just wondering because i havent seen this before but is it neccasary and if so whats it for?

For what year/model are you asking about? Perhaps you are referring to the catalytic converter?

Some more information will help quite a lot.

Well, if you are talking about the '71 240Z that's listed in your profile, the center muffler is exactly that - a center muffler. Nissan used two small mufflers to quiet the exhaust from the factory. This approach was quite common among import cars back then.

Summer, the "middle muffler" could be a resonator, which is essentially a shell of a muffler that is intended to create additional sound reflections in the exhaust. This is done to break up wave fronts, redivert them, recombine them, and cancel out much of their energy. It's also a way to break up strong resonances at certain RPMs -- to smooth out the noise suppression properties over the entire RPM range.

You can replace a resonator with a muffler, which works a bit differently, but still achieves some of that effect. There are a number of small, cylindrical, glass-pack mufflers you can insert mid-pipe. I used a Magnaflow 4" dia stainless steel muffler as a midpipe unit on my exhaust. My exhaust is fairly tame (but with a very nice, deep note at idle).

Summer.

If your car doesn't have a centre muffler it will be a little noisy. To get one fitted go to a muffler shop. They would have to cut out a section of the straight pipe and weld in a small resonator or muffler. Quite a simple job if you have the experience, and a welder. Otherwise take it to a shop.

If your car does have a centre muffler which you need to replace, it can be a dog to do. Take it to some pros. and let them do it. Not a pleasant job.

Edited November 30, 201014 yr by olzed

Well, if you are talking about the '71 240Z that's listed in your profile, the center muffler is exactly that - a center muffler. Nissan used two small mufflers to quiet the exhaust from the factory. This approach was quite common among import cars back then.

The center one was a resonator wasn't it, and the rear a muffler?

The center one was a resonator wasn't it, and the rear a muffler?

The parts microfiche refers to the center device as "ASSY - TUBE CENTER WITH PRE MUFFLER".

The end of tailpipe device is referred to as "ASSY - MUFFLER WITH TAIL TUBE"

Gary S.

Beware of the aftermarket center pipe.

About 18 years ago I installed one in my 78 280Z and immediately experienced a loss in power. The issue was with the way the collector was made, it made a huge restriction. Every parts store I went to had the same exact design issue.

Replacing it with a Genuine Nissan part fixed it completely.

Al

Bit of worthless trivia, most resonators are glass pack mufflers installed in reverse.

Just put the MSA kit on my car and it is louder than the original and I will likely put a couple of car chemistry inserts in the middle collector before I put in a center muffler. HTH, Richard.

When I redid my exhaust, I just found an aftermarket generic resonator and had it welded in. Worked like a charm, and looks snazzy in polished stainless when it is up on a rack.