Dinan's Free Flow Exhaust improves exhaust flow by reducing back pressure, resulting in increased power output and a great sporty sound that is civilized when you want it to be and pleasantly aggressive under harder acceleration with zero drone.
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. Other aspects on the other hand 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 back pressure. 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.
Benefits of the Dinan F90 M5 Free Flow Exhaust:
+ +10 HP @ 6600 RPM, +8 FT-LB @ 6600 RPM
+ Enjoyably louder, sportier sound
+ Four massive 4" diameter clamp-on, double-walled, polished and laser engraved exhaust tips.
+ 100% 304 stainless steel construction
+ Larger diameter piping for increased flow (83mm vs 80mm)
+ 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
+ Easy bolt-on installation with included mounting hardware