[ayyy]

Hey everyone,

A friend and I just finished up the "PE Mod" to my mufflers and I'm very happy with the result. However, I kinda got addicted to the open X pipe-back exhaust sound of not having mufflers while the exhaust was off the car. So, I was planning on installing some kind of electric exhaust cutout system somewhere before the mufflers.

However, I was wondering if a nice sound and even exhaust flow can be achieved with just ONE electric exhaust cutout. I ask this because I bought a QTP low profile electric exhaust cutout a while back for my old car but never got around to installing it, so I wouldn't have to go out and buy another one if I can make this work.

I have the N54 E92 335xi, so pretty much every part of the exhaust system is separate (dual exhaust). Still, I was looking at the exhaust diagram (see image below), and can see that there is one segment where the pipes may join, that being the X pipe right after the secondary cats. I guess my question is:

1) Do the separate dual exhaust pipes actually cross over within this X pipe assembly?

2) Would I be able to "intercept" a segment of this crossover to route to my cutout?

3) Will the cutout even fit underneath the car in this area without being much lower than the rest of the underbody? I plan on buying lowering springs soon and then air ride suspension in a year or two, so the car will be pretty low.



The exact cutout I bought can be found here in case you want to look at how it's shaped.

If it's a matter of "no, this would be impossible," then I would probably go the route of buying an identical cutout from QTP and mounting them in that straight section of pipe before each muffler. But I'm simply just trying to make use of the parts I already have.

Thanks in advance!

Originally Posted by ayyy

I would probably go the route of buying an identical cutout from QTP and mounting them in that straight section of pipe before each muffler.

That would probably be your best bet.

There's a thread/pic of that exact setup around here somewhere; looked very clean and sounded nice FWIW.

[ayyy]

Originally Posted by FCobra94

That would probably be your best bet.

There's a thread/pic of that exact setup around here somewhere; looked very clean and sounded nice FWIW.

Thanks for that response Cobra. Taking another look at that exhaust photo, I'm wondering if that "X pipe" is actually just a big empty chamber. If so, would I not be able to just cut a section out and route my cutout pipe off of that chamber? Assuming there's room underneath the car to do so, which I haven't checked yet.

Either way, any more opinions would be appreciated. Thanks!

[LQQKOUT]

You can look into welding a Y-pipe after the X-pipe or getting a second cutout. Or you can just replace the secondary cats with cutouts .

[dapz325]

You could aways just settle with one open pipe. Wouldnt do too much of a difference since a pe mod is just a muffled straight pipe. If you want a louder sound , delete your cats or replace with vibrant res. Dont know your mods but kittyless downpipes is where its at.

[ayyy]

Originally Posted by LQQKOUT

You can look into welding a Y-pipe after the X-pipe or getting a second cutout. Or you can just replace the secondary cats with cutouts .

Thanks for the suggestions, although I'm not sure I'd want the exhaust to ever go down to one pipe. Although depending on what the inside of that X pipe chamber looks like it might actually be that exact thing.

Originally Posted by dapz325

You could aways just settle with one open pipe. Wouldnt do too much of a difference since a pe mod is just a muffled straight pipe. If you want a louder sound , delete your cats or replace with vibrant res. Dont know your mods but kittyless downpipes is where its at.

I was thinking this initially, but would that cause uneven backpressure? Or would the exhaust gasses just automatically want to travel to the area with the least backpressure (the cutout)? For example if I did it right after the X pipe, on only ONE of the pipes (let's say the driver's side), would the majority of the exhaust then move through and exit the X pipe on the driver's side? Or would still half of the exhaust gas exit the X pipe on the passenger side, thus completing its journey all the way out to the tip while the other half is exited through the cutout on the driver's side? I basically just don't want to produce uneven vibrations or wear if the backpressure will be uneven as a result of this.

I will absolutely be doing VRSF catless downpipes sooner rather than later, but would like to keep the secondary cats. I just don't think I could take a completely catless car, like my friend's Audi, that constantly is giving me a headache from the fumes. But yes I'm hoping the primary cat deletes from the catless downpipes will improve the sound quality and volume.