mfrasca

Just a heads up. I put a Magnaflow full system on my 545i and it is ridiculously loud. The drown between 1500-2500 rpms is crazy. Just thought I would let anyone know that is thinking of going this route. Going to remove and sell if anyone is interested. I'm in Mass. No shipping. Part # 16558

myxyzxo

I was thinking of getting that as well.. But after hearing a few clips on youtube, I opted not to. Should also mention in the past I;'ve noticed that newly installed exhaust or muffler deletes tend to sound loud. After awhile they die down a bit.

quanger

Drone can be easily manipulated by install 23" caped J Pipes near each tail pipes. Drone frequency can be calculated. My original set up were just X-pipe and 2 magnaflow. Yeah, It drone between 1700-2500. Beside the drone, the sound was Amazing. I then have 2 bottle type resonators installed. The sound calm down, but the drone still there. Then i found a page from a Mustang's forum about drone issues. Which led me to the calculation below for the J-pipes installed:

The calculation for length goes like this (try stay with me here):

(RPM of drone you want to eliminate * 4 exhaust pulses per rotation) / 60 = Pulses per second

-then-

Velocity of sound waves (1150ish ft/sec) / Pulses per second = Feet per pulse

(Feet per pulse / 4 for a quarter wave tube) * 12 (to convert to inches) = Length needed

--So to eliminate drone at 2300 RPM (my highway regular cruising speed) it'd be:

(2300 RPM * 4) / 60 = 153.3

1150 / 153.3 = 7.5

(7.5 / 4) * 12 = 22.5 inches

It sounded silly, but it works for me. The drone at freeway cruising speed is 95% removed. Now it sounds a bit better than Factory set up. But too quiet still for me. I'm considering remove the resonators, since I have learned how to manipulate the drone.

The below link has some pictures of my setup, for anyone considering doing the full cat set up:

https://5series.net/forums/e60-parts...-141035/page2/

myxyzxo

Quanger. You should change your name to FrankenE60 .

BrandonSS

Quanger isnt full of it. It's basis is hermoltz resonance. The exhaust style is very popular in the Nissan Z/inifiniti G platforms. And yes, it does work beautifully.

myxyzxo

I read his link & do believe he is correct. Just scary when under neath his car

Boost7

I'll leave the Magnaflow to the American muscle cars....not my taste.

quanger

LoL, I've tried which ever way to make it work. My exhaust set up went under the the saw 3 times, trial and errors. But in the process, I learned something new. LoL give my Franken exhaust a break. My AWD limited space compared to your RWD. Trust me, I'm in the work to redo this set up myself. Have my fingers crossed and insurance proof are up to date. I'm not going to burn my car down.

The purpose of the capped J-pipes are to reflect the drone frequency back into the system. So when the 2 frequencies meet, they canceled out each other.
The length of the J-pipe is determine the frequency of the RPM. The shorter the J-pipe the lower the RPM drone. The longer the pipe, the higher drone RPM. I picked 2300-2400 RPM because that is my most frequent highway RPM. I can't imagine I have to endure the drone at that RPM on a longer trip.

quanger

Boost, unfortunately the Borla that fit yours does not fit mine. To compare, Magnaflow has a deeper tone than Borla. That was what I'm looking for. Personal preferences I guess.

Boost7

This exhaust looks freaking nice..who makes it?