donzi matt

iTrader: (1)

My plans next year for my little 22 Crownline involve a nasty little stroker small block I recently purchased. This boat serves duty fairly regularly as my tubing and ski rig, and also the boat the wife likes to use from time to time. Currently it has silent choice and no mufflers. My problem is the cam in this motor is probably not going to be real happy about silent choice and may have a reversion issue even with my stainless marine exhaust with the pipes closed. If that is the case I am going to end up having to pin the diverters open, as I don't want to change the cam. I am looking for the absolute quietest muffler available for a motor near 500 horsepower. I plan to keep the Y-pipe plumbed in to the exhaust. I really need to keep this thing as toned down as possible or the family may revolt on me.

For those interested, the cam is a RMbuilder 234/240 .580/.568 112+4 hydraulic roller.

I may rig a y-pipe up and fire the motor on the floor and let it idle around 650 and see if it is pulling water back in, but I can't do that until the end of the season when I yank the old motor. I don't know how accurate a test that will be though as it won't have the drive to use as a restriction or water on the other side of the pipe.

Any suggestions are greatly appreciated.

Holy Smokes

iTrader: (2)

What about CMI Sound Elimination mufflers?

http://teaguecustommarine.com/em0011...lers-4-x6.html


I have a set of 4" thru transom mount #39111.
http://www.offshoreonly.com/forums/s...flers-4-a.html

Well below price of new. Make offer.

Griff

Pinning the diverters open won't solve the reversion issue. You need to elimiate the Y pipe and get longer risers that mix the water farther back.

Budman II

iTrader: (1)

Teague switchable tips or turn downs would be the direction I would go. Buddy of mine had the Teagues behind a 500 HP, and it knocks the edge off the sound nicely, leaving a low rumble. Turn downs would be the quietest solution.

3pointstar

I feel your pain - we have Captains Call and when pulling the kids on tube or skiing our little one screams because of the noise. Of course we are no where near 500 hp - (7.4mpi 310hp) --

There are a number of good resources on this site - their suggestions seem reasonable - but this type of engine is way above my league.

safe boating

3pointstar

SB

iTrader: (1)

Matt is on a lake with a low Db law (82db I believe) and no switchable exhaust. Which he has, so i guess he doesn't care, which I didn't, until I kept getting 'popped' . But that was years ago. Don't know how the Po Po's are around here lately with that sort of stuff.

donzi matt

iTrader: (1)

I have never had an issue with switchable exhaust, but I also don't switch it on the fly. It is either open or closed. I am sure the boat would fail the Winni noise test right now with the exhaust open but I rarely run it that way as this is more of a family boat.

The plain and simple fact is this motor is overkill for what I use the boat for, but I don't care and I will do what I need to make it work. Keeping it quiet is paramount though, because if nobody wants to use the boat because it is too loud then it isn't worth owning. If I have to buy longer risers and run external mufflers such as the CMI, then so be it, as long as it is quiet enough to be enjoyable. Frankly, I see this motor ending up in more than this boat as time goes on, but for now I have a wounded motor in my bowrider, and a horny stroker motor sitting in my shop, so it is going to go in and work, I just need to figure out how to do that.

SB

iTrader: (1)

I wonder if Donkey Dik's would work okay wih your set up and your famdamily would be fine with it once they (DD's) get over the water when on plane.

CC230

I just fired up my 383 on the stand with stainless marine exhaust and the switchable tips. Before I put the tips on it was unexpectedly loud, could be the tails are long and the water hits them way back, just putting the tips on toned it down and with the tips closed through the mufflers it really worked, I was impressed. Had nice tone instead of the bark.

Budman II

iTrader: (1)

Wow Matt, you sound just like me with my 489. I tried and tried to find a way to run mine with silent choice - really liked the flexibility of being able to switch it thru the prop. I even bought a set of Lightning collectors with the diverter built in. Ran what I thought was a very mild cam for the engine to allow running the switchable exhaust - 225*/230* @ .050 and 114* LSA. Alas, it was not meant to be. I was getting reversion on the stand even with the standard Lightning collectors installed. Had to modify the collectors to extend the inner pipe and ditch the silent choice. Went with a set of the 6.5" Corsa muffled tips. Knocks the sound down pretty decently, but still gets a little annoying when it hits that certain resonance at 12-1500 RPM's.