I have been digging around the interweb for some time trying to find a decent before/after sound for one of these resonators. So far I have seen a lot of people just mashing the throttle under zero load in the drive.
I plan to do the change to chuck the heat soak in the bedroom. There is a bit of a hill near where we live that has a very convenient pull off to a forest service road. I can station the wife to record me pulling this hill before and after to finally post up a decent before and after comparison.
It won't happen till next spring as the shop I use and trust are super busy with local harvesting this time of year and the harvest trucks take priority over our 'toy'
Maybe find a tunnel or over pass with the pas side window open.
That would work as well. Just not around Walla Walla. We country bumpkins don't have any of those fancy tunnels and big over passes. :)) Nearest tunnel is several hours away in the Columbia river gorge. That hill near us is 10 miles away. So hill it is.
I like the idea of the wife recording as I pass as this is what folks would experience from us passing by. I don't imagine any obnoxiously loud droning would be heard up front.
Even a tall wall will reflect noise
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I have a old radio shack DB meter and it still works to help before and after comparison. No clue how calibrated it is but still will show a difference.
I ended up going with the magna flow. It's twice the money but also twice the weight. It is necked down to four inches and at the time I was concerned but now am quite happy with it and would replace with the same. I think it's a bit quieter that the 5050xl, but only my opinion. Would like to one day compare and actually know.
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Was explained to me that the exhaust could actually be a convergent cone from a foot or so from the turbo to the end of the tail pipe because it will still flow at the same speed because it is cooling down and shrinking. Who knows. All I know is I'm happy with the results. Noticeable but not obnoxious. I will disclose I prefer the sleeper loud everything. Cars boats motorcycles quads buggies coaches exc.
Scott
Good idea Scott, I have a DB meter app on my Iphone that also records and will show the peak DB. So I could have that app working while the wife does video on her phone.
Doesn't have to be uber accurate as it's just an A vs B comparison.
The App I have is from Electroacoustics lab. Here is a link to the specs on that app. It's free and can be calibrated and it's easy to use.
NIOSH Sound Level Meter App | NIOSH | CDC (https://www.cdc.gov/niosh/topics/noise/app.html)
Exactly
Ism exhaust resonator options (https://www.foreforums.com/index.php?topic=42354.msg424132#msg424132)
Scott
Could do bedroom before and after too.
I use the Magna flow the same as Scott. I am really pleased with it but with the
Jake I shouldn't use it in town anymore as I can hear it up front and with the old
muffler I couldn't hear it at all.
Was the compression brake added later? I thought the 320's just had the trans retarder.
Just a mellow rumble.. I pulled the east bound hill out of Albuquerque 6 weeks ago against a concrete wall and it is mellow. I opened the window for a bit but being 101 deg didn't leave it open long. Sounds sweet. Anyone complaining about what I hear is just looking for something to complain about and I have better hearing than most 20 year olds. If the numbers on a meter make some feel better go for it. Myself I go for mellow rumble whatever number that is. I've had resonators on everything from 300 hp to 650 and I could come thru your hometown and never disturb you with the 650. Of course I've never been one to play with a jake brake because that's another level.
Now doing a comparison sure it's more noticeable than a stock muffler, it would be disappointing if not.
Not so worried about the actual numbers. As even if it is a bit louder It will only be momentary as I pass by the random pedestrian. And the DW sleeps just fine in the co-pilots chair and doesn't need the boudoir going down the road. :))
I'm just more curious as to what it actually sounds like. With all the recording capabilities of the modern cell phone. I'm actually very surprised that not a sole has bothered to record it pre/post change out. It's even hard to get a before after on car muffler changes. Just lots of no load revving in the driveway. Which is rubbish and provides nothing constructive to anyone.
It is my intention to change that when I change ours.
I wish I had thought when I was climbing out of Albuquerque east bound but I didn't. It was hot and I was watching coolant temp and rpm as well. That would be a good spot and seems someone is usually on that route. Maybe one will see and catch the sound. Even more real test is to get the wife to open bedroom window a tad on the drivers side and record.
I added the Jake Brake so I have both a retarded and a engine brake ;D
Dub, I wasn't specifically referring to the forum & it's members. Sorry if I inferred that.
When we lived in Germany. I wanted a better sounding exhaust for my 2007 BMW Zed4 3.0si. I never could find any video other than some dipstick revving the heck out of the car in the driveway. Same for motorcycles or pretty much any vehicle. You would think that the muffler/resonator builders would get off their duff and make a few videos of drive by's under load for various engine types.
Are your rotors rusty yet? With a Jake and retarder, you likely don't need to dirty up the treadle valve much.
Your right about that Big dog sitting still gunning an engine doesn't tell the tale like an engine in a pull.
Still need the brakes from about 7 miles an hour to stop.
When I pulled into a Boondockers welcome host last week he ask what I was running I told him a 450 Cummins with a resonator— he said it sure sounded sweet coming up his drive
He was an semi retired trucker he had turned 84 that day and told me he had been driving since he was a teenager
I'll just have to settle for "It sounded sweet"
Chris
Straight pipe 4" to 5" sounds good 400ISL
We have a series 60 that was bought used with 5 in straights, short and no resonator.. in my opinion the truck omits noise pollution and is scheduled for a resonator.. we have another series 60 that has 7 in straights that reach 13 ft which makes them probably 8 ft long that is mellow and needs no resonator. The bigger the diameter and longer the length the sweeter the sound but choke an exaust with small tubing and your not going to be very "cool" if you will and definitely need a resonator if not a muffler. No expert here but I have tinkered with sound and looks on a few diesels. Our coaches won't vary like that because of the limits on tube length. Someone get the lady to go to the bed room window and collect some sounds for us. Sounds of the engine exaust that is.
opening the drivers window whilst pulling a grade will give you
a pretty good idea of the sound you are making.
Some yes but the bedroom drivers side window will put you right at the pipe.