exhaust cut-outs ..... thoughts

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  1. Canadian1968

    Canadian1968 Well-Known Member

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    I do have headers . 2 1/2 mandrel bent with X pipe. Dyno max Ultra flow.

    In my opinion a decent flowing exhaust.

    Reading the post, not sure if I have made up my mind yet to try cut out yet. BUT if I do ,will do it on the cheap . A set of "header reducers" welded into place , and make a cap. Cost about $40 . I would have to unbolt them by hand , but like I said just want them for the track so who cares.
     
  2. 383man

    383man Well-Known Member

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    I do not run them. I use TTI 2" headers and their 3" exh X-pipe system out the rear of the car. And I use the Dyno-Max Ultra-Flow mufflers. Myself I like the sound of the closed exh system as it just sounds nice to me without to much noise. I race through the full exh system as I have never uncapped my car. I really dont think it will pick up much uncapped and I like to race it just as I drive it on the street. I love the closed exh when you can hear the sound of th cam and some solid lifter sound. Ron
     
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    • mopar blood

      mopar blood Well-Known Member

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      Do it! used them at the track about 1 10th n half difference in performance.
      also great on street, when i see a cop in distance i close them.
      love the expression on folks when i open them.
      have them on a 472 hemi w/ 3" exhaust flowmasters
      you won't be sorry!
       
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      • malex

        malex FBBO Gold Member FBBO Gold Member

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        I thought about cut outs on my Dart exhaust but decided against them. Behind the 2.125 X 3.5” TTI’s I chose to go with 3” into 3” Dynomax Ultraflow mufflers and 3.5 after.

        D847B092-7550-4337-BE9F-CE67864E6A42.jpeg

        82CABC1C-334B-447A-A46B-D5E8F2DAB85D.jpeg
         
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        • Canadian1968

          Canadian1968 Well-Known Member

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          damn that's big !
           
        • 493 Mike

          493 Mike FBBO Gold Member FBBO Gold Member

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          But, it slows the flow velocity. As the exhaust gases cool in the muffler they condense so a smaller tailpipe is better to keep the velocity up. Now in this case I believe the OP is going for appearance. When I was young we would cut up driveshafts to get big fat extensions!
           
        • alfaitalia

          alfaitalia FBBO Gold Member FBBO Gold Member

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          If it's a drag race car (and therefore at max or peak revs 99 percent of the time that matters) then ultimately big pipes will flow more gas away and give max power....but in a street car which is often at low revs gas velocity slows (as said above) and you lose cylinder filling as there is no back pressure to hold the fresh charge in the combustion chamber on the valve overlap....unburnt fuel goes out of the exhaust valve...power (and low down torque) is lost. The lumpier the cam (and the longer the exhaust cam duration) the worse the problem. So if peak power is all that matters to you run open headers or cutouts...if you want a nice flexible street car, sensible size pipes and a little back pressure along with pipes and headers the correct tuned length is the way to go.
           
          Last edited: Oct 27, 2020
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          • malex

            malex FBBO Gold Member FBBO Gold Member

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            —-
            I chose to drop the pipe size to 3” to quieten it down, the stepped up tail pipes won’t hurt it. I’m hoping to get thumbs ups rather than a noise citation.
             
          • mopar blood

            mopar blood Well-Known Member

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            never the less, its still way cool to open and close at the flick of a switch.
             
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            • 493 Mike

              493 Mike FBBO Gold Member FBBO Gold Member

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              The way I see it, as long as Harleys can run straight pipes I'll never accept a loud exhaust citation!
              Mike
               
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              • dvw

                dvw Well-Known Member

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                My street car has 3” Ultraflows with turn downs.11.01 thru the exhaust. Earlier in its life with 3” Flowmasters. 11.66. Removed the exhaust system (76#). Same day 11.61. Good system looses next to nothing except added weight. My wife’s 9-1 comp factory head 360 Challenger has never run w/o full 2 1/2” exhaust and air filter 12.52@110. Same with my sons 360 turbo 62 Savoy. Full exhaust 9.55@142.
                Doug
                 
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                • malex

                  malex FBBO Gold Member FBBO Gold Member

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                  ——
                  Cutouts certainly will get attention when you choose to get it. Us muffled guys will just have to scoop up whatever way cool there is left over.
                   
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