I know now why to remove the ST. :mad:

Da*n the vibration noise it makes. On the rare occasion that it stops for a second, you can hear the sweet sound of the engines. And then it starts again... Grr..

I'm on the market for a set of clamp-ons right now. Let me know if you see a good deal my way.

Btw I'm allready running 30P's.
I'ts standard with 377 Scorpions.

Silent Thunder Remove / Tips
 

Fastech 353 with pair of 500's. I have a huge hole in the bottom of the ST box. Not sure if to patch this hole or switch to tips.

My concern is the labor to remove the raw tips and replace them with Corsa CC .. wow -- that is a lot of work in 100 degree weather. I was hoping for more of a slip-over chrome tip with a flapper valve that can be installed in minutes? Anyone heard of this?

What happens if I run this with the hole? Funds are a little short to be buying $1000 in Corsa CC diverters.

So if I get all these posts right ... I can pull off the ST box with a few bolts and so tugging. --- then there are unpolished stainless tips sticking out about 4" or so. -- I can buy some rubber 4" flappers and clamp them on and be done with it? Is that correct? Or maybe someone has something sexier that clamps on fast.

I will change to Corsa CC when I pull the engines for rebuilding as I have 400+ hours now on HP500's with zero problems. I just don't want the hassle now.

they are not even 4" long (out) past the flange, but yes enough to get a flapper on.

can someone point me in the direction of rubber flappers to buy to keep a stock look?

also how long does this mod take...we have a 03 292

does this mod increase the chances of water ingestion?

I used these when I pulled mine off...

http://us.binnacle.com/p2320/EXHAUST...duct_info.html

Price is right, and you can't even see the tips when it's in the water. My stock tips also had internal flappers, so between the two, I don't think you will have any problems with water ingestion.

Mine took about an hour from start to finish, and one of the blind nuts came loose back in the corner of the swim platform. I had to lay on my side with a long pair of vice grips to get the bolt out, then seal the hole up. Once you get the bolts out, it takes a little encouragement to break it free. And it is HEAVY. A 2 person job for sure.

thanks for the info...did the removal make the boat a lot louder? i think my boat could use a little more noise.

Before I got my current 353 I had a 312 that didn't have the silent thunder box on and it was pretty loud, but I just dealt with it.
Now the 353 has the normal setup and I like it better (looks better also), it has captains call so I can have it either way I want when I want.

It made it perfect in my opinion. Still very easy to have a conversation, in fact I didn't tell my wife and she didn't even notice until the boat was idling at the dock and she walked behind it. Much better rumble and sounds great when you hit it coming out of the hole. I have Warmed over 454 Mags with Gil exhaust and it sounds great.

Can always slap it back on in an hour or so if you don't like it!

thanks for the info guys...i think this is a nice little winter project along with a few others...

I have an 02 292. Mine is coming off this winter or early spring. Just putting the flappers on. Boat sits low enough in the water probably won't see. Plus lost one of the bolts coming home from my season ending trip.

we just removed ours...someone on here said it weighed 270 lbs...not even close...it was more like 50-75 lbs. not sure why that number was so inaccurate. anyways all we have left is to install some flappers and see how she sounds.

It sounds a lot better. I removed mine and put some 8" slash cut pipes on the back. Looks good and sounds WAAAAY better!

I can imagine the dry weight is something like 50-75 lbs. But when on the boat, they accumulate water and become much more heavy. I would imagine the numbers you've heard is not far from true.

i guess the wet weight makes sense...I would be hard pressed to think it would be 300 lbs though. mainly i am looking for better sound and better performance out of the hole...our 292 is really sluggish to get on plane.

exaust tips
 

So I take it the consensus is that the stock stainless weighted flappers wouldn't be sufficient in stopping water injestion? Even with the CC down tube just upstream of the flappers?

For 9 bucks a piece I think it's worth putting external flappers on in addition to the internal weighted ones. That being said, I went boating for a few weekends with no external flappers. I was very careful, and it was on a calm lake. I now have the rubber ones installed as well.

X2 for $10 a piece...add the external flappers. Is $40 really worth risking rebuilding / replacing a motor.

Sorry for digging up an old thread but I have been thinking about removing the ST box as well. I see all the talk about the SS tips being there, that's awesome. My question is, the ST box has little black rubber tips that the water from the exhaust runs out ?? Im not familiar enough to know is terminating the water something else that has to be handled too ?? Or is it just running out if the SS tip all are talking about and then running out of the block rubber tips ?? This is a 1999 382 Fastech I'm asking about. Thanks guys for any help or pics you can share. SJ

Just ss tips That dump exhaust and water into St box
Rz to remove then put on the rubber flappers.

Great to hear. Hoping it's as simple as it sounds. Thanks.

The ST boxes are held in place by 4 bolts. 2 on the transom and 2 under the swim platform. Remove all 4 bolts and the box will come off, pretty easily, Might have to give it a little tug and pull..LOL.

Having a helper for this is useful, especially when it comes time to get the 2 transom thru-bolts that run into the engine compartment. Yes the rubber flappers are important, just an extra pre-caution to hopefully prevent any ingestion. Everyone seems to forget to add that you have to reinstall all 4 bolts you initially removed after ST box is off. Simply put a small bead of 4200 around the bolt head or hole, reinstall and tighten them down. As you snug them up the 4200 will push out around the bolt head guaranteeing a nice water tight seal.

Thanks again for the info. I'm looking forward to getting this rattle box off. Thanks guys.

Ok, got the ST box all removed and can't believe I didn't do this sooner. Lol. Now just curious, what does everyone do with the big box they removed ??

removed mine off my 271 and it is now sitting in my shed and will go with the boat if/when I sell it

Sat in the barn for 2 years before making it's way to the dump trailer. I got tired of moving it while looking for things. Some try to sell them, not sure what kind of luck they have. If you got the room i'd say keep it for now.

That's about what I figured guys. Thanks again. SJ

Well...
Time to bring this back to life Again!
Thinking about doing this on my 312. Does it really make the porpoising better?
I know taking weight off the back has to help, like getting Merc's heavy exhaust system off, but is it a big help in how the boat handles?
I like the idea of 6" slash cut stainless tips too for looks, but who has the best available now!

Mercury told me that swapping to their headers (CMI) on my 6.2 MPI's would add 35-40 hp per side depending on the rpm's...
That & the weight savings should add up to some performance increase.
Was told to do a little head work to match the headers too, but still in the thinking stage for a winter project.

Resuscitating this beat-up horse. Just bought a 2000 271 FASTech. Bone stock. 1st mod is removal of Silent Thunder. But seems like it has been worked-on before. The two bolts on the port side seem to be from the outside bolting up into the swim platform. But the starboard side, has nuts with what seems as bolts (or perhaps studs?) coming from inside the boat/swim platform, down out through the ST contraption. Nuts then thread up to tighten. They are also not in the same relative locations as the "factory-looking" port side. Can someone please chime-in to confirm this is not the factory setup? My main concern is how to get to those bolts on the starboard side from the inside to pull them out once ST is removed. I guess I can leave them there and re-tighten with sealer but hate to have two bolts sticking out under the swim platform for no reason. Surely they'll generate a scar on my head at some point in the future...

I am still in rookie purgatory so cant post pics...

Done. Easy. Sounds great, and more than anything; glad to remove that weight. Installed the simple rubber flapper contraptions and added the drive shower. Probably will cut those swim ladder bolts flush with the nuts so they don't end up causing any head scars....
https://cimg9.ibsrv.net/gimg/www.off...3968d88555.png

Sorry to bring back this one back AGAIN, but I also want to lose my silent thunder exhaust. I would have really liked a boat with Captain's Call / Silent Choice, but that didn't work out and installing it after the fact is quite a bear. Does anyone else have switchable mufflers like Silent Lucidity or can send a link to some decent options? All my searching has not really turned up anything too good yet.

Hi Rippem, saw your posts about Silent Thunder boxes ect. I have a 2000 382 fastec and looking for a silent thunder box and s.s. stock thru transom tips. I have corsa mufflers and flaps to get rid of . thanks for your time ,let me know if you might know anyone that may have one. cheers mike in so. calif. 951-265-1863

Wanted. Formula 382. ''silent thunder ''exhaust box
 

Wanted: Silent thunder exhaust box for a 2000. Formula 382 fastec. I have s.s. Corsa mufflers now. Willing to trade for stock silent thunder setup. 951-265-1863 mike. Calling is best