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donzi018
03-21-2002, 11:11 AM
I was wondering if straight exhaust pipes were illegal. I dont think they are but I hear some people say that they are. Does anyone know?(waker44@aol.com)

Sam
03-21-2002, 11:32 AM
It's not the pipes that pose the leagl question, it is the noise they make. I have straight exhaust on my sixteen, meaning no muffler system. I had mine checked by the local marine patroll for the leagle deciple reading in my area. They do this by taking a reading three feet from the boat while the boat idles. Each state may have a different leagle level. If it's to loud then you obviously need to make some changes.

Sam

Looped
03-21-2002, 12:00 PM
Also, if you are talking about the chromed type of headers that are all one piece that go straight threw the transom looking like this:
http://www.cpperformance.com/images/210-26200.jpg
Then you need to make sure that they are water jacketed NOT water injected. The injected ones do not get cooled down enough for an enclosed area and are illegal in closed hatched engine compartments I'm pretty sure.

Craig

Rootsy
03-21-2002, 07:20 PM
Sam,

My 16 has mufflers instead of bullets out the back. i've sort of been thinking of switching to 4 inch straight bullets though. how many decibels did your boat register at idle? apparently < 90 dB?? my only concern with the bullets would be coming off plane too fast, or when in reverse and taking a big ole fatal shot of H2O up the pipes. my mufflers have flappers on em...

Sam
03-21-2002, 07:51 PM
If my memory is correct it was 89 or so, I'm goin to have it done againg this spring. I have heard that I may have higher noise levels due to the upgrades. Any thoughts ?

Sam

Rootsy
03-21-2002, 08:19 PM
Michigan is 90 dB max within 100 feet of shore correct? and yes it will probably be louder with the larger camshaft due to the increased overlap. how do they measure? directly behind in line or at a right angle to the exhaust exit? it'll be a bit more quiet on a very humid damp day than a dry cool day. if you really want to go overboard you could always tune the bullet length so that you hit a node at idle rather than the peaks of the sound pulses and they will cancel each other out sorta kinda but not really very much. then there are the mufflers....

do you have any problems with water going back up the pipes? i sort of want to either get rid of the mufflers or lose the flappers...

Sam
03-21-2002, 08:40 PM
You lost me with your thought about the bullet length, what are you talking about. As for taking water up the pipes, don't think I ever did and my mechanic didn't say anything once he had the motor apart.

Sam