I am looking for a way to reduce the drone from my SLP Loudmouth exhaust. For some reason my car is exceptionally bad, and it might have something to do with my headers :shrug: but since I can't switch to Long Tubes, they have to stay. It is bad enough to "buzz" the t-tops, vibrate your vocal chords when you try to speak, and it even seems to have vibrated my rear speakers a little loose... serious drone! I like loud exhaust but this 1.5k RPM-2.3k RPM (cruising range) drone is too much. The strange thing is that I think my car sounds perfect and doesn't drone like this for the first 2 minutes when the car is cold, it seems to warm up and that when things get bad <img src="images/icons/confused.gif" border="0"> .

So far I have narrowed it down to three choices and I need some of your opinions here.

Xr1 Borla muffler: But my ground clearance is an issue, my car is lowered and I am scrapping the edge of the resonator now on speed bumps, 5 inch diameter might get ripped off. Also, this is a pricey gamble, I have seen the video of the Camaro with this done (posted on all of the boards) and I like how it sounds, but sometimes these things can be decieving and you can't tell if it cleared up the drone. The original message thread from it was lost in the LS1.com conversion and I don't remember what the owner had to say about it.

Dynomax Bullet: The ground clearance is better and the price is right, but I am concerned that it might not help with the drone as much.

Custom Chambered I-pipe: (GMMG Style) The ground clearance is perfect with this idea since it is roughly the same size as the rest of the piping. Also, it is custom order I could have it made as much as 23 inches long and just mate it up with the opening of the y-pipe. Cost is about $70, but it will take about a month to have fabricated. I just have no personal experience with this type of "chambered exhaust." The person who turned me on to this idea (from the LS1.com forum) had a smaller one made to replace his resonator and says that it eliminated all of his drone and make it deeper in tone. But I am worried about it not flowing as well as the other designs (loss of HP?) and actually not working on my car, that seems to be more "prone to drone" than others.

Any input here would be greatly appreciated.

 

No ideas? How about just a couple of votes?

I am leaning toward the GMMG knock off idea, but does anyone have some opinions on how well the chambered exhaust pipes flow? I would be doing a 2.5 inch center baffle which I believe is the same that GMMG uses. All total the 23 inch length is about 3/4 of the 32 inch (16 x 2 <img src="gr_images/icons/wink.gif" border="0"> ) length of chambered piping on the real GMMG and it would have less bends, but the location is less ideal than their system.

Does anyone know how well these flow? The one on the far left to be particular:


[ February 08, 2002: Message edited by: BlackHawk ]</p>

 

I put a dynomax bullet in place of the loudmouth resonator and it's still too loud. I have a ARE 422ci motor with longtubes, though. Recorded 104 decibels from 40 feet away accelerating out of a corner. Yipe.

 

Those chambers look pretty restrictive...I have thought about going that route though, but now i'm pretty set on the Hooker catback: cheap, flows really well, little/no drone, and sounds great!

Chris

 

Hmmm the drone from my loud mouth actually quieted down after I had my headers installed.

I too thought about getting a chambered muffler, though a bit more expensive. Not because I thought my current set up was too loud but I was hoping for a different better sound. I figured that the chambered muffler couldnt be too restrictive since many braxxton and GMMG owners love it and Ive never read a complaint about losing power.

BlackHawk: Those are some intersting pics, do you know if all chambered muffler look that way from the inside or just those? Ive never have a chance to look at some but I have heard how the Braxxton sounds on our cars and I loved it.

<img src="graemlins/formula.gif" border="0" alt="[Pontiac]" />

 

[quote]Originally posted by Trans Am WS6 RGS:
<strong>Hmmm the drone from my loud mouth actually quieted down after I had my headers installed.

I too thought about getting a chambered muffler, though a bit more expensive. Not because I thought my current set up was too loud but I was hoping for a different better sound. I figured that the chambered muffler couldnt be too restrictive since many braxxton and GMMG owners love it and Ive never read a complaint about losing power.

BlackHawk: Those are some intersting pics, do you know if all chambered muffler look that way from the inside or just those? Ive never have a chance to look at some but I have heard how the Braxxton sounds on our cars and I loved it.

<img src="graemlins/formula.gif" border="0" alt="[Pontiac]" /> </strong><hr></blockquote>

Yeah, I have heard that LT's do quiet down the drone, but I have the little JBA's and I am starting to think that they do the oposite <img src="gr_sad.gif" border="0"> .
Really, I don't think that my car is just too loud, at wide open throttle it is absolutely sweet. I dont't seem to have the "common" problems with the LM sounding crappy when cold (in fact it sounds better cold <img src="images/icons/confused.gif" border="0"> ) and mine hold it's composure all the way to 6k RPM with no major poping or pinging. It's just this damn deep vibrating drone that occurs right at cruising range that is driving me nuts, it's really bad.

As for the design of chambered (GMMG Style) mufflers, this is what they all look like insde. I'm sure that you are aware that the GMMG system is a copy/imitation of a system that GM offered for Chevelles and F-Bodied cars back in the late 60's, and the place that is willing to do the custom muffler/piping (www.sweet-thunder.com)mainly does reproductions of those systems, and since the "chambered" design has not been changed since the 60's it is the same. I am just a little worried about flow characteristics, it kind of looks like it could be a turbulence nightmare, and that's why I figured I would post the question here. Hopefully someone with a little more experience and knowledge on exhaust will be able to help. Heck, the inside of a Flowmaster makes no sense to me, I just don't know enough about exhaust muffling and flow characteristics to say this is good or bad.

 

Just add one more dynomax bullet at the rear of the car where the muffler is supposed to go. That should help alot.