| Author |
Message |
    
Mako
| | Posted on Tuesday, October 23, 2012 - 11:05 am: | 
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going to try ebr ecm for fmf pipe. will update soon. |
Clk92vette
| | Posted on Tuesday, October 23, 2012 - 11:41 am: |
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If you look at Dean's pics it is pretty clear what is going on in this muffler. The majority of the flow goes straight through the main pipe, hits the back of the can, goes forward through the large pipe opposite the two exit pipes,hits the top end of the can, and reverts back out the two exit pipes. The big holes near the front of the collector allow some flow and sound waves to head directly through the openings in the baffle plates and toward the exit pipes and create the helmholtz chambers. The small holes between the third and fifth baffle plates allow some flow to bypass the main flow path and head directly out the exit pipes. At higher flow rates/rpms, a lower percentage of the flow is bypassing the main reversion path. Mako has eliminated the reversion path but still has a helmholtz chamber in effect. Mako, what ecm are you using? |
Chessm
| | Posted on Tuesday, October 23, 2012 - 12:21 pm: |
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so for us with cali bikes, where is the cat in that exhaust? |
Albert666
| | Posted on Tuesday, October 23, 2012 - 12:55 pm: |
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the part that says c/s same as euro bikes |
Chessm
| | Posted on Tuesday, October 23, 2012 - 01:21 pm: |
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thanks albert! |
S21125r
| | Posted on Wednesday, October 24, 2012 - 12:57 pm: |
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"The big holes near the front of the collector allow some flow and sound waves to head directly through the openings in the baffle plates and toward the exit pipes and create the helmholtz chambers."
I believe the Helmholz chamber at the front is completely closed off from the rest of the muffler - otherwise CAT equipped bikes would have a portion of exhaust gases that would bypass the CAT and would be untreated. If that is the case, and I think it is, then all exhaust gases have to go through the tri pass chambers - there is no by pass route.
Would be in interesting experiment though to create a small by pass by knocking a hole in the bulkhead separating the helmholtz from the rest of the muffler. |
Mako
| | Posted on Friday, October 26, 2012 - 10:43 am: |
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Just put in ecm for fmf pipe. runs way stronger and I am slowly removing restriction to try and find a good balance of noise and power. |
Mako
| | Posted on Thursday, November 01, 2012 - 12:03 am: |
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very little restriction and 1700 to 4000rpm great torque. flat from 5k to 7k roll on acceleration but on drag like launches it rips all the way to redline? pulling front wheel on first to second shifts at 7500 ft elevation. I guess around ten plus hp gain. |
Mako
| | Posted on Thursday, November 15, 2012 - 08:21 pm: |
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just blocked off the holes in front chamber, what a pain it is welding the two layer exterior of the muffler. will test tomorrow. |
Mako
| | Posted on Thursday, November 15, 2012 - 08:23 pm: |
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sorry s21125r I did cut two chambers off. |
S21125r
| | Posted on Friday, November 16, 2012 - 11:41 am: |
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Yep - so all you really have is a extremely heavy straight pipe. Either buy a used muffler and try again or...
experiment - cut the thing at the seams, remove the remaining bulkheads, replace the solid mid pipe with perforated tube and pack it with rock wool/fiber glass. Weld it back up and you'll have a really large volume glass pack that should be quieter than your average slip on. Probably easier said than done, but I don't think you can do any further harm.
Good luck! |
Mako
| | Posted on Saturday, November 17, 2012 - 10:49 pm: |
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just what I wanted. still wanted to be able to use muffler as a jacking point. |
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