Register

If this is your first visit, please click the Sign Up now button to begin the process of creating your account so you can begin posting on our forums! The Sign Up process will only take up about a minute of two of your time.

Results 1 to 7 of 7

  1. #1
    diamondave's Avatar
    Join Date
    Sep 2004
    Location
    marana, AZ
    Posts
    2,729
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    bcm unitized muffler

    i am planning on getting a zdz100 sometime in the near future, i was going to get stock mufflers, now i see the bcm unitzed muffler, what advantages(if any) does this give? in a car engine you would use a H pipe or X pipe to get more low end torque, and help draw exhaust gas from the other side by way of vacuum, does this give any of that effect? i am also curious about weight, performace, sound(relating to stock mufflers), and how far forward the "barrel" sits, i have seen people have to cut out cowls for there stock muffler "barrels" as well as the down tubes of course, does this sit back any, id hate to have to cut the cowl all the way accross the front to cear it, any info from anyone??

  2. #2
    diamondave's Avatar
    Join Date
    Sep 2004
    Location
    marana, AZ
    Posts
    2,729
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: bcm unitized muffler

    so no one has any opinion on that unitized muffler???

  3. #3
    Zeeb's Avatar
    Join Date
    Nov 2004
    Location
    Highland Utah UT
    Posts
    3,848
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: bcm unitized muffler

    Well technically this is Mike's support forum although other folks do post here occasionally.

    I'll run my own thoughts past you for your consideration.

    While I've not run the unitized muffler, I'm not a fan of BCM stuff from my experience with them on other engines, they tend to be restrictive and big requiring more extensive cutouts to the cowl. It seems to me that the unitized muffler would just create more heat dissapation problems than dual singles. Heat dissipation on ZDZ engines is quite critical and mine are baffled to keep 'em cool. The possible torque increases you mention on a car I don't think will happen on a two stroke twin cylinder engine as both cylinders fire at the same time. If you want to get more power/torque from the exhaust system on a two stroke, you need to look at running pipes and those are a whole different ball game. Otherwise, just a good low restriction muffler or if noise is an issue and/or money isn't, cans can be a good alternative but they do add weight as well as expense.

    JMHO, YMMV...
    Zeeb

  4. #4
    diamondave's Avatar
    Join Date
    Sep 2004
    Location
    marana, AZ
    Posts
    2,729
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: bcm unitized muffler

    thanks, im leaning toward the regular 2 mufflers and you kinda solidified that, especcialy if noone jumps on here within the next few weeks and says the bcm is way better for some reason, than the 2 muffs it is, i plan on ordering sometime later this month, my 110yak is due in after the 1st they say, the reason i was kinda interested is someone at my field made their own muffler for a twin, and it was one big chamber, he said he gained rpm from it, but after looking more at the bcm pipe, i noticed my friends almost seemed like he had 2 headers going back to a big chamber, the headers were longer and put the can further back, more like a can set up i guess, but he had welded a big thing together or something, he was very happy with the power and the location for set up, with bcm it doesnt look like headers at all, so maybe thats where my buddy gained his power...stock mufflers should be good for me, noise is not an issue yet at my club, and guys with stock da's and stock muffs say its plenty of power for the plane im getting, so this should be just as good if not better since the zdz is lighter than the da according to the specs on both sites, im not ready to jump into pipes yet, not until i need to, so far my other zdz's have had the power to pull the planes theyve been in on stock mufflers, this will be my 1st twin, have a 60 and 80 so far, love them both, thanks again for the info, id love to hear more if you got it

  5. #5
    diamondave's Avatar
    Join Date
    Sep 2004
    Location
    marana, AZ
    Posts
    2,729
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: bcm unitized muffler

    oh btw, i never new both cylinders fired at the same time, how about that, learn something new everyday

  6. #6
    Zeeb's Avatar
    Join Date
    Nov 2004
    Location
    Highland Utah UT
    Posts
    3,848
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: bcm unitized muffler

    Well the usual reason you see slightly better performance from cans or something like your buddy built is due to lower restriction. Some of the in-cowl muffs out there are really not much good at all. While the length of the header tube on a full pipe system is critical along with the total length and positioning of the pipe's internal components, it doesn't do anything for the performance on a can.

    Example is my ZDZ-50NG. I initially set that up with a SlimLine inverted Pitts type muffler after having tried the BCM on another model with a 50. SlimLine does not advertise a muff for the ZDZ-50, but the muffler for the DA-50 is interchangeable with the ZDZ. I had numbers on that engine for RPM, temps etc. and installed it on another model which was setup for a canister since I wanted to try it.

    It is quieter, but I'll tell you that it is really disconcerting to not be able to hear the engine on downlines and so on, then there's the comment from a fellow flyer "that thing sounds like a sewing machine".... I got zero performance increase, it took more work to install, weighs an extra 6oz. and cost an extra $100.00. You can double those figures for a twin.

    Like you, initally I'd thought the two cylinder engines fired opposite each other when trying to figure out which sparkplug wire went where as my ZDZ-100NG was my first twin as well. Then it dawned on me that if one considers the nature of two strokes and the common intake system for both cylinders, it can't be any other way.

    I put the ZDZ-100 on a Hangar 9 33% Edge (the one in my avitar) and a buddy has the same model with the DA-100. The DA spins the same prop at a bit higher RPM but it is well broke in while mine's only got about 4 gallons through it. But between the the NiMH batteries he's using and the DA, his is 2lbs. heavier than mine. The performance on both models is spectacular and you'd be hard pressed to tell any difference on uplines, but mine fly's a bit lighter....
    Zeeb

  7. #7
    diamondave's Avatar
    Join Date
    Sep 2004
    Location
    marana, AZ
    Posts
    2,729
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: bcm unitized muffler

    awesome!!, thanks for the info, i do see some people at my club with cans, even on a da150 its too quiet imo, like you said if someone else is flying you cant hear his, never know if hes dead stick until he gets on the throttle, never heard the sewing machine comment, thats funny, i like th sound of pitts style mufflers, cant wait to get the twin, will order soon i think so i know i have it in time for the plane, im sticking with zdz even though i am in tucson and i can go get a da or 3w downtown, i dont like 3w's, but the da was tempting, since i wouldnt have to worry about shipping if i need to send it in for anything, but (zdz)mike has given me such good service i got to stay with him, he gave me a break when i sent a 80cc in for check out after a crash, and both the 60 and 80 have been wonderful engines, reliable and powerful, so zdz100 it is!!


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
All times are GMT -6. The time now is 03:38 AM.

SEO by vBSEO 3.6.1 ©2011, Crawlability, Inc.