The M2 Competition finally got the engine the M2 deserved. The S55 twin-turbo six pulls like an M3, but the factory exhaust makes it sound raspy and flat, and the stock muffler hangs low and sags under the rear bumper.
The Dinan Free Flow Axle-Back Exhaust with X-Pipe for the BMW F87 M2 Competition fixes both. Redesigned internal baffling and larger 70 mm piping (up from 65 mm stock) give the S55 a deeper, throatier note, and an X-pipe in place of the factory resonator adds volume and smooths out the rasp. It is 100% T304 stainless steel and finishes in quad 4 in. (102 mm) double-walled, laser-engraved black ceramic tips. On Dinan's dyno it adds 6 HP and 5 lb-ft at 6,300 RPM.
M2 Competition Axle-Back Exhaust Sound, With the Valves Intact
The factory computer-controlled exhaust valves stay in play. At low speed they limit noise, so cold starts and highway cruising stay civil. Under high load they open fully and let the S55 breathe. Dinan's install guide calls for no coding or tuning.
Install and Legal Status
The muffler section bolts on, but the X-pipe does not. It replaces the factory resonator, so the stock exhaust has to be cut at two points measured from the catalytic converters. Dinan quotes 2.5 hours of labor. If you are not set up to cut and clamp exhaust pipe, have a shop handle it. Because it does not affect emissions, Dinan lists it as legal for sale and use on emissions-controlled vehicles in all 50 states. Dinan part number D660-0082-BLK. Sold by AutoTecknic, an authorized Dinan dealer.
What's Included
- Dinan T304 stainless steel valved muffler assembly with X-pipe
- Quad 4 in. (102 mm) laser-engraved black ceramic exhaust tips
- Hardware kit with clamps, couplers, valve mounts and extension harnesses
Key Features
- Dinan-tested +6 HP and +5 lb-ft at 6,300 RPM
- X-pipe replaces the factory resonator for more volume and a smoother note
- Larger 70 mm piping vs. 65 mm stock for freer flow
- Factory exhaust valve function retained: quieter at low speed, fully open under high load
- 100% T304 stainless steel construction
- Quad 4 in. (102 mm) double-walled, clamp-on black ceramic tips, laser engraved
- Replaces the low-hanging factory muffler for a cleaner rear view
- Emissions legal in all 50 states (does not affect emissions)
Vehicle Fitment
Fits the S55-powered BMW M2 Competition:
- BMW M2 Competition / F87 Coupe (2019-2021): M2 Competition
Not compatible: 2016-2018 F87 M2 (N55 engine). For that car, see the Dinan Free Flow Axle-Back Exhaust for the F87 M2. Dinan does not list the M2 CS for this system.
Installation Notes
Budget about 2.5 hours on a lift. Unlike Dinan's earlier M2 axle-back, this system requires cutting the factory exhaust for the X-pipe, so have a cut-off tool ready or book a shop. Follow the Dinan instructions included with the system.
- Raise and support the car, let the exhaust cool completely and remove the center brace.
- Support the muffler, then mark and cut the stock exhaust at Dinan's measured points behind the catalytic converters.
- Unplug both exhaust valve motors, unbolt the four hangers and remove the stock exhaust.
- Transfer the hangers, then fit the valve actuators, brackets and springs to the Dinan valves.
- Slide the X-pipe onto the cut pipes with the 63.5 mm clamps, then hang the muffler and attach it with the supplied couplers.
- Install the four tips, center them in the bumper cutouts and torque all clamps to 45 ft-lbs.
- Reinstall the center brace, connect the valve harnesses, then heat the exhaust and recheck clearances.
