My current engine makes 1300HP through Stellings dry pipes. At idle I was measured at 108db. I finally decide to go with GGB's 4.5" Extreme clamp on mufflers, but I wanted turn downs as well. I spoke to Graham at GGB, and he custom made a set with turn downs for me. I drilled the ends of my Stellings pipes to allow water in at the end of the tail pipe and clamped on the new mufflers.

I finally tested yesterday, and wanted to share the results.

On the hose in my driveway, 89-90db from 10 feet behind transom.
In the water, 84-85db from 10 feet behind the transom.

I was amazed! For the first time ever, I can have a conversation while on plane. At idle the valves are louder than the exhaust. You can't beat having 1300HP and waving to the Water Nazis as you go by at 100+mph.

That is great to hear, I am a new dealer for GGB and have their mufflers on my personal boats and IMHO their products are first class.

Dave,

That must make a whole lot of bubbles at idle. I remember blowing through my silly straw in my glass of milk to make bubbles high enough to come over the top of the glass. It must look like that.

Anyway,
What kind of numbers did you get?

GGB makes a nice muffler, there's 2 sets of 4.5 clamp ons in OSO classifieds.

The mufflers in the classifieds are not the new extreme design. They are not nearly as quiet.

Vinny,
I was in 3' rollers so 94mph was all I good get with the new maximus at 9% slip. I'll know more on Sunday, once I get the 2" shorty Bmax on.

They work well in the 800 to 900 hp range.

Dave,

Good luck with the testing. Most of all be safe. It looks like we will have a great weekend for testing. Keep me posted with the results.

"we"
Don't tell me you can't wait any longer.
LMAO

You're right, I should have said YOU........ I am still going to wait until May 1.. I should take up a ride up to see you.

I wish I had as spectacular of results. When I tried the GGB mufflers inserted into my existing 4.5" tailpipes, I didn't see a db reduction. There was slight change in tone, but nothing showed up on the meter. After some minor discussions, GGB agreed to buy them back.