[GhostyM]

So I wanted to get catless downpipes and run it with my Comp exhaust on my M8 (M8 forum is dead so I'm posting here).

Now I'm aware that BMW is tracking tunes and whatnot, so I'd rather not do that, is there any fix for the inevitable CEL I'll be getting or am I better off just getting a new exhaust, rather than downpipes?

EDIT: Through some sleuth searching using Google (bimmerpost sucks with searches), it seems I need to get an O2 bung extension from like Fabspeed and that "should" work with ER downpipes?

[onfireX5]

Originally Posted by GhostyM

So I wanted to get catless downpipes and run it with my Comp exhaust on my M8 (M8 forum is dead so I'm posting here).

Now I'm aware that BMW is tracking tunes and whatnot, so I'd rather not do that, is there any fix for the inevitable CEL I'll be getting or am I better off just getting a new exhaust, rather than downpipes?

EDIT: Through some sleuth searching using Google (bimmerpost sucks with searches), it seems I need to get an O2 bung extension from like Fabspeed and that "should" work with ER downpipes?

For some strange reason those types of extensions are hit or miss. Sometimes they work great, sometimes they do not work at all. Has to do with DME learning, fuel type and the moon phase. If you try them, I would use an obd2 module and reset all learned parameters to give relearn a chance. Good luck.

[Higgs Boson]

leave the cats in place if you don't want to tune

[r33_RGSport]

Originally Posted by GhostyM

So I wanted to get catless downpipes and run it with my Comp exhaust on my M8 (M8 forum is dead so I'm posting here).

Now I'm aware that BMW is tracking tunes and whatnot, so I'd rather not do that, is there any fix for the inevitable CEL I'll be getting or am I better off just getting a new exhaust, rather than downpipes?

EDIT: Through some sleuth searching using Google (bimmerpost sucks with searches), it seems I need to get an O2 bung extension from like Fabspeed and that "should" work with ER downpipes?

O2 bung extension is hit and miss like onfireX5 said.

The one guaranteed work is mini-cat. But it has age to it.

The other way is just to do the secondary delete.
I've sold a lot more secondary catless downpipe than the primary. Because it adds volume to the exhaust note.

[GhostyM]

Originally Posted by r33_RGSport

O2 bung extension is hit and miss like onfireX5 said.

The one guaranteed work is mini-cat. But it has age to it.

The other way is just to do the secondary delete.
I've sold a lot more secondary catless downpipe than the primary. Because it adds volume to the exhaust note.

Thanks for the help!

As far as % volume increase how much louder is a catless primary/secondary compared to a single catless secondary in terms of volume? What is a mini cat? I want to retain my stock mufflers for the quiet/loud exhaust control.

[r33_RGSport]

Originally Posted by GhostyM

Thanks for the help!

As far as % volume increase how much louder is a catless primary/secondary compared to a single catless secondary in terms of volume? What is a mini cat? I want to retain my stock mufflers for the quiet/loud exhaust control.

You can do that with Remus exhaust or Akrapovic exhaust.
Both brands have valve system that uses the factory control.

Volume wise, full catless about 50% louder. Secondary catless, about 20%.

Here is my IG link for M8 Competition with just secondary catless.
Will sound the same as your M5. Same engine, same exhaust layout.



I have more videos there for other combination.

Mini-cat, you can Google it.