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exaust pipes, short or long make a difference?

Discussion in 'The Garage' started by supersize75k5, Nov 10, 2004.

  1. supersize75k5

    supersize75k5 OrganDonorRacing.com

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    Yet another question from me...

    is there any performance advantage of having longer pipes that dump out the back on a truck?


    I plan to either have the pipes run through my crossmember and out to the back, or turn them out and have them dump right behind the cab, the 40 series I have would sit ight next to the rocker/under the cab tucked up.


    any advantages to either one? will it sound different? as for sound/loudness....I am younger and like my trucks loud, not to mention pulling up to some 4 banger and romping on a big block should sound pretty sweet /forums/images/graemlins/peace.gif

    thanks in advance,

    shawn
     
  2. k20

    k20 3/4 ton status

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    shorter make em louder. When I got my truck it had a 50 series run out the back, quiet. Then I turned it out in front of the rear tires and its much louder. Cant say much for perf gain, cause I put on headers at the same time. Then I went BBC, and that little gain didnt make a diff lol.
     
  3. supersize75k5

    supersize75k5 OrganDonorRacing.com

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    I have another quick question for you, where did you get you valve covers? I would like to find a set in that style???

    I like burt4x4's too

    /forums/images/graemlins/ears.gif
     
  4. k20

    k20 3/4 ton status

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    I got mine from sdpc2000.com . They were like 20 bucks cheaper than the rest. When I ordered mine they werent offering powdercoating in a color, so I had to paint mine, and drill my own holes for oil and breather. If I was ordering now, definately order the pre-powdercoated (orange to be like me lol), and I believe they are now pre-drilled.
     
  5. 79cheyenneblazer

    79cheyenneblazer Registered Member

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    shorter pipe does make it loud, but longer pipe makes it louder, if you have long pipes after a muffler it gives it a chance to build up echo inside the pipe, we had glasspacks and turn downs on our 63 impala while we were putting it back together, and it was decently loud, then the night we put the tails on, it was so extremely loud we had to put quieter glasspacks on it so it didn't sound like open headers, but if you get to a point of pipe being so short like open headers, becareful to have enough backpressure otherwise you will burn your valves, racers that run open headers usually run high RPM's with quick bursts, so there is no chance of burning valves. There should be 1/2 a pound of backpressure.
     
  6. Ruthven13

    Ruthven13 1/2 ton status

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    To tell yo the truth, the best sounding truck I have ever heard was my old '78 Bronco. Had a 460 with headers and glasspacks, 2.5 in all the way back. I had it come out at a 45* right at the rear corners. Besides having it come out all the way at the back keeps it a litle quieter inside. No problem at all setting off car alarms. And it could still shoot a 3' long flame out if I key popped it /forums/images/graemlins/thumb.gif . Too bad the truck no longer exists but the motor is powering my jet boat!
     
  7. tx_sub

    tx_sub 1/2 ton status

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    with regards to longer pipes being louder than shorter, i disagree to an extent. here's the explanation. the exhaust pulses for a certain rpm produce a certain frequency. due to the sound and pressure waves being contained in the tubing, the oscillations will interfere with each other constructively and destructively, creating nodes. these nodes are points of zero vibraton. in between the nodes are the peak amplitude (read loudest and most vibration) the distance between these nodes is a function of many variables, of which i forget. now to the point. if you cut off your exhaust at a node, it will be much quieter compared to if you cut off the pipe in the middle of two nodes. since nobody really hooks up an oscilliscope to their exhaust pipes, its just the luck of the draw where your cut will be. maybe on the "tuned" exhausts, they factor this in, but for the average joe muffler guy, its not a concern.
     
  8. firefighter184

    firefighter184 1/2 ton status

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    If you point them striaght down at the ground under your truck, they will seem very loud because the noise bounces off of the ground and your truck. Pretty cool on pavement, terrible on a dusty trail...
     
  9. 79cheyenneblazer

    79cheyenneblazer Registered Member

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    well I was talking about my experinces since our family has been in the exhaust business for almost 30 years. P.S. where did you find all that out at? sounds interesting
     
  10. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    shorter pipe does make it loud, but longer pipe makes it louder, if you have long pipes after a muffler it gives it a chance to build up echo inside the pipe, we had glasspacks and turn downs on our 63 impala while we were putting it back together, and it was decently loud, then the night we put the tails on, it was so extremely loud we had to put quieter glasspacks on it so it didn't sound like open headers, but if you get to a point of pipe being so short like open headers, becareful to have enough backpressure otherwise you will burn your valves, racers that run open headers usually run high RPM's with quick bursts, so there is no chance of burning valves. There should be 1/2 a pound of backpressure.

    [/ QUOTE ]

    That is the biggest bunch of bullshit I have ever read in one post.

    More efficient exhaust systems do not cause burned valves, overly lean fuel mixtures do.
     
  11. tx_sub

    tx_sub 1/2 ton status

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    i'm an engineer, er student. i get to play with signal generators and learn what makes the waves go where and why. really boring.
     
  12. 4xcrazy

    4xcrazy 3/4 ton status

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    [ QUOTE ]
    [ QUOTE ]
    shorter pipe does make it loud, but longer pipe makes it louder, if you have long pipes after a muffler it gives it a chance to build up echo inside the pipe, we had glasspacks and turn downs on our 63 impala while we were putting it back together, and it was decently loud, then the night we put the tails on, it was so extremely loud we had to put quieter glasspacks on it so it didn't sound like open headers, but if you get to a point of pipe being so short like open headers, becareful to have enough backpressure otherwise you will burn your valves, racers that run open headers usually run high RPM's with quick bursts, so there is no chance of burning valves. There should be 1/2 a pound of backpressure.

    [/ QUOTE ]

    That is the biggest bunch of bullshit I have ever read in one post.

    More efficient exhaust systems do not cause burned valves, overly lean fuel mixtures do.

    [/ QUOTE ]

    Ditto

    /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif
     
  13. 4xcrazy

    4xcrazy 3/4 ton status

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    Dude just run your pipes as you mentioned already, out the side, but i would have them pointing at about a 45 degree angle towards the back. Think it would look cool.
     
  14. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    [ QUOTE ]
    [ QUOTE ]
    [ QUOTE ]
    shorter pipe does make it loud, but longer pipe makes it louder, if you have long pipes after a muffler it gives it a chance to build up echo inside the pipe, we had glasspacks and turn downs on our 63 impala while we were putting it back together, and it was decently loud, then the night we put the tails on, it was so extremely loud we had to put quieter glasspacks on it so it didn't sound like open headers, but if you get to a point of pipe being so short like open headers, becareful to have enough backpressure otherwise you will burn your valves, racers that run open headers usually run high RPM's with quick bursts, so there is no chance of burning valves. There should be 1/2 a pound of backpressure.

    [/ QUOTE ]

    That is the biggest bunch of bullshit I have ever read in one post.

    More efficient exhaust systems do not cause burned valves, overly lean fuel mixtures do.

    [/ QUOTE ]

    Ditto

    /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/rolleyes.gif

    [/ QUOTE ]

    Double ditto

    Getting back to the original post though. I would say as long as you are running headers, collectors, some length of pipe, two mufflers (I'm assuming duals here), then running turnouts or pipes out the back, you have more than enough "length"to keep the engine from running lean (without tuning), and again length is a relative term. Make sure your engine is timed and tuned after you install the exhaust and you will be fine. As for placement of exit, that depends on several factors (one of which being personal preference). If you are going to wheel the rig (say on rocks), the biggest concern is going to be clearance and distance from crush points. You are going to want to keep the exhaust high and clear of pinch/smash (i.e. along the rockers which may cause a problem if you exit in front of the rear tires, and also a problem on departure if you send them straight out the back without protection) points. Several members here have some pretty good wheeling setups, you may want to start a post asking for pics and experiences.....

    FWIW, hope this helps.
     
  15. 84_Chevy_K10

    84_Chevy_K10 Banned

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    It also depends on how tall your truck is. I know everyone around here cuts off sheetmetal behind the rear tires and worries about smashing their pipes, but with the 38.5s and 6" of lift on mine I've never hit that portion of sheet metal or my pipes on the ground, which are behind the rear wheels at 90s.
     
  16. supersize75k5

    supersize75k5 OrganDonorRacing.com

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    [ QUOTE ]
    38.5s and 6" of lift on mine I've never hit that portion of sheet metal or my pipes on the ground

    [/ QUOTE ]

    tim, you got to come wheel in az, they got rocks and holes that swallow 44's in some of these places /forums/images/graemlins/yikes.gif

    thanks for all the teh guys, I am going to see if I can tuck it up and go out the side, this all depends on what limitations my frame mounted booster and mc will give me /forums/images/graemlins/peace.gif
     

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