Comparison test of BBK for the E9x M3 - Surprising results!!!

[Hujan]

I have Brembos and the pedal feel and modulation is fantastic compared to stock. It sounds to me like the Brembos in the test were not setup/bled correctly.

Also, I think it's a fair criticism of the test to say that the results should be viewed with skepticism because of the different pad compound. I would like to see the test repeated with same pads, same tires, same surface, and no reasons to question whether any of the kits were installed correctly.

[s85e90]

Originally Posted by Hujan

I have Brembos and the pedal feel and modulation is fantastic compared to stock. It sounds to me like the Brembos in the test were not setup/bled correctly.

Also, I think it's a fair criticism of the test to say that the results should be viewed with skepticism because of the different pad compound. I would like to see the test repeated with same pads, same tires, same surface, and no reasons to question whether any of the kits were installed correctly.

That (as stated) would defeat the purpose of the test. The test was conducted with the supplied pads, the pads you would get if purchased. The constant is the test vehicle.

[Boss330]

Originally Posted by Hujan

I have Brembos and the pedal feel and modulation is fantastic compared to stock. It sounds to me like the Brembos in the test were not setup/bled correctly.

Also, I think it's a fair criticism of the test to say that the results should be viewed with skepticism because of the different pad compound. I would like to see the test repeated with same pads, same tires, same surface, and no reasons to question whether any of the kits were installed correctly.

As far as I'm concerned, there is no reason to question a correct installation of any of the BBKs. As I wrote previously, they describe in detail how they followed even the bedding in procedures with typical German precision. They had top notch personell and a brake specialist present for the test.

If anything was wrong, it's more likely they had a faulty product from Brembo IMO

And to reiterate once more, the tires and surface WAS the same for all of the BBK's. And they bled the Brembo's twice because they thought it was not bled properly. If they managed to install every one of the other BBK's correctly, why should they suddenly be incapable of installing just one of the BBK's?

Of course pads are a very important part of any brake system. The point here was to test the performance of BBK's as delivered on the market by the suppliers. That's what the customers get and that represents the real world performance of these kits. If they all should have been tested with a pad that was not supplied with the BBK, how would that be representative of what a customer can choose from? For instance the PFC has a limited availability of brake pads, because of it's design. Should every BBK be tested with a compound that was available for the PFC, but one that neither of the other BBK manufactures recommends or markets?

That would be like testing all cars in a comparison test on the same type and brand of tire, even though the manufacturer doesn't actually sell the car with those tires...

IMO, what they have done here is to test a complete product, available to the customer over the counter.

[admranger]

Very interesting.

[bdaddylo]

Originally Posted by VictorH

Seriously? This is the standard by which almost every car magazine measures braking performance and the brake pad issues was addressed by the OP. It would be nice to read this test in English but the German's are usually pretty logical and systematic in evaluating these types of things. What test would you propose that would provide better objective information?

This is probably the most objective comparison we will get regarding BBKs in our cars and appears to be well done. The fact that the results don't support what many people may have believed just goes to show that objective facts don't always fit your belief system. Thanks for posting.

Seriously, put down your car magazines and go drive your car on a track. Ilia's comments are right on the money in regards to BBKs. It's not all about a distance measurement, but how it performs and feels after repeated stops.

[The HACK]

Originally Posted by bdaddylo

Seriously, put down your car magazines and go drive your car on a track. Ilia's comments are right on the money in regards to BBKs. It's not all about a distance measurement, but how it performs and feels after repeated stops.

If I read the OP right, the stopping distance is as measured in an average over 20 stops from XXX-0 kmph. That's actually a pretty accurate metric to measure against how it would perform on track/repeated stops.

[VictorH]

Originally Posted by bdaddylo

Seriously, put down your car magazines and go drive your car on a track. Ilia's comments are right on the money in regards to BBKs. It's not all about a distance measurement, but how it performs and feels after repeated stops.

Curious, what would you propose as the objective measure of how these kits perform?

[ilikebmxbikes]

Originally Posted by The HACK

If I read the OP right, the stopping distance is as measured in an average over 20 stops from XXX-0 kmph. That's actually a pretty accurate metric to measure against how it would perform on track/repeated stops.

What is the interval between their stops? Brakes heat up real quick on the track if your hammering on them.

I think this brake test is great for what it is. I have two sets of stoptech trophy on my bmw's and am happy with the results but have seen first hand many instances where stock brakes over heat on the track and never an instance with a set of brembo GT.

[Acree]

The thing that most people fail to realize is 99% of the time, for cost savings, engineers will spec out a brake system that has the capability to stop the car from its top speed, once.

[Sleeper519]

Love mein Stoptechs and Pagid RS-29s!

[r53s65e90]

What they describe in the test for the Brembo GT are bleeding problems that I think they couldn't figure out. Nothing surprising about the brembo pads though. Based on my experience with the 365 kit, the original pads SUCK ROYALLY!!!! They are worse than stoptech pads on stock rotors. Also keep in mind that they kit they tested is the EU TUV approved kit with 380mmx32mm rotor and a narrow pad of about 50mm. In the US the kit is 380mmx34mm with 58mm. The tested kit is not available in the US.

[Boss330]

Originally Posted by Acree

The thing that most people fail to realize is 99% of the time, for cost savings, engineers will spec out a brake system that has the capability to stop the car from its top speed, once.

Vehicle approval procedures in Europe require both hot and cold brake testing and has deceleration rate requirements with requirements for repeated decelerations from the different speeds described in the directive.

Auto Bild also wrote that for their normal testing they "only" did the brake tests for each speed interval 10 times... So every car they do a test of, the brakes has to withstand at least 10 decelerations from 100kph and 10 from 200kph. Not 100% sure if they always do 10 stops from top speed as well, but in this test they did 20 from 250kph...

[Boss330]

Originally Posted by r53s65e90

What they describe in the test for the Brembo GT are bleeding problems that I think they couldn't figure out. Nothing surprising about the brembo pads though. Based on my experience with the 365 kit, the original pads SUCK ROYALLY!!!! They are worse than stoptech pads on stock rotors. Also keep in mind that they kit they tested is the EU TUV approved kit with 380mmx32mm rotor and a narrow pad of about 50mm. In the US the kit is 380mmx34mm with 58mm. The tested kit is not available in the US.

Agree that it sounds like bleed problems, but odd that they couldn't bleed the Brembo kit properly. Perhaps something wrong with the calipers?

[Beedub]

Originally Posted by swhat

I agree with Ilia. This test is very flawed. Stopping distant is not a comparison for BBKs. If anything it should be heat dissipation. The varying braking compound doesn't make this an even comparison.
With stopping distant, it's is determined by tires, environmental conditions, and brake pad/disc temperatures, and of course the biggest factor of them all, the human driver. If the brake kit can lock up the wheels after 40x hard braking, than it's good.
People normally upgrade their brakes because after repeated hard braking, the OEM brakes become squishy due to inadequate cooling. e.g. Brake fluid boils, brake pads melting.
In the case of this comparo, they used RS29 pads and the ferodos. RS29 is an enduro racing compound vs the Ferodos which I consider to be a street/light trackday compound.

+1000000000000000

it needed to be with the SAME compound. i never ever had an issue with the stopping power of my stock z4m CSL brakes, they felt incredible, the problem was it couldnt do it for a decent period without smoke, brake fade and lots of grumbling....

[Beedub]

Originally Posted by Ilia@IND

I'm not able to read the article, but a few questions come to mind immediately:

-Did these journalists install the same brake pad compound in each kit? It looks like some kits are using Pagid RS29 pads and others are using a different pad.

-Did these journalists measure any other parameters than stopping distance?


A few things to consider:

-Stopping distance is largely a test of pad compound, and less so a test of the design of the brake caliper or rotor. An excellent compound in the original BMW brakes can produce a very low stopping distance, provided that the tires have enough grip to operate up to the compound's ability.

-Brake calipers and rotors are upgraded to increase their thermal capacity, not their one-time stopping distance. The key is not what the brake system can do once, rather the question is what consistency does the brake system offer over time?

Most E9x M3 owners that drive their cars quickly around the track have noticed that even with an excellent brake pad compound (which does provide better stopping distance), the original BMW E9x M3 brakes will eventually fade and fail with hard use.

This test does not appear to test brake operating temperature over time, nor does it seem to graphically represent performance (brake fade or lack thereof). This test also shows several of the brake kits loaded with Pagid's RS29 pads (an excellent track brake pad), and the other kits loaded with other pads (I am assuming Ferodo FM1000 for the Brembo kit, and stock for the BMW kit).

For an empirical test I would have loaded all of the brake calipers with a high performance pad like the RS29, and logged brake fade in some way.

As-is, even the stopping distance test conducted here is of no use. The data is not accurate due to the inconsistency in pad compound.

Absolutely.

[s85e90]

Oh please. Everyone here wants to tailor a test to what they want to hear. Ilia is not right and neither are the above posters. What's hard to understand? The test was done with the supplied pads, the same pads you get when you buy the kit. Why on earth would they test them with all the same pads? For the test the car is the constant and the brakes are the variable. People are unhappy to hear the brembo didn't do well and now want to criticize everything.

[dazzabb]

Dunno how long the Brembo GT kit has been sold for, but surely if the Brembo's were that bad, word would have spread like wildfire and they would never have sold any!

[Boss330]

Originally Posted by Beedub

+1000000000000000

it needed to be with the SAME compound. i never ever had an issue with the stopping power of my stock z4m CSL brakes, they felt incredible, the problem was it couldnt do it for a decent period without smoke, brake fade and lots of grumbling....

Do you also think a comparison test of 5 performance cars should be run with the same tires? Even though you couldn't get that tire fitted from the factory...

How would that be representative of the product you actually could buy from the showroom? Sure you can change tires AFTER you have bought the car, but so you can with brake pads on a BBK. Point is that they test what you actually get supplied from the manufacturers, not how it would perform if you modify their BBK. Just like any track test comparison of a M3 vs RS5 vs C63 AMG is done with the tires as fitted from the manufacturer, so was this BBK test done as regards brake pads. This is how they perform out of the Box. Not how they could have performed if you changed the product they delivered...

[Boss330]

Originally Posted by Beedub

+1000000000000000

it needed to be with the SAME compound. i never ever had an issue with the stopping power of my stock z4m CSL brakes, they felt incredible, the problem was it couldnt do it for a decent period without smoke, brake fade and lots of grumbling....

Originally Posted by dazzabb

Dunno how long the Brembo GT kit has been sold for, but surely if the Brembo's were that bad, word would have spread like wildfire and they would never have sold any!

I agree, and that's an indication of something perhaps either being wrong with that Brembo kit or that the brake pads had issues or just wasn't good enough for 20 repeated stops from each speed...

[Beedub]

AP have never supplied their kit with the Pagid RS29. It comes with the apf404 pad. I just don't like the inconsistencies I'm seeing, how many more where their that we aren't seeing??

however i can't defend the brembo on a 20 stop brake test, that is poor performance whatever the pad it comes with, that SHOULD be able to do better than stock on a brembo bbk

it would have been nice to see another section adding the rear kits on to to see how much if any difference that makes.

[s85e90]

People will always try to defend what they want the outcome to be irregardless of what the actual test produces. Funny

[1MOREMOD]

stoptech street pads are not that great surprised they did well. i use cobalt xr2s in mine.