Is swear by these things,, Steve is going to use them on his 427 hybrid

http://www.dynomax.com/press_releases/dynomax%C2%AE-introduces-revolutionary-drone-free-muffler.html
 

Are you running an H-pipe?  That effectively changes pipe lengths and can cut out some of what you are experiencing.  You can also install a "resonator" just before the tail pipe exit that helps to kill the amplification.

MustangSteve wrote:

"I LIKE THE SOUND BUT WANT SOMETHING THAT SOUNDS DIFFERENT".   Sounds like something I would come up with...

The thing is I love the over all sound, not to loud, a little crackel like a glaspack and a little low rumble like a turbo.  If I could go from 1900 RPMs directly to 2100 RPMS this would not be an issue at all  

change the length of your exhaust pipe.  You can try both lengthening and shortening. You will have to play around a bit to get a proper length to remove the resonance and still have the looks you want.  You can also change the diameter of the after-muffler pipe.

Hey Daze, is this the pipes you uploaded the image of awhile back with all the welded angles and no real bends?

I once read a fine article about the wave form generated by small ford engines in particular, and how the wave length happen to ring our exhaust systems, (not simply the muffler, but everything behind the exhaust manifold), like a bell.  It explained that running a pipe between the left and right side, perpendicular to the flow, but not penetrating the system, would very effectively change the harmonic of the pipes.  So say for example, you have dual exhaust, and emulate an H-pipe just in front of the fuel tank, or in front of the rear axle.  Just tacking it between the pipes, uninvolved in the flow, changes the harmonic of the pipes.

I suppose if you wanted to test this without going to the trouble of tacking in a "dead flow" chunk of pipe, you could take a heavy c-clamp, or several pair of large vice grips clamped along your pipe somewhere and change the vibrating characteristics similarly.  I'd be curious to know you yours turns out!

Lance

GPatrick wrote:

So how about that H-pipe?

exhaust has an x pipe

The valve in the VT mufflers seems to work very well in Don's mufflers on his 66 GT.  It eliminated his drone issues.  I think the variable nature of the valve system is what makes it work.

Like so many gearheads out there, if I cannot see it, then it is not real, but it is coming more apparent there are higher tech answers to many questions.  I like the idea of the separate chamber pipes, kind of like Ford does on the air intakes to the engines.  But you have to be fairly high tech and do some experimentation to figure that stuff out...  I am glad to see some of you are stepping out of the old methods and into new territory.  I am listening to see what happens.

Greg B wrote:

maybe a shorter, or longer muffler of the exact same type you have.   That should change your tuning fork.

worst part is the thing looks like a tuning fork.


 

Don wrote:

My  "hero" now that's what Im taking about,, oops I mean the steering linkage   just like I like it
 

ya that was before I rebuilt the control valve.  Does this look a little better?

Daze wrote:

Don wrote:

My  "hero" now that's what Im taking about,, oops I mean the steering linkage   just like I like it
 

ya that was before I rebuilt the control valve.  Does this look a little better?

Did that Mustang valve turn out to be useful?

Daze, I like what GPatrick and GregB said.  In the late '50s and into the '60s, Ford used "resonaters" on their exhaust systems, in addition to the muffler.  I would think they knew what they were doing.  Those old cars with 390 FEs making large HP did not drone.  As to what GP and GB were saying, I think if you change one exhaust, aft of the X pipe, it should change the tendency to drone.  On that Gal, you have plenty of room to add a resonater behind the rear axle.  One could easily be made from an piece of old drive shaft cut to the length you need, with pipes welded to both ends, as an example. 
Just thinking out loud.
Good Luck.