[quasitime]

I'm contemplating downpipes, but I'm one of those odd ones that actually likes the quiet operation of our stock setup.

Safe to say there's no way to get the performance of an aftermarket downpipe, without the added noise level?

Opinions welcome...

[Eric335]

Catted downpipes would be a good bet. AR makes a nice set. Quieter while also allowing higher boost, but wont work as efficiently as a catless setup

[parky1215]

that's not possible. but if you have coupe, you can change stock midpipe x-pipe to sedan's resonator to further reduce noise.

[quasitime]

Yeah from what I read here, the noise level will go up no matter what. I was definitely looking at the AR catted pipes ...

[Ilma]

I had the same concern about installing downpipes.

However, Mike@N54 let me listen to his setup (catless downpipes with stock exhaust) and took me for a spin and that changed my mind entirely.

If you are retaining the stock exhaust system, then catless downpipes are hardly louder than a stock setup except in two situations:

1) Cold startup will be much louder for about a minute = no big deal.

2) WOT after 4K rpm will sound louder than stock, but still not what I would consider obnoxiously loud. It's actually a really nice sound level that's more aggresive than stock, but still very acceptable in terms of loudness.

While cruising around town, there is hardly any difference from stock setup sound levels at all.

It's a nice balance between noise and performance.

[SeanS54]

^^^ this is true...

I wouldn't even call it noise... it's hardly noticeable... no drone and no dramatic sound increase.. it sounds like a stock exhaust just a small tad louder... at least on my E90 w/ stock exhaust

[Zebra99]

Originally Posted by Ilma

I had the same concern about installing downpipes.

However, Mike@N54 let me listen to his setup (catless downpipes with stock exhaust) and took me for a spin and that changed my mind entirely.

If you are retaining the stock exhaust system, then catless downpipes are hardly louder than a stock setup except in two situations:

1) Cold startup will be much louder for about a minute = no big deal.

2) WOT after 4K rpm will sound louder than stock, but still not what I would consider obnoxiously loud. It's actually a really nice sound level that's more aggresive than stock, but still very acceptable in terms of loudness.

While cruising around town, there is hardly any difference from stock setup sound levels at all.

It's a nice balance between noise and performance.

I had this set-up on my E93. Just as beautiful as having a PE with stock DP's.

In this case more flow and stock like operation - was beautiful.
- more gurgling, growling and backfire - epic sound

[quasitime]

Originally Posted by Ilma

I had the same concern about installing downpipes.

However, Mike@N54 let me listen to his setup (catless downpipes with stock exhaust) and took me for a spin and that changed my mind entirely.

If you are retaining the stock exhaust system, then catless downpipes are hardly louder than a stock setup except in two situations:

1) Cold startup will be much louder for about a minute = no big deal.

2) WOT after 4K rpm will sound louder than stock, but still not what I would consider obnoxiously loud. It's actually a really nice sound level that's more aggresive than stock, but still very acceptable in terms of loudness.

While cruising around town, there is hardly any difference from stock setup sound levels at all.

It's a nice balance between noise and performance.

Very good info, thanks. I will definitely be keeping the stock exhaust, so this fits my situation exactly.

[dfjaws]

+1 to all of that. I have 3" kittyless downpipes and a stock exhaust and love it.

This video doesn't have the best sound quality but if this helps give you an idea... sounds stock like with a little more volume to it. No drone, no rasp.

[Envuks]

Originally Posted by CalBear_335i

^^^ this is true...

I wouldn't even call it noise... it's hardly noticeable... no drone and no dramatic sound increase.. it sounds like a stock exhaust just a small tad louder... at least on my E90 w/ stock exhaust

Agree 100%. I like the stock exhaust note. The downpipes make it a tiny bit louder, but not enough to be conceded about. Personally, I wouldn't consider an exhaust on this car because I didn't want the noise. The DPs are perfect. Find someone local and listen for yourself.

[quasitime]

Thanks! I guess what I'm used to listening to in clips are downpipes paired with some crazy loud/unique exhaust. It's hard to get a feel for just the DPs.

[jetblackcoupe]

I have stock with catless downpipes (cp-e). Idle is louder for a short time. Overall tone is deeper but volume level did not increase significantly unless past 3500-4500 rpm... Also there is some rasp nearing redline especially when oil isn't near 230/240F.

[quasitime]

Is it true that all downpipes sound relatively the same, given that they are the same type (catless, etc) ?

[dlbrooks18]

As others have said dp's plus stock exhaust is the way to go, that is my setup

[Red_Bean_Bun]

Now you guys got me thinking about this setup ...

[quasitime]

To me, it just comes down to catted vs catless options, noise, and smell. All things I'm picky about. Plus I live in California so emissions are a bitch.

On top of that, catted options are so much more limited.

[jyeah]

I was very much in your same shoes and I did a lot of research before I bought my AR catted DP. I didn't want the car to sound louder and prefer it to be stock quiet (I had the BMW PE before and sold it because it was too loud and droned).

So to answer your question, it's safe to say there's no way to get the performance of an aftermarket DP, without an increase in the sound level.

Here are some thoughts:
Cons:
1. More likely than not, you will hear wastegate rattle (especially at cold starts, you might even get a few glances at your car from other people), this is the sound that bothers me the most
2. Your exhaust sounds will be louder even with a catted DP (if you're really sensitive to sounds, you will definitely notice), but it's fairly tame
3. Any problem you experience with the turbos will be blamed at your DP by the dealership (since turbos are covered to 8 years/82,000 miles)
4. More likely than not, you will smell unburnt fuel at stops
5. SES light may appear

Pros:
1. More HP
2. Less turbo lag
3. More HP potential with tunes

I'm really happy with my AR catted DP, except for point 1, 4, and 5 in my cons list. Hopefully, I can get rid of these issues with my next upgrade and fix.

[quasitime]

So you are running AR catted DPs, stock exhaust, and still smelling a bit of it. Pretty surprising.

Have you thought about messing around with E85 to change up the smell, something like 30% with a tune/maps made for it?

[jyeah]

Originally Posted by quasitime

So you are running AR catted DPs, stock exhaust, and still smelling a bit of it. Pretty surprising.

Have you thought about messing around with E85 to change up the smell, something like 30% with a tune/maps made for it?

I was fairly surprised too when I smelled it. It's not strong, but definitely there sometimes. Maybe it's not from the DP's as I got the lean fault codes pointing to bad injectors or vacuum leak, but I don't recall smelling it with my stock exhaust. It's at the dealership now as I speak, so I'll find out later.

I'm not going to bother with E85, too much hassle.

[jyeah]

If you're around LA, maybe we can meet up sometime and you can see if this is something you really want to do.

[E90Company]

What I like the most about downpipes is the turbo spool

[parky1215]

Originally Posted by quasitime

I'm contemplating downpipes, but I'm one of those odd ones that actually likes the quiet operation of our stock setup.

Safe to say there's no way to get the performance of an aftermarket downpipe, without the added noise level?

Opinions welcome...

If you are thinking about going with catless downpipe, I have barely used ar design catless downpipe with integrated vibrant resonators in it. This may be suitable for you as it gives you same power gain as catless downpipe but with reduced drone and noise.
If interested, check my sales post.

http://www.e90post.com/forums/showthread.php?t=789294

As long as you have secondary cats in place, you won't smell much gas after cats get warm.