Van exhaust?

Slant 6 Engines

  1. moparblood

    moparblood Well-Known Member

    Messages:
    207
    Likes Received:
    56
    Joined:
    Dec 24, 2014
    Location:
    n.y.
    Local Time:
    6:56 AM
    78 /6 4 speed currently has a glasspack on it.
    real loud, i have a 2 1/4 exhaust manifold from dartlite going to put on, free some HP.
    whats best muffler and should i put resonator, will that be too much back pressure?
     
  2. nitro_rat

    nitro_rat FABO Gold Member FABO Gold Member

    Messages:
    94
    Likes Received:
    27
    Joined:
    Apr 25, 2020
    Location:
    Texas
    Local Time:
    4:56 AM
    I like the dynomax hemi super turbo. Dynomax makes a round case "rv" turbo muffler that may fit under your van. Make sure to run a full tail pipe over the axle and turned out the side. 2" is fine for the tail pipe. This will be much quieter inside (and safer from an exhaust gas entry into cabin standpoint) than a turn down or side exit exhaust.

    Any "turbo" style muffler will work but the Dynomax is the best flowing. Generally any muffler with a larger case will be quieter than the same style muffler with a smaller case. Also offset inlets and outlets are quieter than centered.
     
    • Agree Agree x 1
    • burdar

      burdar Owen's Dad

      Messages:
      1,124
      Likes Received:
      191
      Joined:
      Aug 15, 2013
      Location:
      Iowa
      Local Time:
      6:56 AM
      I've heard the Dynomax mufflers are just a rebranded Walker Turbo muffler. You can probably find Walker mufflers locally for less money then a Dynomax.
       
    • nitro_rat

      nitro_rat FABO Gold Member FABO Gold Member

      Messages:
      94
      Likes Received:
      27
      Joined:
      Apr 25, 2020
      Location:
      Texas
      Local Time:
      4:56 AM
      Bum dope. Walker does make Dynomax but a Walker turbo muffler is a cheap "installer" grade muffler. A Dynomax Super Turbo has internal passages equal in size to the inlet diameter. A Hemi Super Turbo has a large case for more internal volume.

      They're not the same thing or the same price...
       
      • Agree Agree x 1
      • theFightingFew

        theFightingFew Always Learning/1975 Valiant Custom/1974 Valiant FABO Gold Member

        Messages:
        117
        Likes Received:
        152
        Joined:
        Apr 9, 2020
        Location:
        Philadelphia, PA
        Local Time:
        7:56 AM
        @moparblood I was just going through the same exercise so I figured I'd chime in. I put a 2.25 on a month or so ago and initially put a glasspack on it... i enjoyed it for a while, don't get me wrong it sounded fun, and throaty, and loud but since my valiant is my daily driver i started to get sick of it... i was hearing my muffler more than the "sounds of driving" whether it be cruise'n or haul'n... which is one of the reasons why i like driving so much in the first place! In any case after watching tons of different you tube videos on different installs I narrowed it down between two flowmasters - the HP2 and the delta 50... i ended up going to the quiet side with the delta 50... i'm happy with it... quiet down the street, perks up when i hit the pedal... has a healthy sound... i think it fits my 4 door just fine.

        Exhaust always seem like a divisive topic
         
      • burdar

        burdar Owen's Dad

        Messages:
        1,124
        Likes Received:
        191
        Joined:
        Aug 15, 2013
        Location:
        Iowa
        Local Time:
        6:56 AM
      • moparblood

        moparblood Well-Known Member

        Messages:
        207
        Likes Received:
        56
        Joined:
        Dec 24, 2014
        Location:
        n.y.
        Local Time:
        6:56 AM
        if i'm getting this correct, i should get both offset in n out?
        What about a resinator?
         
      • nitro_rat

        nitro_rat FABO Gold Member FABO Gold Member

        Messages:
        94
        Likes Received:
        27
        Joined:
        Apr 25, 2020
        Location:
        Texas
        Local Time:
        4:56 AM
        A resonator is easy to add later if you find your new muffler to be too loud or to have a drone at highway speed.
         
        • Like Like x 1
        • nitro_rat

          nitro_rat FABO Gold Member FABO Gold Member

          Messages:
          94
          Likes Received:
          27
          Joined:
          Apr 25, 2020
          Location:
          Texas
          Local Time:
          4:56 AM
          Dynomax 17741 is a 6" round body muffler with 2-1/4" offset inlet/outlet and a 14" long body. That will probably work for you.

          Dynomax 17777 is a 2-1/4" in/2" out oval body muffler with an 11" long case. Probably the best choice for a car.

          A muffler shop can bump up a stick of 2" to slip in the 2-1/4" outlet of the round body muffler. That's the way I'd go for your van. If it's still too loud I'd add a glasspack in the tail pipe for a resonator.

          The bends of a tail pipe going up over the axle, back down, and then out the side (5 bends all 45° or greater) will significantly quiet the tone over any other configuration.

          Looks like all of the larger/longer body Dynomax mufflers are 2-1/2" pipe and up. I like the 17741 for your application though.

          All the Super Turbos have the same size internal tube as the inlet up to the 2-1/2" pipe size. The 3" inlet mufflers have 2-1/2" internals.
           
        • slantsixdan

          slantsixdan =..=

          Messages:
          6,737
          Likes Received:
          1908
          Joined:
          Jan 7, 2007
          Location:
          Vancouver BC
          Local Time:
          4:56 AM
          There is no special 2-1/4" exhaust manifold from a Dart Lite. The Dart Lite/Feather Duster got the same exhaust manifold as every other '73-up Slant-6 engine, and its outlet size is 2", though it can be honed out a little if you want to.

          Those "turbo" mufflers like to set up a drone that will cut right through you with an inline-6 engine, and Murphy's Law dictates it'll be at its worst at exactly your most common cruising speed. Get a real muffler instead: a Walker № 50051 (Hemi Ram truck muffler). Huge capacity for excellent flow, made of stainless steel for nice long life, excellent sound control at all engine RPMs. Use a 2-1/4" headpipe off the manifold and into the muffler. Use a 2" tailpipe out of the muffler, and if you want it extra super quiet, put a resonator in the tailpipe. If I'm rich, I like a Flowmaster HP2 stainless unit with 2" in and out. If I'm broke, I like a Walker № 17198 4" round can-type unit, 2" in and 2" out, with offset outlet next to a proper hanger bracket.

          Tailspout outlet between 45° and 90° outward, and 45° or more downward.

          With or without a resonator, this system will have a whole lot less restriction/backpressure than the original-equipment system, but won't drive you bonkers with noise (loud exhausts are fun for maybe a week, then they get old).
           
        • Bill Crowell

          Bill Crowell FABO Gold Member FABO Gold Member

          Messages:
          945
          Likes Received:
          488
          Joined:
          Oct 16, 2007
          Location:
          Diamond Springs, CA
          Local Time:
          4:56 AM
          "Oh Danny boy, the pipes, the pipes are calling..." - Irish traditional song.
           
          • Like Like x 1
          • nitro_rat

            nitro_rat FABO Gold Member FABO Gold Member

            Messages:
            94
            Likes Received:
            27
            Joined:
            Apr 25, 2020
            Location:
            Texas
            Local Time:
            4:56 AM
            If your muffler shop has a pile of cut offs out back the "resonators" off of a late model Challenger or Charger make an excellent muffler for a slant. 2" offset inlet/outlet, straight through design. I was afraid it would be loud because of the straight through design but it's actually quiet and much less restrictive than stock. I run one on my '68 Dart.
             
          • moparblood

            moparblood Well-Known Member

            Messages:
            207
            Likes Received:
            56
            Joined:
            Dec 24, 2014
            Location:
            n.y.
            Local Time:
            6:56 AM
            Dan, the current pipe that came with the van is 1 7/8 why did they reduce it so small?
            so if i just put a 2 1/4 pipe i don't need to change manifold?
             
          • nitro_rat

            nitro_rat FABO Gold Member FABO Gold Member

            Messages:
            94
            Likes Received:
            27
            Joined:
            Apr 25, 2020
            Location:
            Texas
            Local Time:
            4:56 AM
            1-7/8" is a normal factory exhaust size.

            No mods are necessary to connect a 2-1/4" pipe to the factory manifold. You can enlarge the stock outlet but it's best to leave it a little smaller than the pipe size.
             
          • slantsixdan

            slantsixdan =..=

            Messages:
            6,737
            Likes Received:
            1908
            Joined:
            Jan 7, 2007
            Location:
            Vancouver BC
            Local Time:
            4:56 AM
            Because 1-7/8" pipe costs less. No other reason than that.

            Correct. That's what the factory did on the Feather Duster/Dart Lite (and on all Slant-6s starting in '77-'78): bolted a 2-1/4" headpipe to the same manifold they'd previously bolted a 1-7/8" headpipe.
             
          • MOPAROFFICIAL

            MOPAROFFICIAL FABO Gold Member FABO Gold Member

            Messages:
            6,476
            Likes Received:
            5428
            Joined:
            Jun 1, 2016
            Location:
            Beach
            Local Time:
            4:56 AM
            Dynomax ultra flo
            Only loudish when you get on it.
            Similar to glass pack design... but way better sounding! I won't use anything else anymore. Tried most except pypes,thrush,zoom. I'll never use those pos mufflers. Floblaster really sucks.
             
          1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
            By continuing to use this site, you are consenting to our use of cookies.