Time to do brakes. Pads & Rotors.

[houtan]

Originally Posted by ShocknAwe

Hm. Not a bad idea.

Bnks pretty much summed it up.

[juld0zer]

Originally Posted by bNks334

The DSC module actually has a function that increases brake pressure over time based on the estimated brake pad life (drukmodel_ha or something like that). By removing the sensor you can assume this function no longer works and you may experience a bit more pedal travel than "normal" when the pads start to wear down (which is normal lol).

I have both my sensors cut off and the wires tied together so I can permanently delete the annoying service notifications (car permanently thinks the pads are new).

Is there a document which details this?

It does seem true because all the cars that come in for brakes at work have wickedly sharp pedal response. Fit new pads, reset CBS and even after bedding them in (pads only or pads and discs) the response is very much muted compared to before. Next time i get one i will fit a new sensor and reset it and go for a drive to test it. I remember i fitted new pads and discs to my car and didn't reset the CBS - but i dont recall noticing anything unusual.

When i fiddled with the druckmodell parameters in coding, what i noticed was the traction control was more gentle. I set everything to M3 parameters and the traction control is pretty much useless. The idiot light blinks but the car still spins the tyres. Im back to stock coding now.

I tied my sensors aside too. But if grinding down the sensors to simulate first trip stage of the sensor (half worn pads) will yield sharper brakes then i might explore that when i have some more time to tinker

[bNks334]

Originally Posted by juld0zer

Is there a document which details this?

It does seem true because all the cars that come in for brakes at work have wickedly sharp pedal response. Fit new pads, reset CBS and even after bedding them in (pads only or pads and discs) the response is very much muted compared to before. Next time i get one i will fit a new sensor and reset it and go for a drive to test it. I remember i fitted new pads and discs to my car and didn't reset the CBS - but i dont recall noticing anything unusual.

When i fiddled with the druckmodell parameters in coding, what i noticed was the traction control was more gentle. I set everything to M3 parameters and the traction control is pretty much useless. The idiot light blinks but the car still spins the tyres. Im back to stock coding now.

I tied my sensors aside too. But if grinding down the sensors to simulate first trip stage of the sensor (half worn pads) will yield sharper brakes then i might explore that when i have some more time to tinker

True, what you say makes sense too. Druckmoddell might be a factor all the other functions use to bias their application as the pads wear down. Like, brake pre-tensioning would need to be biased based on pad wear to work right, or, even the e-diff would need a formula to bias brake application based on pad wear to work consistently... Grinding down the sensor and running full sized pads would result in over-application of the brakes wehn DSC uses any of its functions. For this reason I think Druckmoddel should be coded off if you do not replace brake sensors when you do your pads. If you don't disable druckmoddell, I think it's pretty certain some kind of pad wear based DSC function is going to over-apply itself.

I think my theory on what druckmoddell does makes sense too though. With all the other functions existing why wouldn't BMW also try to provide consistent pedal feel across all pad life? I have never noticed whether or not a stock car experiences more brake pedal travel as the pads wear down because I've always ran with my sensors tied up and all features coded off (per-tensioning, Rain brake assist, etc...). I also always drive with DSC completely off (except in snow I use dynamic traction control as it's intended to be use din this situation). If what I say is right, then I need to code druckmoddel off (which I already did). If what you say is right, then it's a moot point for me because I don't have any of the brake related functions enabled (except e-diff).

Moving to M3 settings doesn't work the way you want because we don't have any of the same brake related components, pressures, pump sizes or pretty much anything in common with an M3's brakes lol You'd be telling DSC to use the wrong brake bias and line pressures to apply itself.

[ShocknAwe]

bNks334

So lets say I did the RB 2 piece kit houtan mentioned, and cut/splice my existing brake wear sensors together rather than get a new set. How do I code the Druckmodell parameters? Assuming I even need to.

I don't want to lose DTC function. I never use DSC, but I drive with DTC generally full time. Only turn off the whole system when I'm specifically out for unbridled hoonery.

[thakid22]

Originally Posted by bNks334

The DSC module actually has a function that increases brake pressure over time based on the estimated brake pad life (drukmodel_ha or something like that). By removing the sensor you can assume this function no longer works and you may experience a bit more pedal travel than "normal" when the pads start to wear down (which is normal lol).

I have both my sensors cut off and the wires tied together so I can permanently delete the annoying service notifications (car permanently thinks the pads are new).

Are you sure that parameter is increasing brake pressure, with time/wear?
Look at the pads. When new, only about 70% of the pads surface touches the rotor.
The 15% to each side of the middle is chamfered/beveled. As the pads wear, much more contact area with the rotor is permitted. It's not until the pad linings or toward the end of their life that 100% of the pad face can even touch the rotor. At this point, braking does feel quite sharp. And it should, with the whole pad being used.

I would imagine, that the DSC computer actually REDUCES brake pressure with additional miles/wear/age. However, not enough to maintain linearity throughout the life cycle of the pads, because things definitely get more responsive with wear, as you pointed out.

[bNks334]

Originally Posted by thakid22

Are you sure that parameter is increasing brake pressure, with time/wear?
Look at the pads. When new, only about 70% of the pads surface touches the rotor.
The 15% to each side of the middle is chamfered/beveled. As the pads wear, much more contact area with the rotor is permitted. It's not until the pad linings or toward the end of their life that 100% of the pad face can even touch the rotor. At this point, braking does feel quite sharp. And it should, with the whole pad being used.

I am just making an assumption on what druckmoddell does. It's some kind of function used by DSC which is based off the brake pressure sensor. The function is used by DSC for things like building rear brake pressure when the front brakes are at the ABS threshold.

I was basing my reply off of another users feedback that cars with worn down pads still have immediate pedal response despite the pads being worn down. It was more so theory than a definitive function.

I was actually trying to remember the name of the function off the top of my head when I typed that. I looked back at my coding spreadsheet I put together and found that the function I am referring to is actually: C0F_BBV_KORR_VA/HA

What I am saying would have more to do with distance than contact area. When the pads wear down more pedal travel/fluid movement is required before the pad contacts the rotor surface when braking. You can see how when your pads wear down your brake fluid reservoir will be low on fluid since the pistons are constantly pushed out further.

Originally Posted by thakid22

I would imagine, that the DSC computer actually REDUCES brake pressure with additional miles/wear/age. However, not enough to maintain linearity throughout the life cycle of the pads, because things definitely get more responsive with wear, as you pointed out.

Maybe someone else has more info, but when I was playing with coding I researched that C0F_BBV_KORR_HA/C0F_BBV_KORR_VA is some kind of front and rear pad wear correction function and C0F_DRUCKMODELL_HA/C0F_DRUCKMODELL_VA is some kind of pressure model for front/rear brakes.

[bNks334]

Originally Posted by ShocknAwe

bNks334

So lets say I did the RB 2 piece kit houtan mentioned, and cut/splice my existing brake wear sensors together rather than get a new set. How do I code the Druckmodell parameters? Assuming I even need to.

I don't want to lose DTC function. I never use DSC, but I drive with DTC generally full time. Only turn off the whole system when I'm specifically out for unbridled hoonery.

https://drive.google.com/open?id=0B9...zlFUlpaYXZJTlE

That's everything I've gathered on the functions. Maybe cutting off the pad wear sensors doesn't effect DSC and the sensors are only their for service warnings. Teves documentation only states that the MK60 module contains the function responsible for calculating brake pad wear, which might be the C0F_BBV_KORR_VA/HA functions I actually meant to refer to. You can use NCS Expert/NCS dummy (gives you definitions of the German functions) to play with MK60 settings listed in the above spreadsheet.

Either way, I have no noticeable side effects of cutting off my pad wear sensors and resetting the service light.

[ShocknAwe]

Originally Posted by bNks334

https://drive.google.com/open?id=0B9...zlFUlpaYXZJTlE

That's everything I've gathered on the functions. Maybe cutting off the pad wear sensors doesn't effect DSC and the sensors are only their for service warnings. Teves documentation only states that the MK60 module contains the function responsible for calculating brake pad wear, which might be the C0F_BBV_KORR_VA/HA functions I actually meant to refer to. You can use NCS Expert/NCS dummy (gives you definitions of the German functions) to play with MK60 settings listed in the above spreadsheet.

Either way, I have no noticeable side effects of cutting off my pad wear sensors and resetting the service light.

Thanks. If you do a short press (DTC) do you get intervention?

[bNks334]

Originally Posted by ShocknAwe

Thanks. If you do a short press (DTC) do you get intervention?

Yeah of course. As far as the car knows the sensors are still connected. The question is wether or not having old pads and a new/spliced sensor will affect dsc.

[juld0zer]

All modern cars with disc brakes are self adjusting by design. As the pads wear down, the piston extends out of the caliper bore to keep the gap between pad and disc relatively constant. The square shaped piston seal facilitates this by allowing the piston to extend and by pulling it back slightly. If this was not the case, pedal travel would become very long as pads wear.

For this reason, all DSC interventions of the brakes should yield a constantly similar response throughout a pad's life assuming pads have the same compound all the way to the backing plate. Which is another possibility because i've also noticed cars with worn pads also have almost black wheels. It seems as though the pads get extremely dusty as they near replacement thickness - or at least genuine pads do.

You were the leading force for the DSC coding after the guy with the X1 totalled his car and abandoned us. You gave me the info to convince me to have a play with different settings

thakid22's post definitely sounds plausible. The big chamfers on the leading and trailing edges are mainly there to reduce noise.

[bNks334]

Originally Posted by juld0zer

You were the leading force for the DSC coding after the guy with the X1 totaled his car and abandoned us. You gave me the info to convince me to have a play with different settings

What you say about the brake pads makes sense. So no ill effects from deleting the brake pad wear sensors. They are purely for estimating pad life for the service light.

I abandoned the idea of coding looser DSC settings and just decided to learn to run with DSC off lol. Not much to gain by trying other chassis settings. The under/over steer thresholds and the steering angle thresholds are going to be the two driving factors over DSC intervention. Seems like the 128i got some stricter thresholds than the 135i and the 128i would have more to gain by trying to code the 135i settings.

[ShocknAwe]

houtan

Think the supplied pads with the RB kit are the best option for street pads and those rotors ?

[houtan]

Yeah I think so. But it wouldn't hurt to call RB and double check. Also ask them what the turn around time is on shipping. My buddy's order was delayed about a week so he called to find out why. I believe it had something to do with them having the pads cut.

[ShocknAwe]

Originally Posted by houtan

Yeah I think so. But it wouldn't hurt to call RB and double check. Also ask them what the turn around time is on shipping. My buddy's order was delayed about a week so he called to find out why. I believe it had something to do with them having the pads cut.

Good thought. Thanks man.

[juld0zer]

Aside from the greater pad contact area available with worn pads (or some new pads like a lot of no compromise performance oriented pads, which have zero chamfering, no shims, no tuning weights etc), could the sharp pedal response also be due to reduced piston retraction?

Ie. the ability of the square piston seals to pull the pistons back is reduced according to how far the piston is from the cylinder? The further the piston extends out of the bore, the more side to side movement occurs when braking.

On a side note, it's amazing (and frustrating) how much electronic interference there is in our braking system. The brake pedal seems more like a brake switch - pedal down = i want to slow down. Then a computer does the rest.
Sometimes i wished we had the simpler plain Mk60 module, instead of the E5

[bbnks2]

Originally Posted by juld0zer

Aside from the greater pad contact area available with worn pads (or some new pads like a lot of no compromise performance oriented pads, which have zero chamfering, no shims, no tuning weights etc), could the sharp pedal response also be due to reduced piston retraction?

Ie. the ability of the square piston seals to pull the pistons back is reduced according to how far the piston is from the cylinder? The further the piston extends out of the bore, the more side to side movement occurs when braking.

On a side note, it's amazing (and frustrating) how much electronic interference there is in our braking system. The brake pedal seems more like a brake switch - pedal down = i want to slow down. Then a computer does the rest.
Sometimes i wished we had the simpler plain Mk60 module, instead of the E5

Reading back through this, and having just gone back into the mk60 module the other day, I realize I was referencing the wrong parameter.

There actually is a "brake pad wear correction" parameter. What does it do? No clue... But I am guessing there is an algorithm that biases brake line pressure based on a calculated wear rate. I coded it off and didn't notice much difference thereafter.

As for the complexity, yeah... I just coded off my e-diff because I installed an M3 lsd and yet when I look at my autocross video from last weekend I see that the brakes are being activated mid corner even when I am not on them. It might just be the logging though? I need an aimsolo or something to log the brake switch to see if I am truely getting brake intervention or if the trackaddict app is picking up braking gforce as application of the brakes or something... I guess I could always pull a few fuses to disable abs in order to rule out the false positive but isn't worth the time and effort.

[machine4321]

Stumbled upon this thread while researching durgo/bmP rotors.
I deleted my wear sensors the other day. Prior to going about it I checked continuity to make sure the system is normally closed. My sensors were intact but the wire broke at the sensor.

I broke apart the sensor to see how the system Triggers and once it goes open circuit it trips, but tou guys already know that im sure. What im getting at is there didn't Appear to be any “stages” of wear On the sensor. Just closed or open. If there was any alterations to pedal feel my guess is the resetting of the service milage would be the only way the system would “guess” the amount of wear.

Sorry to bring this one back from the dead but anyone get any cracking on the durago cross drilled?

[asbrr]

I can't comment on the sensor bit, nor can I comment on track usage on the Duragos (meaning cracking - mine have no cracks from street usage only)

I've had Duragos for about 1.5 years now (slotted+drilled) for the front of my car. They look cool, but they have seemed to wear faster than I'd expect with the mileage I've driven. They also seemed to pick up pad deposit faster/easier than my factory roters I had before (same type of pad). I bedded and re-bedded properly with minor improvement.

If I had the choice again I'd stay away from them despite the cost savings, the quality isn't up to snuff IMO

[ShocknAwe]

I coded out my pad sensors and just cut the wires off by the plug.

Buy my RB front rotors. Thank me later.

[bucksur]

i have had the durago/pronto rotors on my car for 3 years and 30k miles with stoptech pads and motul 600 and have done 15-20 track days, some including 140+mph nascar oval sections of track and have had no problem with warping. some 45 minute sessions..