[bigdonny]

updates:

So I went back to the muffler shop and they added a proper Y-pipe further back (slightly further back than it sits stock with the resonator) and right after leaving the lot there is a noticeable difference in performance (might be placebo).

Sound wise it is almost stock, maybe slightly louder when you get on it. When you rev the engine as the tach drops down to idle, there is a slight "buzz" sound coming out of the exhaust that sounds kind of shitty. I bet the resonator dealt with that previously.

My advice: DO NOT DELETE THE RESONATOR

It is very free flowing as it is and takes away drone and/or buzzyness.

Pic for reference attached:

[bigdonny]

Just to clarify, the current set up (cat and resonator delete to stock muffler) is NOT at all droney or too loud. It sounds basically stock all the way through the rev range.

[atmosphericM]

That buzz you're referring to is the rasp. Both the center muffler and the secondary cats were helping mask that before. It's a common side effect of exhaust modding.

Mostly, I'm just glad you got that first collector (which was more like a U-Pipe) replaced because that was surely garbage from a HP standpoint. As far as the Y-Pipe's location, keeping it near stock should be fine. I don't think it would make a huge difference moving it, though... as long as it's a well designed piece. Even your new Y-Pipe leaves a lot to be desired, but that's almost splitting hairs when we are talking about exhaust mods on an N/A 328i.

[Route 16]

To save you guys time and money just follow my set up
https://www.e90post.com/forums/showt...1040488&page=3
I have an extra vibrant 1790 resonator

Get a good intake, delete your 2ndary cats, delete oem resonator and muffler then go vibrant resonator (place it where the oem resonator was) go muffler delete

Page 1 of my link, you’ll see how it sounds, has good rasp, still burbles, barely any drone and it was a family car, good for babies to sleep in still

[bigdonny]

Originally Posted by atmosphericM

That buzz you're referring to is the rasp. Both the center muffler and the secondary cats were helping mask that before. It's a common side effect of exhaust modding.

Mostly, I'm just glad you got that first collector (which was more like a U-Pipe) replaced because that was surely garbage from a HP standpoint. As far as the Y-Pipe's location, keeping it near stock should be fine. I don't think it would make a huge difference moving it, though... as long as it's a well designed piece. Even your new Y-Pipe leaves a lot to be desired, but that's almost splitting hairs when we are talking about exhaust mods on an N/A 328i.

What would a better Y-pipe set up look like?

[Route 16]

Originally Posted by bigdonny

What would a better Y-pipe set up look like?

Generally around where the oem y-pipe meets
I’ve had over 6 muffler/pipe set ups. But don’t worry where the y-pipe starts
Just care about how wide the pipe is, 3 inch diameter max or you’ll lose torque, 2.5 in like oem is better and where to put that resonator or muffler

[atmosphericM]

Originally Posted by bigdonny

What would a better Y-pipe set up look like?

Sorry, I meant to refer to your new collector, not the entire Y-pipe setup. It looks just fine. I'd prefer the pipes coming from the headers (where the secondaries used to be) to be a bit closer together, and use a narrower collector that will create less turbulence, but again this is splitting hairs for this application most likely.



It's all about the relative angles of the two pipes when they meet.

[Doesha]

Originally Posted by bigdonny

Just to clarify, the current set up (cat and resonator delete to stock muffler) is NOT at all droney or too loud. It sounds basically stock all the way through the rev range.

At this point your car probably went through the 300+ mile adaption and your power loss you thought you had didn't happen. You should gain maybe 2 or 3 hp to the wheels with the secondary cat delete at this point.

[bigdonny]

Originally Posted by Doesha

At this point your car probably went through the 300+ mile adaption and your power loss you thought you had didn't happen. You should gain maybe 2 or 3 hp to the wheels with the secondary cat delete at this point.

Yeah, the car pulls really well. I did a charcoal filter delete + K&N drop in + silicon hose intake mod just the other day and that coupled with the exhaust setup gives the car a nice sound and more aggressive feel.

Despite the intake and exhaust mods, the car is probably only slightly louder than its completely stock state. Very slight. The fact is, if you want a more aggressive sound, you have to mess with the stock muffler. I've done some research on this forum and seen the inside of the stock muffler, and it is designed to diminish sound as much as possible. It probably flows horribly as well.

[Doesha]

Originally Posted by bigdonny

Yeah, the car pulls really well. I did a charcoal filter delete + K&N drop in + silicon hose intake mod just the other day and that coupled with the exhaust setup gives the car a nice sound and more aggressive feel.

Despite the intake and exhaust mods, the car is probably only slightly louder than its completely stock state. Very slight. The fact is, if you want a more aggressive sound, you have to mess with the stock muffler. I've done some research on this forum and seen the inside of the stock muffler, and it is designed to diminish sound as much as possible. It probably flows horribly as well.

Originally Posted by bigdonny

Yeah, the car pulls really well. I did a charcoal filter delete + K&N drop in + silicon hose intake mod just the other day and that coupled with the exhaust setup gives the car a nice sound and more aggressive feel.

Despite the intake and exhaust mods, the car is probably only slightly louder than its completely stock state. Very slight. The fact is, if you want a more aggressive sound, you have to mess with the stock muffler. I've done some research on this forum and seen the inside of the stock muffler, and it is designed to diminish sound as much as possible. It probably flows horribly as well.

Yeah I figured she just needs to learn the modifications to the exhaust you've done to her. your correct on the muffler, it is designed to quieter things that's why it weighs like 40 soemthing pounds if I'm not mistaken. I am sure that's why most just delete the muffler and secondary cats period, because of the restriction of flow and weight.