148 replies to this topic

[Nev]

I think people are associating brake fade with total loss of brake power I get fade on track but never total loss. On the road my current setup (std discs, RC5+ pads and front cooling kit) can pull -1.2g of braking force. On the Anglesey International extended part I was seeing only -0.8g on the approach to the hairpin and -0.7g on the next hard braking zone towards the pit lane. In short I am loosing 33% of my brakes when on track and up to 42% when really hammering it. Due to the fact I have good fluid it never boils and always give me a consistent braking experience.

I am about to start some quantitive testing on brake upgrades one by one to isolate what the weak link is and how much better things get for how much money. I have started of with a set of alloy belled discs and will post the results after my next track day.

ETA - IMO 4 pots, fancy disks, etc etc are all pointless on the road so if you don't track, save your money.

I'd be very keen and thankful to see this Steve, as a brake upgrade has been an itch at the back of my scalp for some time. Would you mind answering a couple of questions in the mean time though:

1. On my old setup with R888s, I was able to brake at 1.1g - is that about normal for OEM setup with Mintex 1144 pads?

2. With the R888s on the dry and warm, I could only lock my front wheels up from 60 MPH and below. Is this about normal ?

With my extra rubber now however, I am keen to be able to improve braking to around 1.6g, so that it is approx the same as my acceleration. At the moment the car accelerates faster than it brakes and makes the braking expereince feel woefully inadequate when really tanking it.

[SteveA]

1. On my old setup with R888s, I was able to brake at 1.1g - is that about normal for OEM setup with Mintex 1144 pads?

In my testing the limiting factor is the rubber compound and I think 1.2 is about as much as you will get from road legal tyres.

2. With the R888s on the dry and warm, I could only lock my front wheels up from 60 MPH and below. Is this about normal ?

Braking like acceleration is a curve and you will most likely find the peak of that deacceleration is lower down when the tyres are being pushed to their limit.

With my extra rubber now however, I am keen to be able to improve braking to around 1.6g, so that it is approx the same as my acceleration. At the moment the car accelerates faster than it brakes and makes the braking expereince feel woefully inadequate when really tanking it.

Keep in mind that a slick shod Radical with full downforce pack will only brake at -1.7g so I think -1.6 may be a bit ambitious on legal tyres.

I think the only way to introduce more braking force would be to use a high downforce solution but even then I think -1.6g is probably unachievable. Time and testing will tell though

I honestly don't expect my testing to yeild higher negative g results on the road just less retardation on track.

Edited by SteveA, 16 July 2012 - 10:20 AM.

[Nev]

Thanks Steve, great to have someone using some actual metrics As you can probably imagine, I have amazing downforce with my new splitter and big wing (from 75 leptons+ you can really feel the steering become noticably heavy, and by 130 leptons the car is amazingly planted). Thus, I have my fingers crossed - if I can get my braking even close to a radical I will be happy

Edited by Nev, 16 July 2012 - 10:59 AM.

[Mike (Cliffie)]

I can vouch for George's brakes from when I drove it at Knockhill. Brake fade comes in two forms. 1. The pedal starts to travel longer then eventually goes to the floor-This is boiled fluid, change it. 2. The pedal stays hard but the performance of the brakes deteriorates or fail completely-your pads have overheated or glazed so try a better compound.

[Bargi]

avoid CL all together as far as i am concerned.

True, the 5's definitely, but no reports on the 6's being bad as far as I know.

[Rosssco]

Shouldn't brake 'improvement' be qualified as to wether its an improvement in performance, relating to resistance to brake fade, durability and efficiency, vs. an improvement brake feel and initial bite, which is probably more relevant for road use (but obviously also a requirement for track use). Different combinations of calipers, discs, pads bring different aspects, therefore perhaps there is no one ideal set-up for both road and track.?

[MAXR]

Find me someone who tracks regularly, who has upgraded calipers and doesnt think its a step change improvement.

I rebuilt my aps and they were much better. New pistons etc. They worked well, but they work better on the rear axle with something fit for purpose up front.

I think the aps are fine, only if you upgrade everything else.

I used to have AP front discs & rotors with RS14's all round. I thought they were fantastic until I upgraded to 4 pots on the front & PF pads. Braking is definately better, most notibly under initial hard braking....I didn't notice any fade either.
I agree, regular fluid changes make a big difference, mine get changed every 2 or 3 track days.

Having said 4 pots make a difference, it could also be partially down to the PF pad upgrade. Before upgrading, I was convinced that i would not notice any difference as I thought the setup I had was pretty damn good. Now, I know that it is a noticeable improvement!

...upgrading to 2 Pots on the rear may give another noticeable improvement?

[kipper]

...upgrading to 2 Pots on the rear may give another noticeable improvement? That's my next job, got all of the bits in the workshop, except for the Ali belled rotors. The 290 mm rotors from the Elise Parts are currently not avaliable for the VX ... too busy to produce the bells at the moment...could try the Elise shop....the expense of it all

[FLD]

I can vouch for George's brakes from when I drove it at Knockhill.

Brake fade comes in two forms.

1. The pedal starts to travel longer then eventually goes to the floor-This is boiled fluid, change it.
2. The pedal stays hard but the performance of the brakes deteriorates or fail completely-your pads have overheated or glazed so try a better compound.

Is this why I had 'hard pedal' problems at the national? I got an occasional hard pedal with poor(ish) brake performance. Pushed a bit harder to slow the car but the pedal was noticable hard. I'm on 1144's.

[JG]

No, you probably experienced the hard pedal problem for the reason Ray detailled very nicely in a post recently. (hand on i'll go and find it)

[JohnTurbo]

I did fit the ftr conversion at the same time. Also the hispecs dwarf the aps for piston area. You need the ftr conv to maintain balance. Similarly youd need to do something about balance if you used the ftr brackets with the smaller (asymmetric piston) ap 4 pots. My brakes are epic now anyway, so ive stopped wondering why my stock setup was so lame.

[krambulle]

avoid CL all together as far as i am concerned.

True, the 5's definitely, but no reports on the 6's being bad as far as I know.

May I ask why? What is wrong with them?

I guess when you say '5' you are meaning '5+'?

//Johan

[badgerade]

avoid CL all together as far as i am concerned.

True, the 5's definitely, but no reports on the 6's being bad as far as I know.

May I ask why? What is wrong with them?

I guess when you say '5' you are meaning '5+'?

//Johan

There were reports of the pad material coming away from the backing plate. Several posts on here and on Seloc but I can't find any now!

[Bargi]

avoid CL all together as far as i am concerned.

True, the 5's definitely, but no reports on the 6's being bad as far as I know.

May I ask why? What is wrong with them?

I guess when you say '5' you are meaning '5+'?

//Johan

There were reports of the pad material coming away from the backing plate. Several posts on here and on Seloc but I can't find any now!

Yep check out here lots of people with problems.
Personally I've taken the view that CL tried to create a Pad that is friendly to your wheels and very good braking on track but it's no quite there.

[Bargi]

I can vouch for George's brakes from when I drove it at Knockhill.

Brake fade comes in two forms.

1. The pedal starts to travel longer then eventually goes to the floor-This is boiled fluid, change it.
2. The pedal stays hard but the performance of the brakes deteriorates or fail completely-your pads have overheated or glazed so try a better compound.

Is this why I had 'hard pedal' problems at the national? I got an occasional hard pedal with poor(ish) brake performance. Pushed a bit harder to slow the car but the pedal was noticable hard. I'm on 1144's.

My "little" post is here

[Rally]

I can only speak from my own experience - I'm running CL5s and think they are superb. Immense stopping power, great bite, work from cold and haven't had the 'turn-to-cheese' problem. They are a bit rattly but not enough to put me off them.

[Bargi]

I can only speak from my own experience - I'm running CL5s and think they are superb. Immense stopping power, great bite, work from cold and haven't had the 'turn-to-cheese' problem. They are a bit rattly but not enough to put me off them.

Give it a about a year and they'll be in bits.
Oh wait the box says "Race use only" and so should you drive them on the road any warranty is null and void

[techieboy]

On my third complete set of RC5+ and not a single problem with any of them.

[Bargi]

On my third complete set of RC5+ and not a single problem with any of them.

Given you quoted driving your car on average once a month then I reckon your just filing them down in between changing your exhausts

[JG]

(once a month? once a quarter more like)