big brakes

[sammyb]

with running a 4 pot upgrade (i.e spoon/willwood callipers) would i need to get a biger master cylinder of a ek9 or the likes of??

 

[KieranEG6]

Now those rotors. Those are garbage, and there also expensive as hell for what they are.
Yes the brackets HAVE to be milled. Its the surface where the bracket bolts to the knuckle. Meaning if you whack at it with a bench grinder, it'll be uneven. Now the pad is contacting at an angle relative to the rotor.
Using washers is totally not safe. For one, now the rotor isn't centered anymore (as the MG SZ and Prelude VTEC rotors are hub-centric), and you reduce the contact to the hub/rotor by a factor that is not exactly negligable.

I understand your bias verse your friend, and I counter that with more questions. What rear brakes does he have? What fluid do you run? Do you have the OEM dust shields? Does he have brake ducting? And the bigger factor, does he run a 2 piece rotor? Because an aluminum hat on a 2 piece disc as well as an aluminum caliper, also added to by possibly less front brake bias, a possible lack of mudguards, maybe more open spoked wheels, and not knowing if the pads are tapered or were bedded in correctly, yeah, his may outperform yours. ALSO, and not to hate, but I don't know much about the MG ZS disc other than that is NOT a Honda designed rotor. That car tho it had 11.1" front brakes, did NOT use the Type-R caliper. So I cannot vouch for that rotor being heavier or lighter than the comparable Prelude VTEC disc I use.

Regarding the guy with ITR front brakes, are you running DOT3 or DOT4 brake fluid, what MC/BB do you have and what rear brakes are on it?

Once again, sorry if I come off as a smart ass, but this I feel is a real discussion past "fixed calipers are always better cause they got more pistons."

Do you have standard 240mm rears? If you do, you are most likely over working the fronts leading to them fading quicker than you would expect.

U sure they have to be milled cant you jus gring the extra clearence off the inner edge on the pad carrier to alow for the slight different offset, the pads and cliper should jus slide aside a bit to compensate.

Both run dot 4 fluid. He runs standard discs all round 259mm front and 239mm rears. Both run standard dust sheilds and no ducting. I actualy run rota circuit 10 quite an open wheel. An he runs the standard clio williams wheels lol . Not exactly much open to air.
USED RENAULT CLIO WILLIAMS ONE 087/400 FOR SALE £2995
My pads were bedded in fine. Been a mechanic 7 years bedding in brakes.

I know those discs were just an example of how easy it is to find them.

I dont see why the MC would effect my brakes from overheating.

I do only run standard 240mm but with EBC red rears but still better than his. I know this is a weak point of mine but the point im trying to say how come a car of same ish weight and performance with smaller disc size can out brake and last longer then this supposed super amazing Honda calipers. I know his would be slightly more ballanced, but if what he claims is true with the willwood 4pots bein so inferior than the Type R caliper setup, mine should way out perform his. No?

So basicaly what your saying is if i get ITR calipers, milled and prelude discs redrilled. I will have the best setup i can.

Random point but why do spoon produce a 4pot caliper if the super strong amazing designed sinlge pot standard caliper was so effective???? Or was it of the sole perpose of saving weight???

 

[Kozy]

Calipers aside, the Clio is balancing the braking better between front and rear wheels, so he gets less fade than yours which is using the fronts harder and heating them up more.

 

[KieranEG6]

My brother runs standard calipers on his EK9 rally-car and with a good pad and disc combination he's never had a problem with over heating and there is loads of pedal stamping on some stages. The calipers, much like everything else on the EK9, are well suited to track use.

fair comment but i take it its a striped rally car weighing consideraly less than a fully standard unlightend EG6 (i suppose actualy slightly heavier than standard running the bigger brakes, recaros and b18c).

You would be surprised how much work can be on brakes when your on an open road trying to keep safe distance from loads of traffic all moving at different paces basical like being at the nurburgring but with more bikes (going slow) (ps never been to the ring jus basing from footage i have seen)

my mate on the mountain in his DC2. not what i would call quite on the pace but still giving it some.
YouTube - iom 2008 itr
Usualy more traffic as its still used as a daily commuting route they jus make it one way for safety. (ps is always unrestricted speed limit)

 

[KieranEG6]

Calipers aside, the Clio is balancing the braking better between front and rear wheels, so he gets less fade than yours which is using the fronts harder and heating them up more.

Suppose. I just would have thought the EBC reds in the rear would help compensate a little and balance out.

 

[Kozy]

EBC Reds aren't up to much, and so won't compensate nearly enough. You've got the same setup as me near enough, but I've got EBC yellows (also rubbish) on the front and pattern part pads in the rear. I've done my usual math **** the calculate it all, quite involved taking into account forward weight transfer and the corresponding grip of the tyres, brake torque etc etc and basically my 282/240 setup is about 50% too front heavy, yours is about 40%.

We really need those 260 rears to balance the whole thing out!

 

[KieranEG6]

Yea been planning that for a while but never got round to it.

But in thinking that. What if i get the 260 rears, feel its still not enough and go for the 4pot setup on the front. Wont the balance be out again?

 

[haitch]

Plenty of 4 pot kits out there that are only as good as a good disc & pad combo or slightly better, but the oem set up chews through discs and pads on track, think I went through three or four sets in one year before my Brembos, at approx £350-400 a set thats a lot of money.

For the road a kit is a waste of money, but for track its a no brainer, its an initial big outlay, kit depending, but in the long run its massive money saved, plus all the other benefits, some good points mentioned here from the experts, I just know what works, not sure on the percentages but according to this thread mine is poorly balanced, I have not noticed though

 

[Kozy]

This might help visualise it a little better.

It's by no means perfect, but what is showing is how different setups on the EK4 affect brake bias. The 1-10 X axis is pedal input force in lbs (x10), I put my bathroom scales up against the wall in the corridor and pushed on it about as hard as I would at most in the car and got about 60lbs or so. Some people may push more or less but 60lbs would be a pretty aggressive stop.

The % Y axis is the difference between front and rear braking thresholds. This is worked out for each axle as the ratio of torque applied at the tyre contact patch with relation to how much dynamic load is on it, so a tyre with 1000lbs on it and 800lbs brake force would be at 80%. The difference is then simply the front threshold minus the rear, so 40% on the graph means that the fronts could be at 80% and the rears only 40%.

Obviously as you shift weight forwards, the front brakes are capable of doing more work and the rears less, but in the instance above where you are 40% front biased, once you hit 100% at the front (which is where theoretically the brakes should lock), the rears are only doing 60%. You can uprate the rear brakes to get say a 20% front bias (around what the stock EK9 setup is), and you've effectively taken demand off the front brakes and given it to the rears which were being underworked. This could possibly result in increased total braking forces and reduced wear and fade on the front brakes.

not sure on the percentages but according to this thread mine is poorly balanced, I have not noticed though

It depends how hard you brake, as to how front biased you are. For track work, where 90% of your braking is full bore, then massive front brakes and tiny rears work just fine as you'll be unloading the rears so much that you really don't want much torque from the rear brakes otherwise you'd lock up. You can see this in the graph above on the far right as the bias goes increasingly rearward the harder you slow down. You're unloading those rear wheels very fast, but you can't reduce brake pressure to them in a static system! This is essentially the basis of those EBD systems on new cars, they can reduce rear brake pressure in relation to calculated tyre loads... all very clever, I was thinking about designing one and retrofitting it to an EK actually...

On the road, where you will be using a wide range of braking forces the rears have more load, and so can take a larger proportion of the total braking force, which reduces load (and in turn wear and heat) on the front brakes.

In summary, huge front brakes and standard rears are all good and well on a track car, but for day to day driving, those rear brakes are more important than you might think!

Not sure if this makes any sense whatsoever, if the brake experts think I'm talking out of my arse please do tell me!

 

[Kozy]

You know what, I should really have better things to be doing at 11pm on a Friday night...

 

[haitch]

^Too much Latin for me.

 

[BrakeExpert]

The Spoon calipers were designed just to save weight, yeah. They help with weight and heat dissapation. For a single stop they don't help at all. This is why for 1200$, most people don't buy em unless they track race and have wheel restrictions and wanna keep the 11.1" sized brakes for 15s.

If you use spoon calipers (the DC2/EK9 ones), those are comparable to the ITR caliper in terms of hydraulic force. So you use a 1" master cylinder like you would with the ITR caliper.

No you don't grind the inside of the bracket because you also have to modify the retaining clips, and the inner gap is greater than it should be.

 

[stevenEK9]

Rubbish about spoon calipers just designed to save weight

4 piston is going to give much better performance and more consistant performance with clamping the pads evenly from both sides of the disc rather than a standard single piston slider assembly

i got to the stage that i needed to upgrade from the 282mm discs as i was having to run some pretty extreme compound pads to stop me fading the brakes, wore through my discs in no time

now with a 300x28mm 2 piece disc setup the discs should last alot longer as i can run milder pads which will stil give the same or better braking force i had before but with the added size and width of the discs everything will stay alot cooler

end of the day depends what you are using the car for and if you are serious about tracking them have a few sets of pads to swap between

for knockhill it's a short track at 1.3miles, but has a few hard braking areas, stomping down on the brakes hard doing lap after lap the brakes don't have much time to cool before being used again

in comparison at the nurburgring there are so much long fast sections that your brakes have sufficient time to cool between corners

 

[BrakeExpert]

Check out a fried ITR pad. Totally smoked, but look at the flatness of the pad (before it gets to the backing plate.) Does the pad look like it jackknifed? You need to look at that brake pad, its backing plate, and the leading and trailing edge, that pad did not have uneven pad wear, the spoon caliper's dispersion of pressure...I mean do you think that its going to increase friction? Or what, grip harder with less PSI? assuming you have ABS, its still gonna give the same friction to the disc before the tire wants to lockup.

 

[stevenEK9]

What?

I was just implying that there is a more effective clamping force with the pressure being evenly distributed to both pads simultaneously and not having to rely on a slider assembly to pull the opposing pad against the disc

4 pot calipers will certainly offer better modulation too over a slider assembly for the above reason

feel is certainly something many people overlook with brakes too, you certainly don't want brakes that are either on or off

and no i do not have ABS, i removed this and the brakes feel much better as a result

 

[BrakeExpert]

ABS cannot affect pedal feel unless theres a problem with the system, not to contradict, but to clarify. ABS only is suppose to operate when a wheel locks, so before this, its a passive system.I've talked to so many people who say they dont like ABS cause the pedal feels different. When in actuality, if you look at the whole car, there are other factors that actually make it feel different.Like the EX civic coupe. (92-95). The one with ABS feels different than one without, right? Same front brake, except that some of those ABS-equipped models came with a 15/16" MC so it allowed for a firmer pedal, but as you can lockup the brakes sooner (so to speak), its okay because ABS is there to help. And there are those without ABS and the same front brake that came with a 7/8" MC. This occured on the EK generation too, with the 99 Civic Si verses the 99 Civic EX coupe.

But the slide pins slide, thats what they do. It allows for even pad distribution otherwise one pad would be thicker than another when they are used up. So yes, sliding calipers CAN be just as good as a fixed caliper. Clamping force is not the factor.
A better arguement can be that the slider pins allow the caliper to twist, or torque, whereas the aluminum calipers don't have slide pins, one could argue the whole caliper torques. But for our purposes and driving on the road, these are near-negligable factors.