Here's the internal's of an 02 OEM muffler. Things I noticed:

Enjoy!

 

 

Awesome post, was always curious how the inside looked! Thanks!

 

You can see the "hammer marks" on the muffler. It required a LOT of force to rip back the 2nd of 2 layers in the muffler. The outer layer, is rather thin and is easy to cut through. The inner layer is twice as thick and was in perfect shape.

Doing it over again, I would have repaired the broken pipe (near the flange between the mufferl and mid-pipe) and replaced the stainless tips with a 2.75 stainless tips (got them from JC Whitney).

In the end, keep the OEM muffler!

 

That is a very cool post, sir. Thanks for taking the time to take pics and show us the internals.

P.S. I do miss the bit of torque the muffler helps with, but I have yet to miss it since I got my WS2 muffler.

 

Wow. Just... wow.

Always wanted to see inside that black box. Nice post, man.

 

For all the n00bs I made the following diagram in Paint. Red line is usual flow, blue is after 3,000rpm when the left exhaust tip "opens" to increase flow.

 

Great thread! I like the arrows too. I was always curious to know how the stock muffler functioned. As for the stock muffler's quality? If it's as good as the stock one on my wife's '91 Maxima, it should last a long, long time. Her's recently lost it's outer skin so I just cut it off. I figure it should take another 20 years to get through the inner skin seeing that it's twice as thick as the outer skin.

Pete, are you happy with the Walker or is the stock muffler better?

 

Very cool! I have read about the "valve" in the muffler and now I fully understand how it works. No wonder they cost 250 bucks. Performance seems to be a priority for our cars, even down to the muffler.

 

I dont think it rpm related that valve more of a pressure related

 

Nice job! I've also always wondered about the famous 'variable capacity' muffler. I even installed one of my beater '93 Altima about 5 years ago and felt a noticeable difference in low end tq and liked the sound it produced vs the regular Altima muffler.

So you're liking the Walker even better? My Max muffler has developed a rattle that's slowly getting louder and it's internal so I'll probably be replacing it down the road w/a larger diameter catback setup...


Jeremy

 

In our 5th gens, 3k is where it builds enough pressure to utilize the second tip, which is what n3985 is saying. So both are true, I guess. So the rate of the spring is designed to be strong enough to hold before <3k and open when at >3k

 

I would think that pressure and RPM would be related.

 

Overall, I am happy with the Walker.

* As quiet as stock
* Fitment is an issue, tends to rub on the rear axle. Will fix that with some kind of shim.
* Overall quality is excellent. Has one less restrictive kink in it than stock. Worth at least 0.025 HP
* Looks great with JC Whitney Stainless tips on it (see first picture above).

 

Only indirectly. RPM + load = resulting pressure at the muffler. Regardless of the RPM the throttle angle will determine how much airflow through the engine there is. 5000 RPM @ 25% throttle, for instance, won't get it done.

 

owesome pics pretty strong muffler, about the only thing that doesnt rust as bad under the car.

 

Nice vid. Actually shows at low rpm/pressure only the right side outlet (passenger) flows the exhaust. Only when revved both pipes dumped the exhaust.

***Happy New Year***

 

If I had to do it again, I would have gotten the OEM muffler ($270+) and a Cattman b-pipe or Walker b-pipe. Not looking for additional HP, just reducing the noise of a broken mid-pipe for the past 2 months. Cattman had no mid-pipes fabricated so I didn't want to wait another 2 months.

But overall cost was cheap (~ $275 for mid-pipe and muffler)

 

Interesting i had always assumed that it was electronic like the one in my 3000GT VR-4. Obviously there is a lot less to fail with a mechanical design, but some performance loss compared to an electronic valve.

 

Thanks for the clarification-makes sense. More air flow in = more exhaust out = more pressure = open the gate.

 

I did the same thing on my old 4th gen muffler. It's hard to resist the opportunity to see how things work.

 

really sick post man! ive been curious for years what the inside of one of these beasts looked like.

 

This also explains why the damn thing weighed 9000 pounds when I took it off the car.

 

Nice post, cool to actually see the inside

 

I always wonder how it looked inside.. thanks!

 

Is there a difference between the 5th gen and the 5.5 gen oem muffler?

 

IIRC the 5th gen muffler isn't a dual stage muffler like the 5.5, however the AE got the dual stage muffler.

 

IIRC all 5th gens got the dual stage mufflers(different designs between the 5th and 5.5's though)

 

This is why I call it a trick muffler!!!!

This ain't trick...at all! LOL.....

 

blow it out ya tail pipe!

 

5th gens and I30s had the same muffler right? Or was it a little different, since on the spec sheets it has 5hp more(from the exhaust IIRC).

 

i would like to see why...

 

Can someone rip open an AE!?!?!

I was under the impression that all 5th gens were the same. GXE, GLE, and SE.

 

good to know...

 

It has always been my impression that the extra 5hp the AE got was from the exhaust.

 

Really cool pic man! Learn something new every day.

 

its both intake and exhaust that were improved.

 

thanks for doing this. really cool to see the "guts" and get a better understanding of how it works.

 

OEM or Nissan? I cant find a Nissan Muffler for anywhere near that price (all close to 400). All "OEM" versions I have seen have a notation that the bypass valve isnt part of that muffler.

 

I have seen a lot of things, the inside of a muffler...not. Great stuff!