The wife and I took a run up to Decatur Indiana and got a tour of the Formula factory yesterday. Of course I was checking out some of the brand spanking new '06 Fastechs coming off the production line and noticed no Silent Thunder boxes, just nice Corsa tips with rubber flaps. I asked our tour guide and he said Silent Thurnder boxes are no more...

Inside the engine compartment are polished Corsa "Quick & Quite" exhaust. I assume there are some muffler tips as well. Reading on the Corsa website it appears the exhaust runs both out the transom and through the prop. Looks like a nice system. Wonder how it sounds and performs compared to the box?

I never thought the'd drop that feature.
It's surprising that they went with a switchable system, which is illegal in many states.

The "box" was definitely one of Formula's hallmarks, no one else had/has a system like that. I'm also surprised they dropped it. Of course, almost everyone I know dumped the box.

I personally like the looks of the older boxes/platforms. However, I did just get done last night gutting the baffles though!

they most likely found they could buy the Corsa transom mount mufflers in quantity cheaper than they could lay-up the box enclosures.

savings on the raw tips they used behind the box
Plus take out the labor of installing the box.

The labor of installing the Corsa's on the transom instead of the raw tips stays about the same.

The mufflers are now the standard
switchable diverters to thru hub is an option as it always was, I believe.

Corsa systems on other boats I have seen are not switchable, and run through the tips and the prop simultaneously. In my opinion, it is quieter than both the older bolt on platforms and the newer style box ones. A friends boat that has this corsa system sounds more vaccum cleaner like than raw. Personally I don't like it. Hopefully Formula will have a custom tuned version of it, otherwise I'd be installing a switchable system very quickly.

Are you sure about this? I've never known a system that continuosly diverts through both the transom AND the prop. It's always one or the other.

FAQ on Corsa's website - see "permanently open diverter" below

1. What is a CORSA Performance exhaust system?

CORSA Exhaust System consists of three major components:

A. Diverters - A diverter splits the exhaust into two exit paths: straight out the hull and down through the propeller. CORSA offers two styles of diverters: a permanently open diverter and a solenoid operated (Captain’s Callä) diverter that offers the choice of thru-hull, or a through prop exhaust exits at the flip of a switch.

Most "factory stock" installations have the permanently open diverter so there is no legal issues in some states where it is outlawed.

Very interesting. Thank you, I did not know that.

The Captains Call is a must! It's a $2,100.00 (list) option, but
worth the money. I can tell a difference with the performance when it's turned on.(Or maybe it's just me)

I agree with getting rid of the box. I took it off of my 99 271 because it vibrated my ladder on the swim platform and made a rumbling sound. The Captains Call exhaust is the way to go.