The N20 in your 328i or 428i is a strong little turbo four. The factory exhaust just does not let you hear much of it. You get a flat, polite tone that tells you nothing about the revs, and a set of tips that disappear into the bumper.
The Dinan Free Flow Axle-Back Exhaust with black tips gives the BMW F30 328i and F32 428i a real voice without turning your commute into a headache. Dinan engineered it to reduce back pressure behind the rear axle, and on their dyno that is worth +4 HP and +3 lb-ft at 6600 RPM. It is civilized when you want it to be and pleasantly aggressive when you lean on it.
How the Dinan Axle-Back Exhaust Sounds on the Road
The biggest worry with any four-cylinder exhaust is drone at highway speed. Dinan tuned this system specifically to reduce low-RPM drone, so the cabin stays calm on the freeway. Open it up past the midrange and the tone sharpens into something that finally matches how the car pulls.
It is built from 100% 16-gauge T304 stainless steel, so it will not rust out the way a mild steel system does. The twin 70 mm tips are ceramic coated in black and laser engraved with the Dinan logo, a clean look against the dark rear diffuser.
Dinan Axle-Back Exhaust Fitment and Legal Status
This is a true bolt-on. It uses the factory brackets and hangers, mounting hardware and clamps are included, and Dinan lists 1.3 hours of labor. Because it sits behind the catalytic converters and does not affect emissions, Dinan classifies it as legal for sale and use on emissions-controlled vehicles. Dinan part number D660-0046-BLK. Sold by AutoTecknic, an authorized Dinan dealer.
What's Included
- Dinan Free Flow Axle-Back Exhaust in T304 stainless steel
- Twin 70 mm black ceramic coated, laser engraved tips
- Clamps and mounting hardware
Key Features
- Dinan-tested +4 HP and +3 lb-ft at 6600 RPM
- Reduced back pressure for a sportier, fuller sound
- Engineered to reduce low-RPM drone
- 100% 16-gauge T304 stainless steel construction
- Twin 70 mm black ceramic coated tips with laser engraved Dinan logo
- Uses factory brackets and hangers for a direct bolt-on fit
- Legal on emissions-controlled vehicles per Dinan
Vehicle Fitment
Fits the following N20/N26-powered BMW 3 Series and 4 Series models:
- BMW 3 Series / F30 Sedan (2012-2016): 328i, 328i xDrive
- BMW 3 Series / F31 Sports Wagon (2014-2016): 328i xDrive
- BMW 4 Series / F32 Coupe (2014-2016): 428i, 428i xDrive
- BMW 4 Series / F33 Convertible (2014-2016): 428i, 428i xDrive
Does not fit the F36 428i Gran Coupe or six-cylinder 335i, 340i and 435i models.
Installation Notes
Dinan lists 1.3 hours of labor. A DIYer with jack stands and basic hand tools can do it at home. Let the exhaust cool fully before you start.
- Safely raise and support the rear of the car.
- Loosen the clamp at the factory axle-back joint and remove the factory muffler from its hangers.
- Hang the Dinan axle-back on the factory hangers and connect it with the supplied clamp.
- Align the tips in the bumper cutouts, then tighten all clamps and hardware.
- Start the car and check every joint for leaks and contact with the body or heat shields.
