1536Z4 wrote: ↑Sat Aug 14, 2021 9:44 pm
Did your Schmiedmann headers and cats fit without any problem ?
No, it is a set designed for an E46 automatic I believe. (and this is a set for the m54, I don't have a z4m but a 3.0i)
My set also isn't the 'copy' of the supersprint design, it's a different design with some crazy bends and curves.
Its this set:
https://www.schmiedmann.co.uk/en/bmw-E4 ... ct=SCM5254
With these headers:
Headers are fine, although very difficult to fit as they have a big pipe diameter and lots of curves, so they mask many cylinder head studs.
(the set they have now for the z4 (so the supersprint copy).. I don't believe they even had that back then when I installed it and supersprint is just very expensive.
The pipes that contained the cats (so the S pipes) had to be shortened, but there was a piece of pipe included that can slot inside the original pipes, so a cut and some special exhaust clamps did that trick.
And also some cuts had to be made and welded shut to align the cats closer together (otherwise they touched the transmission tunnel).
And to mate with the existing exhaust system (that had a much smaller diameter), I think I used a piece of stainless sheet that I bend in a circle and used as a spacer, with a powerful exhaust clamp clamping it shut (I probably made some slits to shrink).
The exhaust set was very cheap, I think I paid €610 incl VAT so about £520, but it took some minor work.
With a professional exhaust shop, that work would probably have taken a full day (fitting the headers not being able to reach the nuts taking quite a portion of that day).
Mind you, this set doesn't fit a british car! (I have a LHD car). That steering column axis going through there is a pain for you guys*.
I don't even know if there's an aftermarket header solution for british m54 cars. I don't know if schmiedmann has a UK set. In the past there has been talk about it but I've never actually seen one that someone fitted
I've seen people modifying RHD S50 headers (e36 m3) (those still were proper headers) for M54 engines (weld on a different cylinder head flange). Because for the s50 engine there was a RHD version made of course.
The M54 exhaust manifold is extremely restricted. Internally about 1x 1" if I had to guess.
That's why I always say: when having an inline six, when it's british made it should be RHD, when it's mainland (or US) made it should be LHD.
Because the I6 has a definate cold and hot side. With british I6's the cold side and hot side are swapped. That way both the steering column and brake system are on the cold side which is way better for performance and build. So there's definately a technical advantage here.
Z4 3.0i | ESS TS2+ | Quaife ATB LSD | Brembo/BMW performance BBK front/rear | Schrick FI cams | Schmiedmann headers+cats | fully polybushed | Vibra-technics engine mounts | H&R anti rollbars | KW V3 coilovers | Sachs Race Engineering clutch