If you have driven an M550i with the windows down, you know the V8 is in there somewhere. The factory center section is built to hush it, with narrow tubing and resonators doing exactly what BMW designed them to do. You want less hush.
The Dinan High Flow Middle Exhaust for the BMW G30 M550i xDrive replaces the factory center section with 3 in. T304 stainless steel tubing, up from 70mm stock, and a mandrel-bent X-pipe. The result is a louder, smoother, fuller V8 note from a bolt-on part, with no welding and no tune.
Why the Dinan Mid-Pipe Uses a Mandrel-Bent X-Pipe
Most X-pipes are stamped, which pinches the tube where it bends. Dinan's X-pipe is made from mandrel-bent tubing, so it holds its diameter through the bend for minimum restriction. The crossover evens out flow between the two banks of the V8, which is what cleans up the tone and gives the exhaust a more consistent, layered sound. It is 100% 304 stainless steel from end to end.
Compatibility, Install and Legal Status
Dinan has confirmed this middle exhaust fits with the factory rear exhaust and with the Dinan Free Flow Axle-Back. It has not been confirmed with other aftermarket rear sections. Installation takes about 2.7 hours with the included mounting hardware. Because it does not affect emissions, Dinan lists it as legal for sale and use on emissions-controlled vehicles. Dinan does not publish a horsepower figure for this part, so we do not either. Dinan part number D660-0080. Sold by AutoTecknic, an authorized Dinan dealer.
What's Included
- Dinan 3 in. T304 stainless steel middle exhaust with X-pipe
- Mounting hardware
Key Features
- 3 in. T304 stainless steel tubing, up from 70mm stock
- Mandrel-bent X-pipe for minimum restriction, unlike stamped X-pipes
- Even flow between both banks of the V8
- Louder, smoother, fuller exhaust note
- 100% 304 stainless steel construction, 55 lbs
- Bolt-on install with included hardware, about 2.7 hours
- Confirmed to fit with the stock rear exhaust or the Dinan Free Flow Axle-Back
Vehicle Fitment
Fits the V8-powered BMW 5 Series:
- BMW 5 Series / G30 Sedan (2018-2023): M550i xDrive
Rear exhaust compatibility: factory rear exhaust or Dinan Free Flow Axle-Back only.
Installation Notes
This is a bigger job than an axle-back. Plan on about 2.7 hours on a lift, and have a helper to support the system while it goes in. Let the exhaust cool completely and follow the Dinan instructions included with the kit.
- Raise the car on a lift and let the exhaust cool fully.
- Support the exhaust, loosen the clamps between the catalytic converters and the rear section, and unhook the center hangers.
- Remove the factory middle exhaust section.
- Fit the Dinan middle exhaust and X-pipe, and loosely install the supplied hardware.
- Align the full system, tighten all clamps and hardware, then start the car and check every joint for leaks.
