Porsche Brembo 996 BBK conversion

[Tbonem3]

Heat capacity, modulation/feel

If you're not going to be stopping hard repeatedly, you're better off with stock brakes.

[eljay]

Sorry to ask a newb question, but given that the 996 kit has less braking torque, are there any advantages over stock ZCP setup?
Are they really just for looks?

I ask because I have ZCP brakes now and need new rotors very soon (and I'll change pads too), so naturally, I'm looking at "upgrades" and the 996 kit option is tempting. Sadly, my car doesn't see regular track duty, meaning I hope "one day" to get back on track, but if that happens, it will be light duty unlike many of you track warriors.
Any recommendation for my situation?

[mrgizmo04]

does anyone run any type of aftermarket master cylinder with this setup or strictly OEM E46? I am not very impressed with this setup on the track (Ds1.1 pads) and am wondering if going to a different master cylinder could help? would 996 GT3 even be a possibility? It has a 27mm piston vs our stock 25.4mm

What you are experiencing with this kit is the lower clamping force generated by the front caliper...
The rears with 30/28mm pistons generate about the same clamping force as stock. The fronts (I was actually surprised how small the calipers and the 2 pairs of pistons were when I was rebuilding a set), with the 40/36mm pistons, generate about 16% less clamping force that stock fronts. This naturally moves the bias backwards, but also front+rear of the 996 kit is overall less than front+rear of stock. Using more foot/pedal force as was suggested...is a solution, but remember that also locks up the rear sooner...
I won't go into too much calc/detail here, but due to pi*r^2 (mainly r^2) term when calculating surface area of pistons, a stock single 60mm piston has a much larger area (and more clamping force for same brake pedal travel) vs 40/36mm pistons.

Regarding the master cylinder...I posted in some other thread, but depending on what threads folks read, good to post again so we as a community grow and learn. Somewhat counter intuitive, but you would want the master cylinder diameter to be smaller that stock to generate more force at the calipers. Per Pascal's law, the force difference is proportional to areas of the pistons - master cyl vs caliper pistons (the circular area, not total volume which takes into account the length/height of the piston or travel of the piston). Think of how your hydrolic jack works, same principle. You pump a handle connected to a small cylinder (equiv of brake pedal/master cyl) which converts the hydrolic pressure to a much larger force via the big piston that allows you to raise the car (equiv of hydrolic pressure in the brake lines pushing against the caliper piston areas).

Doing calculations as well as talking to folks who run 996 kit on track, to enjoy it more...You have to "cheat" the fact that fronts have lower clamping force by putting a higher mu pad there vs the rear (friction coefficient also incorporates into total clamping force on top of piston areas, disc diameter, etc, but not pad size that's more for handling heat). Folks who run same pad front/rear find it a bit underwhelming. Folks who run DTC70 front and DTC60 rear, or I think Radek settled on PFC pads and runs PFC11 front and PFC08 rear, LOVE it.

I will be testing out several setups in terms of BBK. I've run the full ST40 355 front and rear. I felt that rear was overkill (it does have nice benefits of swapping rings and pads front to rear as things wear). Funny enough, I discovered the rear ST40 kit has both pistons which are 28mm. I was actually surprised by this, as ST is well known for making BBK setups, and normally with multi piston setups you want the trailing piston to be larger to counter gas/debri/material buildup as the disc rotates to get even pad wear. The rear having same pistons was a bit annoying with pedal feel and pad wear - pad wear was tapered which also pushes out one of the pistons more so each piston is not handling the same volume of fluid. I've sold off the rear 355 kit. As quick side note in terms of piston sizes, front pair is 42/38 on ST40, which brings the bias and overall clamping force back toward what stock feel is.
Now on the car I have the front ST40 355 and rear 996 kit. I also have the front 996 kit sitting in the garage. I don't know in what order I will run my combo testing ST40 front vs 996 front with the 996 rear. I have same for same pads for 996 front/rear, I don't currently for the ST40 front and 996 rear. For 996 I do have have DTC60 for both front and rear, and I also have a DTC70 for the front, so I can test those combos. When I switch to ST40, I have PFC08 pads (which I love and run all the time), I might need to get a set of PFC08 for the rear 996 kit to run same pad test.

I think what I will find through my unscientific testing, is that, running DTC70 on 996 front and DTC60 rear will actually feel relatively good. This might be a good compromise... I do run brake ducts, so I will need to see how the fronts last/behave. This setup (with higher mu pads in front) would be loosely equivalent to running front ST40 355 kit with same pad mu front/rear (in terms of feel/clamping forces, but we'll see). What might push me toward running ST40 in front instead of the 996 with higher mu pad is if I need more heat capacity (which with brake ducts I should not), but I do run sessions that are much longer than 20-30mins. 355x32 has a lot more meat to handle temp deltas vs 345x28. I will also need to see how swiss cheese front rotors do/last in terms of cracking/longevity and what that will mean in term of change intervals (even with FCP "free" warranty, swapping discs once a year or several times a year might get a bit old), if I can run ST40 meats for several years between changes.

I am excited by having FCP warranty, they do have Hawk pads back in, I know the downside is that dust is corrosive...I'll need to see what feels good for my driving and then decide. This will be multi month period of testing, so don't expect results next month. I'm also not super active here these days, but I'll try to update impressions/findings here and on youtube.

Sent from my SM-G950U using Tapatalk

[selm3]

So what track oriented pad is everyone buying from fcp euro now a days?

[Sergmann]

D737 is the pad shape you are looking for for no "rust ring"

[Tonggi]

996 Carrera (non turbo models) and 986 Boxster S, if you don't want a rust ring, go with the D737 front pads from the 986 Boxster

are those both front pads of carrera non turbo?

I'm currently looking up "Front Pads off 2000 Boxster 2.7L Non S" That is what im using to find the pads for the rear, I believe those are D737. If no rust ring with D737 then im in, I was under impression D738 had better pad surface?

[SWRT_M3]

what car does the Pad D738 come off of? I plan to buy my pads off FCP Euro as well.

996 Carrera (non turbo models) and 986 Boxster S, if you don't want a rust ring, go with the D737 front pads from the 986 Boxster

[Tonggi]

what car does the Pad D738 come off of? I plan to buy my pads off FCP Euro as well.

[robgill]

yea lifetime is hard to beat.

Agreed. I ran both ECS (lasted like 10 track days) and PFC front rotors (going in 11 track days and almost done) with aggressive pads (PFC08). I’ll be switching to FCP ZCP as soon as these PFCs wear out…

[Tonggi]

Tough sell with FCP selling ZCP rotors.

yea lifetime is hard to beat.

[FCD46]

Silbergrau metallic here is a member that has multiple Brembo 996 BBK kits for sale.

https://r.tapatalk.com/shareLink/topic?share_fid=2212386&share_tid=129086&share_pid=129098&url=https%3A%2F%2Fnam3forum%2Ecom%2Fforums%2Fmobiquo%2Fredirect%2Ephp%3Fpid%3D129098&share_type=t&link_source=app

Hey that’s me! Lol, I’m like man that picture looks familiar haha

yes I have (2) full sets of 996 front and rear. 996.351.425 and .426 are the correct fronts you need, everything is at the front page of this post!

electric yellow (not machined yet)
bright green (I believe the rears are sold, should get payment soon) fronts are machined and I have the rally road brackets on hand.

I followed this post for the part numbers, sourced individually all the new pieces, a second set came for sale at that time so I just bought two of everything and got the second calipers too to have them redone.

feel free to PM me with any questions, I’ll try to answer but most these guys on here would be better able to answer I’m sure!

[Obioban]

anyone try other rotors other than ZCP replacements? like DBA or PFC? Just asking out of curiosity.

Tough sell with FCP selling ZCP rotors.

[Tonggi]

anyone try other rotors other than ZCP replacements? like DBA or PFC? Just asking out of curiosity.

[WOLFN8TR]

Silbergrau metallic here is a member that has multiple Brembo 996 BBK kits for sale.

https://r.tapatalk.com/shareLink/topic?share_fid=2212386&share_tid=129086&share_pid=129098&url=https%3A%2F%2Fnam3forum%2Ecom%2Fforums%2Fmobiquo%2Fredirect%2Ephp%3Fpid%3D129098&share_type=t&link_source=app

[Tbonem3]

Everything you need, is in the OP