Re. swapped M52/S52 exhaust setup
 

I'm currently running the stock 318 exhaust with a modified connector pipe. I'm thinking of doing a custom setup using 2.5 piping and a Magnaflow or Flowmaster muffler. What are some setups that you swapped people use? I feel that the motor is choking on the stock setup as of now.

I'm planning on letting a local muffler shop here in Baltimore install a Magnaflow of similar size and shape as the one they sell in their M3 cat-back kit. That thing sounds pretty good and the can itself is a pretty standard size and shape and isn't much bigger than the one they sell for their ti kit.

Magnaflow is the way to go.
Just be sure it is a muffler with packing material.

I use mine with 2 inlets and one tip.

Would you happen to have a pic of the Magnaflow you are using? I'm going to have this fabbed up in the couple of weeks. Do have any noticeable gains running the Magnaflow? What size piping did you end up using? Thanks in advance.

Here's the info I collected from the Magnaflow site for comparison purposes.

Magnaflow 16528 Cat-back
1999 BMW 318ti
L4 1.9L
5 x 8 x 14in. Muffler
2.5in. Tubing
3.5in. Polished Stainless Tip
SINGLE REAR EXIT

Magnaflow 16604 Cat-back
1998 BMW M3
L6 3.2L
5 x 8 x 18in. Muffler
2.5in. Tubing
3.0in. Polished Stainless Tip
DUAL REAR EXIT

Also take a look at this thread.
http://www.318ti.org/forum/showthread.php?t=30165

Thanks for the info. I was considering 2.75, but if Magnaflow uses 2.5 even on the M3, it should be enough for the M52 to breathe.

Double check the Magnaflow website for the pictures, but I'm pretty sure the M3 setup uses twin 2.5 inch pipes into the muffler.

It will be fine.

I'm using http://www.summitracing.com/parts/MPE-12148/
Muffler, 2.25 in. Inlet/Dual 2 in. Outlet, Stainless Steel, Natural, Each

Or rather, dual 2" in and 2.25" out.

What would be the best pipe diameter size for a custom setup? I was considering replacing the m3 mid-pipe with a similar piece just with larger tubing and no cats, back to a b an b triflo. engine is an s52

Mine is 2.5 custom all the way from the headers to the tip. Racing cat + resonator, Borla turbo muffler 1 in, 1 out. Very happy with the exhaust, sounds low key, no drone, yet provided good air flow for the 6 cyl.

hopefully we can check it out at bimmerfest this year.