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      03-15-2018, 07:30 AM   #35
Lieutenant Colonel

Drives: 135i N55
Join Date: Jan 2017
Location: NY

iTrader: (0)

Originally Posted by bm49 View Post
No work is needed if using the 335i caliper and mounting brackets; this setup was used for decades on all types of BMW including the E92 V8 M3 without attracting a bad reputation when comp pads were used. It used to be that a BMW owner who wanted to do regular trackwork but not spend much money, could upgrade brake fluid and pads, get some spare wheels with semi-slicks and have fun. I recall doing exactly that to about 6 different cars dating back to the 1980's E30 models with no brake problems whatsoever. To me the ultimate test of the adequacy of the single caliper brake setup was participating in a 2.5 day regularity event at Mt Panorama in 2010. I had a great time running the car as hard as I dared and a subsequent inspection of the car showed nothing other than the type of pad wear expected under such extreme conditions; sadly a standard 135i would not have given me the same positive outcome if only fluid and pads were updated. The prospect of constantly dropping into limp mode on every lap would have been even more dissappointing.

At the risk of upsetting some forum members I believe that many automatically seek after-market brake solutions (i.e BBK's) that are overkill for track days and more importantly for a road registered car, potentially an illegal modification that may invalidate their insurance cover unless the modification is covered by an engineering report and an RTA mod plate. My experience with getting an engineering report for my rear roll cage and minor coilover suspension mods leads me to believe that approval of a BBK would be very expensive as an engineer would need to conduct extensive tests on the adequacy of the braking system probably including track tests. The engineering report for my car cost nearly $2000 despite me providing drawings and CAMS approvals for my AGI cage and the KW Clubsport coilovers having TUV approvals in Germany. Fitting brakes from another BMW model would still require approval but nothing like the amount of potential work needed to assess things like even the adequacy of the fastenings on 2-piece rotors favoured by many BBK manufacturers.
I liked where you were going with the first part... but then you lost me.

135i calipers are more than sufficient for track use. The "melting" or "failing" phenolic piston situation is completely overblown and is not likely unless you have some serious issue with generating heat (which ironically is usually generated from having very good brake torque). Limp mode? what did you expect from a twin turbo car that you most likely tuned for over 400whp? Time for more cooling mods.
135i: E30 map by TwistedTuning, VRSF DP, Kerscher +15mm fenders, Kosei K8R 255/40/17, M3 control arms, UUC trans mounts, DV+, Whiteline RSFB, 5" intercooler, Charge Pipe, PC925 (23lb), UUC SSK, YCW Coilovers 6k/16k, Monroe shock mounts, Diff lockdown, Catch Can, N20 TMAP, 335is clutch, SMFW, 034 engine mounts, M3 Steering rack