Formula Silent Thunder Removal
 

Hey guys so heres the deal i am really interested in purchasing a 1989 formula 242 ls and i love everything about the boat except for the fact that its to quiet for me. i know that you are able to remove the whole swim platform and then just throw exhaust tips on but i really want to keep the swim platform on because in my opinion it makes the boat look better. so basically i am just asking how to make the boat louder without removal the swim platform. Also if possible could you guys send in some pictures of it Thank you! - Hunter

There are drain plugs on the bottom side of the swim platform. They keep the swim platform filled with water and muffle the exhaust. If you remove the plugs the platform wont hold water hence louder exhaust. G. luck.

adding to Del Flores comment. Many have drilled larger holes in the underside of the platform. The larger the hole the less water the platform will hold. The sound will be more noticeable when running, as the underside of the swim platform is submerged at idle. Many have also cut the baffles out inside the platform too thus eliminating the obstacles the exhaust must travel through to escape. There are many threads on these steps in the Formula section. Just do a search

Friend with a 89/272 with 600 HP a side drilled four 2" holes in the bottom. Sounds great motoring down the lake.

I was thinking of splitting my platform in half. Then installing pipe inside the platform. Then re-assemling it.

A few of us have already done this I ran stainless pipe thru the inside of the platform, just got a little more sound and it warm up the platform a little.

Do a search here or the formula section,under 242exhaust. Good luck

Don't drill holes in "bottom" of deck. unless they are significant, you will not accomplish your objective. My opinion and past experience doing this procedure. Not an opinion based on a friend of a friend accomplished this data. 😏

Look inside the silent thunder deck exhaust ports. Just inside there is a fiberglass/composite wall internal to the ST compartment.
It acts like-is the same as a baffle in an automotive muffler.

Take a hole saw, on an extension inserted through the square exhaust tip.
Cut a hole through the left side of the baffle.
Set off to the side, if you choose to open up the exhaust even more, there is room to cut out a second hole like a set of binoculars.
If you want a straight through sound, the tubing is your next option. But requires removing the ST.
My procedure can me accomplished in about an hour.

I cut my baffles out and drilled holes in the bottom to drain the water on the one I had. Make Damn sure you check the transom/stringers in the boat before you buy it, they were famous for those platforms leaking around the mounting bolts and the tie down rings were under the waterline on those boats as well........Trust me on that one, I learned the hard way

Friend has an 89 311 with this platform. After engine rebuilds I used some, let's say "extrication equipment" to cut large squares in the bottom of the platform to drain water out when on-plane (approx 4" x 6" ish?). I also went in and "removed" those baffles. The result was a MUCH deeper throatier sound when at speed. It was a little louder, but not "dry-pipe" loud.