I want to install a quad exaust on my 550i I got the info for a setup from this video but since its a 545 in the video clip im thinking im gonna need different part number than what he used ...i did some research but all i got was diffrent threads with all sorts of brands,opinion and ideas....but nothing on a 550i pipe diameter .....any info will help thanx!!

 

3", stock tips are 3" apiece also.

 

And now that I think about it....maybe 3.5......gosh. It's a bigger pipe than I am accustomed to but Im now doubting myself...

 

Stock piping is 2.25" from stock resonators to y pipe then 3"+ into stock mufflers. Going dual exhaust, use 2.25" all the way out. You will be increasing the flow area.

 

I'm confused because the 550i is stock dual to begin with. It just goes down the driver side into one 2in/2out muffler. The only difference with a quad exhaust is one of the pipes is redirected down the passenger side. You can still have a similar stock setup if your worried about losing velocity by installing a 2in/2out in the center leading into one resonator on each side. I thought the piping was 2.25" all the way down the driver side so I was thinking of bumping it up to 2.5" piping which is suitable for a dual system from 250hp up to 350hp. I was thinking of installing a cherry bomb vortex in the center leading into jones exhaust resonators then dual tips on each side on my quad system. It looks like you have a center 2in/2out muffler in the center then another muffler at each tip?

 

stock isn't true dual exhaust.. have you looked under the car? exiting the headers on each side to the 3inch ypipe, then it goes 3 inch single to the back and splits again into two different mufflers on ONE side of the car.

 

I'm going off of what I've read and the schematic of the OEM exhaust.http://www.getbmwparts.com/media/ima.../1/1912335.gif

I see what you mean. Do you know where to get 2.5" aluminized mandrel piping for the quad setup.

 

That is correct. After having my system for a month I'm really liking it. No drone and no difference in the butt dyno.

 

What size piping did you use. Did you use standard pipe bending or mandrel pipe bends