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2004 dodge ram 2500 5.9 cummins ?

Discussion in 'Ram Trucks' started by gmcplowtruck, Jul 27, 2009.

  1. gmcplowtruck

    gmcplowtruck Member
    Messages: 48

    i recently picked up a 2004 dodge ram 2500 4x4 quad cab short bed diesel truck with all the bells and whistles love the truck has 251000 miles on it paid $8500 and had to put tranny tires and universals on it truck gets 18 mpg around town and 23-24 mpg on highway empty well pulled out quikly the oter day and truck got uder got under to find out exhaust was rusted in front of muffler and snaped off my question am i better off strait piping the truck or putting muffler back on which gives me better mpg hp what do you guys think all comments apreciated
     
  2. BigDave12768

    BigDave12768 PlowSite.com Addict
    Messages: 1,446

    Only problem with straight piping it is you will lose back pressure. It will also be louder. So without back pressure you will lose low end power. You can get mufflers and complete systems fairly cheap.
     
  3. gmcplowtruck

    gmcplowtruck Member
    Messages: 48

    ok so im better off putting the muffler back on i really thoght it gave me more power without thanks forthe advice
     
  4. BigDave12768

    BigDave12768 PlowSite.com Addict
    Messages: 1,446

    Stock trucks with stock turbo's need the muffler for back pressure. If you went straight pipe with no back pressure your Turbo would take longer to spool up. This is called Turbo lag. This is where you would feel a loss in power. Waiting for the turbo to spool up. So as the tranny goes through gears and drops Rpm's every gear. Your turbo would be late in helping.

    This theory goes out the window if you have a heavily modded truck with an over sized turbo and such. But since we are talking stock aplication here and not some 500+hp truck. I would put a mufler back on. Plus the droan of a straight pipe would be so annoying. But thats just my opinion

    And if you getting your 18mpg on a 04 you have a 305hp motor? with 3.73? Check vin for 8th digit 6=305hp C=325hp. The 305hp motor has a smaller turbo than 325hp produced after 1-1-04. So I am sure you are not winning any races off the line. This arguement has been beaten to death online.
     
    Last edited: Jul 28, 2009
  5. gmcplowtruck

    gmcplowtruck Member
    Messages: 48

    it is a 305 but i ot the truck for a great price and i origanally was using an 01 dodge gasser that was geting 5 mpg plowing and had no power to carry the salt i carry i was looking at the truck and im gonna see if the exhaust shop can weld the seem it broke clean because the system is in really good shape exept for that one spot
    thanks for your help
     
  6. got-h2o

    got-h2o 2000 Club Member
    Messages: 2,439

    Wrong on the backpressure thing, and mufflers only quiet them, they really have nothing to do with backpressure......pipe size does. Turbo'd vehicles do NOT require back pressure. There have been countless discussions, dyno tests, etc to prove this. Although you may think you feel power loss, its not the case. You could essentially run a wide open turbo and have no adverse effects (aside from potentially lighting the truck on fire!). The wastegate controls exhaust output from boost, not backpressure. Boost is produced under a load. You could floor it in neutral and barely produce boost, barely opening the gate. VVT's are different, but use the same principal. You want it to breathe, its the best thing for a turbo. Breathing better means lower EGT's, lower EGT's means more power, and more efficiant fuel consumption.

    Jump on me all you want, I've got 3,400 posts, 4 years on a diesel forum, and have owned 8 modern diesels to back this up. I have a 5" straight piped single stack on one of my trucks and its no slower than my other with stock exhaust.
     
  7. exmark1

    exmark1 PlowSite.com Addict
    Messages: 1,321

    Your dead on! I have a 2003 & 2001 Dodge and a 2000 7.3 Ford all are 4" exhaust straight piped turbo to tail pipe. We have NO issues with turbo lag, back pressure etc... actually helps ALOT with fuel milage as well
     
  8. got-h2o

    got-h2o 2000 Club Member
    Messages: 2,439

    OH and BTW, that seems like a great deal you got on the truck too. I'd have bought it for that.
     
  9. BigDave12768

    BigDave12768 PlowSite.com Addict
    Messages: 1,446

    Get into a pile once in a driveway and you will never plow that driveway again unless its a free one for a family member

    <object width="445" height="364"><param name="movie" value="http://www.youtube.com/v/7iiZZ0rjoDA&hl=en&fs=1&border=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/7iiZZ0rjoDA&hl=en&fs=1&border=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="445" height="364"></embed></object>
     
  10. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,992

  11. exmark1

    exmark1 PlowSite.com Addict
    Messages: 1,321

    We have plows on all of our trucks, never had a complaint! The plow makes enough noise the way it is
     
  12. cretebaby

    cretebaby PlowSite Veteran
    Messages: 4,162

    Calling for Camden

    Camden..................Camden.........................Camden

    I think you need to post that picture you got for Dave again, :nod::D
     
  13. got-h2o

    got-h2o 2000 Club Member
    Messages: 2,439

    Just a little more helpful info real quick too. Headers and backpressure.......PRE-turbo. That's pretty self explanitory.

    Lastly, post-turbo backpressure is going to be caused by the smallest exit point, regardless of where it is in the system. The turbo exhaust exit is a cetrain size, so anything after that will have no negative affects. Once again, larger exhaust is beneficial to lower EGT's.

    I'm not going to argue. Take my posts for what they're worth. I'm only trying to help. I've done my research and clearly understand the physics involved in how a turbo works.
     
  14. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,992

    Yes you do:salute: but I could argue that gas flow restriction due to improper bending of incorrectly specified pipe size of the exhaust could actually produce higher restriction then the turbo exhaust exit, at the cost of performance of course. That would highly unlikely though it quite possibly has been achieved in a Midas shop somewhere.
     
  15. got-h2o

    got-h2o 2000 Club Member
    Messages: 2,439

    I agree. The opposite affect would cost performance, namely due to higher temps. Backpressure on turbo'd vehicles does and can exist, but that's not necissarily a good thing. Stock exhaust is typically pretty restrictive. No mandrel bends.
     
    Last edited: Jul 29, 2009
  16. M1N1TRK

    M1N1TRK Member
    Messages: 48

    Yes the more back pressure you have going from the manifold to the turbo will create a faster spool up on the turbo and less lag.

    You esentially do not need to run any exhaust tube after the turbo if you dont want to. The only reason they have them is to keep the soot from making a mess under the trucks.

    If you look at any after market diesel muffler you will see that it is nothing more then a resonator. I can stick my arm through my muffler from one side to the other with out an issue.

    The diameter of the pipe is what you need to be carefull of. A stock diesel truck with horse power up to 400hp is good with a "true" 4 inch system. if you want to go with a 5" system then you need to put out anywhere from 400 to 600 hp and then after that you will need to run a 6 inch or larger.

    I will be putting a 5" stack on my truck soon for the reason that i am putting 350hp and 621 ft. pounds down to the wheels right now with only an air intake, intake elbow from the intercooler to the engine and a diablo sport tuner set on extreme. any other mods to the truck and i will not see the power gains that i could with a larger exhaust.

    A stack on a pick up is just a glorified straight pipe also since there is no muffler involved with the install. FYI
     
  17. basher

    basher PlowSite Fanatic
    from 19707
    Messages: 8,992

    Not on the duramax[​IMG]

    duramax-text.gif
     
  18. nickv13412

    nickv13412 Senior Member
    Messages: 621

    Now that this thread has caught my attention, id like some reading material on how backpressure would lead to cooler EGTs. It goes against everything I learned in Thermodynamics I and II. Im gonna agree with the guys saying that a straight pipe will reduce EGTs, unless the pipe is too small and restricts flow too much, or too large to the point where the exhaust flow is turbulent and causes restriction as well. And i dont belong to any diesel forums, I already spend too much time on these plowing ones. ;)
     
  19. gmcplowtruck

    gmcplowtruck Member
    Messages: 48

    thanks guys alot to think about may strait pipe in a year or put exhaust on but got it welded today for $25 so when that breaks ill do something if i put an exhaust on or cold air intake do i have to put extra gauges on the truck
     
  20. JohnnyU

    JohnnyU 2000 Club Member
    Messages: 2,040

    You don't really need gauges as long as you're running stock programming, but as soon as you start making modifications, it's never a bad idea to install gauges in order to monitor your vital engine parameters. I always recommend Exhaust temp, Trans temp, and boost pressure. Fuel pressure (lift pump or rail pressure would both be nice). With those parameters under surveillance, a problem can be quickly spotted, diagnosed and hopefully repaired or have the truck shut down before serious damage occurs.

    I'm running EGT, Trans Temp and Boost Pressure on my truck.