BMW E46 High Flow Manifold Kit M52/M54 + 300-Cell Cats
BMW E46 High Flow Manifold Kit M52/M54 + 300-Cell Cats
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E46 6-cyl · 300-cell catsSCM5254
+20
HP
+37
Nm torque
304
Stainless
Complete system · BMW E46 six-cylinder · left-hand drive · professional fitting recommended
01Overview
The complete Schmiedmann high-flow system for the six-cylinder E46 — headers and 300-cell Euro3/D4 metal sport catalysts in one set, so the whole front section goes on together.
Schmiedmann call this one of the most effective ways to make power on a 6-cyl E46. On their own test 330i, with a sport rear silencer fitted, it returned +20 HP and +37 Nm.
Built from 304 stainless steel. It gives the car a deeper, harder edge — Schmiedmann's own advice is to pair it with a rear silencer that isn't too loud.
This is the full set. If you already have your catalyst section sorted, the headers are available on their own.
Schmiedmann call this one of the most effective ways to make power on a 6-cyl E46. On their own test 330i, with a sport rear silencer fitted, it returned +20 HP and +37 Nm.
Built from 304 stainless steel. It gives the car a deeper, harder edge — Schmiedmann's own advice is to pair it with a rear silencer that isn't too loud.
This is the full set. If you already have your catalyst section sorted, the headers are available on their own.
02In The Box
- High-flow sport manifold, 304 stainless steel
- 300-cell Euro3/D4 metal sport catalysts
- Adapter set including Y-piece, for cars running a single pipe to the rear silencer
Also needed
- Pipes from the catalyst back to your rear silencer
- Lambda probes for after the catalyst
- 6-speed and automatic cars: extension pipes to set the cats further back
Running a twin-pipe system? Then the Y-piece adapter stays in the box.
03Specification
Part numberSCM5254
Material304 stainless
flange is mild steel
flange is mild steel
Catalysts300-cell metal
Euro3 / D4
Euro3 / D4
Inlet pipes43 × 30 mm
Outlet after cats50 mm
Weight27,00 kg
Package size148 × 48 × 23 cm
Quantity per car1 set
ApprovalNot E-marked
04Fitment
Fits BMW E46, all six-cylinder models — the M52TU and M54 engines.
Built for left-hand-drive cars. Not for the xi all-wheel-drive models or the four-cylinder engines.
6-speed or automatic? It fits — the catalysts simply sit a little further back to clear the longer gearbox.
Not sure which engine you have? Send us your VIN and we'll confirm it before you order.
Built for left-hand-drive cars. Not for the xi all-wheel-drive models or the four-cylinder engines.
6-speed or automatic? It fits — the catalysts simply sit a little further back to clear the longer gearbox.
Not sure which engine you have? Send us your VIN and we'll confirm it before you order.
05Fitting Notes
Guide time9–14 hours
Hand these to whoever fits it — they save a lot of time on the car.
01Mark each lambda probe before it comes out. They go back in the same front/rear positions. The wires are never cut or extended.
02Lift the probes out of their holders and route them behind the engine, over the transmission — the original wiring then reaches comfortably.
03One manifold has a pressed dent from the factory. That is meant to be there — it is what gives clearance to the gearbox.
04Stock runs two heat plates under the car, this system runs one. Four nuts used as spacers between the plate and the floor give back the clearance.
05The middle-section rubber mount carries over from your original system, so the standard mounts go straight back on.
Worth ordering with it: stud bolts 11-12-7-593-376. They have a torx head and are shorter than standard, which makes getting the nuts on far easier in a tight space. Schmiedmann's own recommendation.
