Hollowing-out stock muffler

[STEVEBROOKS]

I've straight-piped my truck, and while I really like the sound (around town) and its effect on lowering EGTs while towing, it really has a bad drone while towing (approx 1900-2000 rpm). I want as little exhaust restriction as possible, so I'm considering hollowing-out the stock muffler (extent TBD) and trying that. Has anybody done that? If yes, how did the sound compare with stock and straight-piped (if you've done that)? I'm especially interested in how much drone the hollowed-out muffler produces. Also, if you've done this, did you completely hollow it out or only partially remove some baffles?



Thanks!

Steve

 

[keimmmo]

I don't know about your 3rd Gen, but I gutted the muffler on my '01. 5 and love it. It REALLY helped the turbo spool up quicker, which helped my low rpm power. It also helped my fuel economy and lowered my exhaust temps. The only time I notice any more noise than stock is at full throttle at low speeds. I have NO drone at any speed or load!



You have to leave the support baffles in place when you gut a muffler or the ends will break out in short order. I owned a muffler shop for years and am an old "hotroder". I can walk you through it if you are interested.



Steve (another one)

 

[JHardwick]

I gutted my 55 gal. drum within a couple thousand miles and love the sound.



With the windows up, I could tell no difference in the cab. If you have the windows down and are up against a wall of some sort, look out! I was once headed up an on ramp with 4 horses on the goose with living quarters, that load and a wall about deafened me lol. With the windows up and the tread plate mudflap, I'm not sure I'd have heard it. I'm sure that mudflap redirects some sound as well.



I'm still not sure what you all are calling drone. Mine will "braaaaaaap", but I've yet to feel a vibration in the cab. If the windows are up, it sounds no different than the factory exhaust.



The guy in the building next to my machine shop is a diesel mechanic. He is also the guy who actually enjoys his work and comments regularly about the sound.

 

[keimmmo]

While cutting out everything inside the muffler WILL flow better than stock and give a little sound, there is a lot more tecnology inside a muffler than most people realize!



For example. On the outlet pipe if you leave about 1/2 to 1 inch of pipe and heat and flair it you can improve the outlet flow about 25% compared with just leaving the cut off end. The rear chamber on the muffler on my '01. 5 is a resonator chamber. If you take a torch and cut a 2 inch hole in that rear baffle plate in line with the inlet pipe, the muffler will be quieter... and it stands to slightly improve the flow compared to stock.



I know most people hate exhaust work and very few really understand how it is supposed to work. But, it is something I enjoy and have really studied out.



Steve

 

[STEVEBROOKS]

Keimmo,

Yes, I'd be very interested in any advice you can give on how to best gut the muffler. Being specific about what to/not to cut and how much would be extremely helpful!



JHardwick,

How did you do yours? What I mean by "drone" is that, at the rpms mentioned, the air inside the cab literally resonates with a deep, strong hum. At first it's tolerable, but after a long haul it gets to be too much. Keep in mind that the problem only exists while under a load while towing. Other than when towing, it's tolerable, but still (to me at least) louder than stock.



Thanks guys,

Steve

 

[WyattEarp]

Getting rid of the muffler was the best thing i could have done, the only thing is i was very tempted to just leave it without using the replacement kit from Geno's Garage, the sound bouncing off of the buildings was awesome and as far as a drone sound maybe i didn't hear it or i just really enjoyed the sound of the exhaust coming straight out of the resonator can.

The next to go might be the exhaust back from the resonator, because stacks are in the near future.

mileage as of today 89,232 miles and runs like it did when i brought it home

 

[keimmmo]

We can communicate directly by e-mail. You can contact me at <keimmmo@prodigy.net. mx>.



Steve Keim

 

[keimmmo]

Plan "B". I tried to give you my e-mail, but it didn't show up. Send me a Personal Message through TDR. I'll be looking for one.



Steve Keim

 

[rbattelle]

I have heard JHardwick's truck first hand, and it sounds outstanding from outside the cab. I have also driven his truck and can vouch that there is no additional noise over my truck (which still has the guts in the muffler).