Another Muffler Thread
 

Hey Guys, I just put Pypes 2.5" exhaust, H-pipes and Spintech 9000XLs (the quieter vs of the 9000) and while I love the sound, its too much resonance. The damn interior vibrates. The volume in the interior is fine, its the resonance that is giving me a headache.

I don't want Cadillac quiet but I want a muscle car throaty roar with no drone.

What muffler should I try next. :attention

I see you already posted in the exhaust section. If you do a search for "drone" and "resonance" there is a lot of good information to examine. Some of the issues discussed are the X verses the H cross-over, headers verses logs/RA manifolds, certain mufflers and where they're located. It might be more involved than just muffler choice.

Something to consider to is the factory added resonators/tuner pipes to some automatic cars back in the day.

I like the Dynomax ultraflows. They are reasonably priced, flow well and sound good. I have them on my Pontiac and my GMC Yukon.

I'm a little confused. Your picture shows an X pipe, but you state you had an h pipe installed. Is the picture you posted not of your car and just a stock image of a like system?

There is a general rule of thumb on muffler type that fits different cross-overs. If you go with an H, you typically want a chambered muffler like a Flowmaster. If you go with an X pipe, you generally want a packed muffler like what pypes sells, or a magnaflow etc.

Putting a chambered muffler behind an x pipe is a recipe for massive drone.

Spinttech doesn't really say on their site if their mufflers are a straight through packed design or if it is a chambered design, or a hybrid of the two.

Regardless, if the car is rattling itself, that is also some of the resonance you're getting. How you deal with that is by adding a constrain layer to the body panels (usually floor boards) that are resonating. This is your typical dynamat product. 70% coverage on large flat panels will reduce harmonic resonance by quite a bit.

Follow with a mass loaded vinyl on top of areas around the mufflers and you'll knock down a good bit of the sound that the muffler is putting off itself.

I've always used H type crossovers, but my experience has been opposite. Lots of drone with chambered, none with perforated/packed. I like the ultraflows a lot on anything I've ever used them on.

Chambered mufflers will always tend to drone regardless. You have a giant wall perpendicular to your exhaust pipe that sound waves hit, and bounce back into the exhaust from.

Depending on the length of pipe in front of that chamber wall depends on the frequencies that start getting doubled on top of each other.

If for instance you have 3 feet of pipe in front of that first wall in the chambered muffler, you are going to amplify the doubled frequencies from around 15 hertz (below human hearing threshhold) all the way up to about 300 hz, which is well into our hearing threshhold and also a frequency that likes to vibrate loose plains of material.

DITTO

That is my first choice go to muffler for any car.

I've had "H" and "X" pipes in front of them, 2 1/2" and 3", and the Dynomax always satisfies with a nice rumble, no drone, and they flow pretty well too.

Dynomax or Goerlich xcellerator

I used Dynamax ultraflows and didn't have much droning. After switching to Borlas I had lots of droning but by adding Vibrant Resonators part 1793 the problem went away. Put them immediately behind my headers.

Anyone have Dynomax ultra flows with headers and an H pipe..

The Ultraflow seems like a Magnaflow which I had and took off cause it was too quiet. :D

Yes. Get compliments all the time on the sound. Most importantly it doesn't annoy me on the inside. As for your comparison to Magnaflows, I would disagree completely about the sound QUALITY. I wouldn't have a magna flow on anything... Personal opinion of course.

Agree. Just installed my second set of ultraflows on my gto after one of them rusted out on the bottom. All 2.5" and Xpipe and its not that loud for a straight through muffler

Ha! I have never heard that comment about Magnaflow mufflers!

Dynomax super turbo, affordable, nice sound , h pipe with hooker headers. since 1988 no drone and 3:90 gears. 3000rpm everywhere.

They sound good with an X pipe too!

Sent from my SM-G973U using Tapatalk

Just gear the car to keep the rev's above the drone range, lol!

Somewhere above 4500 sounds good and then your worries shift to wondering about the speed rating of your tires!

Yeah

your first pic shows an X pipe, not H... which do you have?

also consider pypes race pro mufflers, they are the same design as ultra flo's, straight through perforated pipe with a fiberglass packing. i run them with a pypes 3" X system & headers on a 467 stroker. they are actually very quiet at idle & cruise but really come to life when stepping on the gas. & very little to no drone IMO compared to what ive heard on other cars with flowmasters & smaller engines & pipes. they are priced lower than ultra flos & are a little thinner for better ground clearance.

the super turbos will be much quieter than magnaflows & wont flow as well as a straight through muffler.

Does the outside edge of them mufflers need tilted down? Pic 'looks like' they're really close to the floorboard.

Clay