BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i) - 135i Turbo Engine (N54 / N55), Exhaust and Drivetrain Modifications https://www.1addicts.com/forums/ Technical talk specifically related to the N54 and N55 turbo engines, exhaust and drivetrain in the 135i. en Sun, 16 Aug 2026 05:35:16 GMT vBulletin 60 https://www.1addicts.com/forums/images/misc/rss.jpg BMW 1 Series Coupe Forum / 1 Series Convertible Forum (1M / tii / 135i / 128i / Coupe / Cabrio / Hatchback) (BMW E82 E88 128i 130i 135i) - 135i Turbo Engine (N54 / N55), Exhaust and Drivetrain Modifications https://www.1addicts.com/forums/ E82 135i N55 blue smoke on warm starts https://www.1addicts.com/forums/showthread.php?t=2251674&goto=newpost Sat, 08 Aug 2026 14:47:49 GMT My 2012 E82 135i with the N55 has a very particular smoking issue: On cold starts, everything is normal. Zero smoke, even when (once warmed up) pushing the engine, decel, anything I throw at it. If I stop the engine after driving about 30-40min, when the engine is warm, and start again within... My 2012 E82 135i with the N55 has a very particular smoking issue:

On cold starts, everything is normal. Zero smoke, even when (once warmed up) pushing the engine, decel, anything I throw at it.

If I stop the engine after driving about 30-40min, when the engine is warm, and start again within 15-20min, it has bluish smoke only at idle, until I start driving or rev the engine above 2k rpm for about 2 min, and then it stops completely and drives normally, no smoke either accelerating or coming to a stop, or idle at a red light.

Somewhat similar issues I found online turned out to be the PCV valve, or valve stem seals but they had either smoke on hard pulls or when coming to a stop.

Any ideas before I decide to replace the valve cover w/pcv valve? ]]> 135i Turbo Engine (N54 / N55), Exhaust and Drivetrain Modifications nkeor https://www.1addicts.com/forums/showthread.php?t=2251674 Are CATTED downpipes worth it on 135i N54? https://www.1addicts.com/forums/showthread.php?t=2249102&goto=newpost Fri, 17 Jul 2026 17:49:21 GMT I've been away from the forums for a few years, sorry if this has been asked prior: Can anyone share their experience replacing stock downpipes with high-flow "catted". I'm looking at VRSF high-flow "catted" but wonder if the upgrade is worth the cost (performance wise). It would run around $500 for the downpipes and I'd need a shop to install. Currently the only mods on my 70k mile 2008 135i are a VRSF 5" intercooler and VRSF charge pipe with a stage 1 tune. Car is in mint condition and a blast to drive but after a few years at stage 1 some addition horses would be fun.

Thanks in advance ]]> 135i Turbo Engine (N54 / N55), Exhaust and Drivetrain Modifications bmwisme https://www.1addicts.com/forums/showthread.php?t=2249102