M3 Exhaust System Terminology

[RElias21]

Let me start by saying, I've tried to search, but I find the searching on this forum to be difficult.

I was hoping someone could clarify all the different parts/terminology of the M's exhaust system.

For example, what is an X-Pipe? Test Pipe? Mid Pipe?
When someone just says exhaust, does that mean from the cats and back?

If someone could list all the consecutive components/parts of the exhaust from the engine to the tips after the muffler, that would be great.

Thanks in advance

[BrewRifle]

It goes like this - Headers / X-pipe (primary and secondary cats and resonators) or midpipe / Exhaust.
Test pipes only replace the Primary Cats, which reside on the X-pipe or midpipe

Exhaust usually refers to the portion just after the X-pipe on our cars.

[rjd598]

i'll leave this photo here because it helped out a lot when i first started learning about exhaust systems. i won't answer all your questions, but here are the simple ones:

we have an x-pipe. see how they are shaped?

test pipes replace the primary cats on our cars. the most power/sound will come from "deleting" your primary cats. test pipes are popular versus getting a full x-pipe because they are much cheaper and subjectively yield the same results.

i would assume mid pipe refers to xpipe. most people use the term xpipe. based on context it might refer to a specific part of the xpipe?

when someone says "exhaust" it could mean anything. usually they just mean the muffler. there are the tips, muffler, and xpipe.

[Beemdog]

Pic of the exhaust system:

X-pipe is the center section (the "X" is under the black cross-brace).
Toward the front of the car next to the black transmission cover are
the primary cats. This is where a "test pipe" would go.

Replacement muffler portion would be an "axle-back", everything aft of the X-pipe..

[jphughan]

I've always thought the M3's stock headers (aka exhaust manifold, the part that attaches to the engine) are a work of art. For comparison, here is a C6 Z06's stock headers:



And the M3's:





In case you weren't aware, the reason for the much more complex design on the M3 is so that all cylinders have equal-length exhaust tubes. Further reading here if you're interested: http://www.vikingspeedshop.com/equal...ust-manifolds/

[RoleeM3]

Just one more reason why I love the S65 she looks and sounds good. What else can one say.
But you definitely need to mod or change the exhaust. She will come alive then.