Neighbor-friendly dawn patrol exhaust modification

[shufflehuff]

I thought I would post a quick update to my exhaust modifications. I have posted on this thread before, but here is the latest update. It has taken a few different versions to get this right. I have trimmed the new 90 degree elbows, and I think this will end up working well. A lake test is next. I will post decibel results after the lake test. I do have a few left over elbows that ended up not working for me. None of these have be cut. If any Ballers could use these please let me know and I will send them your way.

 

 

[DoubleD]

I did something similar as the OP but spent a bit more doe to make it look stock. I have a 2008 MasterCraft ProStar X14 with the LY6 400 Hundo HP engine and it came with no cats in the manifolds and no mufflers. Seeing the brand new ProStars come with turn down tips, I researched the flange diameter and hole locations and found they an exact match to what I have. So instead of pulling the old tips, I modified the new tips and mounted them to the existing, and no digging into the boat. I does seem quieter from the drivers seat but have yet to ski it..

 

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[epnault]

@DoubleD I like what you did there. My '16 ProStar does not have turn down tips. So all you did was remove the rubber flapper and screw on this modified tips? To you band saw cut the parts?

[Mastercrafter]

I did similar to @DoubleD using Malibu tips (1/2 price). The screw holes weren’t quite right so I made slots out of them. Need to get some better hardware for mounting, but installation was quick and easy on my 2015 Prostar.

 

 

 

[UWSkier]

I've had these on the boat for almost 3 years now and haven't needed to snug them up since the week I installed them. Never did anything other than clamp them down with the worm drive clamps that came on the Nibco.

[epnault]

@Mastercrafter

 

Can you share a source for that gasket please? What is the price on the MasterCraft tips?

[Mastercrafter]

@epnault , MC tips are like $340 each, and Malibu tips are $150 (greatlakesskipper). Gasket was simply cut with a razor blade from 40 durometer 1/8” rubber sheet found here:

 

https://www.mcmaster.com/rubber/rubber/high-strength-multipurpose-neoprene-rubber-sheets-bars-and-strips/

[epnault]

Holy crap - $340 each is dam crazy. I will get my complaining neighbors to pitch in ;)

[DoubleD]

@epnault sorry for late response. Yes, just got slightly longer screws and used same holes with a gasket that can handle heat. I used a hack saw to cut mine since I don’t own a band saw.

I got the stock tips through Bruce at Action and were about $600 all in. If I’m gonna do it, it’s gonna be perfect. Nothing but the best for The Beast. ??

[epnault]

@DoubleD - Thanks for the response!

 

 

[FSSPCat]

I’ll be installing my FAE on my 2000 RLX very soon.

[FSSPCat]

 

[Vernon Reeve]

Fresh air exhaust made a huge difference on our previous Malibu Response LX. Both in noise and in no exhaust swirling around the back when idling around the lake. I did always worry about doing bat turns however. But handled it fine for the very few times I did one.

[FSSPCat]

@Vernon Reeve thats awesome to hear. Main reason I put it on was that I have two small children now so want to avoid unnecessary harm there. The noise reduction is going to be great too. Won’t have my boat in the water until June at the earliest to try it out.

 

[ReallyGottaSki]

140mm 4ply elbows installed on the rcb, trimmed and tested this week

The hard droning we here in the boat from under the platform is gone

I'm certain the neighbors they point at each morning find it positive

 

 

[03RLXi]

I want to do this but not enough gap between outlet and the wedge/scarpa bracket :-(

 

[thager]

Nothing a grinder wouldn't easily handle

[ReallyGottaSki]

I concur, plenty of meat there to grind.

too bad the rcb outlets are so unnecessarily large. 140mm/5.5" ID silicon elbows are scarce

 

I thought up of a name for these things,,, snufflers

[Deke]

@ReallyGottaSki where did you purchase the 140mm/5.5" ID elbows? I'm pretty sure that's the size for my '99 RLX. I'll probably have the same issue as @03RLXi with the wedge. The boat is not here to look.

[ReallyGottaSki]

@Deke ,

welp seems at these diameters, its no longer inconsequential costs like the 3-4" stuff

 

but here was my source

https://hpsperformanceproducts.com/products/hps-5-and-half-inch-silicone-90-degree-elbow-coupler-hose-high-temp-reinforced-140mm

 

[UWSkier]

I couldn't fit the NIBCO on my boat with the wedge bracket where it is either. I ended up shaving down the nibco on the side that contacts the wedge bracket until it was probably only about 1/8" thick. Just enough room to get it and the hose clamp on. It's been working great for 3 years that way.

[03RLXi]

I'll have a look at how much I could shave off edge of outlet when I collect boat from storage next month. Might need to resort to a split piece of stainless steel tube as a joiner between the outlet and the silicone elbow. Or just fit SS elbows rather than silicone? These aren't the right size but you'll get the idea https://www.aliexpress.com/item/1005001422163109.html?spm=a2g0o.productlist.0.0.447023b6n9lKmQ&algo_pvid=40682374-8be1-4f54-9d73-546e33dc7859&algo_exp_id=40682374-8be1-4f54-9d73-546e33dc7859-0&pdp_ext_f=%7B%22sku_id%22%3A%2212000016054432458%22%7D&pdp_npi=2%40dis%21NZD%2110.81%217.58%21%21%21%21%21%40210318cf16618041130493072ec774%2112000016054432458%21sea&curPageLogUid=X4yarztMTwSG

[Hucklefin]

So what's the long term word on running no rubber flappers? I was able to come across some malibu stainless tips, but a little apprehensive to install on my 94 Prostar because I am required to get rid of the flappers.

[DW]

@Hucklefin - removing rubber flappers will allow backwash to run up the exhaust and potentially as far as the exhaust valve. Flappers also add a level of noise reduction. Flappers are an easy DIY project to add to ss tips.

[epnault]

@DoubleD

I am finally doing this mod this year.  One more question please.  Are the stainless screws on the stock flange self taping or are they through screws with nuts on the back side of the hull.

[UWSkier]

5 years later and my down-turns are still attached.  I tightened them once.  No silicone, no set screws, no extra holes drilled and no hydro-lock issues with the flappers in place.

[braindamage]

^^^this.

i did same as UW skier for my TXi in 2019 and mine are still attached and going strong!

[Hucklefin]

Malibu turn down tips, ran like this about 50 hours last season, used silicone to install with thru-bolt fasteners. No issues whatsoever. A lot of people on teamtalk were suggesting I use 5200 sealant, which is absolutely not necessary.

[epnault]

Has anyone tried these off skidim?  MasterCraft ones are on back order.  I want to install them on my 2016 ProStar

https://skidim.com/3-1-2-turn-down-exhaust-outlet-6-flange/

 

 

 

[Hucklefin]

2 hours ago, epnault said:

Has anyone tried these off skidim?  MasterCraft ones are on back order.  I want to install them on my 2016 ProStar

https://skidim.com/3-1-2-turn-down-exhaust-outlet-6-flange/

 

 

 

They look exactly the same as the Malibu ones but +$50 a piece. 

[epnault]

True. The only difference noticed is that the MasterCraft ones are 3.5" in and 4" out.  Wonder if that has to do with the flange size on the transom

 

[RAWSki]

Do those really make a difference?  I remember when Malibu first installed down turned tips many years ago they actually made their boats louder!  (Of course there may not have been any baffles in them of course)

[Mastercrafter]

@epnault here’s a pic of the Malibu tips on a Prostar, just right over the existing stainless steel flange with some rubber in between. I had posted this a couple years ago above, but the pictures are gone.  
 

@RAWSki definitely quieter,  but I suspect they rob some power too since they’re quite a bit more restrictive.  

[rq0013]

@Mastercrafter can you fold down the platform with those Malibu tips? 

[Mastercrafter]

19 minutes ago, rq0013 said:

@Mastercrafter can you fold down the platform with those Malibu tips? 

It juuuuust hits the end of them when the platform is past vertical, but I still fold down for storage. Removing about 1/4" with a grinder would solve the problem completely. 

[rq0013]

@Mastercrafter Good to know. 
 

Which tips did you use? After some searching Malibu has some with 6” flanges and 3.5” diameter and 6.25”flanges with 4” diameters tip.
 

Is the 2014 and newer prostar 6.25” flange with a 3.5 diameter tip? 

[Mastercrafter]

34 minutes ago, rq0013 said:

@Mastercrafter Good to know. 
 

Which tips did you use? After some searching Malibu has some with 6” flanges and 3.5” diameter and 6.25”flanges with 4” diameters tip.
 

Is the 2014 and newer prostar 6.25” flange with a 3.5 diameter tip? 

 

These are what I used. 

I'm not sure what standard 2014+ Prostar is/was. My 2015 came with rubber flappers. I think the malibu flanges above were just a tad smaller than what's in the boat. 

https://www.greatlakesskipper.com/malibu-boat-exhaust-tip-3221015-stainless-steel-3-1-2-inch

[epnault]

@Mastercrafter

Thanks for all the help sir!   I got the rubber you suggested yesterday.

Did you cut off this section like DD did with the MasterCraft ones?

[Mastercrafter]

33 minutes ago, epnault said:

@Mastercrafter

Thanks for all the help sir!   I got the rubber you suggested yesterday.

Did you cut off this section like DD did with the MasterCraft ones?

Yup, I did. I used a bandsaw but abrasive wheel would work too. Then flattened on a belt sander. 

I had to turn the holes into slots as the MC hole pattern is on a slightly bigger circle, but they're still clocked correctly. 

So, rather than use countersunk screws, I used flat base screws with washers to hold the Malibu tips to the OEM flanges. 

Hope that makes sense. If you have questions, my cell is two-four-eight 798-1958

[epnault]

Got it.  Makes sense.

Thank you @Mastercrafter

[epnault]

I actually got the MC tips faster than planned.  My commitment to you all is to get before and after video/sound bites in the boat, pass by, and static on shore drive away so you can evaluate.  Thanks for all the support

[Jody_Seal]

i have dual exhaust on a 08 196.

Skied with the boat friday...32mph i thought i was at 36... where does one get those cool down tips? are they 4" exhaust or 3.5"?

Edited April 2 by Jody_Seal

[Mastercrafter]

27 minutes ago, Jody_Seal said:

i have dual exhaust on a 08 196.

Skied with the boat friday...32mph i thought i was at 36... where does one get those cool down tips? are they 4" exhaust or 3.5"?

https://www.greatlakesskipper.com/malibu-boat-exhaust-port-3221015-1-silent-tip-3-1-2-inch-stainless
 

here are 3.5”, 4” available too, I think. 

[6balls]

I don't remember where this thread has gone since 2019 and I'm not going to go back an read all of the posts--but my late bro Jim put this on his 6.2 Prostar and the thing was so quiet you would think it was electric.  Minimal to no wake impact.  That inboard could sneak up on a duck if it wasn't breaking water which is about all you heard.

He skied weekday mornings very early in front of expensive homes that liked to complain--thus the mod to keep his course in the water and passion available.  

https://www.freshairexhaust.com/

 

 

[EFW]

1 hour ago, 6balls said:

Couple years ago I think I put this up. Same idea. I think the idea here was to - kill the enemy. Not much new under the sun.

[epnault]

Alright guys.  I finally was able to do a test with stock Prostar with just the flapper and the turned down tips.  I also included my ski buddies 205 in the test.  I only achieved 1db reduction. Essentially hardly noticeable.  I did a pass by as this is what my neighbors will hear and recorded the dbs on an app.  Pretty expensive for 1db but it looks cool on the lift now.  Ugh
 

 

 

[UWSkier]

Those metal down-turns don't turn enough and run too far from the water line to make a big difference in overall sound.  They change the tone and intensity of the sound slightly but they don't redirect it as much as the custom jobs others on this thread have implemented.

[skibrain]

I’m a big fan of fresh air exhaust. (6balls link above). Helped install on my buddy’s 2004 LXi went from obnoxious loud to quiet running. 
 

Loud pipes don’t save lives, they piss off the lake neighbors. 

[DW]

Another effective noise abatement tool is the Silent Rider muffler.  The 2 MC's on our lake with them are noticeably quieter than the inline twins.  

[Gale K]

15 hours ago, skibrain said:

I’m a big fan of fresh air exhaust. (6balls link above). Helped install on my buddy’s 2004 LXi went from obnoxious loud to quiet running. 
 

Loud pipes don’t save lives, they piss off the lake neighbors. 

@skibrain What kind of spray does it generate, and can you tell on the wake?  Does the LXi have a manual wedge, and is it still on the boat?

I took the manual wedge off our '00 Response so it would fit in the garage (no joke, the couple of inches saved (compared to in the down position) was enough to get the door closed (platform off)), and I can see spray out from under the platform that the wedge used to knock down. No affect on the wake, but I can see it.  I wonder if the wedge in the up position might mitigate any odd spray off of the FAE...