RacingBrake 4 piston fixed caliper install tease...

[JCz04Bimmer]

Same boat indeed. I run DTC60's and am considering the switch the PFC08's. I've been plowing through the DTC60's lately so I'm hoping the PFC08's offer a bit more life to justify the added cost.

So will that 7855 shape from PFC work out of the box with the rear RB rotors?!

(I just bought and installed new OEM rear rotors -- GRRRRR -- so this is for when those wear out.)

[The HACK]

Originally Posted by JCz04Bimmer

Same boat indeed. I run DTC60's and am considering the switch the PFC08's. I've been plowing through the DTC60's lately so I'm hoping the PFC08's offer a bit more life to justify the added cost.

So will that 7855 shape from PFC work out of the box with the rear RB rotors?!

(I just bought and installed new OEM rear rotors -- GRRRRR -- so this is for when those wear out.)

I'd wait for RacingBrake to confirm it, but I'm 99.95% certain it will. The only unknown here is the RB rotor being 2mm thicker than OEM/PFC Direct Drive rotors, you may need someone to shave 1mm off of the face of the pad before they'll fit.

But even OEM rotor/pad, when brand new, there's at least 1mm of play/space between the pad and rotor surface. I'm going to have to order new pads before June anyway so I'll let you know in 2 weeks.

[JCz04Bimmer]

Originally Posted by The HACK

I'd wait for RacingBrake to confirm it, but I'm 99.95% certain it will. The only unknown here is the RB rotor being 2mm thicker than OEM/PFC Direct Drive rotors, you may need someone to shave 1mm off of the face of the pad before they'll fit.

But even OEM rotor/pad, when brand new, there's at least 1mm of play/space between the pad and rotor surface. I'm going to have to order new pads before June anyway so I'll let you know in 2 weeks.

Haha. I like the precision of your certainty. Sounds good. Don't forget to update the thread!

Agreed re: the OEM rotor/pad combination having some play... so I don't think it'll be a problem. Even with brand new rotors and brand new pads, I have at least 1mm of travel on the piston to work with. Just remember loosen the brake reservoir cap and watch for overflow. Been there. Done that.

PS. Probably having my master cylinder replaced this week. At 63K miles and plenty of track days, I think it's time. My pedal has always been a bit mushy (bled frequently, correctly, and have stainless lines) and I think the seals are fatigued. I'd rather be proactive about it, y'know?

[The HACK]

60K miles = REPLACE ALL RUBBER PARTS in my maintenance book. When I hit 5 years I proactively changed out all the suspension bushings, when I hit 60K miles (which will likely be around 10 years) all other rubber parts including radiator hoses will likely follow, along with water pump.

[JCz04Bimmer]

Originally Posted by The HACK

60K miles = REPLACE ALL RUBBER PARTS in my maintenance book. When I hit 5 years I proactively changed out all the suspension bushings, when I hit 60K miles (which will likely be around 10 years) all other rubber parts including radiator hoses will likely follow, along with water pump.

Yep! The various bushings around the car -- suspension, subframe, engine, etc -- were all replaced at around the 40-50k range

[pal]

My StopTech 4-piston BBK (355mm rotors) clear the barrels of OE 18" rims but need a 12mm spacer to clear the spokes.

[The HACK]

That's typical of aftermarket BBKs that use standard issue 2 piece floating rotors. Those rotor hats push the centerline of the rotor out anywhere between 1/2" to 3/4", thus the entire caliper assembly moves out 1/2". It's unlikely the StopTECH caliper is significantly wider (by 12mm) than the OEM caliper.

The issue with my fitment of the RB 4 piston caliper is, of course, the opposite. I had ample spoke clearance but zero barrel clearance. The curvature of the outside of the caliper appears to have been designed to accommodate a much larger diameter rotor, end result is, while the middle of the caliper has significant barrel clearance, the two outer edges of the caliper comes in contact with the barrel once the wheel is fitted.

I MIGHT pick up a set of AP Racing calipers from Essex and have a set of brackets custom machined from T-6061 aluminum EVENTUALLY. But not now.

[The HACK]

I decided to grind down my caliper carrier in the rear slightly to gain more clearance with the rear rotor just in case, and adjust the rear parking brake and realized...

The studs are in the way.

Just in case anyone needs to adjust their parking brake, and have studs installed in place and loctited like mine, you will need to take off the rotors and adjust the ring. Here's how I did mine:

Put the e-brake handle down, take the rotor off, adjust the wheels and expand the shoes until the it expands to a point where you can put in the rotor but the inside drum of the rotor touches the shoes. Back off 3-5 clicks on the wheel, put on the rotor and pull the e-brake, and see if the rotor stays tight.

[dubsesd]

Originally Posted by The HACK

That's typical of aftermarket BBKs that use standard issue 2 piece floating rotors. Those rotor hats push the centerline of the rotor out anywhere between 1/2" to 3/4", thus the entire caliper assembly moves out 1/2". It's unlikely the StopTECH caliper is significantly wider (by 12mm) than the OEM caliper.

i can take some measurements, but the rotor is 2mm away from the tierod/knuckle. there is no way to push the caliper any further in since the rotor cant be pushed any further in.

[The HACK]

Got one newly machined caliper from RacingBrake to see if it clears the OEM 18" wheels up front. It's close, I think a 5mm spacer would make it work.

[dorifto88]

wow that looks close

[The HACK]

Originally Posted by dorifto88

wow that looks close

Two things to keep in mind: Those wheel weights aren't your normal low profile wheel weights. For some reason my mechanic ran out of those flat weights and had to use these. Plus they double stacked it. So normally the wheel weight won't touch the calipers. MINE was the worst case scenario. The wheel turns, and the inner weight touches the caliper. A 5mm spacer would fix it if you have these type of weight. The spoke interference is typical of larger calipers, although in this case it's not as bad as it looks. Again, a 5mm spacer would fix it. If you look at BMW's floating caliper design, the end of the caliper closer to the hub tapers in. On a fixed caliper with pistons on both sides, that isn't possible. You have to have room to accommodate the pistons on the outside as well.

So all things considered, it resolved the wheel barrel clearance issue I had earlier, and it allows for a fixed caliper with MINIMUM use of spacers for clearance (5mm less offset is the same offset I currently run on the aftermarket, replica Alpina Dynamics). At this point I am satisfied to call it "fit" for use. Some other more BBK friendly wheels, like APEX wheels, may clear without the need of spacers.

[The HACK]

So the two options I presented to RacingBrake are:

1. OE rotor, Caliper Upgrade: This upgrade will require a 5mm spacer to clear the spokes on 18" OEM wheels on E46 M3 and MZ4 Coupe, but the upgrade can be done with either OEM rotors or OE replacement RacingBrake rotors. This will be needed for spoke clearance, at least on the MZ4 Coupe. I don't know about E46 M3s, but the factory 18" wheel does not seem like it has better spoke clearance.

2. Full replacement "Big" Brake Kit: We took some measurement today on a spare hub, and it appears he's got enough room to move the rotor and caliper back by at least 8mm. This means he can offer a slightly larger, 350mm rotor with a new rotor hub and bracket assembly that moves EVERYTHING back 8mm. However this will require the dust shield to be completely removed. This will not fit on an OE rotor, you'll have to buy RB rotors, calipers, and carriers.

There is, of course, the unspoken option. A 360mm kit that will likely require 19" rims to clear, or 18" rims with massive spacers (15mm). That you can already buy.

You guys tell me (or RacingBrake) which you would rather have, a kit that requires a 5mm spacer, or a kit that requires NO SPACER but complete removal of the dust shield.

[The HACK]

He also showed me the 4 piston rear caliper kit, looks promising. The parts are in already, and I assume when the new caliper bracket/rotor hubs are assembled for test fit I'll test fit the rear calipers too.

[jon1275]

I run 6pot Alcon up front and 4pot in rear with OE CSL calipers and brake duct kit/plates. Running DTC70 front and DTC60 rear Hawk pads. This has been a great set up for track day car run mainly at road Atlanta. I have had trouble in past with overheat but not a problem since duct kit installed. Some friends and I hired Andrew Davies to do some private track tutoring last weekend. He loved my brakes and confidently ran a 1:39 at road ATL after only driving my car for 15minutes!

[tikamak]

Originally Posted by jon1275

I run 6pot Alcon up front and 4pot in rear with OE CSL calipers and brake duct kit/plates. Running DTC70 front and DTC60 rear Hawk pads. This has been a great set up for track day car run mainly at road Atlanta. I have had trouble in past with overheat but not a problem since duct kit installed. Some friends and I hired Andrew Davies to do some private track tutoring last weekend. He loved my brakes and confidently ran a 1:39 at road ATL after only driving my car for 15minutes!

Where did you get the brake duct kit from?

[Blind32]

Originally Posted by tikamak

Where did you get the brake duct kit from?

+1 Also very interested in your duct kit!

[The HACK]

Late update on this, first, I put in PFC-08 pads in the rear. Perfect fit with the *7855 pad shape in the rear.

http://store.bimmerworld.com/perform...nts-p1061.aspx

For those of you worried about the fitment and availability of pads for the rear with the OEM caliper and RB rear rotors, there are some choices. You can either run RB's XT series pads, or you can buy PFC-01, 06, 08 and 011 pads for the rear in the 7855 shape, or get any of the pads you like to use and shave ~1/4" off the bottom of the pad/backing plate. I'm about to head to Auto Club Speedway this Friday to test out the PFC-11 front, PFC-08 rear combo on OE calipers and RB rotors.

Also, RB has offered me a full set of front and rear caliper upgrade to fixed billet aluminum 4 piston calipers, so they do have kits that fit now, but the problem is, I'm now looking for work for the 3rd time in 2 years...Given the uncertainty of my job situation in the near future, I told RB that I'm going to hold off on upgrading both the front and rear calipers, at least until I start working again.

If anyone is interested, the rear calipers and the front calipers that fit (fronts require a 5mm spacer) are available and in stock I believe. Hoping the interview tomorrow goes well and I can pick up a set for next year's use (was hoping that the job situation would have cleared up by now, apparently the job market hasn't fully recovered yet).

Below are pictures I took of the PFC 7855 pad shape compared to RB's ET500 for RB rotors.

[v3.2mc]

no job =
good luck, sir!

on a side note, your developement here has prodded me into purchasing the front kit. i'm holding off on the rears as i just put OE on in march. thank you for your work on this!

[Krypptic]

I switched to that size for my rear pads when I changed rotors to performance friction. I wonder if these calipers would work with my set up.

As for now, I will wait. Just had to replace the abs hydraulic pump.

[The HACK]

Originally Posted by Krypptic

I wonder if these calipers would work with my set up.

Yes they will.

[tikamak]

Subscribed. My car needs a brake upgrade due to the supercharger's added power, i am liking what i see, better buy it now than later when its big money