Dual muffler drone experiment.

Discussion in 'Technical' started by scooper77515, Apr 11, 2011.

  1. darren

    darren Member

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    I think you might be on to something there. lol.
     
  2. PAINTANK

    PAINTANK Cometosis Obsessivus

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    Obviously some here have never dealt with 120Db roar during 80% of their driving experience or their wife and kids refusing to ride with them because "daddys car hurts my ears". Unable to use the mirrors and being able to feel the vibrations in your butt after you get out. It is impossible to use the radio or talk to anyone inside while driving. Mine did it between 35mph and 50mph or what I like to call all the time when I was driving. It wasnt as bad as open headers but it was just as impossible to bear after more than 2 or 3 minutes. Drives longer than 30 minutes were awful.

    Age has nothing to do with wanting to eliminate an uncool drone. Droning isn't "cool exhaust sound" its a huge problem. Simply "run it out the back" isnt an option on a budget. You all know how hard it is to get an out-the-back exhaust set up with a factory tank. This guy just wants it to sound good without being deafening inside. I got mine to stop by exiting it 3 inches outside the rockers under the doors. It was still louder than I liked to I gave up. 40s are loud without a few feet of pipe behind them. Its just how they are. I understand why dont yall?
     
  3. doncraft

    doncraft Member

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    I just turn off my hearing aids:biglaugh:
    Don
     
  4. Mavman72

    Mavman72 Gone backwards but lookin' forward

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    If its too loud...Your too old!!!...:party3:
     
  5. scooper77515

    scooper77515 No current projects.

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    I don't even wear my hearing aides when driving. And seriously, I DO wear them at work.

    I have a 35dB loss in both ears.
     
  6. ford84stepside

    ford84stepside Lone Wolf

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    Scott, I hate to say it, but you are gonna have to run them over the axle to quiet the drone. I just had mine done today, and the drone is GONE!! You wouldn't believe the difference inside the car, you can actually hear the radio now. I'm running glasspacks with 2.25" pipes, and it sounds great. Even if you just go over the axle and turn them out or down, it will really make a difference.
     
  7. franktf

    franktf Member

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  8. doncraft

    doncraft Member

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    seriously I do turn them off.:rofl2:
     
  9. scooper77515

    scooper77515 No current projects.

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    Seriously, I don't wear them at all in the car.

    So, is the "over the axle" cancelling out the drone because of the extra length of exhaust tubing? Or just because it gets it outside the bottom of the car? And if the second, why doesn't exiting out the side do it?
     
  10. 72MAVGRABHER

    72MAVGRABHER Maverick Mechanic

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    mine is over the axle and i still have drone. but im running a 40 series flowmaster
     
  11. Bryant

    Bryant forgot more than learned

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    on my old fox body mustang i had a MAC cat back exhaust. it was a chambered type muffler very similar to the flowmaster. it had a section of pipe that went over the rear axle then ended at a ball socket. then there was another section of tail pipe that would bolt on to that section. i didn't put the last section on for a few months when i put that system on. it sounded great, had no drone. then i put the tail pipes on and it droned as bad as a fox mustang could drone. so tail pipes wont simply fix the drone. im sure there is math that you can use to figure out the best length to cancel out any drone, but who wants to do math. i would suggest putting pipes that go over the axle and cross over the leaf spring to dump right behind the tires.
     
  12. ford84stepside

    ford84stepside Lone Wolf

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    I can't tell you for sure, it may be one or the other or a combo of the two. I was just going to do a side exit behind the tires, but after looking and measuring and putting a piece of pipe there, we determined there was enough room to go all the way out the back. I'm thinking the extra length of pipe after the mufflers has to be a big part of it, just like your "H" pipe changed the RPM range of yours. Mine is still loud, but it's behind you now, so maybe you are outrunning the drone instead of it being right under the car, I don't know. It quieted it down a bit at idle, so now you can hear the thump of the cam better, but still it talks when you mash it. And like I said before, no drone at any speed or RPM. I'm happy with mine, wish I had of done it sooner.:thumbs2:
     
  13. scooper77515

    scooper77515 No current projects.

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    OK, finally capped it off at the H-pipe, and drone is gone. Still dumping at the axle, but only on one pipe (passenger side).

    For some reason, even though it ran fine with one tail-pipe capped and both mufflers still attached, it didn't run nearly as well with it capped at the H-pipe. And it picked up another sound, sorta like a drone, but at all rpms, and I am sure it was the left bank of cylinders hitting that "dead end" on the exhaust and bouncing back into itself on the way back to the H and finding it's way out. It was very faint, and most people wouldn't have noticed it at all, if they weren't listening for it, like I was.

    The car idled rough, hesitated on takeoff, but once I got it up to 2000 rpms, it still had that good torquey pull through about 6000 rpms. So i think I will pull the H-pipe off and fabricate a more subtle transition for it without the 6" dead-end after the left leg of the H, and siamese it through the one super 44, keeping it 2-1/2" all the way through, for now.

    I may swap out for a 3" in/out muffler later on, maybe or maybe not a flowmaster. Most likely a single glasspack, cherry bomb, or similar.
     
  14. scooper77515

    scooper77515 No current projects.

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    Aint this the ugliest thing you ever saw in your life??? :vomito:

    But, it is what I needed to do to make it temporary and reversible.
     
    Last edited: Apr 5, 2012

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