Dinan Free Flow Axle Back Exhaust | 2018-2021 BMW M5 F90 (D660-0079) Dinan

2018-2021 BMW M5 Stainless Steel Free Flow Axle Back Exhaust by Dinan

The F90 M5 has impressed users and critics alike with its awe-inspiring power,

effortless delivery, and general embodiment of what BMW has always been about – refined performance. Form

and function reign supreme from the factory in true German form. On the other hand, other aspects may not

be as carefully cultivated. The stock exhaust note on the F90 M5 as an example, while no slouch, is

probably best described as having a subdued aggressive note. Dinan believes for such a powerful and

impressive car however that the vehicle deserves to be able to bellow a bit louder and more aggressively.

The F90 M5 is the alpha on the public roads after all. Dinan’s goal is to let the machine sound the part

in addition to performing it. With Dinan, there is no reason to sacrifice anything in the process to meet

that goal either. Whether that be in the form of drone, civility, appearance or any other aspect.

In order to achieve desired sound volume and tone, Dinan felt becoming of the F90 M5

the tubing was enlarged to 83mm (vs 80mm stock) to allow freer flow throughout the entirety of the

system. The larger tubing is fed into a muffler that is typical of all Dinan exhaust design and utilizes

absorption and reactive technologies designed to improve exhaust flow and reduce backpressure. The

combination results in increased power output and a great sporty sound that is civilized when you want it

to be, and pleasantly aggressive under hard acceleration. This is partly courtesy of the retained

computer-controlled exhaust valves that limit noise during low-speed driving and open fully during high-

load conditions to allow free flow and greater sound as the bulk of the gases are bypassing the muffler.

Like all Dinan exhausts, our M5 free flow exhaust is engineered to reduce low-RPM drone so the cabin of

the vehicle is still intimate and not drowned in an excessively loud tone. With the Dinan exhaust

equipped on the M5 you get the best of both worlds; aggressive tone/sound and civility. A combination

that we have termed internally as “refined aggression.”

Sound isn’t the only aspect of the exhaust that has been modified. The Dinan F90 M5

exhaust has been skillfully crafted entirely out of T304 stainless steel and TIG welded for the best

visual appearance and color. The entire system is then brush finished to further guarantee an immaculate

looking system out of the box. The attention to detail is not limited to parts of the system you can’t

see once the exhaust is installed but is also extended to the exhaust tips themselves. The Dinan exhaust

sports enormous, quad 4″ (102mm) clamp-on, double-walled, polished and laser engraved exhaust tips. Dinan

has retained its signature straight-cut tip design, safeguarding its unique and elegant styling position

amongst a crowded marketplace full of angle cuts. The tips masterfully fill up and accentuate upon the

factory cut-outs showcasing an extremely aggressive, yet refined, styling that will turn heads even

before it is heard.

Features

• 100% 304 stainless steel construction
• Four massive 4″ diameter clamp-on, double-walled, polished and laser engraved exhaust tips
• Larger diameter piping for increased flow
• Stock exhaust valve actuators reused and operation of exhaust valve is unchanged so exhaust tone can

  be adjusted via the M-drive settings

• Computer controlled exhaust valves are retained and limit noise during low speed driving and open

  fully during high-load conditions

• Twin secondary exhaust valves are a whopping 76mm diameter, making them 30% less restrictive than the

  OE valves

Benefits

• Enjoyably louder, sportier sound
• More Power: + 6 HP @ 6600 RPM, + 5 LB-FT @ 6600 RPM
• Easy bolt-on installation with included mounting hardware

Applications

• 2018-2021 BMW M5

What’s In The Box?

• 1 – Free Flow Axle Back Exhaust

References

• Installation

  Instructions

Warranty

• Manufacturer Standard Warranty