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Non OEM muffler

Discussion in 'References' started by o8k, Jan 23, 2010.

  1. o8k

    o8k Member

    I did some poking around and cant find much on people swapping out mufflers. Using "muffler" or "exhaust". So, I'm looking for some people who have done it what model to use that is close.

    I measured 1.75" out of my manifold, and it necks down to 1.25" to muffler opening and exit.

    Any takers?

    Looking at this one:
    http://www.amazon.com/MagnaFlow-11133-Stainless-Steel-Muffler/dp/B000XQM1J4
    or better
    model 11113 ....

    in which case i would have to lose 1.25" plumbing down stream of the current muffler...
     
    Last edited: Jan 23, 2010
  2. starpuss

    starpuss Member

    1.75" out at manifold, you should necks up to 2.00"or 2.25" muffler
     
  3. draggbody

    draggbody Member

    i own an exhaust shop and i wouldnt do ANY more than 1.5"... magnaflow doesnt offer anything that small, and if they did i think it is to much flow... stick a turbo muffler on it and some fresh pipe and call it good...
     
  4. o8k

    o8k Member

    Thanks for the replies. Since this post found a little more to read about backpressure, exhaust tuneing, etc. It is still a little sketchy in my mind but i seemed to at least be able to grasp this:

    BACKGROUND:
    Backpressure is a term used to describe the resistance to flow in a volume (in this case the exhaust). Simply put, the "least resistance" always best. But this is where many people get it messed up. The "least resistance" is variable with respect to the RPMs. So the concept of large pipe large volume exhaust may be great for high RPMs, it is very much contrary to "ideal" for low RPMS. Thus the conundrum. Most manufacturers make something that is the best compromise across all rpms. But is basically considered the benchmark by which engine tuners have to work with. As you increase volume and pipe diameter, you "help" high rpms and help maintain torque past peak. If you go the other way (shrink pipe/flow) you hurt torque after peak, but can significantly increase it before peak. When there is resistance to flow, there can be a pressure inversion which drives exhaust back into the cyl wasting volume for fresh air/fuel mix and thus kills torque and rate of torque (power).

    MY approach:
    I want to swap mufflers from stock 1.25" to 1.75" but neck the muffler ouput down to fit the original 1.25" pipe out to the tail. my hope is that i will increase volume and flow a little but not enough to cause any ill effects. Based on what "i think" i know, i will have a little better torque at high rpm at the sacrafice of losing a little at lower RPM. Since this is a in-line 3cyl that is designed for performance at higher RPM, I should be ok. Even though the exact mathmatical backpressure dynamics model on changing to this muffler exscapes me, my hope is it wont be a significant change.

    Comments/Thoughts?

    Another note: those goofy shaped pipes found on some motocross motorcycles (and found hidden on some italian sports cars) I believe are mathmatically modeled to provde min backpressure across all RPMs without dynamically changing pipe shape. e.g. the dynamic backpressure is dirived from flow through the system (RPMs) and its resonating effect of the funny shaped pipe (kinda looks like bugle or a funnel)
    http://www.rc-trucks.org/Motocross-Tuned-Pipe.jpg
     
    Last edited: Jan 25, 2010
  5. fupabox

    fupabox Well-Known Member

    Are you referring to expansion chambers like on a 2 stroke??...That appears to be a tuned 2 stroke pipe..they work differently than a reg muffler,and help refill the cylinder by creating a lower pressure wave on the pipe side (something along that line anyway)..won't work on a 4 stroke,though a pipe from a 700 or 800cc street bike(single exhaust model) may work well with a small diameter and prob sound really good...thats where I'm thinking of going when it warms up around here
     
    Last edited: Jan 25, 2010
  6. o8k

    o8k Member

    Yes! like the 2-stroke expansion chambers. This concept has also been adapted for 4-stroke formula-1 (/me thinks) (AKA megaphones for motorcycles etc). Used it as an example of "tuning" exhaust for a sweet spot to illustrate my point.
     
  7. o8k

    o8k Member

    One thing i dont understand, is all the posts regarding 4-stroke exhaust tuning is predicated upon the idea that there is a period of time that both the intake and exhaust valves are open at the same time. I dont have the experience to know if this is true for only some engines, or true for all engines absolutely or not true at all.
     
  8. fupabox

    fupabox Well-Known Member

    I would think the easiest way to tune for both performance and sound would be the good old supertrapp..they are still around though pricey..should be able to find a good used one with some luck..http://www.supertrapp.com/
     
  9. o8k

    o8k Member

    Update: This is true, its called "valve overlap" and if you have a "2-stroke" tune chamber on your 4-stroke motor, the "backpressure reverberations, will flow exhaust back into intake and to the exact opposite of its 2-stroke cousin, the 4-stroke will puke and make bad torque/HP.

    So, i guess my point is, if you goof w/ your exhaust, you "may" inadvertantly end up with reverberations that could have negative consiquence on your performance.

    This seemed to clear all these loose threads in my head up for me:
    http://www.btc-bci.com/~billben/camlore.htm

    Again, thanks for the comments and thoughts.
     
  10. greg0187

    greg0187 Moderator Staff Member

    Geeze... You guys are getting technical. Good read though. I don't think I would worry too much about "reverberations". Its not like your re-designing the exhaust system by replacing the muffler. :p
     
  11. o8k

    o8k Member

    Which was kind of my original thought... New muffler won't user change my performance much. But I tend to over analyze stuff on occasion =P.
     
  12. fupabox

    fupabox Well-Known Member

  13. greg0187

    greg0187 Moderator Staff Member

  14. o8k

    o8k Member

    ROFL, sounds like a frog with gas!
     
  15. erixun

    erixun Member

    I am still giggling about that video, maybe it was a cricket with gas that got ate by a frog? Anyway that was funny!
     
  16. fupabox

    fupabox Well-Known Member

    o8k...turn on google translate and check this site...custom suzuki exhausts with pipe diameters listed...if translate won't work on far left scrolling column...suzuki is 6th last japanese script on left (for "insert japanese script") then your truck model pops up..http://wiruswin.com/..lots of nice photos and specs..also for other kei trucks as well...enjoy:)
     
  17. o8k

    o8k Member

    Thanks for the post, not bad! 125-200 USD range stuff, all seem to open up exhaust to 45mm (~1.75") all the way through.
     
  18. fupabox

    fupabox Well-Known Member

    Ya that's the info I wanted you to see.:)..pipe diameters and the relative muffler size...wonder how they sound....searching for just that info atm...:pop:
     
  19. Doddy

    Doddy Member

    muffler

    I wanted to change the sound of the mini, atleast beef it up. i thought i would use a harley davidson stock muffler off a 2010. it didnt sound at all what i was going for, out side its sounds like a eurocar or a civic, but inside it sounds like a ferrari, wish it drove and felt like one..
     
  20. Stuff99

    Stuff99 Moderator Staff Member

    when my muffler goes (which should be this summer by the looks of it..) im gonna look for a nice stack muffler :p
     
  21. Acerguy

    Acerguy Moderator Staff Member

    One thought....how about looking for any sort of "sport" muffler for a 600-700cc sport bike? Granted, mini trucks don't rev nearly as high so won't flow nearly as much....hmmm...or maybe a sport bike muffer from something smaller? :confused:
     
  22. Doddy

    Doddy Member

    well i got the harley muffler free and i would be willing to try a sport muffler if i get it free to.
     
  23. draggbody

    draggbody Member

    the type of vehicle that a muffler comes off of is not going to alter the sound... a harley sounds like a harley because of the engine, not the muffler... what im saying is you could put a sport bike muffler on a harley and its still going to sound like a harley, or vise versa...
     
  24. Doddy

    Doddy Member

    I understand that, like I said I just want it to sound better. But what can u do about a small 3 cylinder?
     
  25. draggbody

    draggbody Member

    dont get high expectations... its still a 3cyl, i would look for a 24" long glasspach w/ 1.5" inlet/outlet, thats probably as good as it gets...
     
  26. greg0187

    greg0187 Moderator Staff Member

    Here's the one Ketzer has... Stock Hayabusa. Says its nice and quiet like the OEM muffler.


    [​IMG]
     
  27. Doddy

    Doddy Member

    a stock muffler using the trucks origional motor?
     
  28. draggbody

    draggbody Member

    there is a bunch of hype... as far as performance mufflers goes, there two basic styles... strait through perforated type and baffled style... a magnaflow, glasspack, gibson, borla, etc is an example of perforated... flowmaster and all of the replicas are examples of baffled style... but, each of these style mufflers will only sound a certain way on any given application...

    can you "tune" any exhaust, of course... there are more variables than you can imagine, down to what material you make the system out of, is that going to matter in everyday applications, no... so what you have to consider is what is practical??? no muffler shop is going to have 1 1/4" pipe, so that is out... but they do have 1 1/2" pipe, so that is practical... now what about mufflers??? a strait through style is going to be a smoother and typically quieter muffler because there is accoustical material absorbing sound... if you put a baffled muffler on it, there will be a more metallic raspy sound, because there is nothing aborbing the sound, it just redirects it the sound and based on the design internally, it will cancel some of the sound waves, thus producing a quieter sound...

    i own a muffler shop and i have two suzukis that i plan on building exhaust for both trucks... i will build a different one for both trucks just for comparison...
     
  29. Doddy

    Doddy Member

    i will be waiting for the results!
     
  30. Acerguy

    Acerguy Moderator Staff Member

    Cool. Great info, dragbody!
     

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