sdwndr

I agree that you shouldn't judge an exhaust by a sound clip, but when I listened to the Bassani or Borla clips, they blew me away and the Corsa clips I heard gave me shivers, so I used that side by side comparison as the basis for my decision (and one of the clips was off the Corsa website, if they couldn't make it sound good to me, that worried me). Would have loved to hear them in person first though...

Regardless, I am once again in the dilema where I hear some people saying Dynamat works great to reduce drone and other saying it is a waste of time and money. I have not been convinced enough to drop the hundreds of dollars to get it done. I can't image spending hundreds of dollars installing this, adding all that weight to the car, and then having it do nothing to accomplish my goal for installing it in the first place. And that comment of it actually getting louder because you have reduced the road noise (which makes sense) scares me even more.

Any explanation for these people that claim to dynamat their trunk and under their rear seats and have major effect on the drone? What the hell?!

CrazyAl, basically you are saying all I have to do is insert two Borla XR-1 mufflers on each side of the exhaust just before the Bassani mufflers and this will elimate the drone? How does this effect the sound and performance?

hawgman

Well, not to dispute what Crazy Al said, but I significantly reduced cabin exhaust noise with sound deadener. I have FRPP Borlas on mine and it was pretty loud. Installed fatmat extreme in the trunk and under the rear seat and it is quieter now than it was with stock exhaust. Hell, I can hear my supercharger again

sdwndr

And here we have someone else in favor of the sound deadening! Why would this work for some people and not others?!

Stang Skeleton

The sound deadening material definitely made a difference with the Bassani X and muffler set up. The Bassanis in particular have a very distinct tone and not as much drone as the borlas or magnaflo. But they were definitely loud b4 the dynamat. The loud wasnt necessarily what was annoying in my opinion, but rather the drone at low rpms. The sound deadening made a a difference in the drone, but only to a perfect amount for the bassanis imo. (note: this set up is still quite loud, it helped with drone alot more then loudness) Ive heard the borlas and magnaflows inside the cabin, and dont think it would have really helped as much in those cases. Its definitely better than nothing to have some sort of sound deadening because it does help, but some people may not find it worth the money for the result they get. Although, i would say that if someone who didnt drive the car everyday got in to listen for before and after, they would notice a very slight difference (still noticable though). But for someone who drives the car often it makes alot of difference. In this particular case though with the bassani set up, it was just the perfect sound point.

CrazyAl

I think the sound deadening performance may vary depending on the exact source of the noise and where the may is located with respect to it.

For example, if you mufflers are the main source of the noise and then you mat the hell out of the trunk area, that would probably have a decent effect.

If for some reason your spare tire well was resonating due to the frequency of your particular exhaust setup, and then you deadened it, then you'd probably have a good benefit as well.

...but there are many possibilities for how exhaust noise is being transferred into the cabin, and there are many different combinations of exhaust parts, each of which will have a different noise characteristic. So what works for one person, and what works for someone else are two different things.

The only thing I can say with certainty is that most sound deadening materials are much less effective for strong, low, tones, such as exhaust drone. As I mentioned before, this is well documented in literature and you can read all about it in various books.

In my car I'm sure the exhaust was quieted down somewhat. But the other sounds of the car, and road noise, basically disappeared. This made it SEEM like the exhaust was louder. Now then I don't have a drone problem, so I can't say empirically what would have happened to the drone "before and after", but after deadening the heck out of my car, I can still hear the exhaust just fine.

Resonators will NOT cause any drop in HP of your car. They are basically a very small, "straight-through" muffler, that serve to "break up" the long lengths of tubing to prevent them from having a resonant frequency that co-encides with the engine, thereby preventing droning. Becasue they are a "straight through" design, they have no restriction on the exhaust flow. You can use a purpose-made "resonator" for this, or you can use any small muffler. I used the Borla XR-1 bullet mufflers becasue they are small OD, non-restrictive, and they are made out of the same 304 stainless as the rest of my exhaust. If I had to do this again, I would probably buy something else--not becasue of performance (they work damn good) but because of fitment. I had to do a lot of fiddling and modification to get them to fit, when they should have been a very simple drop-in install.

BradInFl

Does anyone know how many square feet it takes to cover the trunk and under rear seats? I am planning on buying some fatmat or one of their competators of ebay tonight. Thanks

CrazyAl

Just guesstimate and buy a little more.

The trunk floor is what, about 4' x 4'? That's 16 square feet, plus a little extra to get the sides of the spare tire well. Call it 20 sq. ft.

Behind the seats? Depends on how much you want to do, but assuming you're going for some significant coverage, that's about 4 ft x 3' or so: 12 sq. ft.

I'd grab some extra for the body sheet metal in the trunk area. 36 sq. ft. total?

jwgroovin

At the risk of hijacking your thread, I have Mac axlebacks (loud WONDERFUL sound with horrendous drone at 2000rpm), Bassani catted x-pipe (mellowed the Macs and killed some of the nagging high frequency drone) and BBK shorty headers. After installing the headers, I was horrified when I turned the key and my wonderful exhaust sound had been completely muted by the BBK headers!! Deeper, yes, but definately not as loud. My son, standing outside the car, however, said it sounded even better. Confused, we took videos and discovered the headers killed almost all the high frequency sound getting into the cabin through the body, making day to day driving much more livable (drone isn't COMPLETELY gone, but almost). From the outside though, it's an awesome tone. At the Ford Nationals in Carlisle a few weekends back, I had more questions and compliments about my exhaust note than anything else. Even the lead Ford engineer (that Vietnamese guy) loved it.

Just a thought.

John

BradInFl

Thanks crazyal. I tihnk I am going to order this Ebay Mat Does anyone see any reason why I should not get this product?

MikeVistaBlue06

See this thread:

https://mustangforums.com/m_1344532/tm.htm

Damplifier Pro works very well. I can actually hear my stereo now and carry on a conversation in the car. I got the most bang for the buck doing the trunk, doors, rear quarter panels, and front quarter panels (see pictures). I also bought a gallon of his spray stuff and did the rear outside quarter panels where you can't get in there.

Take your knuckles and rap gently on the metal. Where you hear it ring, that's where you need the sound deadining material.

The best place to use for a non-damped area is the roof of your car. Rapping gently on the roof will let you know what you don't want the rest of the metal to sound like!

Hope this helps.

Mike