Just got a flyer from Livorsi, They have mufflers called the silent power e series mufflers. Are these the relabeled HPI's or are they something different?

I got theat flier also. Don't really understand the 550HP Natural versus 750HP blown ratings though. What is the difference?

Troutly - The exhaust tips that extend into the silent thunder box are standard 4" tips with three screws. It looks like the pattern might be the same diameter. Did you have an issue with the two middle muflers being too tight together? It looks tight. Motors are stock 454 mag's.

Yves 3-bolt pattern was reversed than his thru hulls he used marine sealant and drilled another three holes and it was done. Don't forget the drain hole goes down!!!

hello everybody, I just put on the GGb mufflers. They seem to be fantastic. Almost too quiet for a blown 502, but no noticeable loss of power, speed,or rpm, and I don't think I'll be kicked off any lakes for being too loud.
-sleek willy.

Troutly - I looks like that with your trim rings that your total outside diameter is probably 6". Measuring the pattern on my silent thunder box in the basement my existing 4" exhaust tips are 5 1/2" total width so going to 6" total width with the new mufflers should fit. EMI 4" exhaust tips are advertised as 6" overall width.

I installed the GGB 4" transom mount - over 650 hp [part number m-4011]. the boat is a Sleekcraft 28' Enforcer tunnel V, powered by a 871 blown 502 , around 800 hp. GGB claims about 1% power loss at this level while being within about 1 db of Ca. 2005 requirement. I don't notice any loss of rpm or mph, but it's amazingly quiet !!! They are very compact [6" o.d. x 6.5" long] and cleared the swim platforms which was more or less why I bought them, the Gatlin mufflers by IMCO are too long. Rex marine should have thier new mufflers availible by now ,they told me they would be 6" o.d. x 9"+- which is too long for me but the price was compareable and they claim no power loss while meeting California's 2005 noise laws.
I like the sound and even if I lost 8hp, power isn't my problum, I just need more prop. Good luck to all.
-Sleek Willy

Hello,

I installed GGB 4" exhaust tips last weekend and had it checked at the Sheriff department this weekend. It still fails... 87 decibles. I need to hit 80dbs by August 15th. Does anyone know of a tip that will quiet a single 454 down significantly? I don't care about power loss, only running legal.

The GGB tips are straight-thru and just have some sound deadening material around the inside. I think I need something that will change the diirection of the exhaust and really quiet it down. I'm not sure if anything like that exists. Also, if I have to completely change the exhaust system out it fix it, that would be too expensive for this boat... I' pay a fine and then sell if off the lake.

Thanks!



Tom

The only way to get that quiet is to go through prop. If you got the the tip mufflers, you should be able to add a second one either before or after the tip to further quiet the system.

Scarab22-1998,
What engine/hp do you have that you got 87db with?
What state is requiring 80 db in Aug...

Thanks,
Rick