Muffler Delete or Secondary Cat delete - 128i N52

[Bimmer-Bob]

Originally Posted by carscatscoffee15

My current set up is AA headers + axle back exhaust with my secondaries and resonator still on (128i N52). I'm debating on either keeping my secondaries and getting a section 2 delete or getting the Supersprint Section 1 straight pipes with their section 2 tuned resonator. Anyone have any experience or take on this set up? The car isn't my daily so the noise won't be an issue I just wouldn't want it to be drone-y too raspy.

I've been thinking about the Supersprint section 1 straight pipes for a while now. I've got AA headers and a MagnaFlow cat-back (includes muffler and resonator), so the secondary cats are really the only stock part of the exhaust left. Seems like a no brainer, but I'm just not sure what to expect in terms of tone, volume, or fuel smell (which definitely increased a little after the primary cat delete).

Supersprint has a killer sale right now, I think through the end of the month (20% off). I sometimes wish I had just gone with Supersprint from the headers all the way back, but $$$. The section straight pipes themselves aren't too bad, especially right now.

[carscatscoffee15]

Originally Posted by Bimmer-Bob

I've been thinking about the Supersprint section 1 straight pipes for a while now. I've got AA headers and a MagnaFlow cat-back (includes muffler and resonator), so the secondary cats are really the only stock part of the exhaust left. Seems like a no brainer, but I'm just not sure what to expect in terms of tone, volume, or fuel smell (which definitely increased a little after the primary cat delete).

Supersprint has a killer sale right now, I think through the end of the month (20% off). I sometimes wish I had just gone with Supersprint from the headers all the way back, but $$$. The section straight pipes themselves aren't too bad, especially right now.

I'm in the same boat but also wonder if I can have a shop fabricate some sort of high flow cat so I can have a happy medium. I also wouldn't know how that would affect emissions in my state (NYS)

If it is, then I'd have to either go the high flow cat route or keep my stock pipes and just switch em when that time for inspection comes but I also worry about getting pulled over often

[Bimmer-Bob]

Originally Posted by carscatscoffee15

I'm in the same boat but also wonder if I can have a shop fabricate some sort of high flow cat so I can have a happy medium. I also wouldn't know how that would affect emissions in my state (NYS)

If it is, then I'd have to either go the high flow cat route or keep my stock pipes and just switch em when that time for inspection comes but I also worry about getting pulled over often

I tend to think that the secondary cat delete won't do much, and may be much more trouble than it's worth. For one thing, it can obviously complicate emissions testing, depending on which state you live. That doesn't affect me at the moment, but I'm concerned with going through all the trouble and then finding the whole set up too loud, or too fume-y.

Still, I like the idea of eliminating what must be the most restrictive part of the exhaust path that remains, and kind of go through this in my head every year when Supersprint has their sale, lol. Maybe I'll take the plunge one day.

[Rmtt]

Originally Posted by Bimmer-Bob

I tend to think that the secondary cat delete won't do much, and may be much more trouble than it's worth. For one thing, it can obviously complicate emissions testing, depending on which state you live. That doesn't affect me at the moment, but I'm concerned with going through all the trouble and then finding the whole set up too loud, or too fume-y.

Still, I like the idea of eliminating what must be the most restrictive part of the exhaust path that remains, and kind of go through this in my head every year when Supersprint has their sale, lol. Maybe I'll take the plunge one day.

From what I have seen....the secondary cat delete really isn't worth the hassle for the gains you see.
And some people don't like the drone it creates on some setups.

I contemplated it when switching over to the MagnaFlow setup as you could get their cat-back with resonator which I did, or you could get their other setup which hooked straight to the headers and was straight piped to their muffler. It was listed for the 135i...but worked on the 128i as well.

It's an easier install as you don't have to cut any pipes.

I went with the other because it was something like $600 cheaper, plus I didn't want any excess drone or smell of gas.

[carscatscoffee15]

Originally Posted by Rmtt

From what I have seen....the secondary cat delete really isn't worth the hassle for the gains you see.
And some people don't like the drone it creates on some setups.

I contemplated it when switching over to the MagnaFlow setup as you could get their cat-back with resonator which I did, or you could get their other setup which hooked straight to the headers and was straight piped to their muffler. It was listed for the 135i...but worked on the 128i as well.

It's an easier install as you don't have to cut any pipes.

I went with the other because it was something like $600 cheaper, plus I didn't want any excess drone or smell of gas.

A member on this forum has a similar exhaust set up as I do save for the secondaries (he doesn't have em, I still do) and reports no drone

[Rmtt]

Originally Posted by carscatscoffee15

A member on this forum has a similar exhaust set up as I do save for the secondaries (he doesn't have em, I still do) and reports no drone

Maybe the drone may just come with certain aftermarket exhausts.

I know I have a friend with AA headers on an otherwise stock exhaust 328...and you can't even tell his car has headers.

[Olgeezer1]

Just deleted secondary cats,had stainless straight pieces welded in. Otherwise stock exhaust w/Golf T mod. N52. Was looking for a subtle increase. Don't know that I really got it. Very slight improvement if any. A little more noticeable at full throttle maybe. According to a couple of dynos I've seen there's a few hp there, 5-9, but that's not anything you're going to feel. My exhaust guy said on his car he noticed a slight improvement in mpg (non-BMW) from 12 ltrs/100k to 11 ltrs/100k. After living with this for a while now I'm coming to like it more. There's a little more base in the tone of the exhaust a better sound throughout the range. It's a subtle change, but for me this might be just right.

[E82Fam]

Originally Posted by mitchellbrown98

I originally had the BMW performance muffler, and thought it sounded great, but wanted my 128 to be slightly louder. I went with the secondary cat delete and it is the perfect volume and sound now. Not too loud or drony with the windows up but sounds great with them down.

I have the same setup but haven't deleted the secondary cat yet! Do you have a video you could send of how yours sounds?

[xxatticus]

Originally Posted by E82Fam

I have the same setup but haven't deleted the secondary cat yet! Do you have a video you could send of how yours sounds?

Second the sound clip request!

[christian_128i]

If I were to proceed with deleting my secondary cats, will I have fitment issues with active autowerke headers? I saw a post about it on a different thread but the member was referring to their e90, and the only suitable brand that fit their secondary delete was AFE. Can someone clarify this, please?