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View Full Version : will increasing the water flow quiet the exhaust?



SeaSlut
06-16-2001, 07:35 PM
The local sheriff, "Boat Chick", told me I was 2 db over some new law. STUPID LAW!
If I open up the port from the bowl to the motor to increase the water flow will it make the SeaSlut quieter?
i.e. more water flowing thru the exhaust=more sound dampning.
Can I hurt something; or overwhelm my cooling system, burst my heat exchanger, introduce gremlins, set the planets out of alignment or ruin my summer?

Timer
06-16-2001, 08:25 PM
SeaSlut, that should quiet it down but make sure you don't have the water going in at low RPMs as you might draw some into the engine through the valves.
I'm assuming you have the wet exhausts such as Bassetts. If you have some kind of water jacketed exhausts, I would think more water would do something for you, but maybe not as much.

froggystyle
06-16-2001, 10:32 PM
Your formula only works to a certain degree. Like Timer said, more flow at low RPM's will be a lot louder, because you will be screaming about how you just bent a rod in half from Hydrolocking your motor. If you run the baffle style mufflers with Bassetts, and a working water injection system it will be as quiet as you will get. If you open your valve more, you will decrease the engine temp a lot, and reduce performance accordingly. Better off installing an adjustable valve controlable by you up front, opening the what appear to be -8AN couplers up on your headers (You will find that one end is closed off quite a bit) a little, and only opening your valve past "Low" when the man is around. Best of luck.

SeaSlut
06-17-2001, 04:47 AM
I have the original berkeley exhaust, thru the transom.

hoolign
06-17-2001, 07:59 AM
check out www.bassetracing.com (http://www.bassetracing.com) they'll tell you the proper way to run your headers or logs,i put a valve up by my seat,it took about 20 minuites,and works good ,better than havin to sneak around my headers to adjust the flow,i did that after going through the bent rod,broken rocker,disitagrated lifter b.s.never mind the instant suntans i got on my elbows, the local roscoe.p. coletrain was on my case, now i just idle out 1/4 mile from the gereatrics after i launch and they don't bother me

froggystyle
06-17-2001, 09:12 AM
You are getting popped on a Through the transom system???? Wow, that's anal. Well, in that case, it probably doesn't have mufflers anywhere in it. Add some mufflers and be done with it. I would not increase flow though.

Gerrit
06-17-2001, 10:14 AM
Cut the end of a set of BBC tall valve covers(or ford pinto if you want to go the cheap route..Junkyard), bolt and seal them to the transom, so that the exhaust is forced under the waterline. I did somethin similar, with no loss in power ,cause at full bore the inside of valve covers are still larger(back pressure) than the exhaust tips exit hole. I'll explain more if you need!

SB
06-21-2001, 07:26 AM
Thanks, Gerrit, I'd like to know more about using the valve cover on the exhaust. How much quieter is it, and what's the HP penalty? I've seen the ad for the $450 mufflers, anyone know how they work?

spectras only
06-21-2001, 03:41 PM
SB, Phone Dave at California Marine [604-278 1880] he has those muffling devices Gerritt talking about.He made those since the early seventies [look up the october Hot Boat Shoptour article by Brian Davidson].It basically diverts the exhaust exit downwards the water,with no power loss,hence no baffles applied.While the boat idles it's completely quiet since the cover is under water.However under way it's out of the water,thus no added backpressure to robbing horsepower.I've seen the same item resurrected by a californian company claiming it being a new item.Remember,when you see the sherriff with his decibel meter prowling around ,make sure you idle away from him past 50 feet.The max decibel level is measured from fifty feet behind the exhaust underway.
[This message has been edited by spectras only (edited June 21, 2001).]

429CJ
07-18-2001, 08:10 AM
Just so you guys know, you can still get a boating ticket even if the officer is not using a decibel meter. 654 H&N - excessive noise. This is a catch all section.