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Pick my next mufflers *VOTE*

Discussion in 'The Garage' started by Jonny-K5, Jul 13, 2004.

  1. Jonny-K5

    Jonny-K5 1/2 ton status

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    which of these two mufflers would be better for max HP, and have a more aggresive sound. louder the better.

    motor is a 355 chevy built more for hp than torque. around 400 hp and 380 ft-lbs torque.

    im leaning towards the dynomax, i've never heard them but they sound like they'd be badass. i've heard a single 3" magnaflow w/ cat that sounded good, but a little tame for this truck. maybe duals w/o cats would be better.

    Or, if you have a better option for around $150 a pair chime in. I've got a Flowmaster 40 series on my blazer and i want to try something different.


    Heres the links to the mufflers

    Dynomax: #289-17218

    http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1363&prmenbr=361

    Magnaflow: #642-11216


    http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=85512&prmenbr=361




    .
     
  2. Bhintz

    Bhintz 1/2 ton status

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    I like #3 staight pipes
     
  3. Jonny-K5

    Jonny-K5 1/2 ton status

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    [ QUOTE ]
    I like #3 staight pipes

    [/ QUOTE ]

    /forums/images/graemlins/grin.gifnaaa, i dont think that would be loud enough.
     
  4. fad2blk99

    fad2blk99 1/2 ton status

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    if you got deep pockets, go w/ Borla /forums/images/graemlins/waytogo.gif
     
  5. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    I like #3 staight pipes

    [/ QUOTE ]

    I prefer straight pipes myself. /forums/images/graemlins/thumb.gif
     
  6. 84gmcjimmy

    84gmcjimmy 1 ton status

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    isn't there a problem with back pressure when running no muffler?
     
  7. BlazerGuy

    BlazerGuy 3/4 ton status

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    [ QUOTE ]
    isn't there a problem with back pressure when running no muffler?

    [/ QUOTE ]

    Yep, you lose low end power but you gain it in the top end... /forums/images/graemlins/waytogo.gif
     
  8. 84gmcjimmy

    84gmcjimmy 1 ton status

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    is the lost amount in the low end noticable?
     
  9. backcountry

    backcountry 1/2 ton status

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  10. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    [ QUOTE ]
    isn't there a problem with back pressure when running no muffler?

    [/ QUOTE ]

    Yep, you lose low end power but you gain it in the top end... /forums/images/graemlins/waytogo.gif

    [/ QUOTE ]

    That is a myth that I have dispelled numerous times on this website and I'm not going to do it again.

    Simply put, anything you can do to reduce restriction will increase power across the RPM range. Everything after the headers is "restriction."

    Backpressure does nothing but rob power from your engine. Some pipe is necessary for proper scavenging but everything after the headers is restriction.

    "Ok Tim, then why do people burn valves with open headers/non-restrictive exhausts"

    Becauase their fuel mixture is too lean as a result of the increased airflow and they have not compensated with the proper jetting.
     
  11. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    [ QUOTE ]
    [ QUOTE ]
    isn't there a problem with back pressure when running no muffler?

    [/ QUOTE ]

    Yep, you lose low end power but you gain it in the top end... /forums/images/graemlins/waytogo.gif

    [/ QUOTE ]

    That is a myth that I have dispelled numerous times on this website and I'm not going to do it again.

    Simply put, anything you can do to reduce restriction will increase power across the RPM range. Everything after the headers is "restriction."

    Backpressure does nothing but rob power from your engine. Some pipe is necessary for proper scavenging but everything after the headers is restriction.

    "Ok Tim, then why do people burn valves with open headers/non-restrictive exhausts"

    Becauase their fuel mixture is too lean as a result of the increased airflow and they have not compensated with the proper jetting.

    [/ QUOTE ]Bla bla bla...I could feel a lack in low end when I drove to the muffler shop with open headers compared to driving back with my flowmasters plumbed back in.
     
  12. backcountry

    backcountry 1/2 ton status

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    Some back pressure is good down low. /forums/images/graemlins/peace.gif
     
  13. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    Some back pressure is good down low. /forums/images/graemlins/peace.gif

    [/ QUOTE ]

    Once again, bullshit.

    Provide just one reputable source that states otherwise and I'll retract my statements.

    Anything you can do to reduce backpressure will improve power and efficiency.
     
  14. sickquad

    sickquad 1/2 ton status

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    I could be wrong but I think in near stock configurations, which we have, exhaust valves need some backpressure to work correctly. And at low RPM's no back pressure causes a parasitic lose to the motor since the exhaust valves need the back pressure to operate correctly.

    I'm just trying to remember what an engine builder told me once.

    This all goes out the window at higher RPM's when the parasitic lose is negligible due to the rotational momentum of the motor. Also a motor can be built to run with no back pressure.

    It would be great to hear this from someone who really knows this info through testing and real world results.

    Any engine builders on this board?

    -Chris
     
  15. backcountry

    backcountry 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    Some back pressure is good down low. /forums/images/graemlins/peace.gif

    [/ QUOTE ]

    Once again, bullshit.



    Provide just one reputable source that states otherwise and I'll retract my statements.

    Anything you can do to reduce backpressure will improve power and efficiency.

    [/ QUOTE ]

    Do you happen to have a dyno? Try it!
     
  16. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    [ QUOTE ]
    [ QUOTE ]
    Some back pressure is good down low. /forums/images/graemlins/peace.gif

    [/ QUOTE ]

    Once again, bullshit.



    Provide just one reputable source that states otherwise and I'll retract my statements.

    Anything you can do to reduce backpressure will improve power and efficiency.

    [/ QUOTE ]

    Do you happen to have a dyno? Try it!

    [/ QUOTE ]

    I don't need to. The scientific process doesn't require that you do an experiment to verify every known law of science.

    [ QUOTE ]
    I could be wrong but I think in near stock configurations, which we have, exhaust valves need some backpressure to work correctly. And at low RPM's no back pressure causes a parasitic lose to the motor since the exhaust valves need the back pressure to operate correctly.

    I'm just trying to remember what an engine builder told me once.

    This all goes out the window at higher RPM's when the parasitic lose is negligible due to the rotational momentum of the motor. Also a motor can be built to run with no back pressure.

    [/ QUOTE ]

    Meaning no disrespect to you in the least bit, that is the biggest bunch of nonsense that I have ever heard.

    The exhaust valve has a spring to close it. It doesn't need exhaust back pressure to close the valve. It will do so when the cam moves, allowing spring pressure to pull the valve closed.

    It is nearly scientifically impossible to build an engine that will have NO backpressure. The exhaust ports create some sort of backpressure to begin with. Without SOME pipe, the head will be less efficient at scavenging the exhaust gasses from the cylinders following combustion, but anything after that, ESPECIALLY a muffler, is restriction.

    I'm not out here to say that everyone needs to run straight pipes, or open headers, because that is just not practical for the street as it is too loud.

    Go to the strip though and you'd be hard pressed to see someone run anything but open headers. They're not losing any low end power by doing so, in fact, they're gaining power from idle on up by doing this.
     
  17. backcountry

    backcountry 1/2 ton status

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    [ QUOTE ]
    [ QUOTE ]
    [ QUOTE ]
    [ QUOTE ]
    Some back pressure is good down low. /forums/images/graemlins/peace.gif

    [/ QUOTE ]

    Once again, bullshit.



    Provide just one reputable source that states otherwise and I'll retract my statements.

    Anything you can do to reduce backpressure will improve power and efficiency.

    [/ QUOTE ]

    Do you happen to have a dyno? Try it!

    [/ QUOTE ]

    I don't need to. The scientific process doesn't require that you do an experiment to verify every known law of science.

    [ QUOTE ]
    I could be wrong but I think in near stock configurations, which we have, exhaust valves need some backpressure to work correctly. And at low RPM's no back pressure causes a parasitic lose to the motor since the exhaust valves need the back pressure to operate correctly.

    I'm just trying to remember what an engine builder told me once.

    This all goes out the window at higher RPM's when the parasitic lose is negligible due to the rotational momentum of the motor. Also a motor can be built to run with no back pressure.

    [/ QUOTE ]

    Meaning no disrespect to you in the least bit, that is the biggest bunch of nonsense that I have ever heard.

    The exhaust valve has a spring to close it. It doesn't need exhaust back pressure to close the valve. It will do so when the cam moves, allowing spring pressure to pull the valve closed.

    It is nearly scientifically impossible to build an engine that will have NO backpressure. The exhaust ports create some sort of backpressure to begin with. Without SOME pipe, the head will be less efficient at scavenging the exhaust gasses from the cylinders following combustion, but anything after that, ESPECIALLY a muffler, is restriction.

    I'm not out here to say that everyone needs to run straight pipes, or open headers, because that is just not practical for the street as it is too loud.

    Go to the strip though and you'd be hard pressed to see someone run anything but open headers. They're not losing any low end power by doing so, in fact, they're gaining power from idle on up by doing this.

    [/ QUOTE ]

    Tim,

    For the most part this is a four wheel drive site. Race cars and four wheeler's are totally different when it comes to a properly built motor. Typically 4 WD engines need more torque down low. It amazes me on how many kids want and do build their 4 wheeler engines to produce high rpm's with gobs of hp. Torque is where it is at in most 4 wheel and street engine applications for that matter.

    I have built and run test on my engines, including my current 350 Chevy engine with many scenarios. Stock exhaust manifolds, steel headers, ceramic coated headers etc. The best performance and torque from these tests where; ceramic coated headers, 2 ¼” tubing from the collectors back about two feet with crossover pipe. Then 2 1/2” tubing for about 1 foot to the mufflers then 2 ½” tubing from muffler the rest of the way out behind the rear wheels.


    There are many other factors to take into consideration, such as; the temperature and speed that the exhaust gasses exit. For example; regular steel headers cool much quicker than ceramic coated ones do. If this is what you are referring to back pressure, I would agree with you that this can cause too much back pressure.


    I agree with you on one of your opinions though; Race cars with lots of horse power and rpm’s have different requirements and can run open exhaust. This is not the case with most of our stock or slightly modified engines.

    I noticed on a few of your posts that you appear to like to argue; your opinions as well as mine are not always going to be right. There are far too many scenarios to be right in every case. /forums/images/graemlins/peace.gif


    http://www.iamnotageek.com/showthread.php?t=58653
     
  18. Jonny-K5

    Jonny-K5 1/2 ton status

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    [ QUOTE ]
    Bla bla bla...I could feel a lack in low end when I drove to the muffler shop with open headers compared to driving back with my flowmasters plumbed back in.



    [/ QUOTE ]

    same here, when i drove mine to the muffler shop part throttle low rpm torque was considerably less with open headers.


    [ QUOTE ]
    Go to the strip though and you'd be hard pressed to see someone run anything but open headers. They're not losing any low end power by doing so, in fact, they're gaining power from idle on up by doing this.




    [/ QUOTE ]


    first of all, i dont think the people at the dragstrip care about off idle torque. i think you'd be hard pressed to find a guy there that could give a damn if his setup sacrificed low rpm part throttle torque for high rpm HP.

    also, just because you see people at the dragstrip doing something doesnt always mean its better. alot of people pull the aircleaner off the motor for a run,thinking its restrictive. many hot rod mags have proved that it doesnt help at all, and can hurt performance compared to a high flow filter.

    they have also done similar test comparing several mufflers and open headers.power gains are very slim if at all with open headers, and some setups made a little more power even.same thing with having pipes that are too big for your motor. you dont need dual 3" pipes on a motor than only makes 200 hp. you lose velocity.

    [ QUOTE ]
    It amazes me on how many kids want and do build their 4 wheeler engines to produce high rpm's with gobs of hp. Torque is where it is at in most 4 wheel and street engine applications for that matter.


    [/ QUOTE ]

    just for the record, this motor is not going into a 4wd truck. its a 2wd street/strip truck.
     
  19. 84_Chevy_K10

    84_Chevy_K10 Banned

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    [ QUOTE ]
    I agree with you on one of your opinions though; Race cars with lots of horse power and rpm’s have different requirements and can run open exhaust. This is not the case with most of our stock or slightly modified engines.

    I noticed on a few of your posts that you appear to like to argue; your opinions as well as mine are not always going to be right. There are far too many scenarios to be right in every case. /forums/images/graemlins/peace.gif

    [/ QUOTE ]

    1. There are no opinions being stated here. What I have stated is scientific fact not subject to opinion.

    2. You do not know what you're talking about and I will prove you wrong shortly.

    3. I do not enjoy arguing but I get extremely pissed off when people spread the wrong bullshit information.

    4. If you think nobody that races is concerned with torque it's a good thing you make your living doing something besides racing.
     
  20. 84_Chevy_K10

    84_Chevy_K10 Banned

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