[nbay89]

Can someone give me the pros and cons of cat versus catless down pipe? Any harm in terms of mpg with one versus the other? Or with a down pipe in general? Is there a huge sound difference between the two? It would be paired with a CTS intake and MPE. Thanks!

[thejeremyman9]

You need to do your homework if you are asking basic questions like that. Read threads. Watch videos.

Catless:

1. More volume, more rasp (compared with both stock and catted aftermarket)
2. Bad smell (subjective, but there WILL be a lot of exhaust fumes)
3. Slightly more performance than a good catted DP, somewhat negligible with stock turbo application.
4. Will not pass emissions. CEL unless tune removes it.

Catted:

1. A little more volume than stock, but not much.
2. Shouldnt get any smell increase over stock really.
3. More performance than stock. Good catted (fabspeed, AA) should net you nearly the same performance as catted with stock turbo.
4. Fabspeed, AA will pass emissions; no CEL. Others will eventually throw a CEL and probably not pass emissions.


Also, consider potential fitment issues.

[mcintoshf30]

Originally Posted by thejeremyman9

You need to do your homework if you are asking basic questions like that. Read threads. Watch videos.

Catless:

1. More volume, more rasp (compared with both stock and catted aftermarket)
2. Bad smell (subjective, but there WILL be a lot of exhaust fumes)
3. Slightly more performance than a good catted DP, somewhat negligible with stock turbo application.
4. Will not pass emissions. CEL unless tune removes it.

Catted:

1. A little more volume than stock, but not much.
2. Shouldnt get any smell increase over stock really.
3. More performance than stock. Good catted (fabspeed, AA) should net you nearly the same performance as catted with stock turbo.
4. Fabspeed, AA will pass emissions; no CEL. Others will eventually throw a CEL and probably not pass emissions.


Also, consider potential fitment issues.

Honestly catted just isn't worth it; multiple people have eventually blown their expensive "No CEL" cat after doing more mods and pushing even stock turbo, and I'm not talking about flame tunes. If you are even considering upgraded turbo at some point just go catless. And even some FBO guys have blown their 1K kitty in downpipe. But hey to each their own 🤷

[Yungsta]

Originally Posted by nbay89

Can someone give me the pros and cons of cat versus catless down pipe? Any harm in terms of mpg with one versus the other? Or with a down pipe in general? Is there a huge sound difference between the two? It would be paired with a CTS intake and MPE. Thanks!

Yes, paired with a good high flow catted DP or catless will make your exhaust come alive. My vote goes for Fabspeed catted. Definitely worth the cost and sometimes you can get a good deal here on the forum.

[BMWILUVU]

I would either stay stock or go cat-less.

[thejeremyman9]

You're going to hear arguments from both sides. I would disagree with the "catted isnt worth it" argument as it very much is for some people, myself included. I debated for a year while doing other mods and ended up going fabspeed. Yes, it is expensive, but i took a do it once and do it right approach. My #1 advice is if you are thinking catless is to smell/experience it from someone else's car first. I have a catless car that is not my BMW/daily so i know what it is like. Part of the reason i did not go catless in this case. In my case, the catless "wasnt worth it" based on my own weighing of pros/cons.

[JaredG_F30]

No one mentioned cost. Catted is 5-8X more expensive then catless.

[mike@x-ph.com]

Originally Posted by nbay89

Can someone give me the pros and cons of cat versus catless down pipe? Any harm in terms of mpg with one versus the other? Or with a down pipe in general? Is there a huge sound difference between the two? It would be paired with a CTS intake and MPE. Thanks!

Catless: cheaper, louder

Catted: a mild increase in sound over stock, no fuel smell. If picking Active Autowerke or Fabspeed catted you won't get a CEL

The power increase is the same on the stock turbo. Catless will offer more power on an upgraded turbo

[mcintoshf30]

Originally Posted by thejeremyman9

You're going to hear arguments from both sides. I would disagree with the "catted isnt worth it" argument as it very much is for some people, myself included. I debated for a year while doing other mods and ended up going fabspeed. Yes, it is expensive, but i took a do it once and do it right approach. My #1 advice is if you are thinking catless is to smell/experience it from someone else's car first. I have a catless car that is not my BMW/daily so i know what it is like. Part of the reason i did not go catless in this case. In my case, the catless "wasnt worth it" based on my own weighing of pros/cons.

I daily catless... If you are stopping at FBO then catted is fine but anymore more than that it's just a waste of time and money..

[johnung]

Originally Posted by nbay89

Can someone give me the pros and cons of cat versus catless down pipe? Any harm in terms of mpg with one versus the other? Or with a down pipe in general? Is there a huge sound difference between the two? It would be paired with a CTS intake and MPE. Thanks!

You already heard the pros & cons from others. I eventually chose the Fabspeed HJS catted downpipe. Awesome quality, fitment, power and sound. I've got stock midpipe and M Performance Exhaust. Sounds amazing!

Easy to justify when I read all the guys complaining about labor to swap stock DP back on to pass emissions. I'd never do catless because of terrible smell.

Yes it's more expensive but...Several times a year it's discounted by 15%, plus you can then sell your stock downpipe to put the money towards the Fabspeed. Awesome because you never worry about emissions. Just drive!

[nbay89]

Originally Posted by johnung

You already heard the pros & cons from others. I eventually chose the Fabspeed HJS catted downpipe. Awesome quality, fitment, power and sound. I've got stock midpipe and M Performance Exhaust. Sounds amazing!

Easy to justify when I read all the guys complaining about labor to swap stock DP back on to pass emissions. I'd never do catless because of terrible smell.

Yes it's more expensive but...Several times a year it's discounted by 15%, plus you can then sell your stock downpipe to put the money towards the Fabspeed. Awesome because you never worry about emissions. Just drive!

That would be the same exhaust setup as I have. Any videos?!

[ChrisFulton]

Originally Posted by johnung

You already heard the pros & cons from others. I eventually chose the Fabspeed HJS catted downpipe. Awesome quality, fitment, power and sound. I've got stock midpipe and M Performance Exhaust. Sounds amazing!

Easy to justify when I read all the guys complaining about labor to swap stock DP back on to pass emissions. I'd never do catless because of terrible smell.

Yes it's more expensive but...Several times a year it's discounted by 15%, plus you can then sell your stock downpipe to put the money towards the Fabspeed. Awesome because you never worry about emissions. Just drive!

I have this same combination of Fabspeed and M exhaust. Very pleased and agree that it sounds great. Wouldn't want my car any louder.
Fabspeed is excellent quality, no CEL, no stink.

[mike@x-ph.com]

Originally Posted by ChrisFulton

I have this same combination of Fabspeed and M exhaust. Very pleased and agree that it sounds great. Wouldn't want my car any louder.
Fabspeed is excellent quality, no CEL, no stink.

[Polo08816]

If you aren't going to daily your car in traffic, then catless may be okay. If you are, re-consider.

[e38740imd]

Originally Posted by Polo08816

If you aren't going to daily your car in traffic, then catless may be okay. If you are, re-consider.

i have Catless and the smell doesnt bother me. there is a strong smell but with windows up i cant smell it during the winter. ive had a catless car 8 years so im used to it but the n55 smell more than my m30 cars

im big into cars so the smell makes me feel alive

[mcintoshf30]

If you keep the car long enough to where the turbo blows, it'll actually blow out your expensive catted downpipe as well. Embrace catless people.. we'll be all forced to drive Tesla's one day so experience your car now for what it can do...

[mcintoshf30]

Originally Posted by e38740imd

i have Catless and the smell doesnt bother me. there is a strong smell but with windows up i cant smell it during the winter. ive had a catless car 8 years so im used to it but the n55 smell more than my m30 cars

im big into cars so the smell makes me feel alive

Can't wait to be full E and smell straight corn hahaha

[Logicoeur]

Originally Posted by e38740imd

i have Catless and the smell doesnt bother me. there is a strong smell but with windows up i cant smell it during the winter. ive had a catless car 8 years so im used to it but the n55 smell more than my m30 cars

im big into cars so the smell makes me feel alive

Alive but losing brain cells.

[Logicoeur]

Originally Posted by mcintoshf30

If you keep the car long enough to where the turbo blows, it'll actually blow out your expensive catted downpipe as well. Embrace catless people.. we'll be all forced to drive Tesla's one day so experience your car now for what it can do...

That's not a reason to go cAtless lol.

"eat as much lead as you can before there isn't any left!"

[mike@x-ph.com]

Originally Posted by Logicoeur

That's not a reason to go cAtless lol.

"eat as much lead as you can before there isn't any left!"

[TSA8151]

https://youtu.be/vRp7tYWnJJs?t=29