Silent Thunder Exhaust
 

If I remove my exhaust box, will I

1. See a performance increase?

2. Have to change exhause tips?

3. Wish I'd left the damn thing alone to begin with?

382, Motors are stock HP500EFI (for now;) )

I'm running Innovation 600's in my 382 with Silent Thunder. When I spoke to the engine builder, his feelings were:

1. Probably not - the exhaust passages are pretty big.
2. Definitely.
3. Probably, but it depends on your tastes.

I have a 271 with a 500EFI, I took it off last year after running with it for 2 years. Think I may have seen some increase in speed, but it probably has more to do with getting rid of the weight than reducing backpressure.

It is definetly louder, but I have Silent Choice so it is not a bother when in a harbor. I will say that there was not much of a noise difference at speed with or without the Silent Thunder, it's all at idle.

As far as whether I should have left it alone, as was said above, it all depends upon your tastes. I can make poeple jump when that 500EFI comes to life with the Silent Choice off, but that is generally just plain rude (although fun when in the right crowd).

You will have to get new exhaust tips, I used Eddie Marine SS angle cut tips.

:cool: :p :D

On of our members modified his Silent Thunder system by removing the internal baffles and enlarging the outlets and making new stainless exhaust rings and flappers.
I think I still have his pictures and details at home. If so I'll send them to you.
The problem with the Silent Thunder is that it will only support just so much horsepower before the exhaust pressure begins to blow out the transom seals. I don't remember what that limit is.

Many of our customers remove the Silent Thunder and none of them have changed the exhaust tips. The important thing is to add the external rubber flappers on the existing tips. Haven't noticed a performance increase,guess it's just a noise thing for some. But it's easy to switch back if you get tired of the noise. Don't fill the holes,just put the bolts back in and your're ready when you want to reinstall.

Box is out of here
 

Gonna pull the box off next week, will see about the tips then.

Thanks for all the responses:cool: :D :D

silent thunder
 

Iggy,
Can you email me that info and pics as well?
Thanks, Craig


Also, does anyone know about how much HP it takes to blow out the transom seal gasket. I'm running about 470 HP and mine leaks a little. That shouldn't do it-must be the age (1990).How much trouble is it to replace the seal?
Would running with the plugs in the bottom of the platform out cause it to not leak due to less pressure?

Craig,
I have the pics on my home computer (I think). I'll let you know.
As far as replacing the seals, the entire platform has to be removed first. I think it's only four or six bolts.
I've heard of some that were all but impossible to break loose.
While it's off you should check the plywood bulkhead inside the platform, where it meets the transom, for rot. I understand it's pretty common.
I know I'll have to replace my seals some time soon. If I stand on the platform while the engine is running it leaks exhaust around the seals at times.

Hot Water
 

Send me your e-mail address so I can forward a copy of the platform mods.
Use the address that's in my profile and I'll send them out first thing tomorrow.

Sorry guys I seem to have lost them.
I wrote the person who sent them to me and I hope to hear from him soon.
Will let you know what happens.