Exhaust Resonators

[330ciSport]

Guys, seen some chat on this on e46fanatics but no real answers to the questions.

I understand there are two in the exhaust system which can effectively be removed. Any ideas on which one is best or can both come out?

Other than some severe weight loss,any other gains? Exhaust note? Does anyone supply replacement sections rather than a cut and weld job?

Finally, whats all the chat about "flaps/valves" in the rear box which can be opened or closed?

[BigFas]

You have 2 resonators, one towards the engine, one towards the rear silencer. One or both can be removed, it purely depends on your own ears. Emissions will be untouched as your cats are in your manifolds so will be identical.

Eisenmann make sound pipes which replace both sets of resonators or just one set. If you remove one set of resonators, people normally choose the one towards the back of the car, no real reason for this, just easy to get to I guess.

Your exhaust has a butterfly valve, this basically means that when you're at a standstill, at a traffic light or something, only one of your exit pipes is open, only when you pull away, will the other open, this is for controlling noise levels. You can keep this valve permanently open, just reach in, unplug the pipe going to the valve and plug the pipe with a golf tee.

[330ciSport]

Excellent, I knew there would be good use for those used mashed plastic tees! Well done Fas!

[Durgesh]

Yes a golf tee would work, but I have a screw in mine. Its a little more secure.

Make sure you don't just pull it out, and not cap it, because you will lose a little low end torque.

Durgesh