New Project

[Suprgnat]

My latest project arrived in the mail today!



330i/Z4 front calipers 34116769093 and 3411676909 with 34116769097 carriers. I'll be combining them with Z4 34116794427 lightweight rotors. This will be a 57/24/330 combination versus 54/24/300 stock. Owing to the aluminum calipers and the aluminum hats on the rotors, according to the BMW ETK this combination will weigh a little over 1 pound LESS than stock.

These will be combined with 42mm 34216768697 and 34216768698 calipers in the rear as used in the Performance Brake kit. With the slightly larger pistons and slightly smaller diameter rotors in the front, this front and rear combination should bias similarly to the Performance Brake kit as well.

Build will take a while because of a busy work schedule and I figure I'll wait until the "big reveal" to divulge color, etc, but in the end I think this will be very much in the spirit of the rest of my build and the car.

For those of you who don't already know, I went through this process with 335i calipers and Z4 35is rotors only to find they just wouldn't fit under my 17" stock wheels and was unwilling to go to 18" wheels.

http://www.1addicts.com/forums/showp...2&postcount=23
http://www.1addicts.com/forums/showp...7&postcount=26

[andrey_gta]

Will you be doing the ECS tunning caliper guide pin bushings with caps.

[Suprgnat]

Originally Posted by andrey_gta

Will you be doing the ECS tunning caliper guide pin bushings with caps.

I already have the Bimmerworld version.

[andrey_gta]

Originally Posted by Suprgnat

Owing to the aluminum calipers and the aluminum hats on the rotors, according to the BMW ETK this combination will weigh a little over 1 pound LESS than stock.
With the slightly larger pistons and slightly smaller diameter rotors in the front, this front and rear combination should bias similarly to the Performance Brake kit as well.

I find this fact so cool - functional weight savings.

BTW these calipers look really nice in Candy red or any color paint with pearl. Mostly because of the heat sync design.

[bNks334]

I am interested in doing something like this down the road on my 128i. Just how much additional braking power do you think you picked up with this setup?

Also, I am a little confused when you say "With the slightly larger pistons and slightly smaller diameter rotors in the front, this front and rear combination should bias similarly to the Performance Brake kit as well." Aren't you increasing the diameter of the front rotors?

As for the rear, you mentioned new calipers. Did you go with larger rotors in the rear as well?

Heat, braking power, and weight are my main concerns for doing this retrofit.

EDIT: Additionally, did you need to recode the car during any of this? I believe the BMW performance brake kit requires a code change as well as the 335i brake upgrade...

[Suprgnat]

Originally Posted by bNks334

I am interested in doing something like this down the road on my 128i. Just how much additional braking power do you think you picked up with this setup?

Also, I am a little confused when you say "With the slightly larger pistons and slightly smaller diameter rotors in the front, this front and rear combination should bias similarly to the Performance Brake kit as well." Aren't you increasing the diameter of the front rotors?

As for the rear, you mentioned new calipers. Did you go with larger rotors in the rear as well?

Heat, braking power, and weight are my main concerns for doing this retrofit.

The new setup is still in the process of being rebuilt and powder coated. Braking power (torque) will increase, but I haven't yet done the calculations. I still need to get an accurate measurement of the torque radii (center of hub to center of piston)

What I meant is: The 135 calipers have 28, 32 and 36mm pistons which are equivalent to a single 55.714mm piston. The 330i/Z4 pistons are 57mm. The 135i rotors are 338mm diameter versus 330mm for the 330i/Z4. Owing to the 135is smaller pistons, the torque radius difference between the 135i and the 330i/Z4 calipers is probably even greater than the 4mm difference in radius of the rotors. Slightly bigger pistons, slightly smaller rotors.

No, I didn't change the rear rotor diameter.

Heat should be better as the 330mm rotor has more thermal mass than the stock 300mm rotor, "braking power" (torque) will be greater and, as I mentioned above, the total unsprung weight in the front will go down by slightly over a pound per side. The weight of the 42mm rear calipers is about the same as stock.

[bNks334]

Thanks for the reply! I'll be watching to see how this turns out as this is a fairly cheap retrofit.

Just wondering how ABS will act with the new setup without recoding.

[Black Prinz]

Subscribed as also not willing to increase to 18's.

Thanks for sharing!

[Blacksport]

Originally Posted by bNks334

Just wondering how ABS will act with the new setup without recoding.

ABS needs no recoding or adjusting with a change in brakes. The speed of the "reluctor" wheel on the hub is read by a sensor, and reacts to a slowing of the wheel by releasing fluid pressure...a BBK upgrade will work just the same.

[Suprgnat]

Originally Posted by Blacksport

ABS needs no recoding or adjusting with a change in brakes. The speed of the "reluctor" wheel on the hub is read by a sensor, and reacts to a slowing of the wheel by releasing fluid pressure...a BBK upgrade will work just the same.

Curious as to what the "required" re-coding for the brakes does, then.

7. Concluding work and coding

The retrofit system requires encoding.
-Reconnect vehicle battery
-Encode retrofit with Software Service Station (SSS) via the path -Retrofit I Sports Brake-
-Perform quick test
-Reassemble vehicle in reverse order of removal
-Perform function test

[bNks334]

Maybe It's more for DSC than ABS? There has got to be pre-programed parameters and thresholds for each model relating to braking and stability control modules. There is no question about that imo.

The question I have though is, is it detrimental to braking ability to not update the cars software to reflect the brake retrofit. Can the cars computer operate properly using the stock parameters? Or, do the thresholds need to be updated to prevent abs/dsc miscalculations?

I'd imagine brake bias is pretty damn important on a track on a car equipped with an e-diff...

@ Suprgnat: any calculations on brake force would be much appreciated! I don't have nearly enough knowledge to do it myself, but I'm sure there are plenty of people who would be interested.

[Blacksport]

The ABS system and the braking system are entirely separate systems, except at the point where the ABS detects that a wheel is slowing in relation to the other wheels, at which point it will reduce hydraulic pressure to that wheel's caliper.

The ABS system does not know what caliper, pads, or rotor diameter that it's monitoring. It is only watching the reluctor wheel (aka "tone" wheel) for speed differential from the other tone wheels. This is also the system that monitors tire pressure...a low tire will spin slightly faster, setting off your tire pressure warning light.

I have the BMW performance 6-piston front BBK with 1.5" larger rotors, and I can tell you that they work fantastic...way better feel and bite then the stock front brakes were. No "coding" whatsoever, and none was mentioned in the included instructions. I have a huge 6-piston Wilwood setup on my Durango...also on my brother's FRS, and another brother's Honda Fit (4-piston). A previous BMW I owned, an 01 M Roadster S54 had a 4-piston Wilwood front setup; all these BBK upgrades with no coding or re-flash, and they all work perfect. Go ahead and get your setup coded if you feel the need, I'm sure the "coder guy" will take your money...

[Suprgnat]

Originally Posted by Blacksport

No "coding" whatsoever, and none was mentioned in the included instructions.

I'm familiar with how anti-lock brakes work. Regardless, I don't know, and am curious at to what, the Performance Brake coding the instructions ( found here: http://www.1addicts.com/forums/attac...6&d=1211916392) does. No, the sky is not going to fall without it.

Originally Posted by bNks334

@ Suprgnat: any calculations on brake force would be much appreciated! I don't have nearly enough knowledge to do it myself, but I'm sure there are plenty of people who would be interested.

I don't have a real measurement for the friction radius, but assuming a friction radius equal to the rotor radius minus the piston radius and all other things being equal, the fronts have about 23.6% more torque and the rears have about 9.4% more torque.

[Blacksport]

Did some checking on this and the BMW world is all over the map on this. Most BMW BBK owners, me included, have had no coding done, and report no problems...a few had it done, but aren't aware of any difference. One person said his brake pedal felt less spongy, a truly ridiculous statement; they probably re-bled his brakes during his coding service.

Obviously, the coding would be a tweaking to the ABS or DTC since the braking system is entirely hydraulic when operating without ABS intervention. But it seems to me that other factors; the weather for instance, or a change from old, hard, dry all-season tires to new, sticky max-performance summer tires would actually have more effect on brake performance than a brake upgrade would.

I'd have to know exactly what the coding change would alter before I would consider it, especially a year after I changed to the BBK, along with 18" wheels and Conti's non-runflat, max-performance summer street tire. This setup works flawless by any way you measure it: pedal modulation, pedal pressure, wet vs dry performance, and my favorite; hauling the car down from high speed. And don't forget looks...no "sliding caliper" will ever look as good as a 6-piston aluminum caliper sitting on a huge rotor.

[bNks334]

Originally Posted by Blacksport

Did some checking on this and the BMW world is all over the map on this. Most BMW BBK owners, me included, have had no coding done, and report no problems...a few had it done, but aren't aware of any difference. One person said his brake pedal felt less spongy, a truly ridiculous statement; they probably re-bled his brakes during his coding service.

You're right, every thread I find seems to be based around speculation. What we all really need to know is what the coding changes lol.

Would changing brake torque and bias have an effect on how DSC and CBC apply the brakes to stabilize the car? Seems like there are a lot of threads that discuss how these systems cut in unnecessarily mid-corner. Wider tires would allow for a greater lateral grip (which may exceed the lateral g-force allowed before CBC kicks in) and the system might end up over applying the brakes if there is greater initial bite/torque than expected?

Not sure if CBC is even applicable to the 128i since it was a 1m thread I was reading... (http://www.1addicts.com/forums/showt...=578573&page=2)

[Blacksport]

Just picked up the car from Eurowerks in Deerfield Beach; they did the AA reflash after I installed AA headers and Stage 3 intake...here's my reaction: WOW!...this thing is fast now, huge improvement from about 3500 rpm up to the redline. I hated to part with 2800 bucks, but consider it a fair trade for 30-35hp. Very, very pleased now... IMHO, the engine power now is more "equal" to the outstanding chassis and excellent brakes, both of which I've improved.

They were showing me some of the projects they're working on, some very sick stuff...one of the "older" guys there actually knew about my racing in IMSA GTU, so that was pretty cool talking about the old days...We starting talking about BBK's, so I asked if they coded their BBK installations...I got a bunch of blank stares...and a few chuckles...No, they've installed dozens of BBK's for their customers, and never had any of them coded.

[Southjersey128]

I had mine coded after I installed my BMW Performance BBK, just because the instructions said it had to be done. Whats another $100.00 to have the dealer code it so that it is up to BMW specs. I couldn't tell the difference before and after, but like you said, we don't really know what it changes in the system. If it means the abs system can stop 1 inch shorter from 80 mph it could be worth it. No down side really, and I've learned over the years to just chalk $100 more up to BMW ownership privilege.

[Suprgnat]

Front caliper are prepped and ready for masking and powder coating.
The usual process:
Clean and degrease
Mask
Bead blast
Degrease again in TSP
Phosphoric acid etch
Treat with Alodine 1201

[andrey_gta]

Originally Posted by Suprgnat

What I meant is: The 135 calipers have 28, 32 and 36mm pistons which are equivalent to a single 55.714mm piston. The 330i/Z4 pistons are 57mm. The 135i rotors are 338mm diameter versus 330mm for the 330i/Z4. Owing to the 135is smaller pistons, the torque radius difference between the 135i and the 330i/Z4 calipers is probably even greater than the 4mm difference in radius of the rotors. Slightly bigger pistons, slightly smaller rotors.

How do you convert the 2x(28, 32 and 36mm) pistons per caliper to a single 55.714mm piston? I dont understand how to convert this to compare say the 135i 6-pot to the F30/F22 4 pot fronts

How does this compare to the single-pot 335i calipers?

[Suprgnat]

Originally Posted by andrey_gta

How do you convert the 2x(28, 32 and 36mm) pistons per caliper to a single 55.714mm piston? I dont understand how to convert this to compare say the 135i 6-pot to the F30/F22 4 pot fronts

How does this compare to the single-pot 335i calipers?

First, one only calculates the area of the pistons on one side of the caliper.

Area=PI*R^2, so A=(PI*14^2)+(PI*16^2)+(PI*18^2)

Equivalent diameter=sqrt(A/PI)*2

335i caliper pistons are also 57mm, but the calipers themselves are likely stiffer than the 330i/Z4 calipers.

[Suprgnat]

Just a quick snap taken this morning at 0-dark thirty before heading to work. I haven't installed the pistons yet, but I'm very happy with how they came out. Dropped them off at Valley Custom Powder Coating in Lathrop, CA at 10 AM and got a call at 15:30 saying they were ready to pick up. I did all the prep and masking, so it was $60.00 out the door for both calipers and both carriers.

[asbrr]

Damn that looks nice...can you just start a business selling these as a kit (front and rear), I'd be your first customer