Brembo Big Brake retrofit kits for E28/E23/E24

[Ken H.]

Correction here, Tom.
Lucifer's Hammer is running the brake setup from the Euro E34 M5 3.8 liter.
This has the 345 x 32 mm directional 2-piece front rotors and the 328 x 28 mm vented rears.
Front calipers are 4-pot (2-piston); rears are 2-pot (single piston). Don't recall offhand what the piston diameters are.
Master cylinder is a 25mm from the E32; stainless lines thruout.
This setup was chosen to get maximum swept area; tradeoff is the front calipers are quite heavy, so the whole setup didn't do unsprung weight any favors.
Front caliper: 13.15# (per side)
Front pad: 4.59#
Front rotor: 21.82#
ATM, I don't have the rear component weights at hand, but they should be available on the web or in the forum archives.
This arrangement mandated using a 17-inch rim, combined with 2.5 mm spacers at the front.
As set up, the inner barrels on the Style 5s clear the calipers by maybe 3 mm, so not a lot of room to spare.
Given that LH is/was set up for autobahn-type use, I have yet to see any handling or brake fade issues coming off of Colorado's passes.

HTH

[tschultz]

I didn't realize your rear rotors were bigger dia than my fronts! Very similar to E46 M3 rotors.


Also, I will mention our D4C Sponsor AAS this year was working on a similar brake solution aimed more for E34 owners. Take a look at what they are doing as it is somewhat similar.

[BenGerman]

removed to keep it more readable.

Weight distributions: not considered in the calculations. My numbers are the simple distribution of brake torque between front and back. The weight distribution of the car will of course affect the behavior of the car under brake load.

Idea behind this: the idea is to offer an affordable solution for big brake upgrades. As you say, the floating 540i calipers are great. Plenty of people running them (me included on the 535i) with great success.
I was trying to provide a solution for the people that want more fading resistance and durability from their system. The E31 calipers are stupid expensive ($700+), the E34 Nür brakes that Ken used are even worse and impossible to find. The Cadillac fronts can be bought for $15-25 in local scrap yards according to my latest research. Pads are cheap and a ton of them available. The surface area of the pad is considerably bigger than the pads of the floating E34 calipers, the rotors are larger.
The E34 Nür and E28 M5 calipers are boat anchors, made from cast iron. The modern solutions with fast AL calipers will allow to stay in the same weight range with bigger rotors or be significantly lighter (see Kens example).

The situation is even worse for the E23 guys. There is virtually no upgrade available besides the E32 Rears. The fronts won’t even fit. The cars are heavier and when moved somewhat fast reach their limits pretty quick. When chasing the E28 M5 Crew this year at the vintage on Rt 209 in my M7, the brakes were done by the end of the drive. I was braking as late as road conditions would allow, still there was no chance for the brakes to cool down.

Brake bias: how did you adjust the bias? Since the MC is crossed (FR and RL on one outlet, FL and RR on the other), you would need a pretty complex plumbing, no? Curious if there is a solution out there.

[tschultz]

Fair enough. Cool to offer for E23. Lighter is always better but I get stuck on the wheel size and replacement cost. It is nice to store the car on cheap 15's if needed.

For brake bias, I was lucky enough that my 633 didn't have ABS so I replumbed the system front to rear as you describe with a few lengths of flexible brake line and metric fittings. This was done in the engine bay when I had the engine out and provided a location for a bias valve. I suspect one could remove the ABS module power and replumb at the module if they really wanted to remove ABS on ABS equipped cars. I suspect it is more involved than this, but at least the e28 ABS is quite primitive with very few inputs. With some fittings and new brake hoses you could probably easily do this in the front of the engine bay of the e28.

Currently an abs sensor or hub is preventing my system from working so I don't have abs on the 535is. I was going to see how the bias is set at the track before reinstalling the bias valve.

[LuckyHenriksen]

Thanks so much for all the effort you are putting into this project! I am hoping that eventually there is a set of brackets offered for the E23 to get an upgraded front caliper on there

[BenGerman]

This thread is not dead. I added a couple more rotors to the collection, the stack is now about 7 feet tall.
Finally came to the conclusion that I can change up the offset (76mm) and don’t have to stick with the E28 specs.
The main issue we kept having with the 76mm offset was that the Cadillac calipers would always hit the factory mounts and the only way to solve it would be going to a larger rotor. That would then limit the wheel selection to 17” three piece wheels with thin barrels, which wouldn’t help 90% of the people here.

New in the game:

Euro E46 M3 CSL 345x28mm (53.5mm Offset)
Euro E46 M3 325x28mm (53.5mm Offset)
E82 135i 2 piece (63mm Offset)

The 53mm ones need a 10mm spacers for sure to clear the wheel face. It seems like the E82 rotor with the ATS caliper could be the answer I’ve been looking for, at Least under a 17” wheel.
The 325x28mm will work with the ATS under a 16” Style 5 with a 15mm spacer.





On a last note, the combination of Cayenne caliper, 345mm rotor and E48 wheel is a lot lighter than the factory M5 brake/wheel setup.

[gaza01]

I'm currently looking into doing this using the 996 rear calipers. I offered them up to e34m5 rear discs but the pad sweep was way off. I've just ordered the e38 750 rotors which should work better for pad contact. Will see how I get on with them. If they work then it'll be a case of getting the bracket made up

[BenGerman]

I'm currently looking into doing this using the 996 rear calipers. I offered them up to e34m5 rear discs but the pad sweep was way off. I've just ordered the e38 750 rotors which should work better for pad contact. Will see how I get on with them. If they work then it'll be a case of getting the bracket made up

Interesting, let me know how it goes!
The Boxster with the 300x20mm and the 996 Turbo with the 328x20mm rotors were a perfect fit.








The piston size is the same for all three rear calipers: 996, 996 Turbo and 986 Boxster. The only thing that varies is the pad size and the mounting height.
So in case it doesn't work out, might be worth looking into that.

[gaza01]

I'll check when i get in tonight to see what 996 calipers I have but from the pics the pads in mine are a bit smaller from memory.

[euroclassicmotors]

Hi BenGerman,


This might be helpful for your project.

I have done this system about 5 years ago on E34M5
for a good customer of mine.

The System I did is Front E39M5 345X32mm rotor with
330x20 rear.

Feedback: The bias is right under ~60x40.

I strongly suggest you to move to the larger rotors for
the obvious reasons.

Do not do your system using the 300X28 garbage rotor
which overheats in no time and warps....

Why everybody is hang on this rear E34 540/M5 system ?....
20 years ago sure it was "The Upgrade" but no more...
the 328x20 M5/M3 rotor is win win solution.

Front 345x32mm are Directionally ventilated
Rear 330x20mm are also Directionally ventilated cooling
system.


Front Rotors do have 3mm rust ring which is not problem at all
Rear rotors have 0 (zero) rust ring and because of that makes the
rotor from 328mm to 330mm.

The car stops very very evenly without the very very bad nose
dive which is typical for E28 and E24.

Weight: Sure the larger rotors do add little weight but that matters
only for those who race against the Clock !!!!! which is not the
case with absolute any road ongoing M5 enthusiast...

The road ongoing cars must get larger rotor so that way you can repeat
the stoping exercise over and over and over again without any rotor
warpage and overheating the pads.

Just a suggestion. I am trying to post picture.

Regards,
Anri

[BenGerman]

Anri,

What calipers did you use front and back? What wheels cleared that combination?
Did you use the European 2 piece rotors?

I think the unsprung weight plays a big role in this.

The E34 M5 or 540i system is great for hard street use. It’s even been used on the track successfully.
Anything with more brake torque or surface area will mostly be noticeable in track applications with sticky tires and the need for more long term heat resistance. Keep in mind that you can lock up even sticky 225s with the E34 system, so there is plenty of brake torque available. Your main advantage is that you can beat on the system longer before it overheats.

The added weight from calipers, rotors, bigger wheels and tires will be noticeable driving for sure.

What kind of use does the car with your setup see?

[gaza01]

The calipers i have are like the black one in your pic...so normal 996 ones im assuming?

[BenGerman]

The black ones in the picture are the 986 calipers.
What’s the part number on yours?

[euroclassicmotors]

Anri,

What calipers did you use front and back? What wheels cleared that combination?
Did you use the European 2 piece rotors?

I think the unsprung weight plays a big role in this.

The E34 M5 or 540i system is great for hard street use. It’s even been used on the track successfully.
Anything with more brake torque or surface area will mostly be noticeable in track applications with sticky tires and the need for more long term heat resistance. Keep in mind that you can lock up even sticky 225s with the E34 system, so there is plenty of brake torque available. Your main advantage is that you can beat on the system longer before it overheats.

The added weight from calipers, rotors, bigger wheels and tires will be noticeable driving for sure.

What kind of use does the car with your setup see?

Hi Ben,

The car I installed this system is fast road car. The tires size is 255 40 17
T-Stars 9J all around with Pilot Sport, soft compound brake pads are used

I see your point with the unsprung weight but but but never forget how
many people have you seen to race against the Clock, Ben ?,with E28M5 ?
where are they ? and if you see them on the track they are in a Blue group...
saying at a local caffe shop meeting that, one, visits the track, sure, what's
your lap time ? At Buttonwillow if I see you under 2min with E28M5 then
its worth to talk about how to improve the car etc..but if you are
2.15min then even without calipers, wheels, rotors not worth to talk about
unsprung weight...

There is another trick which many don't realize is that the E24M6/E28M5
are very nose heavy cars. at static my E28M5 was something like 53-54% front..
so do my E24M6. So the rear is light under braking. And why I do like the rear
tire on the M5 to be 245 40 17 rather than 225.

If you think the OEM caliper is boat anchor and the weight is about 12-13pounds
but dont remember exactly..the Porsche caliper is ~5.6 so here you go you save
5-7 pound of were are added to the larger caliper so its not really that bad if
you think so unsprung weight will remain very very close to the OEM but again
that is very neglected....

The Porsche part# have to check I forgot something 424 421 but need to check
for sure...they are from Boxter S model and purchased them from Porsche junk
yard in TX.

The E39M5 rotor I used is std because my customer did not care about the Euro rotor.

Why the E39M5 set up is win win because the rotor is deep down as opposite
of the E46M3. That sad with the E39M5 rotor you will be able to use variety of
wheels

I noted something I would like to suggest. On one of your pic you have the caliper
a lot of room between the rotor ring top area and the caliper. Make sure you
leave about ~1.5mm so that way the pad will cover all the way the surface ring
and leave no rust ring.

I looked over just like you every single possible avenue but kept coming back to
E39M5 set up with the Porsche calipers because made most sense from money
aspect and also parts availability.

The E34M5/540 rotors are not Directionally ventilated. I can assure you that with
sticky tires and a driver that laps under 2min at my home track the E34M5 will be
out of the window...

On my track E24M6 I do have 315 rear tires on front 275 NT01. I do have Brembo 332mm
front and 330 rear, I can tell you that much, I am moving to 355 square because the
system I use is maxed out. 355 Stop Tech aluminum hat rotor is lighter than my 332 Brembo.

Again, the gains from repeatedly stops and the fact that rotors will not warp, and the
system will last so much longer over rights the few pounds added which no one will
never ever take advantage from....


Regards,
Anri

[nik77356]

Man, I really need to be getting back on here more often. I am just now seeing this thread. I am very interested in a kit like this for the race car (I race against the clock, and others, as Anri suggests we don't exist, FWIW).

[BenGerman]

Hi Ben,

The car I installed this system is fast road car. The tires size is 255 40 17
T-Stars 9J all around with Pilot Sport, soft compound brake pads are used

I see your point with the unsprung weight but but but never forget how
many people have you seen to race against the Clock, Ben ?,with E28M5 ?
where are they ? and if you see them on the track they are in a Blue group...
saying at a local caffe shop meeting that, one, visits the track, sure, what's
your lap time ? At Buttonwillow if I see you under 2min with E28M5 then
its worth to talk about how to improve the car etc..but if you are
2.15min then even without calipers, wheels, rotors not worth to talk about
unsprung weight...

But then again, what is worth optimizing for a street car first? Brakes or unsprung weight?

Unfortunately Buttonwillow is 2400 miles from my door or I'd give it a try. Based on your numbers I's expect to find myself in the high 3 minutes.
Just kidding but you get the idea.
I've done a couple AutoX in my car, but other than that it's spirited road driving.

Which doesn't mean that there isn't people out there looking for solutions of cheap and easy big brake upgrades.

There is another trick which many don't realize is that the E24M6/E28M5
are very nose heavy cars. at static my E28M5 was something like 53-54% front..
so do my E24M6. So the rear is light under braking. And why I do like the rear
tire on the M5 to be 245 40 17 rather than 225.

That was my biggest complaint when running in the AutoX. Even with the full Dinan Suspension setup, including sway bars the car nosedives like crazy under hard braking conditions. The weight distribution might be one point, but keep in mind that the factory brake setup also has a 73.4% Noose heavy setup!
Just to compare, E34 M5 is 69.15%, E46 M3 is 60.6%!

The issue I ran into is wheel clearance.
I can build a system for my car with Motorsport wheels, great.
But then all this discussion was for nothing.
Most people run their street cars on 16” wheels. Some people have 17s.
The goal is to come up with a system that fits the majority of the people, is an upgrade over the current options and doesn’t cost an arm and a leg. And that’s where we running into an issue.

If I take the Boxster calipers all around and combine them with a rotor that fits a 16” wheel I will have a weaker system than the E34 upgrade kits.
I can use the Turbo calipers but then the whole upgrade gets unaffordable.
I can use the ATS calipers, but they won’t clear with the deep E28/34/39... rotor offset.

You get the idea.

Building a one off solution for race cars is somewhat easy.
Many people (including you) have done it successfully.
There is a ton of different approaches to it.

Why I invested all this time into researching all the options and ordering a ton of rotors is the fact that I want the system to make sense from a technical standpoint.

If you think the OEM caliper is boat anchor and the weight is about 12-13pounds
but dont remember exactly..the Porsche caliper is ~5.6 so here you go you save
5-7 pound of were are added to the larger caliper so its not really that bad if
you think so unsprung weight will remain very very close to the OEM but again
that is very neglected....

Let's neglect the pads for now.

E34 M5:

Caliper & bracket: 5,100g
Rotor: 9,400g
Total: 14,500g

Factory M5:

Caliper: 5,000g
Rotor: 8,600g
Total: 13,600g

Boxster S Caliper + E39 Rotor:

Caliper: 2,660g
Adapters: 200g
Rotor: 12,000g (US single piece Version, EU 2 piece = 10,400g)
Total: 14,860g

Now add the weight of the 17" wheel to that:

16" Style 5 M5 wheel: 8,600g
9x17" Style 21 Wheel: 9,400g

Plus another 500-800g on the tire. So you easily added another 2-2,500g to each wheel compared to the E28 M5 setup.
Again, I'm not trying to say that it makes you faster or slower, but it impacts your cars handling.

The Porsche part# have to check I forgot something 424 421 but need to check
for sure...they are from Boxter S model and purchased them from Porsche junk
yard in TX.

That's very interesting. With the Boxster S front setup you actually don't get a higher brake torque than with the E34 M5 system.

Assumptions: 1000N Input Force, 25.4mm MC, 0.4 Pad Friction Coefficient

Boxster S clamping force: 8,978N
E28 M5 clamping force: 9920N
E34 M5 clamping force: 11160N

Brake Torque:

Boxster S, 345mm rotor: 571,095 Nmm
E28 M5, 300mm rotor: 496,000 Nmm
E34 M5, 315mm rotor: 578,089 Nmm

So your only real advantage is the bigger mass and surface area of the 345mm rotor.
The pads are basically the same surface (swept) area.

Are you running Boxster calipers all around?

The E39M5 rotor I used is std because my customer did not care about the Euro rotor.

Why the E39M5 set up is win win because the rotor is deep down as opposite
of the E46M3. That sad with the E39M5 rotor you will be able to use variety of
wheels

He should, It's 1,600g (Whats that, 3lbs?) per rotor!
The reason why I'm considering the option of the E46 Rotors is clearance for the calipers to the strut. The wheel choice will be limited, correct.

E39 M5 wouldn't me my first choice for the rotors, more to that further down (E60 550i).

I noted something I would like to suggest. On one of your pic you have the caliper
a lot of room between the rotor ring top area and the caliper. Make sure you
leave about ~1.5mm so that way the pad will cover all the way the surface ring
and leave no rust ring.

That is correct, good input. We have considered that later on.

I looked over just like you every single possible avenue but kept coming back to
E39M5 set up with the Porsche calipers because made most sense from money
aspect and also parts availability.

The E34M5/540 rotors are not Directionally ventilated. I can assure you that with
sticky tires and a driver that laps under 2min at my home track the E34M5 will be
out of the window...

As mentioned above, I don't 100% agree with your choice of the Boxster S calipers.
You are reducing the effective torque that your system can apply. From a technical standpoint, the system is "weaker" than the E34 M5 setup.
Heat dissipation of longer periods of time is where your experience comes in, I can not make any statements in regards of that.

Here is my question to you. Why not run the following setup:

Cayenne 955 calipers: 4430g
Adapters: 200g
Rotors E60 550i: 10,200g
Total: 14,830g

Same weight as the current setup on the car, 4 times the swept pad area, same rotor diameter, 30% more clamping force.
Initial investment is maybe $200 more for the calipers.
The rotors are mass produced, aluminium hat, cheap ($280 for a set) and readily available.

This way you would have a system that outperforms the E34 M5 brakes for sure.

On my track E24M6 I do have 315 rear tires on front 275 NT01. I do have Brembo 332mm
front and 330 rear, I can tell you that much, I am moving to 355 square because the
system I use is maxed out. 355 Stop Tech aluminum hat rotor is lighter than my 332 Brembo.

Again, the gains from repeatedly stops and the fact that rotors will not warp, and the
system will last so much longer over rights the few pounds added which no one will
never ever take advantage from....

Regards,
Anri

So my question back to you is: How do E36 M3 guys do it on the track?
Same pads & calipers as the E34 M5. 315x28mm & 312x20mm rotors.

355mm rotors front and back, are you running 18" wheels then I guess? I couldn't fit those in my 17" 3 piece BBS E48 wheels.

Let's discuss Anri!

[euroclassicmotors]

Let's discuss Anri!

You are on a mission for sure....

But before I reply to you I would like you to answer me
2 Questions I have for you.

1. Are you trying to put together a kit up for sell or ?
2. Budged build for max performance ?

Regards,
Anri

[BenGerman]

Let's discuss Anri!

You are on a mission for sure....

But before I reply to you I would like you to answer me
2 Questions I have for you.

1. Are you trying to put together a kit up for sell or ?
2. Budged build for max performance ?

Regards,
Anri

Both, that's why there is so many options I looked into.

1. Goal: Affordable performance solution to compete with Brembo E31 calipers, but better pad selection and cheaper (the E31 Brembos go for $7-800 now?)
2. Goal: Max performance for under $1500.

[gaza01]

The black ones in the picture are the 986 calipers.
What’s the part number on yours?

Theres 2 numbers on there
996 352 421 & 20.667.01

I’ll offer the up again on the weekend to double check and get some pics as well

[euroclassicmotors]

Ben,

First note I have is AutoCross does not require good brake
system so not really a measuring tape from your experience.
Taking E28M5 to autocross corse is like taking an elephant to
climb 5 story building thru the stairs. Take your M5 to Mid-Ohio
and then you will find out a lot of imperfections.

A good direction of making the M5/M6 system for the better would
be more brake in the back and less up the front meaning absolute
opposite of what you are trying to do. You keep pushing for front heavy
braking and all of your calculations and approach do lead to that.

Yes, the E34M5 single piston caliper does have a little bit more
torque than the front Porsche Boxter S 4 piston caliper and I was
aware of that when I did this but my goal was more brakes in the
back.

Yes the bias is not controlled via adjustable race knob from inside but with
increased surface friction pad and 330mm rear make it a stronger braking,
and very little less clamping torque to the front shifts the bias towards the
back and make the car to stop a lot more even.

I can tell you have not been into E24M6E28M5 with more bias in the
back so that way under heavy braking the nose of the car is not heavy
and that will impact the suspension set up as well, and making the
classic M5 to stop more evenly without nose heavy is easy on the suspension.
Never forget under heavy braking the asphalt surface is never
smooth, so those small impacts will affect the suspension compression.
Making the front nose heavy via more brakes in the front means that
225 or 235 tires will get more heat, consider that as well.

Again the E28M5/E24M6 do much better with less brakes on the front and
more brakes in the back and again you are trying to do opposite.

In your project you should never mention wheels...do you really think
if E28M5 owner likes for example AC Schnitzer wheels in 17" do give a
f that they are 1-2 or 3 pounds heavier than the OEM 16" wheels ? the
answer is no. E28M5 is again not used by E28M5 owners in a race form
rather than restored clean to enjoy piece of history on a Sunday local
car show. And even if those who daily drive there M5s do not need race
set up because they are not racing on the street. Even one takes the
M5 to the track do you really think they drive for 10th of 10th ? nope.
How many E28M5 owners do track their cars and talk about lap time ?
answer is none and if they do 3min on at button willow that means you
are simply enjoying the track fun and not abusing the car.

I feel you have a bite of making a race brake system for street use...
because you are counting grams.

You mentioned E36 ? Sure go drive a fully gutter track prepped E36M3
and you will hate your M5 after that...even fully gutted the weigh
distribution on the E36M3 S52 is about 52% front on a 48% back. The
E28M5 in OEM form is 53-54% nose heavy. For your FIY I have tested on
the corner balance scales that 1% weight distribution is about 175-200pounds
so imagine now to reduce the weight distribution on the M5 2% we need to
remove nearly +/- ~400pounds from the front nose of the car or move the
engine back behind the front axle.

Also you are forgetting something very important when you say E36 race car,
a gutter E36M3 track prepped car is about give or take 800pounds lighter
than the E28M5. So the reduced curb weight on E36M3 with 315mm and
3XX mm in the back, put very aggressive bite pads and good cooling system
so that way when you nearly overheat the rotor for the next corner the system
is chilled and ready to take heat again and again.

How many E28M5 owners do have a race braking cooling system, none. How
many E28M5 owner do drive with a pads which have so aggressive bite that
is uncomfortable to drive around town.

Again, what I do like as a set-up you may not like it. But my preference is
more brakes towards the back which again you are trying to retain the nose
heavy braking system concept and you are not really making a change on the
OEM design, you are making it for the worst if you think..you aim for a lot of
torque to the front from technical stand point as you say.

Please understand I am not trying to brake your balloon with this project but
my cup of tea is different. E34M5 rear brake rotors was an upgrade back in
1995...but tooday I always prefer E39M5/E46M3 rear with the combination
of the larger pad to me its a win win.

Regards,
Anri

[euroclassicmotors]

Ben,

Yesterday I removed my rear wheel on my track E24M6 toy confirm my set up
and found that I have installed the Boxter S Front Caliper NOT the 422 part
number which is rear S caliper which do have the 30x28mm piston size(if not
mistaken).

The front Boxter S caliper do have a 40x36 piston size and have milled it
down about ~12mm so that way the caliper will match the 328x20 rotor and
with the front caliper pad I have zero rust ring and do benefit the larger size
pistons.

Keep in mind on our E28/E24 cars we do have a nice option, our ABS system is
4 channel and that is a absolute benefit to entire package as a set up such as pad
compound, tire size, caliper pistons torque choice list goes etc..

The massive variety of pad compound/s available for Porsche Boxter S is priceless.
and the pads are very very easy on the wallet.

I want to post few pictures for you but this forum does not offer an option to post
pictures...? I want to show you my initial brake system choice but pad options was
zero...or at least porterfiled had to make it all custom which sounded expensive.
The set up I mocked up was 356X32mm 6 Piston caliper and yes they fit under my
BBS E26 which are 17" inches, and have plenty of room to the barrel and the spokes.

Regards,
Anri

[BenGerman]

Ben,

First note I have is AutoCross does not require good brake
system so not really a measuring tape from your experience.
Taking E28M5 to autocross corse is like taking an elephant to
climb 5 story building thru the stairs. Take your M5 to Mid-Ohio
and then you will find out a lot of imperfections.

A good direction of making the M5/M6 system for the better would
be more brake in the back and less up the front meaning absolute
opposite of what you are trying to do. You keep pushing for front heavy
braking and all of your calculations and approach do lead to that.

Anri, have you checked any of the calculations that I provide in this thread or read a little deeper?

From the beginning on I have been saying that the E28 M5 setup is too front heavy in breaking, with a distribution of 73.4% up front.
If you check my calculations, I'm trying to get away from exactly that front heavy distribution and move the bias further to the back.
From my experience (and other on here) the cars feel great with the 68% front, 32% back ratio of the E34 540i.
That's the distribution I'm aiming for.

I don't need Mid Ohio to determine brake bias. AutoX or spirited road driving works great to find out if your car is nose heavy under hard braking.

Yes, the E34M5 single piston caliper does have a little bit more
torque than the front Porsche Boxter S 4 piston caliper and I was
aware of that when I did this but my goal was more brakes in the
back.

Yes the bias is not controlled via adjustable race knob from inside but with
increased surface friction pad and 330mm rear make it a stronger braking,
and very little less clamping torque to the front shifts the bias towards the
back and make the car to stop a lot more even.

See further down.

I can tell you have not been into E24M6E28M5 with more bias in the
back so that way under heavy braking the nose of the car is not heavy
and that will impact the suspension set up as well, and making the
classic M5 to stop more evenly without nose heavy is easy on the suspension.
Never forget under heavy braking the asphalt surface is never
smooth, so those small impacts will affect the suspension compression.
Making the front nose heavy via more brakes in the front means that
225 or 235 tires will get more heat, consider that as well.

Again the E28M5/E24M6 do much better with less brakes on the front and
more brakes in the back and again you are trying to do opposite.

See above, I have been. Even my own car.
Distribution with E34 rears and E28 M5 fronts is 65/35% F/B.
The tail gets significantly lighter at this brake distribution already.
I wouldn't change it any further towards the front than that for a car that gets driven on the street and under wet conditions.

In your project you should never mention wheels...do you really think
if E28M5 owner likes for example AC Schnitzer wheels in 17" do give a
f that they are 1-2 or 3 pounds heavier than the OEM 16" wheels ? the
answer is no. E28M5 is again not used by E28M5 owners in a race form
rather than restored clean to enjoy piece of history on a Sunday local
car show. And even if those who daily drive there M5s do not need race
set up because they are not racing on the street. Even one takes the
M5 to the track do you really think they drive for 10th of 10th ? nope.
How many E28M5 owners do track their cars and talk about lap time ?
answer is none and if they do 3min on at button willow that means you
are simply enjoying the track fun and not abusing the car.

I feel you have a bite of making a race brake system for street use...
because you are counting grams.

An owner that is going to upgrade to a performance brake system is for sure going to notice an increased unsprung weight.
I would rather mount lighter wheels than a big brake kit on my cars. Because it's clearly noticeable.

We can argue about that all day. My opinion.

You mentioned E36 ? Sure go drive a fully gutter track prepped E36M3
and you will hate your M5 after that...even fully gutted the weigh
distribution on the E36M3 S52 is about 52% front on a 48% back. The
E28M5 in OEM form is 53-54% nose heavy. For your FIY I have tested on
the corner balance scales that 1% weight distribution is about 175-200pounds
so imagine now to reduce the weight distribution on the M5 2% we need to
remove nearly +/- ~400pounds from the front nose of the car or move the
engine back behind the front axle.

Also you are forgetting something very important when you say E36 race car,
a gutter E36M3 track prepped car is about give or take 800pounds lighter
than the E28M5. So the reduced curb weight on E36M3 with 315mm and
3XX mm in the back, put very aggressive bite pads and good cooling system
so that way when you nearly overheat the rotor for the next corner the system
is chilled and ready to take heat again and again.

I'm not talking about a track prepped, gutted car.
The curb weight of the E36 M3 is 1460Kg, the Curb weight of the E28 M5 1410Kg.
Aggressive pads (which increase the heat induced into the system) and some light duct work. Factory break system works fantastic.
You are correct on the weight distribution, the E36 does have an advantage there, which is also compensated with a bias.
Same thing for the E46 M3 (60/40%). Would I want this brake distribution on a nose heavy E28 M5 on the street? Absolutely not!

Keep in mind that we have an additional challenge in our vehicles with the Master cylinder.
Our MCs use a uniform piston size and therefore uniform brake line pressures front & back. E36, E46, E31 and many more use stepped Master cylinders, such as 25/20mm or 25/22mm Front/Back.

The only way we can modify the distribution is piston surface area, rotor diameter and friction coefficient.

How many E28M5 owners do have a race braking cooling system, none. How
many E28M5 owner do drive with a pads which have so aggressive bite that
is uncomfortable to drive around town.

Again, what I do like as a set-up you may not like it. But my preference is
more brakes towards the back which again you are trying to retain the nose
heavy braking system concept and you are not really making a change on the
OEM design, you are making it for the worst if you think..you aim for a lot of
torque to the front from technical stand point as you say.

Please understand I am not trying to brake your balloon with this project but
my cup of tea is different. E34M5 rear brake rotors was an upgrade back in
1995...but tooday I always prefer E39M5/E46M3 rear with the combination
of the larger pad to me its a win win.

Regards,
Anri

See above, I never wanted to increase the ratio towards the front.

Ben,

Yesterday I removed my rear wheel on my track E24M6 toy confirm my set up
and found that I have installed the Boxter S Front Caliper NOT the 422 part
number which is rear S caliper which do have the 30x28mm piston size(if not
mistaken).

The front Boxter S caliper do have a 40x36 piston size and have milled it
down about ~12mm so that way the caliper will match the 328x20 rotor and
with the front caliper pad I have zero rust ring and do benefit the larger size
pistons.

Keep in mind on our E28/E24 cars we do have a nice option, our ABS system is
4 channel and that is a absolute benefit to entire package as a set up such as pad
compound, tire size, caliper pistons torque choice list goes etc..

The massive variety of pad compound/s available for Porsche Boxter S is priceless.
and the pads are very very easy on the wallet.

I want to post few pictures for you but this forum does not offer an option to post
pictures...? I want to show you my initial brake system choice but pad options was
zero...or at least porterfiled had to make it all custom which sounded expensive.
The set up I mocked up was 356X32mm 6 Piston caliper and yes they fit under my
BBS E26 which are 17" inches, and have plenty of room to the barrel and the spokes.

Regards,
Anri

So to get this right, you are running a Boxster S front caliper in the rear, with a 330mm rotor and a high friction pad?
What caliper & pad are you currently using in the front with the 345mm rotor?
Have you ever calculated what your Brake Bias is?

Let's compare the numbers and see how far off I am from your solution. I'm an engineer, I make decisions based on numbers.
I'm 100% confident your solution works for your car on the track.

That's why I'm even more interested in some more details.

[gaza01]

Mocked up a bracket today and offered up the 996 calipers to the e34m5 rotors. Apart from cutting the dust shield slightly they fit quite nicely.

Ben
I checked my caliper numbers and they are the same as your black ones. I think it was fouling the dust shield which is why they didn't fit before.

996 CALIPERS ON E28 https://imgur.com/gallery/w6YH5WE

[euroclassicmotors]

Hey Ben,

Sorry for the late reply. I have some notes to discuss.

Anri, have you checked any of the calculations that I provide in this thread or read a little deeper? From the beginning on I have been saying that the E28 M5 setup is too front heavy in breaking, with a distribution of 73.4% up front.
If you check my calculations, I'm trying to get away from exactly that front heavy distribution and move the bias further to the back.
From my experience (and other on here) the cars feel great with the 68% front, 32% back ratio of the E34 540i.
That's the distribution I'm aiming for. I don't need Mid Ohio to determine brake bias. AutoX or spirited road driving works great to find out if your car is nose heavy under hard braking. Distribution with E34 rears and E28 M5 fronts is 65/35% F/B. The tail gets significantly lighter at this brake distribution already.
I wouldn't change it any further towards the front than that for a car that gets driven on the street and under wet conditions.

Yes I checked your calculation as you say we are on the right pad but
I gave you a hint in my previous reply and I don't think you took it.

I'm an engineer, I make decisions based on numbers.

I am not feeling the love of how you approach things as an Engineer and
a Test/Package.

You say that you are happy with 65/35 ratio and you would not go to
lower ratio. But but but I approach things little different, you should
push and test and find out where is the limit of were it will have reverse
affect is what I have done from my end. Engineering approach is always
test the limit/s and then you make a final choice based on a real first hand
test. E28/E24 do have Terrible Wheel Base !!!!! at 103.3" inches.....and
a lot of overhanging weight up the front, yes rear is light but not that bad
if you have the spare tire in place, a 528e do handle 100000000000% better
than the E28M5, they are a lot more nimble, because the M20 based
motor is about 90-100+pounds lighter than the S38.

Based on the fact that the E28E24-S38 nose is so heavy then 65/35 beeak
ratio has to further come down as I prefer, my cup of tea to start is 60/40
with the stock 225 tires. 245 wight tires I would push down for ~56/44
ratio so that way to take advantage from the rear wider tire and with the
combination of leaving the stock sway bar in the back then its a win win.
anyway the bad trailing arm does not like too much bar in back, stock is
fine. Front heavy bar rear soft a sweet street set up.

Brake Pads: I would consider this as perhaps #1 from your project. I have
tested million times, any after market pads Textar, Jurid name it NOT
sold via your BMW dealer will always squeak ! who is that E28M5 owner
or any who wants to have the pads to squeak, nobody but all come with
penalty those OEM pads are a lot softer and they do overheat much faster
do get a lot of dust...and are not aggressive to the rotor. Get any after
market pads which don't make dust but then you get squake and eats the
rotor quick.

(60/40%). Would I want this brake distribution on a nose heavy E28 M5 on the street? Absolutely not!

See you don't like 60/40, but I do, because the advantages with the wider
rear tire is obvious. And always remember I noted to you and I don't think
you evaluate the benefits from 4 chanel ABS system we do have on E28/E24.
I take advantage from this nice option. E30s do have 3 channel and make
the rear braking heavy is tricky.

Another point you must consider that OEM type pads DO NOT have aggressive
Bite that said friction is Linear and that prevents from locking the wheel, and
with the pedal travel been linear do make the car to stop a lot more even and
for a specific given distant. When I installed 355 square set up on our E46M3
its nearly full weight car but track prepped Nick needed to adjust his braking
habits compare to stock system and that is for the better, because the light
pedal do stop the car quick, no need to push deep down.

Keep in mind that we have an additional challenge in our vehicles with the Master cylinder.
Our MCs use a uniform piston size and therefore uniform brake line pressures front & back. E36, E46, E31 and many more use stepped Master cylinders, such as 25/20mm or 25/22mm Front/Back.

See your causing a problem with your choice of calipers which now you have to
work hard to avoid. The Boxter S calipers do have 40/36, rear is 30/28 and the pedal
feel is not lost because you are not increasing the piston size up the front having
those big calipers you are testing. My friend Ed on his E34M5 put back in the days
AMGW211 front calipers they looked eye candy but when you drive the car it feels
like the system has air in and you have to pump several times and make it not pleasant
to drive, removed the AMG calipers and put StopTech 345x32 from E39M5 which was
so much better. Stainless Steel lines are Must in any brake system upgrade yea.

So to get this right, you are running a Boxster S front caliper in the rear, with a 330mm rotor and a high friction pad?
What caliper & pad are you currently using in the front with the 345mm rotor?
Have you ever calculated what your Brake Bias is?
Let's compare the numbers and see how far off I am from your solution. I'm an engineer, I make decisions based on numbers.
I'm 100% confident your solution works for your car on the track.
That's why I'm even more interested in some more details.

On my E24M6 track tool, my current set up is 332 front with 1-2mm rust ring
and 330 rear with no rust ring. So basically Square set.
(the 345mm E39M5 and 330mm rear is what I have installed on my customer's
E34M5)

So on the M6 my front calipers are F40 brembo and rear is the Front Boxter S
40/36 that said my pistons on the F40 are as well 44/38 but they are spread apart
from each other so that way will accept the longer pad.

So in another words you can say my set up is nearly square, stock E24 bias with brand
new E32 master cyl. My brakes are very hard and the pedal is hi meaning that it
start to grab from very early no pedal sink at all. But also I have converted my
system to vacuum booster, so the pedal consistent softness from the hydro system
is gone.

How is this system behave ? you go 100mph and then slam the brakes ABS starts
to trigger, but it is weird feeling...instead of the seat belt nearly braking your
chest ribs the entire car stops with less nose dive and rear holds without lift.
My point is that the ABS prevents the wheel from locking and the rear stops
the body a lot more evenly and you feel the car does not have the conventional
feeling of front heavy nose, (pads are race)

With the standard bias system the E28/E24 will always be heavier on the brakes
on the front even with square set, but we are tricking the system as you say with
pad size and also rotor size. Best is to install an adjustable bias but no E28M5 owner
will ever install...even myself the way I have dialed my braking system I have
absolute no complain and very happy, just need to increase cooling and rotor
size and make them 2 piece but that is not important at all on our discussion,
meaning 355 square will be a lot better and also save weight from my current
set up.

An owner that is going to upgrade to a performance brake system is for sure going to notice an increased unsprung weight.
I would rather mount lighter wheels than a big brake kit on my cars. Because it's clearly noticeable. We can argue about that all day. My opinion.

Engineers are very stubborn people I do know few which we always have
friendly debates for set up, and it's the package, Ben. Never ever look individual components
as you do in this case. I feel how heavy and biased you are on the unsprung weight.....
but but but its an individual component.

I am with you nothing wrong with having the unsprung weight as low as possible, again
I will show you one day what am I doing with my from suspension so I can remove the
Unsprung weight by at least 5 pounds.....per side but for now this will remain in pocket.

But it's package as I approach things, so let's put the scenario with your set up we put your
M5 on OEM 16" square with 225 the package tire and wheel is say 30pounds total. I put on the
car #2 E28M5 square 245 40 17 mounted on 9J wheels. The entire package wheel + tire is say
35pounds I am adding 5pounds more per corner so now we have 20 pounds added to the
suspension, yes you feel it for sure.

To make the comparison very equal we must put both models on absolute the same tire
compound and tire model.

We take both cars to the track or local twisty canyon road. I do promise you that you
your set up after the 3rd corner you will understeer and go straight off the road because
225 tire does not have enough grip to the handle very bad E28/E24 chassis design terrible
weight distribution and terrible short wheel base simply "Hammer" and also the 225 will
overheat in no time, the wider tire will handle the load much better and will give the
driver a lot more grip and confidence to turn eventually will lead to overheat as well but
much much much later down the road.

Also consider another fact, brakes which does not get hot up the front do not add additional
heat to the wheel and tire, more bias up the front aka 60/40 do add more heat to the
rotor for sure. On all E28/E24 the front tires overheat in not time and rear don't get nearly
as hot as the front because the front heavy nose.

So you can argue all day that the unsprung is what you prefer but there is no free lunch...Ben.
car #2 will be on the other side of the canyon because the level of grip will over right your
neglected unsprung weight.....

If you still/will want to argue ? Please call my friend Miki with his E36 2.8 fully tracked prepped
car at 2580pounds. From the longest time we had the same exact argument...He is so stubborn
on the unsprung weight....but in his case is even worst because it's not only that but also Rotating
mass...his car is 750-800pounds lighter than E28M5 as a gross cub weight (no driver)

His "Light weigh" set up was 8J wheels with 235 40 17 Kosei wheel stupid light....

Fast forward, to test the argument what test we did is we borrow Apex Wheels 9.5J and
mounded 255 40 17 so that way the tire has little stretch so that way the benefit is on
its near max potential. We put exact the same tire compound so to make the comparison
fair.

Yes the combo feels little bit heavier when you drive even on the straight. Back on the
track ButtonWillow, put the APP we have so to make the Telemetry data. After the track day we
sat uploaded the data overlapped it with the 245 40 17 from the previous times at Buttonwillow
and the current track. Keep in mind that we are increasing the size on MIki's E36 by 1
size up. In your case from 225 up to 245 is 2 sizes up but not only that, the 225 are
not optimum for OEM 7.5J tire side wall is waaaaay too tall for fast road spirited driving.

After the Telemetry data proved that the level grip thru the corner was obvious and the gains
to be had did increase not only the corner speed but affects the straight line speed because
of increased momentum. As of bonus the tires did hold the heat better than and maintained
more laps. After we did the test Miki said oh well lets order a brand new set via my Apex
account and the argument just ended in a favor of added unsprung weight and the rotating
mass....My point being to you is that you need to look always things as a Package.10 track+
days passed in several different tracks and kept improving, I never ever heard him talking
about unsprung weight of nearly 5 pounds per corner...he just talks about the lap times.

Sort of how S54 vanos system weights about ~3 pounds on the Valve Train. This weight is
absolute brutal number to have in the valve train. block the Vanos system on the S54 and
you will hate everything about that engine.....exact the same example. You remove 3 pounds
from the valve train at 8000rpm but the massive losses from the engine not having the
variable cam timing is so much more that 3 pounds less do have a very very negative on
the Package and make things for the worst and you will never ever feel the missing 3
pounds from the valve train rotating mass, what you will feel is Mini Van Toyota with
family will blow your S54 powered..

Never ever compare E36 nor E46 with 225 tires up the front....E28M5 in its form will
never ever be E36 nor E46.

My personal cup of tea for E28M5 is 9"Jx17" square set (BBS RS is what I like) with
245 40 17 tires square set up. 225 vs 240 tires from say Michelin is 2 pounds difference.
I don't have OEM 16" wheel to measure but my info shows that the weight is 18.9pounds (?)
My BBS 16 (Center) RS converted to 17" lips and barrels on 9J weight 19.3pounds. So
the tire combo with and a wheel is about ~3+/- pounds, this is so neglected for the
obvious grip gain offered from the wider tire.

The only way we can modify the distribution is piston surface area, rotor diameter and friction coefficient

Very correct because we don't have adjustable bias regulator and this is not an
option for road going Classic Sunday funday E28M5 owner, easy on the wallet as well.

Please understand I am not trying to argue nor picking up on you in absolute any way.
We have Tech discussion rather than forum fight. I have been dealing with these older
BMWs for ages now and I love them but I don't love how they handle...and we can do
so much to improve them up just to certain extend and accept for what they are.

On my track E24M6 I have cut the firewall and moved the engine back inside
about 15" inches but now that I am moving to steering rack and also all aluminum
suspension this will require me to move the motor even more so all together will be
about 25" inches. Also I am extending my wheelbase from already extended 105.5 to~108"
inches....so that way my S38 cyl #1 will be placed 100% behind the front axle, I have
done all that bloody work to Fix the E24/E28 bad balance...my E24M6 does not drive
like any E28/E24 becauseI have changed the DNA of the E24.

My heart is divided on 2 I am a Mercedes fanatic as well and I am not kidding you my
W115 240D Mercedes do handle much better and the car is a lot more Nimble when driven
with anger thru the corner because it has 108.3" Inches wheel base and even with the M110
R6 they handle much better than the E28M5. Put a tape as I have done and run the tape
from the wheel bearing across the engine and you will see that the the engine is 3 cyl up
the front and 3 back. On E28M5 S38 run a tape and you will find that the ~4.5 Cyl are
overhanging.

Cut a bracket and put 330 mm in the back from E46M3. For the test get 17 Inches wheels
and put 245 40 17 on 9J in the back try this set up see how you are gong to like it.
I do like the 40/36 front Boxter S mounted in the back.

I see you working on a 3D/Cad ? I would like to get and estimate of something I need
to be done on file. Thanks for your PM I will sent you an email very shortly.

Regards,
Anri

[euroclassicmotors]

Both, that's why there is so many options I looked into.

1. Goal: Affordable performance solution to compete with Brembo E31 calipers, but better pad selection and cheaper (the E31 Brembos go for $7-800 now?)
2. Goal: Max performance for under $1500.

Hi Ben,

Few options to share on your project, food for thinking.

I had exact the same bug as you have now and try to look
over similar option for the requested "Goal/s" Brembo

The eBay deals you could find years ago on Baxter S calipers was
about in range of $450 shipped because no one wanted those

Years pass and people started to cut brackets to fit them to
any make and model because they are cheap. The wrecking yeard owners
sneef that concept and raised the price for those a bit and then it
became hard to buy calipers for cheap to keep what you are after.

After many hours of continues re-serach I looked over and discovered
something very interesting which I should really have done from the
beginning.

Look over the Wildwood selection of 6 piston calipers they do offer.
link is bellow. You have good options of 4 piston calipers or 6 piston
calipers. Also they do offer them with large pistons so that way will
have the nice torque.

https://www.wilwood.com/Calipers/Calipe ... &pistarea=

The other very affordable option who I also had in mind was AP Racing.

https://pitstopusa.com/i-5071397-ap-rac ... discs%2Bap

What's not to like on this option here $277 for Brand New in a box caliper.. https://www.summitracing.com/parts/wil- ... AHEALw_wcB


One of the Wildwood 6 piston option is very nice and easy on the wallet, and
also its light to reduce the un-sprung weight without spending the national debt
of USA.

Then from Jegs you can get rotor rings in say 300 up to 335mm starting from 75
up to $120 with various vents options.

https://pitstopusa.com/c-135321-brake-s ... otors.html

Machine the caliper brackets as you do so far, Machine your own hats hard anodize them
and mount them on the rotor ring, and now we have 2 piece rotor with aluminum hat
which is so much better than the E34M5 options or what ever else option is.

The fact that the Porsche, Cadillac, AMG name it etc calipers are not available to purchase
sort of "now" or you have to wait till something come up on a deal coming from a wrecked
car or what ever the case might be. Those Boxter S calipers which are at least 5+ year old and will
perhaps need rebuild, clean up from minor corrosion etc. but that does not end.

One wants to restore them and buying spray can from pep-boys for calipers is a patch
to make them fresh..for just about 6 months and then the pain is off...then take them
apart and sent them to powder coating.....so now you are cents away nearly match the
Wildwood of 6 piston calipers Brand New in a Box.

The weight of the rotor will be win win and also the price. Via my SSF or World Pack account
the E39M5 or E46M3 rotor is in hi $170+ range and even the rep says all rotors now days are
made in China, I mean when I purchased ignition coils from BMW dealer for S38 B38
the coil says Made in China so nearly everything is made there but does not mean its bad
it's just the quality won't be as how it was from back in 1992.

The Wildwood Package"

- 6 piston caliper is in 5.25pounds range.
- ~310mm 2 piece rotors. Ring is about 7-11 pounds range,
- Aluminum hat 2-3 pounds including the hardware.

So the package combo rotor+caliper will be no more than
13-14 Pounds at max that put the E39M5 rotor 10pounds
each more per side. Even if build 345mm front and the weight
will grow to max 17pounds not more.

The wildwood brakes system. About 4-5 years ago when I
visited San Diego for family trip I always find and manage to slip
and spent all day at my friend Frank Fahey shop. On his
M6/LS he has wildwood brake system front and back but being
long ago I forgot the spec on the brakes. He gave me a a ride
and I was very very impressed how the car stops.

A year later or so when I completed this car E30M3 S54 https://www.euroclassicmotors.com/1990-hot-rod
I installed this off the shelf kit Wildwood front and back and
this exact front 6 piston calipers. Rear is not what would like to be but
works okay. Wanted my cup of tea more brakes in the back but its just fine.
This E30M3 S54 swap the curb weight is 3050 pounds.
The car stops really well without any brake overheat even driven at the
canyon with anger.
If remember correct the front rotor size is in low 300mm range (298mm)
but again its been years since I complete this and memory is lost.

If personally I were to start all over again of making budged BBK solution/kit
for the older Bimmers I would never ever ever ever touch those eBay calipers
that's for sure....

Just sharing my experience which might be helpful in some way towards your
final destination.

Regards,
Anri

[tig]

Ah, the old "overwhelm your opponent with pages and pages of blather" tactic.

TL;DR

[euroclassicmotors]

Ah, the old "overwhelm your opponent with pages and pages of blather" tactic.

Hi,

Not really opponent under your statement...rather
sharing something it actually takes time to test,
re-serach, purchasing parts, Spending money and
spending countless of hours...

pages and pages of blather

Those pages comes from long path someone took,
pages just don't come from the perfectly blue sky...
Perhaps you can write a Romantic Book on how
to swap S54 inside of an E28 but how about S85
with DCT converted to transaxle ? Now we don't have
a title nor single page from the up-coming and very long
and big "Blather" screen script...

Ben and I know the entire process...sitting and re-searching
those parts for days and days and nights and endless of hours
of search. Takes tons of notes on a paper and compare
it's not easy as many think...just grab a part and install it....

It takes dedication, countless of hours, time consuming and not
really seen many people do when develop something similar.
You lose a lot of money into testings, SSF account, WorldPac
orders, returns...etc Road going tests, track day alone is $500
from when at 5am you close the door from outside and walk
quite push the car with a friend because the exhaust is so
loud that will wake up the entire neighborhood which in most
cases leads to a potential problems all the way down to the time
you come back at 8pm. Fuel reserve is On and 3x18 Gallons of gas
are gone at the race track..for just testing...and you need to
re-adjust and then go back..

cek, I am not sure what you are all about with your post reply but
Ben and I we are on the same direction on the upgraded brakes system
and he knows what it takes and the list is very long and the notes are very
heavy which shows the long path one took...

Regards,
Anri

[VintageRacer]

Some great discussion here on brakes. One thing to consider is caliper flexing which will also cause pedal travel to increase. I had this problem on the race car and had to redo brackets and add bracing to keep the calipers from flexing. I've since upgraded to a set of AP Racing units. So beware using calipers designed for street use under track conditions, even monoblock or forged aluminum ones.

Anri is right that the tail does get happy under hard braking going into a corner. To fix this I had to install a smaller piston rear caliper, bias bar and dual master cylinder setup minus the booster. This setup gives a lot better feel and allows manipulation of the brakes at or near lockup. I also run Raybestos Race pads but unless these have at least 300-400F they basically won't do anything

[tschultz]

Anri is right that the tail does get happy under hard braking going into a corner. To fix this I had to install a smaller piston rear caliper, bias bar and dual master cylinder setup minus the booster. This setup gives a lot better feel and allows manipulation of the brakes at or near lockup. I also run Raybestos Race pads but unless these have at least 300-400F they basically won't do anything

I found this as well with E24, but E28 has better balance and not quite as much of an issue.

[euroclassicmotors]

Error.