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| Cure for Exhaust Drone? https://slantsix.org/forum/viewtopic.php?t=49288 |
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| Author: | 64 Convert [ Fri Jul 13, 2012 4:44 am ] |
| Post subject: | Cure for Exhaust Drone? |
I recently installed a complete 2-1/4" exhaust system on my '64 Valiant convertible. The only locally available OEM style muffler, with offset 2-1/4" outlets, was a Maremount. The problem is an annoying resonance at cruising speeds. I guess my choices are to find a different model muffler that is quieter, or figure out a way to stuff a resonator into the narrow space the tailpipe occupies behind the rear axle. Has anyone added a resonator to their early-A? Any recommendations for a quiet muffler? |
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| Author: | vynn3 [ Fri Jul 13, 2012 5:29 am ] |
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There's been some discussion around here about dropping to a smaller diameter tailpipe immediately after the muffler. It works for some, and would probably be cheaper than a new muffler... |
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| Author: | Reed [ Fri Jul 13, 2012 6:29 am ] |
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Walker quiet flow is a good quiet muffler. |
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| Author: | zorg [ Fri Jul 13, 2012 11:55 am ] |
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This might give you a few ideas: http://slantsix.org/forum/viewtopic.php?t=38978 |
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| Author: | 65 dartman [ Fri Jul 13, 2012 12:18 pm ] |
| Post subject: | Re: Cure for Exhaust Drone? |
Quote: . . . . or figure out a way to stuff a resonator into the narrow space the tailpipe occupies behind the rear axle.
There is enough room beside the gas tank on the driver's side for a resonator - the factory did it with the Commando V8 cars in 65-67
Has anyone added a resonator to their early-A? Any recommendations for a quiet muffler? |
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| Author: | SlantSixDan [ Fri Jul 13, 2012 12:43 pm ] |
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There are many more parameters to muffler selection than just shell size and inlet/outlet diameter and placement. What (exact) muffler did you install? A smaller tailpipe and a resonator (4" diameter round muffler, as long as can be made to fit) aft of the axle should help quite a lot, but you may still wind up replacing the main muffler. If you want to try one fix at a time and see if you can avoid replacing new pipework, install a resonator first and if that doesn't do it, evaluate your options at that time. The '73-'76 A-body resonator (see here) will easily fit and work in your '64 the same way it fit and worked in my '65, though some adjustment of the tailspout length may be necessary. Another option is an AP/Goerlich #2089 or #700232, which is another resonator + tailspout assembly that will fit the space between the quarter panel and the gas tank without hitting. That's a 2" in, 2" out item, so the installing shop would use a step-down adaptor to install it. Pay careful attention to how the pipes and muffler are supported, too; some kinds of exhaust hangers transmit much more noise than others to the interior of the car. |
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| Author: | 64 Convert [ Fri Jul 13, 2012 2:22 pm ] |
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If I hadn't had a new heavy duty chrome extension installed with the system, I'd probably go for the stock setup for the later model. I don't know the model number of the muffler, but it was a universal stock replacement. However, the stock one I had on it before was much quieter. Actually, it wasn't quieter while accelerating, but it didn't transmit a resonant frequency that was annoying. I did find a resonator that will fit, but couldn't find any reviews to see if it can do the job as advertised. It's P/N 1790, a stainless steel bottle type made by Vibrant Performance. It's a Canadian company that makes exhaust systems in over 50 countries, so I suppose that means that we in the US get the Chinese version. If that doesn't work, I'll look for a quieter stock muffler. |
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| Author: | emsvitil [ Fri Jul 13, 2012 3:59 pm ] |
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Do a web search on ' 1/4 wave resonator' or '1/4 wave exhaust resonator' example finds: http://www.titantalk.com/forums/titan-g ... drone.html http://www.performancetrucks.net/forums ... ne-489463/ |
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| Author: | Sam Powell [ Sun Jul 22, 2012 10:01 am ] |
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The distance from the muffler to the end of the tail pipe is the perfect size to set up a standing wave when the tail pipe is 2 1/4". It becomes just like an organ pipe. Anything you do to break up that pipe length will change the resonant frequency of the back system. Since my exhaust has no mufflers, it is actually quieter than one with a 2 1/4" pipe on the highway. Of course the turbo breaks up the exhaust pulses so the entire sound generating system is different. Sam |
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| Author: | 64 Convert [ Sat Jul 28, 2012 8:57 am ] |
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Update: I bought and installed the stainless steel bottle resonator from Vibrant Performance, and it looked beautiful, but as expected, it was made in China. I also ordered two stainless steel band calmps from Dynomax, and to my surprise they were made in the USA. The resonator did little to quiet the drone, but it did change it to a less annoying sound. Instead of the somewhat harsh, muffled exhaust beat, it's now more mellow, and at idle it has a beautiful purr from the tailpipe. However, I guess if I want to totally kill the drone, I will have to go to a different muffler. I wish I had used those band clamps to install the muffler, instead of having them welded. The clamps are a wonderful, quick way to join pipes, and they make disassembly a snap, since they don't deform the pipe like traditional clamps. Installation time was twenty minutes, and total cost was about $80 with shipping, but I think I would have been better served by just replacing the muffler. |
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| Author: | Aggressive Ted [ Thu Aug 30, 2012 2:20 pm ] |
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64 Convert, Read my set up in the Engine topic subject (2" or 2 1/4" exhaust pipe) thread. I have tried numerous resonators and none have worked well behind the muffler with a SL6. The way I set mine up works very well by filtering the noise out first......thanks to the Tech (Ronnie) at FlowMaster. Great guy and he has run every combination in their inventory and more.....a real racer. |
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