Dinan Valved Cat-Back Exhaust with Black Tips for G01 / G02 BMW X3 M40i and X4 M40i
Dinan’s Valved Cat-Back Exhaust for the G01 BMW X3 M40i and G02 X4 M40i replaces the stock single-to-dual exhaust with a single straight, unrestricted 83mm T304 stainless steel pipe and four individually functioning quad tips, finished here in black ceramic coating. The factory exhaust valve stays fully functional, so the system still shifts between a quiet cruise and a full, aggressive voice on demand, but a Helmholtz-equipped muffler cancels drone at highway cruising frequencies instead of muting the exhaust note. Dinan has built BMW performance parts since 1979, and it backs this system with a warranty program developed with BMW of North America that can match up to four years or 50,000 miles of factory coverage, so the upgrade adds power and sound without giving up warranty protection.
Design and Performance
The factory-style exhaust valve stays fully functional, opening and closing exactly as BMW intended, so the X3 M40i and X4 M40i can idle quietly in a residential neighborhood one minute and open up on a canyon road the next. Dinan removes the factory’s central resonator and collector and replaces the stock single-to-dual pipe layout with one straight, unrestricted 83mm pipe, letting the Helmholtz-equipped muffler cancel drone at highway speed rather than muting the exhaust note altogether. The result is the low, signature Dinan rumble layered under the B58’s factory character, backed by real numbers on the dyno.
Features
- 100% T304 stainless steel construction, TIG welded, with no hydroformed piping
- Four individually functioning quad tips, 3.75 inches, finished in black ceramic coating with a laser-engraved Dinan logo
- Direct bolt-on design; no cutting or welding required
- Level-1 install difficulty
- Compatible with the Dinan exhaust valve remote for full manual valve control (sold separately)
- Emissions Code 5 rated; street legal in all 50 states
Specifications
- Pipe Diameter: 83mm (stock: 80mm)
- Tip Size: 3.75 in. / 95mm, quad configuration
- System Weight: 53 lbs (stock system: 60 lbs)
- Peak Horsepower Gain: +6 hp @ 6,600 rpm
- Peak Torque Gain: +5 lb-ft @ 6,600 rpm
- Installation Time: approximately 2.3 labor hours
Applications
- BMW X3 M40i: G01 | 2018-2025 | 3.0L Turbo I6 B58
- BMW X4 M40i: G02 | 2018-2025 | 3.0L Turbo I6 B58
Notes
- A polished-tip version is available as Dinan part number D660-0099
- Retains full BMW factory valve control and pairs with the Dinan exhaust valve remote for manual override (sold separately)
- Rated Emissions Code 5 and legal for street use in all 50 states
- Includes a printed installation guide and a laser-engraved Dinan logo on each tip
Frequently Asked Questions
- Does this exhaust fit both the BMW X3 M40i and X4 M40i? Yes. It fits the G01 BMW X3 M40i and G02 BMW X4 M40i, both pre-LCI and LCI, from the 2018 through 2025 model years. Dinan includes the mounting hardware, clamps, and hangers needed for a direct bolt-on installation on either chassis with no cutting or welding required.
- Is the Dinan exhaust valve still adjustable after installation? Yes. The factory-style valve control is fully retained, so the system still switches between a quiet cruise and a bolder, more aggressive tone. Owners who want manual control over the valve independent of the factory logic can pair the system with the separately sold Dinan exhaust valve remote.
- How difficult is the Dinan Valved Cat-Back Exhaust to install? Dinan rates it a Level-1 install at roughly 2.3 labor hours, using the factory mounting points with no cutting or welding required. The kit includes all clamps, hangers, and valve componentry needed for both pre-LCI and LCI G01 X3 M40i and G02 X4 M40i models.
- What is the Dinan Valved Cat-Back Exhaust made from? It is made from 100% T304 stainless steel, TIG welded with no hydroformed piping, and finished with four individually functioning quad tips in black ceramic coating. The factory-style valve stays fully functional, so the system retains BMW’s quiet and aggressive drive modes while opening up the tone and cutting weight versus stock.
- How much horsepower does the Dinan cat-back exhaust add? Dinan measured a peak gain of 6 horsepower and 5 lb-ft of torque at 6,600 rpm on the dyno. The larger 83mm pipe and single straight, unrestricted path free up exhaust flow versus the stock single-to-dual layout, and the gains come without giving up the factory exhaust valve’s quiet mode.
- Is the Dinan Valved Cat-Back Exhaust street legal, and is it covered by warranty? Yes. It carries an Emissions Code 5 rating and is legal for street use in all 50 states, and Dinan backs its parts with a warranty program built with BMW of North America that can match up to four years or 50,000 miles of coverage, so adding it does not have to mean giving up factory-style protection.
About Dinan
Founded in 1979, Dinan is North America’s leading BMW tuner, developing, manufacturing, and marketing a full line of high-performance products for BMW, MINI, and Mercedes-Benz. Dinan works through a nationwide network of Authorized Dinan Performance Centers, including select BMW dealerships and independent BMW service and performance shops. The company’s warranty program, introduced in 1996 with BMW of North America’s cooperation, matches BMW’s new car warranty and covers Dinan enhancements and the vehicle itself for up to 4 years or 50,000 miles. That coverage lets BMW owners add real performance without risking their factory warranty. Automotive publications have tested Dinan-enhanced BMWs against some of the world’s most exotic sports cars for three decades, and the results consistently hold up. Despite that performance, Dinan BMWs keep the reliability and everyday civility BMW owners expect. The product line spans engine, driveline, and chassis components across the full BMW lineup, covering acceleration, cornering, and stopping power. Every Authorized Dinan Performance Center can help build anything from a single upgrade to a complete Dinan BMW.
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