Resonator AGAIN

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Resonator AGAIN

September 06, 2022, 03:23:54 pm

I am looking again at the resonator mod, and have some lingering questions...

1. Some in our group have recommended the Magnaflow for a quieter sound, while still being much better than the OEM. Is the Magnaflow actually their MUFFLER and not a resonator?

2. Has anyone seen a Magnaflow with 5-inch inlet and outlet? I can only find 4-inch.

3. Most installations, old and new, include a piece of flex hose. I understand the utility in getting things to line up. Is a bit of flex necessary to isolate engine movement from the exhaust system? MY stock setup has 1.5 inches of exposed flex, which I can't imagine doing anything, particularly with 24 years of rust and grime. I think I have devised a setup that will go together without the flex, if it is advisable. If advisable, how much length to be functional.

Re: Resonator AGAIN

Reply #1 – September 06, 2022, 03:42:38 pm

Amazon.com: MagnaFlow 7in Round Center/Center Performance Muffler 12774 -...
Used stock flex pipe. No more or less. It is a resonator necked down to 4" in the middle
Scott

Re: Resonator AGAIN

Reply #2 – September 06, 2022, 03:57:03 pm

Muffler or resonator - both terms seem to be used to describe the MagnaFlow depending on where you look. Any practical difference?

As Scott said, the 5" in/out MagnaFlow (12774) and the 4" in/out (12771) have exactly the same diameter bore (4") through the middle.

I used a 12771 on our coach because the pipe from the turbo to the muffler is 4" diameter.

Amazon.com: MagnaFlow 7in Round Center/Center Performance Muffler Exhaust...

Your engine moves around due to the effect of torque. The muffler must be supported at several points. If there is enough play in your muffler hangers to allow for the engine movement, then the flex tubing would not be necessary. I reused the OEM flex tubing for my installation because it worked out well and saved me some hassle.

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Re: Resonator AGAIN

Reply #3 – September 06, 2022, 04:17:04 pm

Thanks guys! My several Amazon searches did not turn up that one quickly, and searching for a "resonator" didn't help. I was leaning toward the "more quiet." I would be fine if the whole coach were silent while underway.

Good tip on reusing the old flex. I am headed out to look at it again.

Re: Resonator AGAIN

Reply #4 – September 06, 2022, 06:39:14 pm

Jones 5050xl is the one I have, louder yes but you can't hear it in the seat. Looks the same as the aero 5050xl but was cheaper

Keith

Re: Resonator AGAIN

Reply #5 – September 06, 2022, 06:43:54 pm

Quote from: hdff – September 06, 2022, 06:39:14 pm

Aero 5050xl is the one I have, louder yes but you can't hear it in the seat

Keith

+2 on that resonator!

Re: Resonator AGAIN

Reply #6 – September 06, 2022, 08:57:27 pm

I didn't use flex pipe and I don't remember any flex pipe used with the muffler.

Re: Resonator AGAIN

Reply #7 – September 06, 2022, 09:52:01 pm

I used the Jones 5050XL wasn't as expensive as the aero and I couldn't tell the difference when I looked at them. it is 5"in and 5"out and 5" all the way through the pipe. I did use some flex pipe wasn't an issue as far as i was concerned. Only time I can hear it is when I'm in the left lane and cross a bridge.
Chris

Re: Resonator AGAIN

Reply #8 – September 06, 2022, 10:48:11 pm

Love the performance increase, and agree you won't really notice it up in the drivers seat. But running it up through the gears in town is another story if you're behind it or on the street. They are all loud since they are just a step above a straight pipe.

Re: Resonator AGAIN

Reply #9 – September 07, 2022, 09:33:40 am

Is there a break year when the size increased? Or was this by engine type? I see references to 4 and 5", I need to measure mine.

Re: Resonator AGAIN

Reply #10 – September 07, 2022, 10:27:45 am

Quote from: Jason – September 07, 2022, 09:33:40 am

Is there a break year when the size increased? Or was this by engine type? I see references to 4 and 5", I need to measure mine.

The M11 has a five-inch exhaust, the 8.3 has a four-inch. But do measure - someone could have gotten creative with a coach in 20-25 years.

Re: Resonator AGAIN

Reply #11 – September 07, 2022, 10:54:37 am

And remember the smallest inside diameter in the total exhaust pipe assembly rules as far as "performance" goes. For instance, my coach has a 4" pipe from turbo to 4" ID muffler, then it transitions to a 5" pipe from the muffler to the 5" chrome exhaust tip. On my coach, the 5" pipe is strictly for show - it does not increase the flow capability (reduce back pressure) of the system.

Re: Resonator AGAIN

Reply #12 – September 07, 2022, 11:11:25 am

The Magnafow muffler having it 4inches in the middle would have been a game changer for
me if I had of known, when I buy a 5 inch muffler I expected it to be 5 inches all the way through
and when they say stainless steel I expected all stainless.

Re: Resonator AGAIN

Reply #13 – September 07, 2022, 02:50:56 pm

Quote from: oldguy – September 07, 2022, 11:11:25 am

The Magnafow muffler having it 4inches in the middle would have been a game changer for
me if I had of known, when I buy a 5 inch muffler I expected it to be 5 inches all the way through

I too felt the same. Didn't see till it was in hand, but after much reading about what Kieth had said about the rate of cooling and flow rate became confident it would be fine in comparison to what I removed. Was seeking cooler bedroom temps and it does help

Re: Resonator AGAIN

Reply #14 – September 07, 2022, 03:12:42 pm

I went with the Jones 5050XL, bought a couple 5" U bends, used the flex pipe and original tip. Also rented a crane to lift the old one out, JK. I wanted full flow so I'm not sure about the 4" middle. DSD and I talked about this but he had already received his so he installed it and is happy. I personally like the sound but I do ride Harleys so... It did get rid of allot of heat in the bedroom along with a 2" insulation board under the mattress.

Re: Resonator AGAIN

Reply #15 – September 07, 2022, 03:56:54 pm

I looked at a bunch of resonators and mufflers. I thought a lot about this one, but a Jones is currently in the cart. Some of you are persuasive. It seems a good balance between performance, sound, price, and shiny and cool. Having a shiny resonator tucked underneath... Does not seem a rational goal, but it affects me too!

I wonder about the 4-inch passage with some of the resonators. I suppose that the baffles outside of that 4 inches add to the effective flow. Just a guess.

I will go out to the coach and give a final plan, to make sure the stuff I have in the cart will be the best approach. I recently had my welder repaired, but I am not ready to use it on the exhaust. Last welding I did was landlord stuff 25 years ago, replacing the diamond plate on dirty, rusty, painted fire escapes. The welds looked terrible but held. I might be OK with clean steel, but I need some serious convincing. I will use the clamps and look to welding it later.

So if the resonator IS part unicorn, I can expect a cool bedroom, an additional 1/2 mile per gallon, better acceleration, more storage, and admiring glances from the ladies AND gentleman from the throaty sounds it will sing. If the bedroom gets bearable a little faster, I will be pleased.

I have thought on another subject, and I have determined that our old FTs are part house and part collector car. That accounts for our behavior.

Amazon.com: 5" Universal Exhaust (MUFFLER) : Automotive

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Re: Resonator AGAIN

Reply #16 – September 07, 2022, 10:23:45 pm

Matt, you may want to consider the 50' of 2" fiberglass wrap, to wrap the resonator and exhaust pipe. That resonator gets pretty hot and is pretty close to the AC fan which is plastic.
I wrapped mine then sprayed it with a black silicone spray that is suppose to help it last longer.
BTY if you do decide to wrap wear gloves.
Chris

Re: Resonator AGAIN

Reply #17 – September 09, 2022, 10:11:17 am

I'm not saying that it is necessary, but if redoing the exhaust, consider replacing the flex pipe. The original piece broke open on our U240 and I had one crack on a semi. I recently replaced the muffler on the U295 with a Magnaflow 12774 and used new flex pipe on it too.

Re: Resonator AGAIN

Reply #18 – September 09, 2022, 11:40:43 am

Quote from: oldguy – September 07, 2022, 11:11:25 am

The Magnafow muffler having it 4inches in the middle would have been a game changer for
me if I had of known, when I buy a 5 inch muffler I expected it to be 5 inches all the way through
and when they say stainless steel I expected all stainless.

Peter, in case you don't know, not all stainless is true stainless. If a magnet sticks to the side, it is 300 grade SS, which has iron product in it. True SS is 304 and then there is 316 as well. You won't see much of this as it is expensive. Oh, we ordered a 5' piece of flex and some 45 degree elbows and a nice exhaust tip for the install. I had a qualified welder and top guru work on mine. Scott, aka DSD!

Re: Resonator AGAIN

Reply #19 – September 09, 2022, 12:37:00 pm

Joe I know there is different quality of stainless but the ends of the Magnaflow is pure steel.

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