exhaust modding.

Discussion in 'Performance Mods' started by linnix13, Mar 6, 2009.

  1. linnix13

    linnix13 Banned

    i have a 80cc 2-stroke Chinese engine. i drilled a 1/4" hole next to the original hole on the baffle on the muffler. and it makes the engine slightly louder and deeper sounding. but it gives me more than twice the power and alow's me to do 55kph as appose to 40kph stock. it also allows me to d0 30kph up hills where i would usually do 14kph. and it makes my acceleration amazing! more than triples it. i go through slightly more fuel but thats ok. so are there any dangerous side effects from this? im ok with having to replace the top end sooner because its only 40 bucks from the manufacturers website for a hole new top end. but could it throw the piston or result it catastrophic failure? ive ridden it for almost 500km like this and it seems fine. thanks

  2. Mountainman

    Mountainman Active Member

    just thinking that your engine was not made for such speeds

    backpressure -- lacking of -- may be a problem

    if replacement monies are no problem -- have fun

    if you are looking for a long lasting relationship
    treat her right...................

    as you ride the motor bike thing
  3. keylan

    keylan Member

    i would love to see a picture of this mod. i would also love to try this!
  4. linnix13

    linnix13 Banned

    sure il post a picture of it! how do i do that??? and in the pick there are 3 holes you only need one. here is what i found, with 3 1/4" holes open the engine sounds deep and very loud, it has almost 3 times the acceleration of stock but you loose about 15 kph of your top speed, with 2 holes it is still loud and only twice the acceleration but you still loose about 7kph of the top end. now with one 1/4" hole you have around 0.4-0.6 the acceleration and you gain about 8kph top speed. and it sounds the same as stock except its very poppy sounding, you can hear the air being forced through the hole and it sounds slightly deeper. all in all you gain probably 14db for sound and gain alot of speed and power and i havnt noticed any worse fuel economy or plug fowling. now how do i post that pick?
  5. keylan

    keylan Member

    there are a million ways to do this, my favorite may not be the fastest, but it is the easiest way to show them off is to host them directly..

    or, if you want, just e-mail it to me and ill host it

    1. snap the picture with your digital camera
    2. transfer to your computer
    3. go to www.imageshack.us
    4. browse to your photo
    5. select the resize option 800x640 or whatever is closest to that
    6. upload
    7. find the code it gives you once uploaded
    8. you are looking for the code that starts with IMG
    9. copy paste into your thread or even into a reply to your thread

    Moddy Edit: We do NOT use IMG tags at MBc.
    Last edited by a moderator: Mar 13, 2009
  6. linnix13

    linnix13 Banned

    k i emailed it
  7. keylan

    keylan Member

    Attached Files:

    Last edited by a moderator: Mar 13, 2009
  8. srdavo

    srdavo Active Member

    We don't use IMG tags here.
    here is a link to how to load pics on MBc.

  9. etacovda

    etacovda Member

    it wont be 14db, 3db is a 2x 'loudness' increase to your ear...
  10. linnix13

    linnix13 Banned

    i dont know when i have my headphones at 84db then i crank it up to 100 db(max) it sounds about the same as my muffler, oh and im talking right at the muffler tip not where i sit or as a person would hear it going by.
  11. kallsop

    kallsop Member

    Generally, 10dB is considered to be twice as loud. 3dB is twice the acoustic power, but human perception needs 10dB to double loudness. That's why upgrading an audio power amplifier from say 50W to 100W is barely noticeable, except to manufacturer marketing departments :)
  12. linnix13

    linnix13 Banned

    so going from 10db to 20 db will be like 20x louder not twice? i guessed by comparing it to my headphones. just turn your music from 80% to 90% and thats how much louder this mod makes it
  13. etacovda

    etacovda Member

    Ah yes, thats correct - its been a while!

    linnix - 10 to 20 will sound 2x louder, but in reality will be 3.333x more powerful accoustically
  14. linnix13

    linnix13 Banned

    ok then so let me tell you that doing this to your muffler does NOT make it twice as loud. it makes it about 1/9th louder
  15. Gungatim

    Gungatim Member

    Does your amplifier go to 11?
  16. linnix13

    linnix13 Banned

    what? i was using my ipod and its in % and i have an amp in my room that goes from 1-10
  17. Gungatim

    Gungatim Member

    Sorry, just an attempt at humor referencing the move Spinal Tap.
  18. uncle_punk13

    uncle_punk13 Guest

    My Bass Guitar amp does...
    LOL!!! Nice reference dude!
  19. CPC

    CPC Member

    so what happens to your speed and noise increase if you drill 1 hole @ 1/8th inch? Has anyone tried?
  20. linnix13

    linnix13 Banned

    i doubt anything would happen exept that it would have a slightly whispe'r sound. just drill the 1/4th hole and if you dont like it than put a bolt through and a nut on the other end. you can try a 1/8th hole. its all about experimenting. happy ridings for whatever you decide to do!