Exahust pipe diamter

Discussion in 'Diesel Tech / 24 volts' started by Tapage, Aug 5, 2005.

  1. Tapage

    Tapage Club 4X4 Panamá SILVER Star

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    Hi all folks .. that is teh question very easy ..

    in my 2H I have the stock 2" diameter from exhaust manifol all the way, wih glass pack.

    What do you have in yours Diesel engines .?
     
  2. crushers

    crushers post ho

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    2 1/2" aluminized with free flowing muffler...
     
  3. Deny

    Deny

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    2 1/2 with a baffle pack, exiting infront of the passenger rear tire. It was quite a noticable difference going from 2 to 2 1/2.
    Cheers,
    Deny
     
  4. Tapage

    Tapage Club 4X4 Panamá SILVER Star

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    Did you thing I need to go to 2 1/2 " in my " stock " 2H .. ?

    Is the answer is yes .. from exhaust manifold without muffler . :D
     
  5. Deny

    Deny

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    I think it will help a bit, but it is no Turbo! No muffler, will be TOO loud, without a turbo. A glass pack on a 2 1/2 exhast is pretty loud, too loud for me, but my brother had the long 2 foot glasspack with 2 1/2 exhast on his BJ60, and it was not too bad (took it off because it now rubs his new 35s)
    Cheers,
    Deny
     
  6. Tapage

    Tapage Club 4X4 Panamá SILVER Star

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    I'm pretty sure that 2 1/2" exaust is not a turbo .. and I know maybe this setup without turbo or muffler comes to loud ..

    But .. sometimes is funny .. ! :D
     
  7. crushers

    crushers post ho

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    i recommend a 2 1/2 for even the NA 3B...
     
  8. Technikev

    Technikev

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    Made a difference in power, I'm assuming. What engine is that on? Do you have a pyro and if so what difference in EGT?


    Wayne: Who do you use for an exhaust shop?

    -Kevin
     
  9. crushers

    crushers post ho

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    i have a shop down here that has been doing my exhaust for 15 years. they know exactly what i want and where. they are expensive to be sure but they do phenomenal work...
    minute muffler...
     
  10. Deny

    Deny

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  11. colin 4

    colin 4

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    I need more top end power for towing. If I'm going to go through the trouble of replacing my exhaust I want to do it right. 2H, h55f, 31's(planning for 33's) Should I go 2 1/2 all the way from the manifold?
    New muffler? What is a free flow muffler? And for pipe diameter, how big is to big on a 2h - need back pressure right?
     
  12. colin 4

    colin 4

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    how necessary is a pyro and why? Forgive my ignorance.....
     
  13. bigbrowndog

    bigbrowndog

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    Safari T3 and 3inch mandrel exhaust with 3inch muffler:bounce: :bounce: . I was told by Qld Transport that a muffler must be fitted otherwise the vehicle did not comply with its relevant A.D.R. Rule:crybaby: and therefore they deemed it as "not roadworthy".:ban: :beer:
     
  14. jzilla

    jzilla

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    have a 3 inch straight through, i figured why not
     
  15. brownbear

    brownbear Mod in Hibernation Moderator

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    2H guys should go to 3" IMOP.....why skimp.??

    I'm doing exhuast next month on my 3B with a turbo, I am going 3" with an almuminzed muffler. Exiting infront of the LH back wheel.

    Right where my dog jumps in :D
     
  16. cruiser_guy

    cruiser_guy

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    I have 2 1/2" pipe that follows the stock routing to help deaden noise and NO MUFFLER. I figured a muffler simply redirects the exhaust flow several times within the muffler thus deadening sound with the accompanying back pressure. I'd rather redirect the flow gently in the pipe with less back pressure. The less back pressure you have the better power you'll have. Of course the back pressure from the turbo gives added power since it's performing useful work in spinning the compressor.
     
  17. colin 4

    colin 4

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    But you have a turbo. If I go 3" will my engine be running rough because I don't have enough back pressure? There must be some sort of science with this stuff isn't there? Surely you diesel heads out there have some sort of max tailpipe diameter equation for a non-turbo 2H? Okay so maybe not.....I'll go as big as I can but my dream is to get a million km out of my truck so I don't want to cause extra wear and tear y'know? Thanks for your patience. ;p
     
  18. Mickldo

    Mickldo

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    Don't be suckered in to running too big. I'm running a 3" mandrel bend on my turboed 1HZ but after talking to a mate who owns a dyno tune perfomance shop and owns a turboed intercooled 100 series. He runs a 2 3/4" exhaust and has run a 3" on his as well. He told me he got more power with the 2 3/4" system. This discussion was a while ago now so I don't remember the hp #. Also can't remember if he was running mufflers or not.
    Don't know about a normally aspirated 2H but if a turboed intercooled 4.2L doesn't need a 3", maybe you can save some $ and go for a slightly smaller pipe.
     
  19. cruiser_guy

    cruiser_guy

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    There comes a time where larger pipe doesn't make economic sense. The back pressure however, from everything I've read, is a myth! Less back pressure is good. The only problem is it's also louder if not properly dealt with.
     
  20. crushers

    crushers post ho

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    yes, pipe size does not make a huge difference to performance. we are not increasing the size of the pipe for this reason, we are doing this to reduce the EGTs stuck in the pipe.
    on the dyno, test rig was a cummins (size and year was forgotten by me long ago) there was a test done here in town, 3",4",6" exhaust and the HP and torque readings stayed the same.
    i recommend the 2 1/2" exhaust size on all the units from the 2LT up to the 1HZ turbo'd. this system has served me good for years, no burnt valves and little restriction to the system.
    if you want to go bigger, good for you. i tried the 3" on the 2LT, it seemed to help the EGTs but an extremely tight fit and a very expensive bill.
    cheers
     
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