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Why do a H pipe on the exhaust..

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by gokartergo, Jan 10, 2004.

  1. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    I have to put new exhaust on my 86 suburban.. After talking to two different smog tech’s I found out I don’t have to have a cat.. It is over 8500 GVW. So I am going to put on a true dual exhaust.. What is the reasoning for a H pipe.. My 77 K5 had it when I got it.. I just don’t know why I should do it… Thanks Dan /forums/images/graemlins/1zhelp.gif
     
  2. Confedneck

    Confedneck 3/4 ton status

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    to balance the exhaust flow.. keeps backpressures equal for smoother power..
     
  3. K10ANDYKHAMNIC

    K10ANDYKHAMNIC 1/2 ton status

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    makes it sound smoother and lower too . ppl ask me if my motor is built and i say not almost stock 305 intake and dual exhuast . /forums/images/graemlins/thumb.gif
     
  4. imiceman44

    imiceman44 1 ton status

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    [ QUOTE ]
    I have to put new exhaust on my 86 suburban.. After talking to two different smog tech’s I found out I don’t have to have a cat.. It is over 8500 GVW. So I am going to put on a true dual exhaust.. What is the reasoning for a H pipe.. My 77 K5 had it when I got it.. I just don’t know why I should do it… Thanks Dan /forums/images/graemlins/1zhelp.gif

    [/ QUOTE ]

    Well he beat me to it, but yes it equalizes the pressure in both sides, the reason is that in the firing order there are 2 cylinders that explode consecutively on one side while the other side is empty so when you don't have the H you will hear rumbling in the exhaust but when you have it it will be smoother and that actually gets you more power.
    Try and put it as close to the collector or headers as possible for the best result.
     
  5. sickquad

    sickquad 1/2 ton status

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    Are you sure about putting it close to the headers? I was told once to put it a foot before your mufflers.
     
  6. tarussell

    tarussell 1/2 ton status

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    It is my understanding that an "H" pipe will help power at certain RPM ranges due to the scaveging(sp) effect . Each side helps out the other to pull exhaust gas along when each cylinder fires . After higher RPM's are reached the pipe is no longer as effective .
    I think the hole theory behind the "H" pipe is to help get the gasses passed along at lower to mid RPM's and the sound is just a side bennefit .JMHO , Tom
     
  7. bigburban383

    bigburban383 1/2 ton status

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    Putting a balance pipe conecting your collectors adds significant collector volume adding more torque.
     
  8. 88Silverado

    88Silverado 1/2 ton status

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    copied this from Flowmaster's website.........

    An "H" pipe, commonly referred to as an equalizer, balance or crossover pipe, connects the two exhaust pipes. It will balance the pressure of the exhaust pulses in the system, thereby reducing interior and exterior sound while increasing power. In general the "H" pipe should be installed as close as possible to the header collector. With manifolds, the "H" pipe should be laced just past where the downpipes become horizontal. "H" pipes should be the same diameter as the main pipes or no-more than 1/2" smaller
     
  9. SUBFAN

    SUBFAN 1/2 ton status

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    I had read somewhere a long time ago that there is a sweet spot for the placement of the crossover pipe. Something like marking the pipes with a crayon, and looking for the 'hot' spot....

    Anyone else have more info on this????
     
  10. Confedneck

    Confedneck 3/4 ton status

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    subfan.. you figure your muffler placement that way, spraypaint all the way from the manifolds back, and where it stops or severeley slows its burning, is where the mufflers go..
     
  11. Muddytazz

    Muddytazz 1 ton status

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    [ QUOTE ]
    you figure your muffler placement that way, spraypaint all the way from the manifolds back, and where it stops or severeley slows its burning, is where the mufflers go..

    [/ QUOTE ]

    Never heard this before....explain more on this if you can
     
  12. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    I had read somewhere a long time ago that there is a sweet spot for the placement of the crossover pipe. Something like marking the pipes with a crayon, and looking for the 'hot' spot....

    Anyone else have more info on this????

    [/ QUOTE ]

    Honestly, it doesn't really matter. It's hard enough to fit an H pipe under there, you put it where it fits.
     
  13. cybrfire

    cybrfire 1 ton status Vendor GMOTM Winner

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    An H pipe anywhere before the mufflers is better than no H pipe. I think they really even out the sound from one side to the other. Done several of these, try to make them the same size as the exhaust tubing but if you have to go smaller it still helps out. Just did my Brother's chevy pickup and ended up do the H pipe behind the transfer case up and over the tail shaft. Bent like this /\ worked out good. Didn't sacrifice any ground clearance.
     
  14. Confedneck

    Confedneck 3/4 ton status

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    ok.. here goes my muffler placement attempt..
    when setting up exhaust..be it with headers or manifolds,
    true duals or with an h-pipe..

    take a can of cheap spray paint.. and start spraying a line all the way from the end of the collector down the exhaust,
    start the truck, when it gets hot enough, the paint will burn off, to a certain point, or will slow dramatically the rate at which it is burning the paint off the pipe.. that is the point in the system where you want your mufflers, for full scavenging and efficiency.. told to me by an old timer /forums/images/graemlins/thumb.gif
     
  15. HarryH3

    HarryH3 1 ton status Author

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    [ QUOTE ]
    I had read somewhere a long time ago that there is a sweet spot for the placement of the crossover pipe. Something like marking the pipes with a crayon, and looking for the 'hot' spot....


    [/ QUOTE ]
    I remember reading that article too. It was either in Hot Rod or Car Craft. They used temp sensitive marking crayons to find the hottest spot in the exhaust pipes. That was the spot where they put in the crossover pipe. /forums/images/graemlins/cool.gif Not that difficult on a drag car, but on our rigs you're doing good to find anyplace at all to install the pipe. /forums/images/graemlins/wink.gif
     
  16. Hustler

    Hustler 1/2 ton status

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    The H pipe is to give you more torque. The closer it is to the collector, the more torque you will get. If you are looking for HP, not torque, then you want to do an X pipe. I don't know if you can do that on a Blazer or Suburban. Also for more HP, you want the muffler as far as you can get it from the collector. The farther away the muffler is the more HP you can get. Of course your torque and HP gains will depend on what you engine puts out to begine with. If you have a stock engine, then you are not talking about much of a gain.
     
  17. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    [ QUOTE ]
    [ QUOTE ]
    I had read somewhere a long time ago that there is a sweet spot for the placement of the crossover pipe. Something like marking the pipes with a crayon, and looking for the 'hot' spot....


    [/ QUOTE ]
    I remember reading that article too. It was either in Hot Rod or Car Craft. They used temp sensitive marking crayons to find the hottest spot in the exhaust pipes. That was the spot where they put in the crossover pipe. /forums/images/graemlins/cool.gif Not that difficult on a drag car, but on our rigs you're doing good to find anyplace at all to install the pipe. /forums/images/graemlins/wink.gif

    [/ QUOTE ]


    Must have been Car Craft, because I remember reading that same article too....and I don't get Hot Rod. /forums/images/graemlins/thinking.gif

    I remember reading that the H-Pipe needs to be as close to the front as reasonably possible, using the hottest part of the exhaust as the "ideal" mounting spot.



    Here's another wrinkle:

    I recently got a full dual exhaust put onto the Suburban and the old timer at the muffler shop said:

    "I don't know why people ask for balance pipes on Chevys...that's a Ford thing!"



    I think he was referring to old Mustangs vs. Camaros, etc. It seemed like an interesting comment...as if the firing order, or other engine attributes made it less necessary for a Chevy.

    The Subs new exhaust now does NOT have a balance pipe...and it's still pretty quiet at normal speeds/ throttle inputs. When I open the secondaries it definitely sounds more "ballsy"....but that might be due to the DynoMax mufflers that replaced the really restrictive stockers too???

    I suspect when I do the next K5 exhaust, I am going to remove the H-pipe also....partially out of curiousity, and also because I don't think I'll have room for one next time around.
     
  18. HarryH3

    HarryH3 1 ton status Author

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    [ QUOTE ]
    and I don't get Hot Rod.

    [/ QUOTE ]
    I dropped Hot Rod a few years ago. Too many $30K engines in $200K custom rides. /forums/images/graemlins/eek.gif /forums/images/graemlins/frown.gif I like that Car Craft mostly does stuff that the average guy can afford. /forums/images/graemlins/thumb.gif
     
  19. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    Ok my sub is stock and it is going to stay that way.. So I really don't see enough of a gain to justify the added cost.. But I am putting on flow masters.. /forums/images/graemlins/thumb.gif
     
  20. SF87K5

    SF87K5 1/2 ton status

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    Anyone have pics of a H pipe set up??
     

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