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Zinger
03-09-2010, 06:57 PM
I'm thinking of running a dry exhaust system, does anyone know of someone running a dry system with any big problems from the law even with clamp on mufflers.

FISHIN SUCKS
03-09-2010, 08:56 PM
What waters are you running? Ocean? Inland lakes? Great Lakes? If the ocean, check with Barry Eller on the board here. I think he was running Gil dry exhaust that really pissed off the Limey neighbor down the street/shore, but I don't believe the law came down on him.

Pismo
03-10-2010, 08:08 AM
Why?

MOP
03-10-2010, 08:59 AM
Why?

Eliminate back pressure, problem is it is scary loud. Adding mufflers kind of defeats the purpose.

Phil

Pismo
03-10-2010, 09:58 AM
Eliminate back pressure, problem is is is scary loud. Adding mufflers kind of defeats the purpose.

Phil

Alienate the world for 10hp..Why?

VetteLT193
03-10-2010, 10:25 AM
I like the sound of through hull exhaust but dry is annoying loud. Even Wet CMI's are really too loud for any length of slow speed running.

As far as the law goes... that depends on location. They are legal in FL. The law in Florida for boat mufflers are only for air boats.

If you plan on taking the boat out of state ever you are pretty much screwed. You are also pretty much screwed when it comes to re-selling the boat. I know for a fact our neighboring states require wet exhaust at a minimum.

Barry Eller
03-10-2010, 10:37 AM
What waters are you running? Ocean? Inland lakes? Great Lakes? If the ocean, check with Barry Eller on the board here. I think he was running Gil dry exhaust that really pissed off the Limey neighbor down the street/shore, but I don't believe the law came down on him.
You remember that story...it was so funny. That happened before I had the 502 and dry exhaust too! I don't have any problems with him anymore...the police took care of that guy threatening me, and the Code Enforcement Officer for the City of Gulf Breeze is my next door neighbor! There are no exhaust noise regulations in Pensacola Bay and surrounding areas. Most regulations apply to lakes and California.

I really don't think dry pipes are THAT much louder than regular thru hull exhaust. They just have a little more "Bark". I just don't "REV" the engine in close proximity to others at docks or anchorages...just use common sense and courtesy. I would have to install clamp on mufflers if I was going to run on the lakes that do have regulations. I have responded to Zingers PM and left him a message.

Zinger
03-10-2010, 12:23 PM
Pismo,
REVERSION thats Why

Carl C
03-10-2010, 12:30 PM
Pismo,
REVERSION thats Why

Yup.

Barry Eller
03-10-2010, 02:16 PM
Pismo,
REVERSION thats Why

Yup.


Yup....I have so much overlap in my camshaft I have to. I removed my Revolution Marine Exhaust and installed the Gil Dry Offshore system.

Pismo
03-10-2010, 02:37 PM
Pismo,
REVERSION thats Why

Once again alienate the world for very little hp. Why? There are better ways to stop reversion, get more LSA, dump further downstream, etc. The mufflers you put on will chew up more hp anyhow.

MOP
03-10-2010, 05:29 PM
Jeff just how big a bump stick did you stuff in there?????????

Barry Eller
03-10-2010, 06:35 PM
Jeff just how big a bump stick did you stuff in there?????????
I talked with Jeff today...he needs dry exhaust or at least water dumping into a real long riser.

As far as how LOUD dry exhaust exhaust is...anyone that has thru hull exhaust hears "Dry Pipes" when they first fire up their engine. With "Wet" exhaust ,when the water finally enters the riser, you can hear a "slight muffling" of the exhaust. Also, Dry Pipes are "Damp" at the tips...the "Water Jacketing" extends all the way to the end of the pipe. I have weep holes in both pipes that keep my rubber flappers wet enough to prevent burning. Dry pipes are not THAT much louder than wet pipes...just has more bark and a different tone...remember I play a Donzi Les Paul through a Marshall Amp...YOU TALK ABOUT LOUD...I CAN SHOW YOU LOUD!!!

Zinger
03-10-2010, 06:56 PM
I'm not a cam expert but there is alot more then just the LSA you need to look at when choosing the correct cam, if your running a stock 502 camshaft you don't need to worry about reversion .
Mop here are the cam specs

•Advertised Duration (Int/Exh): 293/303
•Duration @ .050 (Int/Exh): 234/244
•Gross Valve Lift (Int/Exh): .575/.575
•LSA/ICL: 114/112
•Valve Lash (Int/Exh): Hyd/Hyd
•RPM Range: 2000-6000

Barry Eller
03-10-2010, 07:09 PM
Jeff...read through this thread...it has some good information.

Here are my camshaft specs...Hydraulic Roller - this is an upgrade to a HP 500 cam providing maximum torque and horsepower from a long riser wet perf. exhaust
My camshaft specs... 286 294 226 234 .591 .601 112°



http://www.donzi.net/forums/showthread.php?t=61092&page=2

FISHIN SUCKS
03-10-2010, 07:57 PM
You remember that story...it was so funny.
Loved that story Barry!!!!

The Hedgehog
03-11-2010, 07:19 AM
How much cam do you need? If you are going for HUGE hp, I can understand the need but moderate big you can use exhaust that dumps further downstream. I have a 540 with big heads (Brodix BBIIX) and a big cam. I get no reversion with CMI's.

I have friends with N/A engines that make 750hp that don't need dry pipes.

Ask anyone that has heard me fire up the 540. It is plenty loud.

VetteLT193
03-11-2010, 08:53 AM
I'm not a cam expert but there is alot more then just the LSA you need to look at when choosing the correct cam, if your running a stock 502 camshaft you don't need to worry about reversion .
Mop here are the cam specs
•Advertised Duration (Int/Exh): 293/303
•Duration @ .050 (Int/Exh): 234/244
•Gross Valve Lift (Int/Exh): .575/.575
•LSA/ICL: 114/112
•Valve Lash (Int/Exh): Hyd/Hyd
•RPM Range: 2000-6000

This isn't far off from the 525EFI cam. except the lift is less and some of the numbers are slightly more conservative. The 525 does fine wet. What made you go with that cam? if you are going that aggressive on duration you may as well get the lift too. 525 is .610 intake .632 exhaust.

Anyway, with all that said you need long tail exhaust but wet would work. The EMI's I had would work, the dumps are at the very end of the tail. Stainless makes a set too, or you could go full bling and get the CMI's Merc puts on the 525... or any number of other long tail systems.