Best rear brake upgrade with RS4 B7 fronts on S4?

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lewiswlawrence

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Looking for some advice.

I have a B5 S4 and have been planning a brake upgrade for a while, the rear callipers are starting to need attention so that will be happening soon. I live in rural Scotland and regularly get the opportunity to run out of brakes (deserted twisty open roads), I already tried an upgrade to EBC disks and pads, and have stainless steel braided flexible brake lines. But the standard size disks just cannot take the heat and fade, there just isn’t enough material for the weight of car. I am planning some engine upgrades in the future and really need better brakes prior to that.

I already upgraded to some S8 18 inch wheels to take bigger diameter disks, and have pretty much decided on the RS4 B7 setup for the fronts. Does anyone have a recommendation for the rear to go with that? Are the RS4 B7 rears a straight fit? Would some S8 rears and callipers be a viable (certainly cheaper) option? Will the standard master cylinder be OK?

Thanks in advance,
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Lewis
 
I have rear b5 rs4 312mm brakes on my quattro, very good feel coupled with the front 4 pot ATE Power brake kit which i have...No fade whatsoever and can stop on a dime. The only downside is the discs are very expensive...
 
adamss24 said:
I have rear b5 rs4 312mm brakes on my quattro, very good feel coupled with the front 4 pot ATE Power brake kit which i have...No fade whatsoever and can stop on a dime. The only downside is the discs are very expensive...
Click to expand...

Sounds like you have a nice setup, did you have to change your master cylinder?
 
ive got full B7 set up on my RS4 B5 ... really not a great upgrade in my books, discs are prone to cracking and warping (2 times on mine) , also oem or cheap pagid pads (100 quid) are rubbish, i changed pads on front to ferdoro ds2500 at a cost of 300 pound! which has helped some in terms of fade, but imho look for a different set up.
 
I'd consider B6 S4 calipers on the front, and facelift B5 S4 calipers on the rear with some of Trigs spacer brackets to take the 300mm B6 S4 disks.

That gets you from 320 to 345mm on the front and either 240 (pfl) or 256 (fl) to 300mm on the rear which is a huge improvement over what you have now.
 
i have B7 fronts and B5 rears

Both are bolt on and work very well.

fronts can be expensive and some people seem to have problems with them. I haven't.
I paid less than £800 for discs and calipers for the fronts and the rears were free. there are loads out there, saw some discs up for £300 the other day.
B7 rears need a modification of the hub to allow a bolt to clear on fitting of the caliper but otherwise are less common second hand and can command prices as high as the fronts!
SS lines all round,
EBC yellows up front (Euro120) which I was worried about but actually work very well and have lasted an age.
OEM pads at the back. (£25)

I noticed a change in handling with the unsprung weight change from stock on 8J wheels to B7 on 8.5J but got used to it very quickly.
only used them in "two feet white knuckle emergency stop" scenario once.....they (on decent tread PS2 tyres) ...were quite simply amazing!!

you could have bad luck with anything you buy and there is always something cheaper. depends on what you can get hold of I suppose.

look great as well!
 
@ jcb maybe the b7 work ok on your car (2 litre) and im not meaning to sound like im dissing your car ... but honestly there not upto hard driving on a 450-500hp s4 or rs4 from what ive had and others, Ive experienced a few different set ups on RS4 B5 , B7, STOPTEC, AP, Ceramics , porsche.... porsche seem like mite be a good compromise in braking and $$$$, we have this set up on our Project HULK s4 at 750hp, ive not drived the car myself but reports are good, also a friend has same on a 510hp s4 that performs well too, the RS4 B7 are fine for everyday but if you push are crap and no good at all on track

do look great ! Just think for the money and if i was to do the brakes again id defo go a different route, maybe ok for OP as not sure on his spec and use or abuse!:laugh:
 
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What exactly makes them crap? Disk size and pad compound are the two most important factors. All the caliper does at the end of the day is squeeze the two parts together, and will have little effect on performance so long as its sized correctly.

The b7 disks are HUGE so all that really leaves is pad compound?

Which porsche calipers are you using? A lot of them seem to be designed around 330mm disks.
 
ive always thought the same aragorn ? to be honest im not sure, but all say it, that have used B7 set up hard

the oem b7 disc are vented and drilled but has not got directional vanes to aid airflow, there ok until hot but once hot there bad (1 stop from 150+), could be a combo of bad venting and not a great grade of steel that the disc is made from, race pads and Srf fluid help but still not great

Tarox do a B7 disc replacement in 3 different types and are vented and has direction vanes id like to try to see if this is where the problem is ? also someone told me as the B7 are 8 pots and hold a much greater volume of fluid, a upgraded master cylinder should be used, again would like to try

ill find out what the porsche set up is
 
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Si, the Phaeton cooling ducts aid disc cooling on the B7 discs.

I did a track day not so long ago in my 420bhp S4 with B7 RS4 brakes up front and B6 S4 brake discs (+ Trig's brackets) at the back. I had no problem with my brakes whatsoever, whilst all the other cars around me were cooking theirs. My mate with a track prepped 993 commented on how my brakes felt like they had more stopping power than his, and considering the weight difference of our cars, that's saying something!

I'd say this set up would be fine for you Lewis. Only downside is a very very very progressive pedal feel. My wife's Yaris has more initial bite! But despite that, when you step on them they do shave off incredible amounts of speed.
 
yes agree blue thunder...have heard the phaeton ducts help as my mate has on his s4 (500) with the porsche set up but he also said he noticed a loss in the rain ? . out of interest what pads you using ?
 
Im with si on this, im really not a fan of the b7 setup, my car was running a solid 470bhp and the brakes just couldnt shut it down at all, i have been told that the master cylinder is the likely culprit.

Im now running 625bhp and i seriously doubt my brakes will be up to the task, i have gone from b7 discs and pads to phaeton discs with ferdoro pads and racing blue fluid, i hope this helps. I think the 6 pot porsche brakes will be more suited to the s4 and also a decent match to the master cylinder.
 
the porker set we are using on our project s4 Hulk car is 993 gt2 4 pot cailpers with EBC pads and 322mm drilled disc and vented with rs4 b5 rear disc and pagid pads, must be noted this is a pure track car completely striped so very much lighter.
 
yeh thats not really representative then i guess.

You've basically got standard sized S4 disks, with a fancy caliper.

The caliper wont really gain you anything in terms of thermal mass, it'll improve feel but thats about it. So one would imagine the reduced weight is whats making the difference.

I hear the Master cylinder stuff bandied around a lot, but the piston area on the B7 caliper is pretty much identical to that of the standard HP2 caliper (it has more pistons, but they're much smaller), so its well within specifications of the original master cylinder.

People seem to have this idea that more pistons somehow make a difference to the performance of a braking system. What actually matters is you have CORRECTLY sized pistons, and a disk and pad combination thats large enough to handle the heat generated. 8 pistons isnt neccesarily any better than 4. Larger numbers are simply used to ensure more even clamping force across the pad surface when large pads are used, which makes the brakes easier to control/modulate.

I dont believe theres anything wrong with the B7 caliper or its disk (barring the cracking issues from the drilled disks). I suspect all the problems people have are down to the completely wrong pad being chosen for the work the brakes are being asked to do. If your on track with 600hp, some "fast road" pads simply arent anywhere near the correct compound, in the same way you wouldnt fit some standard Audi pads on a DTM car.
 
Speed or power has nothing to do with braking unless you are forgetting to lift your right foot when braking.
weight COMBINED with speed is the issue.

A bone stock 993 GT2 weighs less than my 1.8tqs as do a lot of the Porsche line up. Add my fat *** and I guarantee you it weighs more.
its the reason they didnt feel that they need discs over 330mm in most applications until they brought in the 350mm + 6 pots.

Can't comment on the performance of one brake versus another as they are on different cars with different pads/fluids/lines etc etc

But you cant say the 8 pot Brembos are bad calipers, they occupy pride of place on pretty much all the high end line up of the VAG and Lambo line up.
pad choice can make a good caliper suck.
so can fluid choice.
so can hoses and a crapped out MC
so can tyres

I drive my car quite hard and enjoy nothing more than a B road assault with plenty of hard braking.
I had a spot of sport with a new M3 down a stretch of the A697, all legal speeds you understand. he may have had much more power but without a straight to use it and without four wheel drive he was stuck looking at me in his mirror...until he outbraked himself on what I can only assume were ****** brakes judging by the smell! he then enjoyed looking at me through the windscreen.

you can cook any brakes if you try hard enough.

I have never had warped discs but have heard they can happen on B7's
never had complete brake fade (but did on the previous calipers)
never had a master cylinder issue even though I run a 1.8t MC on 8 pots, I have less than an 1" of travel and then several inches of modulation that will detach a retina if you are not careful. if you have more than this then you need to sort your fluid and lines out not blame the MC
never had any cracked discs
pad wear is good modulation is good, I dont have to brake as hard to stop from normal speeds and hence save pad life for the nasty stuff)
braking from cold is good
braking when hot is even better (yellow stuff)

I paid less than £1000 for B7 fronts and B5 backs with custom lines.
You could spend a lot more or a lot less but for a bolt on system with no spacers/adapters you will be hard pushed to match the Brembo 8 pot for swept area, piston area/capacity/clamp potential or cost (especially given the number of B7's getting broken).
 
Thanks to everyone for all the advice and good discussion, here is a bit more background.

In the past I have spent a lot of time messing around with brake upgrades on a variety of cars, and for normal road use OEM pads and disks are normally pretty hard to beat, they generally give nice all round performance, good from cold and reasonable when hot. The EBC stuff I currently run is better than OEM once up to temperature as it can stand a little more abuse. I can get two high speed stops before fade where the OEM setup was only good for one, but they are really wooden when cold and even when warm they don’t have the same feel the OEM setup did (I had the braided lines with the OEM setup initially).

I looked into the Porsche setup as it is cheaper than the alternatives, but you end up with a mix of special calliper mountings and unusual pad/disk combinations, or a specially machined disk, all of which I would prefer to avoid. I also looked at an AP setup for the front, and I am sure that would be great, but they are eye wateringly expensive! Also they are non OEM. I finally settled on the idea of B7 RS4 setup for the front. My thinking is that that there is a lot more metal in those disks, the callipers are a straight fit and I get a nice OEM pad/disk combination. Hopefully they should be up to my fast road use, plus they are from the Audi range and look right on the car.

So I am hoping to get a set of second hand B7 RS4 front callipers, recondition them and shell out on some new OEM disks with the “good” (read expensive) Pagid pads which I believe are fitted as OEM. In the future if I run out of brakes I can look into changing disks and pads, but really I am not going to get any more metal/swept area inside my wheels. My S4 is a 2000 facelift model so it sounds like I can exchange my current rear callipers for reconditioned units and use them plus the brackets to fit the B6 S4 rears. Where can I get some of Trig's brackets?
-----
Lewis
 
yes i agree JCB with most, but power defo has a factor, with as you rightly point out weight, as you can go much faster with more power and need to press harder for longer to brake for a turn for instance , ive had my setup completely fade both on track and on road many times, they really dont give me confidence unless not hot

think we all drive hard as own tuned cars some are easier then others on the brakes, on my last track session 10 laps max was what i could do without needing to come into the pits to let the brakes cool, my brakes as well as the whole car is kept in top condition no matter of cost in terms of oils fuilds and pads, you need to try a ceramic set up on a b5 to know what good brakes are or even AP setup far better, i know the cost is much more then what you paid

B7 is far better then stock rs4 b5 brakes but not what id fit again as the porsche set ups seem cheaper and also pads are and ive not heard of warping or cracking issuses at all.
 
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Lewis, OEM pads are made by pagid but im sure there not same compound as there own branded cheap blue boxed pagid pads, the oem are better.
 
I have read that there are different varieties of Pagid pads, there is a VAG specialist reseller called volkswizard that does a lot of business on Ebay who say. “Genuine Audi brake pads are made by Pagid and cost £250 but we can't get much of a discount so we are able to offer compatible pads also made by Pagid which are fine for road use”.
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Lewis
 
two cars doing 100mph about to brake for a turn....it matters not one bit which one got to 100mph the fastest.
more powerful cars don't corner faster than ones with less power and they don't stop any faster than ones with less power.

they are all brembo anyway.
just get your pad choice and disc size right

I would always avoid custom carriers/adapters and machined disc combinations especially since there are some excellent bolt on options.
couldn't care what is written on the caliper personally
 
no your missing the point in what im saying, a 500hp car would be at the corner at 140mph where a 300hp car mite only get there at 100mph

so more heat and friction is needed to be applied in order to make the turn
 
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IM sure i bought my last set of pagid from that guy of ebay, there no where as good as OEM
 
Getting a little off topic here, but usually damage to disks like cracking and particularly warping is caused by a high thermal gradient across the disk (rather than the entire disk). Brake pads by nature of the materials they are made out of are not that heat conductive so don’t radiate heat well, they rely on contact with the disk to conduct the heat away and radiate it to atmosphere cooling the whole system.

Disks usually crack or warp as a result of being used hard immediately prior to the car being parked, so the pads, disk and calliper are stinking hot, the disk stops turning and the section of the disk that is “covered” by the pads and calliper stays stinking hot and the rest of the disk cools quickly in the breeze. Clearly the larger the swept area of the pads, the more of the disk is covered, so with an 8 piston setup this kind of thing could possibly be more likely, pads with a hotter running compound would make this worse. For this and other reasons I always try to do an “in lap”, driving the last mile with gentle braking and off boost to let everything cool down.

Can anyone advise me where I can get a set of Trig's brackets?
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Lewis
 
good info there lewis ... i also try to cool things down as you say both on track and coming home lol
 
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