The E90 335i is the car that made turbocharged BMW tuning mainstream. The engine is the star. The factory muffler does not do it justice. Behind the wheel you get plenty of shove and not much voice, and from the back the stock tips look like an afterthought.
The Dinan Free Flow Axle-Back Exhaust for the BMW E90 335i and 335xi sedan fixes both. It replaces the factory rear section with a 100% 304 stainless steel system and dual 3.5 in. laser-engraved polished tips. On Dinan's dyno it adds 6 HP and 5 lb-ft at 6,600 RPM, where the twin-turbo six does its best work.
What the Dinan Axle-Back Exhaust Changes on Your 335i
Less restriction through the rear section means the engine breathes easier at the top of the rev range, which is where Dinan measured the gain. You also get a fuller, clearer exhaust note under load, and polished tips that finally match the car. The gains are published by Dinan, not guessed. It is an axle-back, so the catalytic converters and everything upstream stay factory.
Dinan 335i Axle-Back Fitment, Install and Legal Status
It bolts to the factory mounting points with about 1.4 hours of labor. No cutting, no welding, no tuning required. One fitment check matters: this version only fits cars with the standard rear bumper. If your 335i has the M Sport (M-Tech) bumper, it will not fit. 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 D660-0012. Sold by AutoTecknic, an authorized Dinan dealer.
What's Included
- Dinan 304 stainless steel axle-back exhaust
- Dual 3.5 in. laser-engraved polished exhaust tips
- Installation hardware
Key Features
- Dinan-tested +6 HP and +5 lb-ft at 6,600 RPM
- 100% 304 stainless steel construction
- Dual 3.5 in. laser-engraved polished tips
- Bolt-on install, about 1.4 hours
- No tuning required
- Emissions legal in all 50 states (does not affect emissions)
Vehicle Fitment
Fits BMW E90 3 Series sedans with the standard rear bumper:
- BMW 3 Series / E90 Sedan (2007-2011): 335i, 335xi, 335i xDrive
Not compatible: cars with the M Sport (M-Tech) rear bumper.
Installation Notes
A DIYer with a lift or good jack stands and basic hand tools can do this at home. Plan on about 1.4 hours. Let the exhaust cool fully before you start and follow the Dinan instructions included with the system.
- Raise and support the car safely and let the exhaust cool completely.
- Loosen the clamp or flange ahead of the factory muffler and unhook the rubber hangers.
- Remove the factory muffler and tips.
- Hang the Dinan axle-back on the factory hangers and connect it with the supplied hardware.
- Align the tips in the bumper cutouts, tighten all hardware, then start the car and check for leaks.
