BGF vs SBP expansion chambers

Discussion in 'Performance Mods' started by cavalierchristian, Dec 2, 2011.

  1. cavalierchristian

    cavalierchristian New Member

    Ok, BGF's exhaust cost's 50 bux vs the SBP's 70 bux. Altough the SBP has a more "customizable" fit do to the seperate sections n all, the BGF looks as if it would suck the air out of the cylinder a bit better, and its chrome! But I guess my main question is, which makes more power? Neither company have poven dyno results... And since neither will back their product with number's, I might go with BGF due to it being chrome and $20 cheaper, it has no muffler, but who really needs one of those (besides the old people). I would assume it would still get amminent back pressure even with out an exhaust. SO there it is, I have weighed my pro's n con's, u tell me some of yours and which would be a better choice for me!
     

  2. motorpsycho

    motorpsycho Active Member

    post some pics. I had no idea that bgf was offering an expansion chamber.
    In the world of chambers, the phrase "you get what you pay for" applies.
    sure, a chrome one would be cool, but does it perform? The sbp one has proven results with many people here.
    I have never heard anyone mention a bgf chamber until now.
    and you do need a muffler on a chamber.
    the muffler will actually make it produce more low end power.
    I have an all chrome chamber from spooky tooth which looks cool, but it really doesn't give much of a performance gain because of the way it's designed. granted, it's better than the stock pipe & muffler, but it's more for looks than performance in my opinion.
    if you look at the sbp chamber, it resembles a proven 2 stroke dirt bike pipe and it's tuneable to your liking.
    sbp has put a lot of research and tuning into their pipes, and they perform very well.
    THAT's why it's $70.00 and not $50.00.
    I want to see this bgf chamber tho.
    **EDIT**
    I just looked up the bgf chamber and come to find out, it's the same design as the spooky tooth chamber (same as the one i have).
    in my opinion, you will get more performance out of the sbp chamber than the bgf chamber. The bgf style chamber does add a little power, but not much over the stock puipe & muffler.
    if you go with the bgf chamber, you will want a muffler on it because it is annoyingly loud (I love straight pipes, and open exhaust) but this thing is just annoying, it doesn't even sound cool without a muffler. I modified the stock muffler to go onto my chamber, so it's still loud and has a good sound, but it's not so loud that it's annoying.
     
    Last edited: Dec 2, 2011
  3. cavalierchristian

    cavalierchristian New Member

    any other takers? And by tunable do u mean where certain lengths of pipe can be removed or added before the expansion chamber on the exhaust? DOes this really make a difference? I figured a "tunable" pipe would be expensive since we are talking the difference between .5hp and 2hp which makes all the difference when it comes to power to weight ratio.
     
  4. motorpsycho

    motorpsycho Active Member

    yes, by tunable, i mean that you can shorten the head pipe (but once you cut it, i don't think you can go back and make it longer again, like if you cut it too short).
    yes it makes a HUGE dofference in performance. If you have a chamber that's tuned correctly, it will give you the same results as if you put a supercharger to the engine.
    it will literally give the engine boost at a certain rpm like a supercharger. I can tell you right now, that the bgf pipe does not give that effect.
    If you have ever ridden an older 2 stroke dirt bike (like a suzuki rm 125), when the pipe "comes on" it is just like a supercharger.
    I personally don't have a sbp chamber, but everything i've read about them is nothing but good things.
    The bgf chamber is exactly what you see in that pic, you can't change it or tune it.
    Personally i think the bgf head pipe is too short before the chamber expands to the cone.
    you really shou;d wait and see if anyone who has the sbp chamber can give you their opinion because it would be best to get the info from someone who actually owns one.
    This is just my opinion, so i may be right, I may be wrong. But since i own a pipe loike the bgf one, i know that it doesn't add a whole lot of performance.
    I mean it does add some, and it's way better than a stock pipe & muffler that's for sure.
     
  5. cavalierchristian

    cavalierchristian New Member

    thanks^^ And when comparing the pipes to what I used to see on my dirt bikes, it seemed as if the bgf was similarly designed. Im just not used to seeing the expansion chamber so late in the exhaust like the SBP. But I will wait n see what everyone has to say about the 2. Heck, I haven't even completely assembled my bike yet and I already want a new exhaust! lolz
     
  6. HeadSmess

    HeadSmess Well-Known Member

    i dont have a muffler on my chamber... its actually quieter than the last job that had a muffler... :thinking: work that one out :jester:

    goes good but :)
     
  7. Barnfresh

    Barnfresh Member

    I read somewhere that many of the chrome bannana pipes being advertsed and sold as expansion chambers actually have baffling in them. Something like a pipe rivited inside another pipe with holes drilled in it. A true expansion chamber is hollow inside and when you fire up an engine with one without any type of muffler on the stinger, you (and your neighbors) will know it!
     
  8. motorpsycho

    motorpsycho Active Member

    I'm not so sure of that because the so called "Bannana pipe" that i have from spoooky tooth has 0 baffeling in it.
    without a stinger or a muffler on it, it's louder than running just a straight peice of pipe. It's VERY loud without a muffler on the end.
    I modified my stock muffler and baffle to go on my bannana pipe, and it's still pretty loud, but it's a good loud and it sounds throaty.
     
  9. Barnfresh

    Barnfresh Member

    Like I said "you will know it". Consider yourself lucky MP, the China man must have been asleep at the wheel while he was putting your pipe together. There are others who also have hollow pipes. I called Spooky Tooth this afternoon and although they are currently out of stock, they told me the chrome bannana pipes they have sold in the past as well as the new batch coming in, all have baffles in them.
     
  10. motorpsycho

    motorpsycho Active Member

    yeah i'm pretty sure that the one I have doesn;t have any baffeling in it. I bought it from spooky tooth about 2 years ago and it was listed as being made by skyhawk.
    it's f-n loud without a baffle on the end!
     
  11. jaguar

    jaguar Well-Known Member

    The main difference between pipes comes from the angle of the final baffle cone. Steeper angle gives more top rpm power but for a shorter range of top rpm. Slighter angle gives less top rpm power but a broader power range.
    Whether a pipe "works" or not is all a matter of whether or not you took the time and trouble to experiment with different lengths of header pipe (between the cylinder and the first diffuser cone) to find just the right length for the top rpm boost. It has to do with port timing matching the sound wave return from the baffle. It is impossible to calculate and can only be found by experimentation. The best length gives the best top speed because the sound wave return timing is such that at top rpm the beggining of the return baffle wave arrives back at the cylinder just as the transfer ports are closing.
    Guess at the length or use a recommended length and you are F´d
     
    Last edited: Dec 6, 2011
  12. HeadSmess

    HeadSmess Well-Known Member

    i managed to calculate my lengths with some degree of success it seems, as im quite happy with the way it works over several others ive played with before...

    blah blah blah blah you only need basic maths to calculate ideal lengths blah blah blah just reduce the number of variables to a minimum. the main variable being the exhaust temp in proportion to stinger diameter that affects the density of gas in the pipe that then affects the speed of sound, which affects the tuned length. :)

    find out the exhaust temp and the rest is easy really.

    the hardest part is layout. where to put the bends and how far apart.

    people used to do it without the help of a computer.

    (and if the stinger is the same length as the reflector/baffle cone, and is stuffed all the way inside the cone, the exhaust volume is DRASTICALLY REDUCED... i also seem to blow no smoke even on a 20:1 mixture...)
     
    Last edited: Dec 11, 2011
  13. jaguar

    jaguar Well-Known Member

    I am close to perfecting my Excel file that allows you to input all the details of length for each pipe section to see if the return waves match the port timing at top rpm. You can find it on my site but wait a couple weeks to download it as the version on there now has errors.
     
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