[e92_bryan]

Disclaimer: if i say something stupid its only because I have only seen my car on a lift twice and its hard to find a full factory exhaust picture on google.

Please correct me if I'm wrong but isn't this how the 328i e90s exhaust is?
1st headers w/primary cats then 2 resonators that form into a y-pipe then some more piping then secondary cats, more piping then muffler?

If I'm write, which I'm not exactly 100% sure
I'm thinking about doing a custom set up, but I have 3 ideas
Option #1 resonator delete with a custom y-pipe to replace it
Option #2 resonator delete with an x-pipe at the point where they are supposed to meet and then run dual pipes until the secondary cat and turn it into y-pipe there
Option #3 resonator delete with and run dual pipes and towards the end farther away from the resonators do an x-pipe quickly followed by a y pipe into the secondary cats

The difference between 2 and 3 is the location of the x-pipe, 2 is right after the resonators and 3 is before the secondary cats w/ a y-pipe

Also are there any possible gains from one of these set ups? and which is most likely to be the loudest, including a muffler delete I already have?

*UPDATE*
Ok thanks guys I had the order of the 2nd cats and resonator mixed up.
I know you can't pass smog without primaries but what about secondaries.
So here are my new ideas
Option #4 x pipe after the second cats and replace resonator with a y pipe
Option #5 y pipe right after 2nd cats then delete resonator and run single all the way to the tips
Option #6 juts a resonator delete replaced with a y pipe

[gewse2k]

headers with primary cats =into= secondary cats =into= resonator (which is also y-pipe 2 >1) -into- muffler.

Just the part between the resonator and muffler is single piped.

At the moment I have an x-pipe instead of the resonator and a muffler. So 2 pipes all the way from front to back. Sound outside the car is great... but because of the resonator delete there's an enormous drone inside the cabin between 1500-2500rpm. And it's a wagon, so i think thats part of the problem.

But because I have a euro car I don't have secondary cats.

[Dylanize]

Some people have noticed loss of torque with res deletes. Back pressure is a big part of that, more so with NA engines. How ever I have seen good gains from removing the 2ndary cats while leaving the res. plus a muffler delete.

[Rival]

i plan to delete the res + 2nd cats

leave primary cats and stock muffler in place.

[Taskmaster]

Just no.

\\\\\=>-------------[--]----[--]= Headers to Y pipe and a single pipe all the way back into a resonator and then a muffler

OR

\\\\\=x========[--]===[--]= Headers to X pipe and dual piping all the way back into a resonator and then a muffler.

[e92_bryan]

Bump

[Taskmaster]

I just gave you the best answer, what else are you looking for?

[Love The Drive]

Don't Remember what thread this was from, but I had a screenshot of it so here you are.

From headers + main cats to..



..to muffler and tips.

[F82M4]

I say do a resonator delete along with a muffler delete and test that out first. If you have drone issues or don't like the sound, go from there. But, you will lose some backpressure due to no muffler or resonator so what I would do is delete the muffler and resonator, and put a nice free flow muffler or a resonated X-pipe in place of the resonator to dual tips.

[Taskmaster]

[SDemetris]

Originally Posted by TheAxiom

haha agreed. This is a totally solved problem. Listen my axiom on this. I personally would do his first option of one tube because racecar, but you're the captain of your own ship. Go completely straight piped like the dude with the e92 that got the MMW headers first a while ago if you really want.

[e92_bryan]

Update, i just did a basic resonator delete and I already had my muffler deleted as well, the resonator made a world of difference

[F82M4]

Originally Posted by black&silver_bimmer

Update, i just did a basic resonator delete and I already had my muffler deleted as well, the resonator made a world of difference

How did they attach it? Straight pipe or y pipe? Do you have any clips? Pictures?

[Dylanize]

Originally Posted by black&silver_bimmer

Update, i just did a basic resonator delete and I already had my muffler deleted as well, the resonator made a world of difference

Did you notice any lack of torque after removing the res???

[mike-y]

Originally Posted by black&silver_bimmer

*UPDATE*
I know you can't pass smog without primaries but what about secondaries.

As long as your smog tech doesn't look under the car, you should be able to pass.

IF the guy looks under the car, and sees you don't have the secondary cats, it's an instant fail. CA requires a visual check of components as part of the smog test. Chances are usually pretty good that they won't look though.