mad4slalom
Senior member
as stated by the m devision guru on an m launch event, when questioned by a journo about the brakes on the m, he said ," i you are having issues with the brakes on the m coupe, you are not using them properly ! 
Porsche brakes
- Thread starter goon
- Start date
c'est donc un imbécile i don't known, but i leave here:
http://www.jedecouvrelafrance.com/f-1152.isere-la-route-napoleon.html
and 2 solutions:
-NO M, beacause a Clio RS is faster and have better brakes :evil:
- a M with big brakes kit
and why the 135i have bigger brake system???
olivierZ said:
i don't known, but i leave here:
http://www.jedecouvrelafrance.com/f-1152.isere-la-route-napoleon.html
and 2 solutions:
-NO M, beacause a Clio RS is faster and have better brakes :evil:
- a M with big brakes kit
and why the 135i have bigger brake system???
+1. I'll go along with OliverZ and GA41 on this. Whilst upgrading to better pads Goodridge hoses make for better braking, its painfully obvious that the set up is for road use (the Z4M is a road car after all not a trackday special).
I'll have to go the whole 9 yards and get a BBK fitted. painful but necessary.
To those who have the APR kit, do you need to change the master cylinder as well or is it a bolt on kit?
exdos said:
I'm not sure that you would necesarily get a shorter stopping distance with a BBL than OEM- thats down top tyres and suspension and driver- but you would certainly get better endurance (not withstanding to your ventilation mods on the OEM set up (did you get that inspiration from a 3.0L CSL race car?).
The OEM set up, even with better pads, braided lines and DOT 5 liquid has its limitations.
we whould do a repertoire of what set up is good for what use.
ChawenHalo said:
Just a quick point but you really don't want t use Dot 5 brake fluid: that is silicone-based, incompatible with any other type of fluid and will not absorb water, which is superficially a good thing, but in reality very bad, as any water in the system will remain as water and a) boil very easily and b) potentially cause corrosion. It is also relatively compressible compared with traditional brake fluid.
You will want either Dot 4 or Dot 5.1. For high performance/track use the best fluids are usually Dot 4. I use Motul RBF 600 mainly because I have a whole case of it ... but it is pretty high spec. high performance fluid, though not the best, it is a pretty reasonable price.
Regarding brake setup overall I have the AP big brake kit: 6 pot calipers on the front and 4 pot on the rear. When I got the car the brakes were pretty well shot, so I am replacing discs and pads this week: Performance friction disks on the front; OEM BMW on the rear (AP are out of stock) and RS29 pads all round; plus new fluid of course. Unfortunately I don't have experience of any other setup so won't be able to compare effectively.
mad4slalom
Senior member
I have no issue with M brakes on either the 3m or the 4m, both excellent, never tracked either though so dont know about that , only issue I have is that the first bit of pedal is sometime harsh and if applied quickly i find it over brakes so i then need to back off, is this what you mean by poor modulation :?
I'm not sure that you would necesarily get a shorter stopping distance with a BBL than OEM- thats down top tyres and suspension and driver- but you would certainly get better endurance (not withstanding to your ventilation mods on the OEM set up (did you get that inspiration from a 3.0L CSL race car?).
The OEM set up, even with better pads, braided lines and DOT 5 liquid has its limitations.
we whould do a repertoire of what set up is good for what use.[/quote]
Just a quick point but you really don't want t use Dot 5 brake fluid: that is silicone-based, incompatible with any other type of fluid and will not absorb water, which is superficially a good thing, but in reality very bad, as any water in the system will remain as water and a) boil very easily and b) potentially cause corrosion. It is also relatively compressible compared with traditional brake fluid.
You will want either Dot 4 or Dot 5.1. For high performance/track use the best fluids are usually Dot 4. I use Motul RBF 600 mainly because I have a whole case of it ... but it is pretty high spec. high performance fluid, though not the best, it is a pretty reasonable price.
Regarding brake setup overall I have the AP big brake kit: 6 pot calipers on the front and 4 pot on the rear. When I got the car the brakes were pretty well shot, so I am replacing discs and pads this week: Performance friction disks on the front; OEM BMW on the rear (AP are out of stock) and RS29 pads all round; plus new fluid of course. Unfortunately I don't have experience of any other setup so won't be able to compare effectively.[/quote]
Yes DOT 5 point something. Whatever stuff they pour down GT2's brake lines. It works well.
The Pagid RS29's bloddy noisy with the OEM calipers they rattle as endurance race pads, they don't have clips at the back and second, well they just squeek very loudly. Not too bad on you disks though.
I wonder if on a €27k / £15k car a full £4k BBK is not overkill?
The OEM set up, even with better pads, braided lines and DOT 5 liquid has its limitations.
we whould do a repertoire of what set up is good for what use.[/quote]
Just a quick point but you really don't want t use Dot 5 brake fluid: that is silicone-based, incompatible with any other type of fluid and will not absorb water, which is superficially a good thing, but in reality very bad, as any water in the system will remain as water and a) boil very easily and b) potentially cause corrosion. It is also relatively compressible compared with traditional brake fluid.
You will want either Dot 4 or Dot 5.1. For high performance/track use the best fluids are usually Dot 4. I use Motul RBF 600 mainly because I have a whole case of it ... but it is pretty high spec. high performance fluid, though not the best, it is a pretty reasonable price.
Regarding brake setup overall I have the AP big brake kit: 6 pot calipers on the front and 4 pot on the rear. When I got the car the brakes were pretty well shot, so I am replacing discs and pads this week: Performance friction disks on the front; OEM BMW on the rear (AP are out of stock) and RS29 pads all round; plus new fluid of course. Unfortunately I don't have experience of any other setup so won't be able to compare effectively.[/quote]
Yes DOT 5 point something. Whatever stuff they pour down GT2's brake lines. It works well.
The Pagid RS29's bloddy noisy with the OEM calipers they rattle as endurance race pads, they don't have clips at the back and second, well they just squeek very loudly. Not too bad on you disks though.
I wonder if on a €27k / £15k car a full £4k BBK is not overkill?
exdos said:
Dear moron,
For some reason, you multiplied the OE single piston area by 2 (trying to account for drivers and passengers?), but didn't do the same for the stoptechs. If you weren't retarded, you would realize the stoptechs have nearly twice the surface area up front.
Also hydraulic pressure doesn't "split," it's equal across the entire system whether you have 1 or 100 pistons.
Aren't you the guy who thinks he's getting a ton of power from an intake scoop? LOL
simonlpearce
Senior member
Lol that was some intro from Smart Guy...
Either way from previous experience on my E36 I have found that in general a BBK won't stop you any quicker, but it will continue to keep stopping you for prolonged periods. The OEM setup would last easily 20min sessions where the BBK would continue to work right up to and past 40 min sessions.
Back to the OP's initial question. Im sure it would be possible to fab Porsche brakes onto the Z given the right carriers.
Either way from previous experience on my E36 I have found that in general a BBK won't stop you any quicker, but it will continue to keep stopping you for prolonged periods. The OEM setup would last easily 20min sessions where the BBK would continue to work right up to and past 40 min sessions.
Back to the OP's initial question. Im sure it would be possible to fab Porsche brakes onto the Z given the right carriers.
A bbk will only stop quicker if fading occurs.
Can that happen on one single brake action?
Maybe on high speed autobahn driving. The energy required to dissipate the kinetic energy of a car adds up square with speed.
So a car weighing 1500kg slowing down from 100km/h to 0km/h must dissipate 580kJ, but the same car slowing down from 300km/u to 200km/u (so the same 100km/u less speed) must dissipate 2890kJ. That's 5 times as much.
So if you want to do that in the same time, your brakes have to process 5 times as much power for the same decelleration.
That's why fast cars have big brakes
And in the mountains brakes can have a hard time too before realizing...
A bbk is mainly stamina.
Larger beefier discs for more heat dissipation and much larger pads for less heat per set surface. That also reduces wear.
Can that happen on one single brake action?
Maybe on high speed autobahn driving. The energy required to dissipate the kinetic energy of a car adds up square with speed.
So a car weighing 1500kg slowing down from 100km/h to 0km/h must dissipate 580kJ, but the same car slowing down from 300km/u to 200km/u (so the same 100km/u less speed) must dissipate 2890kJ. That's 5 times as much.
So if you want to do that in the same time, your brakes have to process 5 times as much power for the same decelleration.
That's why fast cars have big brakes
And in the mountains brakes can have a hard time too before realizing...
A bbk is mainly stamina.
Larger beefier discs for more heat dissipation and much larger pads for less heat per set surface. That also reduces wear.
Harsh first post from Smartguy but he's right about the calcs.
Interesting white paper on big brake kits from stoptech
http://www.stoptech.com/technical-support/technical-white-papers/brake-system-and-upgrade-selection
Another interesting white paper on why its bad to only increase the brake size at one end or the car
http://www.stoptech.com/technical-support/technical-white-papers/white-paper---brake-bias-and-performance-why-brake-balance-matters
Interesting white paper on big brake kits from stoptech
http://www.stoptech.com/technical-support/technical-white-papers/brake-system-and-upgrade-selection
Another interesting white paper on why its bad to only increase the brake size at one end or the car
http://www.stoptech.com/technical-support/technical-white-papers/white-paper---brake-bias-and-performance-why-brake-balance-matters
SmartGuy said:
Dear (not so)SmartGuy,
If there is any movement of fluid (ie a piston being pushed) then the laws of viscous flow state that the pressure in any
parallel branch will be inversely proportional to the number of parallel branches (for a fixed flow).
If the situation is a static one then the FORCE delivered by any one branch of such a system will be 1/n of that applied at the
feed (all other things being equal .. termination diameters etc)
Flow is not important, it's pressure and total piston area.
But bbk's use multiple pistons because of the larger brake pads. The pressure in brakes is so high that you want to distribute that pressur as equally as possible onto the pad. With a larger pad that means multiple pistons. A large piston in the middle would allow the pad to flex and the top and bottom wouldn't distribute the appropriate pressure.
So piston area is one thing, distribute force equally on a much larger pad than stock is another.
BBK pads are sometimes twice as large as stock pads.
As far as exodus' calculations go it seems indeed that he indeed forgot to multiply the stoptech area's by 2...
But bbk's use multiple pistons because of the larger brake pads. The pressure in brakes is so high that you want to distribute that pressur as equally as possible onto the pad. With a larger pad that means multiple pistons. A large piston in the middle would allow the pad to flex and the top and bottom wouldn't distribute the appropriate pressure.
So piston area is one thing, distribute force equally on a much larger pad than stock is another.
BBK pads are sometimes twice as large as stock pads.
As far as exodus' calculations go it seems indeed that he indeed forgot to multiply the stoptech area's by 2...