under heavy braking which isn't utilising the full grip of the tyre, obviously RC6 would be better but I'm really tempted by the RC8 as these would surely use the full grip of the tyres? Also would RC6/8 pads work with Brembo HC discs?

Thoughts of people who have actually used the RC6 and or RC8 much appreciated?

*the brakes would not be used on wet track days or road, I'd swap to OE for this.

 

[Amos91]

What about the DS1.11s? I've not heard any complaints regarding those.

http://www.ferodoracing.com/products/car-racing/racing-brake-pads/ds1-11/

 

[JB21]

What about the DS1.11s? I've not heard any complaints regarding those.

http://www.ferodoracing.com/products/car-racing/racing-brake-pads/ds1-11/

Yeah heard really good things about them myself mate but the coefficient puts me off them and they are more expensive, seems they fall in-between CL5+ AND RC6 coefficient wise and near identical to RC6E. Now I know these graphs don't tell the whole story on the performance of a brake pad but I'd be gutted paying £200 and not being much better then CL5+.

 

[JB21]

@bob the builder you seem to be the only fella I can find on here who has used the RC8, thoughts on the above?

 

[George@RTR_Parts]

Like you say above mate, the graphs don't tell the whole story. The DS1.11 give a very short and consistant pedal feel which is great for heel n toeing and left foot braking on track. They last very well and are genuinely kind on discs, so take this into account when looking at the cost and they are actually better value for money over the life of them against other pads that retail at less.

I've tried quite a lot of pads on various cars, and can supply most brake manufacturers. DS1.11 pads are in my track/race car. Lots of people now running them on track on here , @BeatMasterUK @sonny172cup

 

[JamesBryan]

Might be worth changing the fluid to Motul 660 mate too, i used to use ATE blue/gold and the pedal always went soft and i find it's just not good enough.

Night and day difference with the Motul stuff using RC5+

 

[JB21]

Might be worth changing the fluid to Motul 660 mate too, i used to use ATE blue/gold and the pedal always went soft and i find it's just not good enough.

Night and day difference with the Motul stuff using RC5+

Good shout mate as I use the ATE typ200 and find the pedal can hit the floor under really hard braking, it feels as though the fluid is compressing like its got air in the system. I've even used 2-3L of it bleeding the brakes over this years track days my brakes felt that bad.

 

[JB21]

Like you say above mate, the graphs don't tell the whole story. The DS1.11 give a very short and consistant pedal feel which is great for heel n toeing and left foot braking on track. They last very well and are genuinely kind on discs, so take this into account when looking at the cost and they are actually better value for money over the life of them against other pads that retail at less.

I've tried quite a lot of pads on various cars, and can supply most brake manufacturers. DS1.11 pads are in my track/race car. Lots of people now running them on track on here , @BeatMasterUK @sonny172cup

@George@RTR_Parts what could you do the DS1.11, HC discs and 2L of Motul 660 delivered for mate?

 

[George@RTR_Parts]

will check on the fluid and drop you a PM mate @JB21

 

[JKING3008]

I am using rc8 though I can't comment on any other pad.
Can really give them abuse and they just keep on working. Do squeal a bit when cold and if light braking but when work still from cold.

 

[JB21]

I am using rc8 though I can't comment on any other pad.
Can really give them abuse and they just keep on working. Do squeal a bit when cold and if light braking but when work still from cold.

Cheers mate.

 

[JamesBryan]

Good shout mate as I use the ATE typ200 and find the pedal can hit the floor under really hard braking, it feels as though the fluid is compressing like its got air in the system. I've even used 2-3L of it bleeding the brakes over this years track days my brakes felt that bad.

I've gone through litres of ATE trying to get a good pedal and i've now got it how i want it with Motul after just 1-1.5L.

 

[JB21]

Think @Mini182 has used the RC8's as well...

 

[imprezaworks]

Wonder why that is regarding the fluid

 

[JamesBryan]

The Motul 660 isn't cheap mind, around £16 for 500ml!

 

[JB21]

I've gone through litres of ATE trying to get a good pedal and i've now got it how i want it with Motul after just 1-1.5L.

Awesome mate, that's the next port of call then before buying pads as I've still got some meat left on my CL5+.

 

[JB21]

The Motul 660 isn't cheap mind, around £16 for 500ml!

Worth it though for a nice consistent pedal feel.

 

[JamesBryan]

Awesome mate, that's the next port of call then before buying pads as I've still got some meat left on my CL5+.

Put it this way, on Sunday at Donington braking from 110mph into the first corner not once did i think i wasn't going to stop. My mate in the passenger seat commented how late he thought i was braking haha.

 

[JamesBryan]

Wonder why that is regarding the fluid

I think the difference is just the higher boiling point mate.

280c for ATE and 330c for Motul 660.

50c makes a big difference when the fluid reservoir is located so close to the exhaust manifold on these cars.

 

[JB21]

Put it this way, on Sunday at Donington braking from 110mph into the first corner not once did i think i wasn't going to stop. My mate in the passenger seat commented how late he thought i was braking haha.

Sounds ideal, at Oulton a few weeks back I was defo losing time when braking down into hizzys, shell and cascades. Defo a second or two to be gained with better brakes.

 

[imprezaworks]

Yeah was just thinking boiling point.

 

[Mini182]

Think @Mini182 has used the RC8's as well...

The RC8 are hands down the best pad I have used for track and race in the standard caliper. Great initial bite and pedal feel, very progressive and no fade.

I have used a lot of different pads and the RC8 is by far the best. (I wouldn't want to use them on a road car though). However I will confess one of the pads I haven't tried is the DS1.11 and I do know a few people who swear by them as well.

 

[JB21]

The RC8 are hands down the best pad I have used for track and race in the standard caliper. Great initial bite and pedal feel, very progressive and no fade.

I have used a lot of different pads and the RC8 is by far the best. (I wouldn't want to use them on a road car though). However I will confess one of the pads I haven't tried is the DS1.11 and I do know a few people who swear by them as well.

What discs and tyres did you run with them buddy? You reckon they'd last 5 full open pit track days?

 

[JamesBryan]

One thing i will say is that brakes are a personal preference. What works for some people might not work for others, braking styles vary a lot!

You can't really go wrong with CL's or DS1.11's though.

 

[Mini182]

What discs and tyres did you run with them buddy? You reckon they'd last 5 full open pit track days?

Brembo HC discs - no need for anything else.

Dunlop Direzza tyres.

Depends how you drive, they do last pretty well, but from what I have heard the DS1.11 last even better, but then again they are slightly more expensive to buy in the first place.

 

[mikekean]

If you are running plain discs then go for RC6 or RC8, Ferodo pads are good, i run DSUNO which is pretty much their top pad but as with all Ferodo pads when they get really hot you start to get deposits on the discs which causes judder which is very annoying. I have run RC6 on Le Mans Bugatti with R888's going out for 20-30 mins at a time and didn't get any fade at all. Was my first experience of them and for any car using standard brakek setup it is my go to pad.

On the brake fluid subject i wouldn't waste your time on Motul RBF etc, it's the wet boiling point that counts and on any other fluid but Castrol SRF its really low compared to the dry boiling point. If you want good fluid just buy Castrol SRF, replace it once and year and you are good to go. People will spend thousands on fancy parts but when it comes to brake fluid they want to save £10, Crazy..

 

[JB21]

Some really valid points here fellas, still not 100% sure on which pads to go for, lol. I know I need better fluid that's for sure. Thanks to all so far who've contributed.

Gonna get some decent fluid and see how my CL5+ perform after, also got braded lines to fit as well which should help pedal feel.

 

[JamesBryan]

Thought you had braided lines fitted already?

 

[imprezaworks]

if it was me and after speaking to rob a couple of years ago id opt for the 8's

 

[JB21]

Thought you had braided lines fitted already?

Never got around to fitting them mate as the nut on the NSR hard pipe rounded off on the first turn so just left it to do over the winter. Gonna get myself an SAE hand held brake flaring tool and copper/nickel line to make up the full section from the front a-frame to the flexi as it rusted to sh*t in the middle of the car, may even just make up hard lines to the rear callipers.

 

[George@RTR_Parts]

I think the difference is just the higher boiling point mate.

280c for ATE and 330c for Motul 660.

50c makes a big difference when the fluid reservoir is located so close to the exhaust manifold on these cars.

it's the wet boiling point that matters mate . The 660 is 204c and the ate is 198c, that's why I use/supply the Typ200 as is a good VFM fluid that can be used on road/track at half the price of the 600/660 but similar specs. If wanting to get a better fluid to use hard on track the SRF is the one to get

Is a good point ref the manifold though, I know some people have moved it to the other side of the engine bay for this reason @Tony Hunter for one

 

[JB21]

it's the wet boiling point that matters mate . The 660 is 204c and the ate is 198c, that's why I use/supply the Typ200 as is a good VFM fluid that can be used on road/track at half the price of the 600/660 but similar specs. If wanting to get a better fluid to use hard on track the SRF is the one to get

Is a good point ref the manifold though, I know some people have moved it to the other side of the engine bay for this reason @Tony Hunter for one

Interesting mate, the SRF has a wet boiling point of 270C for reference.

 

[George@RTR_Parts]

I know mate, but at more than 3 x times the cost of supergold a lot of people choose not to use it

if a track/race car and you think you're boiling the fluid it is the one to use though , or look at moving the reservoir to other side of engine bay away from manifold.

Horses for courses , and people have different uses/budgets for their cars :up:

 

[JB21]

Ok so after a little reading it seems that the issue @JamesBryan and I have experienced with the ATE TYP200 is that it seems that its more compressible at high temperatures compared to the other racing fluids on the market such as the Motul RBF 600/660, Castrol SFR. From what I've read this is down to the formula and viscosity (specific gravity), the Motul and Castrol seems to draw less air into the system equating to a firmer more consistent pedal feel at higher temperatures.

Compressibility
This is not a specific DOT call-out, yet it is critically important to racers and enthusiasts. It is listed in SAE J1705, Appendix A, A.2.2.8, under the heading, "Air Solubility." Here it states, “Air Solubility – It has been reported that dimethyl polysiloxane fluid, which is a major part of silicone-based, low water-tolerant type brake fluids can typically contain dissolved air at a level of 16% ±3% by volume at standard temperature and pressure. This compares with a typical level of 5% ±2% by volume of dissolved air for glycol ether based type fluids. An increase in brake pedal travel may be experienced under severe operating conditions, especially at higher altitudes and high temperature conditions."

"The term “dissolved air” (air absorbed from the atmosphere) should not be confused with the term “entrapped” or “free air” since their effects on brake system performance can be entirely different. Air that has been absorbed from the atmosphere does not result in an increase in fluid or system volume, whereas entrapped air or free air does occupy system volume and can be easily compressed when force is applied to the system.“

The SAE standard continues, “A.2.2.8 – Compressibility – Silicone based brake fluids are more compressible than conventional brake fluids and the difference is magnified at higher temperatures.” Silicon-based brake fluids are described by DOT 5 (not to be confused with DOT 5.1), which should never be used in a racing vehicle due primarily to its compressibility.

Compressibility is largely ignored by those selling nearly all the brake fluids on the market -- and with good reason! It is better you aren’t told that their fluid could contain as much as 7% dissolved air!! Once they are tested specifically for compressibility, it is no surprise that certain "high end” racing fluids are known in the paddock for their poor pedal feel.

A research report published by Union Carbide demonstrates a relationship between the compressibility of a brake fluid and its density (or specific gravity). The greater the density of a brake fluid the less compressible it is. As there is no DOT specification, within the scope of the Polyalkylene Glycol Ether-based fluids there can be a density difference range of over 200% between fluids! Since brake feel is so important to driver confidence and, ultimately, lap times

 

[Tony Hunter]

Is a good point ref the manifold though, I know some people have moved it to the other side of the engine bay for this reason @Tony Hunter for one

I have now mounted it in the scuttle panel, so it's out of the way completely, which is even a better solution.

 

[Tony Hunter]

On another note, I may have said this before, but I also use any dot 5 fluid thats going, no fancy stuff for me, bleed them once through the season, (but they don't need doing), and never ever have any pedal feel trouble, always rock solid.
It's the simple things really.

 

[JB21]

On another note, I may have said this before, but I also use any dot 5 fluid thats going, no fancy stuff for me, bleed them once through the season, (but they don't need doing), and never ever have any pedal feel trouble, always rock solid.
It's the simple things really.

Presume your car has no ABS Tony if using DOT5?

 

[Tony Hunter]

Correct.

 

[bob the builder]

i vote for the rc8 pads, its the only one I will use. but as covered earlier it all depends on your driving style.
very good bite even from cold and never had any fade.
as tony I also used any dot 5 fluid and never had any problems but I heat wrapped my manifold.

 

[alistairolsen]

I really cant see how you can boil fluid with a wet boiling point of 200 degrees when it's housed inside a plastic reservoir TBH.
Lines in the engine bay passing a manifold perhaps, master cylinder itself maybe, but not the reservoir.

I also cant see why moving the reservoir would help at all, because even if the plastic could sustain enough heat to boil the fluid, hot fluid expands, so its coming out of the lines, not down from the reservoir, so you'd never draw the boiled stuff into the system anyway.