If you own a BMW and have the slightest interest in modding it, you’ve probably heard about Dinan. Apart from improving every aspect of your car that can be improved, using in-house developed and manufactured parts, the renowned North American tuning house knows a thing or two about how to make a good exhaust system.

Dinan’s proven experience, which spans over three decades, has shown in their latest exhaust upgrade, destined for the  F33 and F36 chassis. That’s the most recent 4 series BMW in convertible and Gran Coupe form, for those of you that are not so familiar with internal BMW coding.

Dinan Free Flow Exhaust On Car
Image Credit: dinancars.com

The 3.0-liter turbo B58 engine powering the 2014-2018 440i is undoubtedly an engineering gem, but it sounds somewhat, well, sterile and dull. That’s where Dinan comes in with this bolt-on free flowing exhaust.

It’s Not Just A Pretty Metal Box

When you look at it, you might say that it’s nothing special. Just a metal box with a couple of pipes and hangers sticking out of it. You’d be wrong. Very wrong.

Inside the “plain metal box”, or muffler to be technically exact, there is something called the Helmholtz chamber. What that tongue-twisting chamber, created by none other than a German, gives you is less drone inside the car as well as reducing back pressure. You also get a much more beautiful sound outside the vehicle, followed with burbles that’ll make you giggle.

Dinan Free Flow Exhaust
Image Credit: dinancars.com

As this Dinan Free Flow Exhaust is an entirely new system, based solely around the goal of giving you more power, the bolt-on exhaust deletes the computer-controlled exhaust valve found on the factory exhaust system and allows the exhaust gases to reach the atmosphere much faster thanks to the hefty 16 gauge mandrel bent stainless steel pipes.

As a result, you get 6 more horses in your horsepower count, and 5 lb-ft of torque more, which I have to admit is pretty remarkable to achieve with just an exhaust. And it’s not just all talk. Those are dyno proven numbers. That just goes to show the expertise Dinan’s engineers have.

Party At The Front, Business At The Back

The Dinan Free Flow Exhaust system is not just go and no show either. First of all, it’s made entirely out of stainless steel, sparing you the headaches of having a rusty exhaust. Then there are the finishes available on the laser engraved end pipes, sticking out of both ends of the car.

Dinan Free Flow Exhaust Polished
Image Credit: dinancars.com

It doesn’t matter if you like classy black or attractive polished details, Dinan’s got you covered. Depending on what tickles your taste buds, you can opt for either the ceramic black or polished stainless-steel end pipes, measuring 89mm/3.5 in diameter.  

Dinan’s engineers also took in consideration that you might have an M-sport package on your car, so they designed this exhaust system in such a way that it can be fitted to both run-of-the-mill and M-sport pack cars.

Not What It Used To Be

Listening to the sound clip provided by Dinan, I have to say that it does sound better and the performance upgrade is astounding, but I’m a bit disappointed at the same time. It’s still missing the gorgeous straight-6 sound that BMW is known for.  But, I guess I can’t blame them for that. It’s not their fault BMW made the B58 sound the way it does. Have a listen to the clip below and feel free to let me know your thoughts.