I can hardly think with all this DRONE...

The best chambered muffler yo9u can buy is a tak-off muffler from a mustang, be it a GT or Cobra. They are Stainless Steel and can usually be had for ~$100 for a pair.

Like these:
http://www.ebay.com/itm/Genuine-OEM...its=Model:Mustang&hash=item1e8658a9f1&vxp=mtr

After you cut off the inlet you can position them up under the rear skirt and cut the outlet and angle it down so the slant is parallel to the ground.
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I put these on a car with Trubenz true duals with an X-Box in the middle position. Drone was horrible, replaced the straight through mufflers with these and the drone dissappeared completely.
 
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I've been worried about having a system with that dreaded drone, as well, so these were my thoughts on setting up a louder aftermarket system that isn't too obnoxious.

Do you have an h-pipe? I'm not sure how an h-pipe would work on a y-pipe before the resonator and whether it would tame the sound down (and especially on a system with the mufflers right at the back of the car), but I know that on my 3.8 Stang, i'd done the exhaust as true 2.5" dual with a MAC catback, and the drone was pretty bad. After i'd put an h-pipe on it, the drone went away and it made a twangy sound into a lower, more sinister note (in the lower RPMS--at higher RPM's you can still tell that it's a V6). The best way to describe it was that the muffler sound had seemed like it was coming from the tailpipes, rather than the middle part of the car, which was where the mufflers also were.

Considering that it looks like my '91 SC shares the same coil pack as my '99 Stang, the engines are even fire, if that helps, and some people have suggested that for performance reasons in being an even fire engine, the Ford 3.8 doesn't benefit from an h-pipe like an odd firing engine would. Even though the engines are even firing ones, i've still experienced a much better exhaust note with an h-pipe.

Has anyone done true duals on the SC's, and have they had any experience to report with an h-pipe before or after the resonator? My attempt at common sense would dictate putting it before the whole system.....because h pipe affects the exhaust pulses, which is why they're almost always put before the mufflers to calm down the rest of the entire exhaust system. Some people say to put an h-pipe before the cats, but any modifications to the pipes before the cats, apparently, may not make it pass emissions.

My other observation is that from the examples that i've seen online from guys taking off their cats on Ford 3.8 engines (and/ or using an X pipe), it yields a much louder sound, but with a raspy, buzzing, unpleasant note. Longtubes give a deep sound, but in a more open system (no cats), they seem to also amplify the worst aspects of the engine's sound in the higher RPM's, almost like a "lawn equipment on steroids" sound, where it sounds great at idle, but terrible as you accelerate.
 
From what I'm gathering (including your input) it sounds like the best bet when building a custom exhaust is to include hi-flow cats.

That said, I've also been considering the idea of dynomatting/hushmatting the interior!
 
Have you looked into the dynmax VT? They are straight through mufflers with a spring loaded valve. It stops drone at cruising and fully opens under acceleration. Drone gone! Sound, awesome. Had them for a year no issues... They have two styles 4-6 cyl and 8 cyl. And relatively inexpensive. I can do a vid with sound if you like. With the magna flows I ran tips past ground effects and only slight drop in drone.The magnaflows were the problem... tips are now flush with effects with the VT's and perfect...
 
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Today's hi flow cat's work well and I am not sure they would hurt performance in anyway. Not like you would remove them and you would feel a difference in acceleration! My true duels on my 95 sound great, no drone. Same with my 89 exhaust but that has a single out resonator so it isn't duels. That also sounds nice with no drone. The guy did great work but it cost close to a grand!:eek:

My last two SC's(sold one, other was totaled), one was true duels the other a single pipe in the middle both had drone BADDDD!! I hated driving them after a while. They had cats but the resonator was smaller and so were the mufflers! So the dreaded drone was there!
 
From what I'm gathering (including your input) it sounds like the best bet when building a custom exhaust is to include hi-flow cats.

When I build my custom SC exhaust, i'm definetely going the route of hi flow cats....not necessarily for any performance gains, but just to tame down the exhaust note. Personally, i've found that the 3.8's are just way too zingy/ twangy sounding without cats, and the SC's natural exhaust note with the high pitch of the blower starts to get too high in the frequency range for my liking.
 
Have you looked into the dynmax VT? They are straight through mufflers with a spring loaded valve. It stops drone at cruising and fully opens under acceleration. Drone gone! Sound, awesome. Had them for a year no issues... They have two styles 4-6 cyl and 8 cyl. And relatively inexpensive. I can do a vid with sound if you like. With the magna flows I ran tips past ground effects and only slight drop in drone.The magnaflows were the problem... tips are now flush with effects with the VT's and perfect...

Yeah, I've been looking at them. I want to keep pretty much the same size muffler that's on there now for simplicity's sake. So I need a 14"-16" muffler with center inlet and offset outlet. That would be p/n 17949. Twice as much $ as the Super Turbo's, but that's still under $100 more.
 
?

The VT's are less than a hundred. I paid 150 shipped for both from autozone. Center in offset out. Turbos are cheap magna flows and you will still have drone...
Yeah, I've been looking at them. I want to keep pretty much the same size muffler that's on there now for simplicity's sake. So I need a 14"-16" muffler with center inlet and offset outlet. That would be p/n 17949. Twice as much $ as the Super Turbo's, but that's still under $100 more.
 
My.system consists of

Ported manifolds
2.5" cat less down tubes
Y pipe
3" 26" long glass pack
3" mid pipe
Y pipe back to 2.5
Dynomax super turbos

Zero drone !
 
Hahahaha, this thread title makes me laugh for some reason. I can just imagine you in your car, trying to enjoy a cruise, and you cannot think because of all of the drone. :D
 
Hahahaha, this thread title makes me laugh for some reason. I can just imagine you in your car, trying to enjoy a cruise, and you cannot think because of all of the drone. :D

Lol, yeah, I just got the car, and during my first drive I'm trying to think about all the things I want to do to it, and I'm pretty much stuck on this one thing... :eek:
 
My.system consists of

Ported manifolds
2.5" cat less down tubes
Y pipe
3" 26" long glass pack
3" mid pipe
Y pipe back to 2.5
Dynomax super turbos

Zero drone !

Interesting - you have super turbos on one end, but no headers on the other. I wonder which is the bigger drone killer?
 
The VT's are less than a hundred. I paid 150 shipped for both from autozone. Center in offset out. Turbos are cheap magna flows and you will still have drone...

That sounds like a good deal! Unfortunately, I just went to the Autozone site and they only carry two Ultraflow style mufflers... The lowest I've found was $90-ish (Amazon free shipping)...
 
Speaking of drone, I went to Indiana to pick up my 89. I had discussed finishing the exhaust on it. I was told it had headers to a flowmaster muffler for a resonator. I figured it had a pipe running to the back of the car but it did not. The muffler dumped under the car.....headers>flowmaster>nothing.....no pipes, nothing.

I drove the car for 13hrs like that. The drone was so loud that it vibrated the dash, side mirrors. I bought ear plugs and they did nothing to stop the noise. Took close to two hrs for my ears to stop ringing and playing tricks on me when I got home. It sounded like a alien mothership was trying to land on my roof!!!
 
Funny stuff Stephen !

The drone from my exhaust system is pretty bad, and for the first year or so, I just wanted to stab a screwdriver in my ear to make it stop. Maybe I've gotten used to it or maybe my hearing is no longer very good, because these days I barely notice it.

David
 
Easiest thing is to replace the 15" magnaflows with some Dynomax super turbo's. Basically a straight through muffler (like Magnaflow) without cats is going to be loud. Even the 18" are going to be marginal out back, and unless the pipes are already run at a 45 deg angle, they won't fit without a bunch of cutting.

The turbo style mufflers are chambered to make the muffler seem like it's 2x as long which increases dampening, but ONLY if they also have packing in them. A chambered muffler without packing will be too loud. For example, the Thrush turbo's are hollow except for their chambers, and are way too loud. The Thrush Hush series is chambered and has packing. I don't necessarily recommend those, just saying they have chambers + packing. There are other better options. The turbo style muffler is an economical way of getting more muffling into the same 15" space occupied by the Magnaflows.

On the other hand, you could also just add cats to it. Then it would be quieter and less stinky. lol

Dave,

Oval or round Dynomax's?
 
Small mufflers do small work.

Turbo-style mufflers will help a lot. A resonator will also help.

However, they work on resonance, so if they are designed for a car with a different number of cylinders, or a different overall pipe length, they won't work as well for you.

You can use absorptive mufflers in conjunction with those to try to keep the sound down.

But the best thing for drone (which is resonance) is a tuned counter-resonance. The stock system had that.

The stock system doesn't sound great ... but it beats the unmuffled sound of this V6! It just won't ever sound like a V8.

The restrictive nature of the stock exhaust is another kettle of fish. Some of the sound attenuation is due to the restriction. But it should be possible to attenuate the worst of the sound without major restriction.

If you have room, I think the quickest way to that goal is a 1/4 wave resonator tube, welded on at right angles. However, the room will probably be an issue, based on the required length.

Failing that, I think that switching to turbo mufflers (for a V6 full-size car) is a good first step.

If that doesn't do enough, I think you will need a custom center resonator.
 
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