Seeking feedback regarding new mufflers and their effect on EXHAUST DRONE

Has anyone in a Pantera had the drone problem?  I know many of you like your cars loud but the drone is a vibration that you hear at 18 to 2,200RPM.

DICK RUZZIN 

Hi Dick, my '72 has a massive resonance around 1800 rpm but it fades quicker than your situation....maybe by 2000 rpm it's mostly gone. In that small range, however, the rumble must be rattling all the neighbor's windows....I'm sure they appreciate that lots!   I don't remember where the mufflers were from but they are stock upswept (i.e., early type) Ansas.  The resonance was there from new, I always assumed it was normal with some of these systems.

NATE,

It isn' normal, maybe whoever had your mufflers before developed the problem and then passed them on.  

Sorry to hear that.

DICK RUZZIN

In the archives are complaints dating back to the '70s of exhaust resonance or drone, and all sorts of fixes that cured or lessened the noise on certain cars. About all they agree on is, it originates from the exhaust. Surprisingly, this is also quite a subject on Corvette forums.

Thanks B,

I guess I will just put them on. Just took a ride to Woodward and back, my head is buzzing.

DICK RUZZIN

In my (Mustang) experience, straight-through mufflers (ie Mangaflow) are less prone to droning while chambered mufflers (ie Flowmaster and I believe the Ansa's as well) are more prone. Also, the further you can move the muffler from the passenger cabin the better off you are. Modern cars intentionally moved the mufflers to the rear of the car rather than underneath the passengers.

The sound is one thing and the drone is another.  

I am very disappointed in the mufflers from Hall as they are presented on their site as "The quiet European muffler" if I recall.  The drone is different but still there, in a slightly lower RPM range. I guess at this point that it is my engine / headers. Their supplier then told me that only "performance mufflers" for the Pantera have been imported into the USA for years.  I checked that with a tech in his company who has been there since 1980 and he said the same thing.  

I spoke to a great engineer at VIBRANT, a company that sells different exhaust parts and he suggests resonators and a flex joint to eliminate vibration and stress in the system.  I really do not have room for both on each header pipe.

There is also such a thing as an exhaust dampner, these are on a lot of cars but each is carefully configured by cam design, stroke, etc.  Very scientific so that is out.

I would appreciate any ideas from anyone with experience in this field.

DICK RUZZIN

Dear Dick,

          Interestingly enough Gerry Romack and the Great Lakes Panteras have done some actual work on the drone resonance problem and find that it is from a Helmholtz Effect or Phenomenon (?).    I am attaching a link to their tech article.  I am intrigued by it and the handful of people that I have surveyed by email with experience doing it report that it *does* notably reduce the resonance.

           http://www.greatlakespantera.c...r%20Modification.pdf

                    Warmest regards,  Chuck Engles

Would you expect anything less from Gerry Romack? He's a genius at work :-)

Shark

Very interesting, I too would like to lessen the 2000 RPM resonance, but the pictures seem to show experimentation, not final product. Is there a finalized "anti-resonance" solution that we can incorporate into our cars?

Dear Modok,

       Alas, to my knowledge, there is no "final solution".  Lacking the resources of Flowmaster, we must rely on ourselves.  

       I emailed about three or four people that Gerry said had followed his method.   I got about two or three replies and they were positive.  The good news is that nobody reported things were worse.  

              Warmest regards,  Chuck Engles

This will not be of much help. Dick. Two obvious problems in designing (or redesigning) your own mufflers:

1)- We are trying to simultaneously remove waste gasses from 300-400+ bhp engines thru sound attenuators (mufflers) the size of kid's lunchboxes due to lack of space, control the  noise from combustion explosions very close by us, and also maximize horsepower from the engine. A dynomometer is a necessary tool for testing power gains or losses IMHO. Everything else is a pure guess.

2)- We need some way of quantifying any change in noise. No one including pro builders of mufflers ever mentions gains or losses in noise levels except subjectively. There are standards for exhaust noise testing with a dB meter but it will not separate 'drone' from other exhaust noises. Depends on your hearing acuity and personal noise tolerance. For instance, I can stand far more volume of Beethoven than what passes for 'music' these days.

Hot-rodders found eons ago that stuffing most any muffler with fiberglas strands or steel mesh works well but not for long. Heat (maybe 350F), vibration and exhaust pulsations soon tear them apart & blow the little fragments out the pipes. Back in the '50s we used brillo pads with the soap removed, or curly steel lathe shavings begged from machine shops . A few muffler mfgrs made take-apart mufflers back then so they could be easily 'reloaded'.

Gerrys a good guy. He'll step up first & go out of his way to help someone. Not many realize just how much good he does for the DeTomaso community. His involvement is over the top. If you know him you'll agree 100%.

Not sure what mufflers these are but they were just awful, just trash. So loud I think straight through pipes would have been better and they continually blew out the "packing / fiber glass". Pat Mical welded a v-band fitting on my Ansa mufflers and knocked out / removed the washer which was sitting at the end of inlet pipe, so much better, quieter etc.

I then decided to modify my Ansa mufflers like previous owners and Great Lakes Pantera had documented. Stage 1 was were I cut open the first 2 "chambers" on the Ansa mufflers and used some nice quality exhaust wadding that came in a woven string type construction. The holes in the tubes were blocked or restricted and these I drilled out and some I drilled bigger. That made the noise level even better, cut out the rasp.

I then went to stage 2 where I cut open the final rear section and modified that piece. I used perforated stainless mesh shaped from the main inlet pipe to each tailpipe. This was so the exhaust wadding would not blow out, this also made my mufflers straight through even though they were surrounded by mesh or tubes with holes, surrounded by the exhaust wadding. The result was an even quieter than it had ever been. The idle is now nice and subdued but it still shows its presence when you step on it. I like the stealth approach and not have ringing ears or a headache if I plan on driving a distance. These mufflers are calming a 640hp 393 stroker. I have never had exhaust resonance on my car, not sure if these mods would help or not.

Can we get a video to hear it?  That looks like a great idea. Wish it was at the tutto this year. 

Ah I wish I could have taken my car to Tutto this year or make a video.. 

Long story but a roller cam follower decided to stop being a roller, sending metal throughout. I am waiting for one of Tim Meyer's blocks so I get the car back on the road.

I did have the car with it's modified exhaust at a previous Tutto though.

I'm working on replacing my current exhaust mufflers (4 glass packs) with Lincoln Navigator rear muffler (resonators), these mufflers are dimensional the same as OEM Pantera mufflers, I'll take pictures as I begin the fab.

Looking forward to your project.

A quick Google search for Lincoln navigator mufflers didn’t put up anything that looked too promising. Can you provide the year of the navigator mufflers?

Larry

2020 navigator, one per vehicle.

If this is it, it does look promising. 🤞

This is the muffler, it will fit in the muffler opening of the car, the muffler can (body) is approx 1/2 inch taller.

This muffler has a two in and two out, this a resonator, I'm facing the system now so I'll take some soundings of the current system which is a double glass pack system so I have the advantage of two in for the muffler.

@johrt posted:

2020 navigator, one per vehicle.

Nice find.  There are quite a few of those on ebay.  There was also mufflers that had one inlet and one outlet.  It looks like the mufflers became available in 2018 and up.  

@johrt posted:

2020 navigator, one per vehicle.

Do you know what type of material these mufflers are made of (mild steel, stainless steel?  

Here are pictures of my Navigator muffler project, I've bolted the tips to the base muffler and the inner tip resonator are bolted to allow tuning if I find it necessary.

What you've done, so far, looks great. That's a great find on the Navigator mufflers too. As you know, the big stumbling block in creating an exhaust system for the Pantera is finding an appropriate muffler cannister. Since they call it a "resonator", I assume it's a straight through design without baffles. Do you know the ID of the inlets & outlets? 

If this works, you should make about 50 sets because they will sell fast.

@davidnunn posted:

What you've done, so far, looks great. That's a great find on the Navigator mufflers too. As you know, the big stumbling block in creating an exhaust system for the Pantera is finding an appropriate muffler cannister. Since they call it a "resonator", I assume it's a straight through design without baffles. Do you know the ID of the inlets & outlets?

It would be interesting to open one up to see what the insides look like?

Resonators are straight thru, I've added DB killers into each inlet and this has reduced the sound level from what it was with the glass packs. I'll add some pic's.

Here added pic's of the muffler can showing type of construction also the tip inner construction.

Here are pic's of the system coated ready for installation.

VERY nice ‼️

I have a feeling they are going to be on the loud side of the spectrum. 😉

👍👍

Larry

I’m curious about the dreaded 2,000 rpm resonance too!

I'll let everyone know the 2000 rpm performances.

How did this muffler project work out. It looked very promising.

how did they work out? my Pantera is deafening loud. headers with 4 glass packs that i’m sure burnt out decades ago