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  • Malibu 247 8.1 muffler delete.


    TimbrSS
    • Year: 2006 Brand: Malibu Model / Trim: 247 LSV Cost: $250-$499 DIY or Professional Install: I installed it / created it Platform Type: Fiberglass Engine Type: Indmar 8.1

    I've had FAE exhaust for years and always wanted to get around to a muffler delete. 1, because the muffler kind of becomes redundant with FAE, and some people noticed a bit of a power bump, and/or an actual sound decrease from the engine bay. Both of those sound good to me. 

    Finally found time to get it done. This was just a quick fix, and most certainly not the cheapest, or most extravagant way to get it done. But the ease and time of putting it together was the main driver of my product selection.

    I didn't like the FAE muffler delete with the mitered 45* angles... The high performance engine guy I am would let that happen.

    The cheapest acceptable way to me would be to get about 4' of stainless and make a bunch of 7.5* pie cuts, form the proper s bends, and then weld away... Probably less than $100, but would take me at least 8 hours a side, cutting, welding, and running back and forth to boat for test fits.

    I decided on a combo of metal and rubber 45* bends to get the job done. The 8.1 has a 4" tube coming out of the exhaust riser to muffler input, and a 3.5" outlet from muffler to transom exit. So I went with a 4" stainless mandrel bent 45, a marine rated 45* rubber elbow, and a stainless 4" to 3.5" reducer. I cut off 2.25" from the rubber 90* 3.5" hose that went from the muffler to transom exit, and put in new 7.5" long (factory length was 9") 4" hose from the riser to the stainless 90.

    The stainless 45* bends were $56 each (vibrant 13104) Amazon

    The rubber 45* elbows with clamps were $62 each. (Trident Marine. Amazon.)

    The 4"-3.5" t304 stainless reducers were from ebay $20 each.

    So $276 before tax.

    I ended up cutting 3.5 or so inches off each end of the stainless bends. Turned out nice, and probably 4 hours max putting it together.

    I started it up on a fake a lake, but didn't put it in the water yet, so I have no idea what difference it makes. I'll have to update in a few weeks.

     

    In this pic from top to bottom:

    1. 3.5" Rubber 90 transom exhaust exit to muffler

    2. 4" - 3.5" reducer

    3. 4" 45* rubber

    4. 4" 45 stainless

    5. 4" straight rubber to riser.

    20200411_105258.jpg.c5001f5f809935f478d9a262a348a7ac.jpg

    20200411_110400.jpg.0c18ff52d7e76cc1468bb1155d0477ed.jpg

    20200411_112718.jpg.e500b7541918b7966abb8e0dfd4a7dd6.jpg

    20200411_123401.jpg.13020b31ab883319f140a7c75267e806.jpg

    20200410_191657.jpg.7649b912b2e7b533c0598c3d74019121.jpg

     



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    Badass.  Well done.   It's nice to have that room back there too with that giant muffler out of the way.

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    This may be a dumb question...but can you do this if you do not have a FAE or a surf pipe?  Just regular exhaust straight out the back?  I am assuming it would be loud?

    mac

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    1 hour ago, Macdaddy said:

    This may be a dumb question...but can you do this if you do not have a FAE or a surf pipe?  Just regular exhaust straight out the back?  I am assuming it would be loud?

    mac

    You could do it. I wouldn't want to. You would probably just make it louder and piss everyone off. A loud speedboat is ok, if it just drives by and goes to the other end of the lake. A wakeboat going back and forth for an hour or two would be annoying. Youd probably buy a 3rd set of Rev 10's and crank the music up louder to gear over the exhaust.

    Go ahead and do it, but not on my lake please.

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    On 4/14/2020 at 7:21 PM, Macdaddy said:

    This may be a dumb question...but can you do this if you do not have a FAE or a surf pipe?  Just regular exhaust straight out the back?  I am assuming it would be loud?

    mac

    The other issue is the muffler helps protect the engine from hydrolocking due to water going up the exhaust.  like when you're making a large wake then stop and turn off engine.  If you have no FAE, no flappers and no muffler that wave could come right into your engine. 

    NO mufflers is safer w/ FAE and Flappers. 

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    Thanks for the comments guys.  I think down the rad I may do a FAE...or if I can get rugger to make one of his😁!

    • Like 1

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    On 4/13/2020 at 9:07 AM, TimbrSS said:

    Incase anyone is curious:

     

     

    I recognize that sound!  big block baby!  Although knowing what I know about you -- your boat probably has upgraded heads, cam, tune, intake, raylar special etc.

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    42 minutes ago, Rugger said:

    I recognize that sound!  big block baby!  Although knowing what I know about you -- your boat probably has upgraded heads, cam, tune, intake, raylar special etc.

    I considered doing that stuff, but after changing out the v-drive gear set to a 1.48:1, I don't need anything else.

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    On 4/17/2020 at 4:13 PM, TimbrSS said:

    I considered doing that stuff, but after changing out the v-drive gear set to a 1.48:1, I don't need anything else.

    @TimbrSS did you do a writeup for that?  i know of a few guys that are trying to do the same.

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    3 minutes ago, jtryon said:

    @TimbrSS did you do a writeup for that?  i know of a few guys that are trying to do the same.

    No. I just swapped a complete V-drive unit. It' pretty straight forward in my case with the Walter V-drive. I would have had it done in a day if I didn't need to replace a slightly leaking transmission seal that I found when I pulled the V-drive. I also updated to a dripless shaft seal and new strut bushings at the same time, since you have to drop the shaft anyways. But after sliding my gas tank back to give a few inches, it was pretty much just a quick Remove and replace deal.

    • Like 1

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