5Series.net - Forums - Pictures, Video, and Details of my Custom Exhaust System.

Gentlemen,

I recently had a custom exhaust system built for my N54 E61 and am very happy with the results. Here is the run-down on the system.

BACKGROUND

For the past 2 years the exhaust on my wagon has gone through many different iterations. First was a simple muffler delete, a fun improvement over stock but it left me wanting more. Next the 2ndary cats were replaced with Vibrant 1792s which offered a slight bump in sound volume.

After a while I got bored and decided to have a local muffler shop do a "custom" system for me, the 3' of oem piping (crushed ~2.3") off the DPs was left in place and the rest of the system was comprised of a Magnaflow resonated x-pipe, 2 Vibrant 1792s, and a muffler delete with a small H-pipe before the tips, all piping after the Magnaflow was crush-bent 2.5". Although there was drone in the 2,000-2,500rpm range, this setup yielded a nice smooth sound, in contrast to the flappy, farty, or raspy sound of many N54 exhausts.

In attempts to kill the drone I replaced the Vibrant 1792s (12") with their longer 18" siblings. Drone persisted but the sound got slightly softer and quieter. I started to research helmholtz and branch resonators and as an experiment had the old 1792 bottle resonators capped and welded into the muffler section as helmholtz resonators, I figured it could only help, WRONG, drone was worse. Immediately I had the muffler shop cut out everything after the Magnaflow resonator so the system is now straight piped with only the Magnaflow resonator in the mix. Surprisingly the system wasn't terribly loud, louder than before, yes, but with the added volume you got more "real" mechanical sounds. I had enough, after hearing a custom single 3" exhaust on my friends E90 (had RBs, now has an FFTEC 6466) I was convinced that was the way to go.

BUILD

Initially I ordered a QTP valve and 2 resonators so the system would be Valve Open: 1 resonator, Valve Closed: 2 resonators. I liked the idea of having options but fitting all this after my rear-axle would be a challenge and after hearing the single resonator setup I was convinced it would be quite enough for me.

Flash forward to October 2015 and I am discussing my plan with Josh at JFR Motors in Costa Mesa, CA. All is good and I drop my car off the next day with the parts I purchased for the build. Here are the specifics on my exhaust system, keep in mind I have AR "off-road" DPs.

Mandrel Bent, Stainless Steel, Tig Welded
Vibrant 2.5" flanges
Custom 2-1 Merge Collector (made by Josh) IN: dual 2.5" OUT: single 3"
Vibrant 1142 3" IN/OUT "Ultra Quiet" Resonator
Vibrant 63004 4"L Flex Section
Custom 1-2 Y-pipe (made by Josh) with dual 3.5" x 12" Slash Cut Tips (Black)

RESULT

The end result surpassed my expectations, drone which used to plague me between 2,000-2,500rpm is gone, there is some resonance around 1,500rpm but this is only noticeable when putting around parking lots. In-cabin sound levels are very manageable and I would say lower than my old system. The exhaust is now more 2 faced meaning when driven conservatively it is rather tame and civil, but when given the beans really rips.

The WOT sound is great and IMO one of the best sounds produced by a twin turbo N54. Most other N54 exhausts I like are paired with single turbos, like my buddies FFTEC E90 (custom exhaust by Filthy Fabrications) and the 829whp E90 by Motiv (exhaust unknown but Youtube it). I can't stand rasp and I am happy to say that this system is also rasp free.

In addition to the increased flow (will dyno again soon) and lighter weight, there is a significant jump in turbo noise, mainly off throttle whistle, I love it! I think this is in part due to the large diameter piping and cleaner routing. The car sounds serious!

As my wrenching skills progress along with my wagon obsession, I become more hesitant to let others work on my car. But after seeing Josh's shop, hearing his thoughts, and seeing his work, I trust him 100% and happily recommend him to others. His shop is called JFR Motors and is located in Costa Mesa, CA. (Orange County)

MEDIA

Here is a short compilation of videos I have thus far, there will be more to come.

Cold Start

Freeway Cruising