Question on GGB inserts?
 

Does anybody have experience with the 4" x 5 or 8" inserts as advertised on OSO? Have twin HP 500's, bumped up to 560 by Innovation on their dyno with CMI E-tops, straight out the transom, and would like to quiet them down a bit. Any suggestions would be welcomed. Gary

I run the 8" long inserts and they do a good job of moderating the exhaust. Sound is good, but tones it down. They do need water - you can tell when the water hits the tails as the sound level drops while the tone becomes smoother and deeper. Makes it easy to talk while engine is running, and more pleasant for a long day out. I noticed no problems with speed loss (running around 450 hp). I know guys running them on much larger power and they had no issues either.

made my pfaffs sound like 454s took them off .. I wish I could cut them in half . they do work tho

TTT, anyone else with experience with these?

I have 4X5 sport on my 525SC with CMI E-tops. Very happy with them, definatley toned down the exhaust note.

It was 6 or 7 years ago but I had GGB inserts for my Stellings exhaust on my Spectre. About 675hp. I liked them cause I could pop them in and out quickly depending on where I was boating.

Might want to look at info and pricing here

http://marineexhaust.ggb.ca/

We purchased the inserts and tips for a new boat build with the 520's, (no silent choice as option on engines when we bought them) . Great looking piece. haven't run the boat yet but awesome thing is the insert is removable. Another thing is they were great to work with.