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Dinan D660-0085 Free Flow Axle-Back Exhaust System for BMW - M340i/M440i

(1984-1989 Buick Electra; 1977-1983 Buick Estate Wagon; 2020-2024 BMW M340i; 2020-2024 BMW M340i xDrive; 2021-2024 BMW M440i xDrive + 3 more models)

Part of: Dinan Free Flow Axle-Back Exhaust System for BMW

Other options in this family: Dinan D660-0085-BLK Dinan D660-0079-BLK Dinan D660-0360

Manufacturer

Picture for manufacturer Dinan

Part Number

D660-0085
9 reviews
Sale Price

$2,349.95

In Stock (10+)

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Usually delivered within 2 days

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Fitment guaranteed

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Product Details

The Dinan Free Flow Axle-Back Exhaust delivers a performance-oriented exhaust upgrade for 2020-2024 BMW M340i and M440i models, combining enhanced sound with measurable power gains. Engineered with precision, this system features larger 76mm diameter piping compared to the stock 70mm system, promoting improved exhaust flow and reducing back pressure.

Performance Gains:

  • Adds 6 horsepower at 6600 RPM
  • Increases torque by 5 lb-ft at 6600 RPM
  • Reduces weight by 4 pounds compared to factory exhaust
  • 30% less restrictive than OE valves with twin 76mm diameter exhaust valves

Premium Construction:

  • 100% 304 stainless steel construction for durability and corrosion resistance
  • Quad 4-inch diameter double-walled, polished exhaust tips with laser engraving
  • Clamp-on tip design for easy installation and removal

Smart Valve Technology:

  • Retains factory computer-controlled exhaust valves for noise compliance
  • Valves limit sound during low-speed cruising and open fully under high-load conditions
  • Reuses stock exhaust valve actuator and adds second valve/actuator to opposite side
  • Promotes even exhaust flow regardless of valve position

This bolt-on system includes all necessary mounting hardware for straightforward installation. The result is a sportier, more engaging exhaust note without excessive drone during everyday driving, making it an ideal upgrade for enthusiasts seeking performance and refinement.

Products specifications

Fits

1984-1989 Buick Electra; 1977-1983 Buick Estate Wagon; 2020-2024 BMW M340i; 2020-2024 BMW M340i xDrive; 2021-2024 BMW M440i xDrive; 2021-2024 BMW M440i; 2022-2024 BMW M440i xDrive Gran Coupe; 2022-2024 BMW M440i Gran Coupe

Brand

Dinan

Exhaust Type

Axle-Back

Tip Diameter

4

Material

Stainless Steel

Prop 65

WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov

Category

Exhaust

Dinan Point Value

3

Emission Code

5

Height

10

Labor Time (Hours)

2.5

Length

54

Max HP Gain

6 @ 6600 RPM

Max Torque (lb-ft) Gain

5 @ 6600 RPM

Product Type

Axle-Back Exhaust

Sub Category

Exhaust and Tail Pipes

Tip Finish

Polished

Warning

California Proposition 65

Weight

68

Width

29

Great database

I am very satisfied with my experience with this. Fast delivery, description of product is accurate, and the price is competitive. Thank you.

Great experience, had what I needed for my vehicle and little wait time for delivery.

Easier to navigate than most!

great

Will a tracking number be sent to me?

User friendly site (mobile) and competitive prices

Quick and east

awesome

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