Mufflers and Evac Kits

[jdotson]

I have read that header evac kits will not work if mufflers are installed unless you put the tubes beyond the mufflers. Has anyone done this yet and how are the hoses plumbed? I can see it working if the exhaust crosses under the engine stand with the mufflers beneath the engine but if they were run straight out each side that could get pretty nasty looking. I suppose you could put the mufflers anywhere using exhaust pipe instead flex pipe and mount them close to the header? Just some thoughts looking ahead at the airboat sound issue. I'd rather work on it now than later.

 

[cntry141iq]

it's raining today and yesterday so I have had lots of time to read and answer on this thing .. don't worry the weather will change & I will get off here.

I put an evac system on my exhaust and it is past the mufflers and it doesn't work. I have re-installed at different depths in the pipe and at different angles and finally just gave up for now. I have been running two large breathers on my engine but that is not getting it done but at least I know where to look for the oil leaks. I am gonna have professor thunder look it over when the new engine goes on there becaus ehe wants me to have one probably as much as I want one. I thought about going to the super duper vacum pump system but that is just something else to break or have problems with. So if this one gets solved let me know too.

 

[c chardt]

I use to have it on open headers and it worked well then I put on mufflers and then built up to much back pressure and would blow the dip stick out so I took them off still had a lot and started leaking oil out of the rear main just put some on the other side of the mufflers and that just about stoped my oil leak so they work well. I will post a picture of it later

 

[jdotson]

Well cntry you have experienced what I am concerned about. I don't really want to do the pump thing either. Right now I am running mufflers that are transom mounted and the evac kit works well but I am quite positive that 90db @ 50' will make them obsolete. I thought this topic might put a little life into the forum today. Seems like the rain has everything a little slow.

 

[cntry141iq]

Tomm. will be bright and sunny .. I hope.

My mufflers are transom mounted as well the only thing I can think is that mine don't work because of the turns I installed to direct the flow towards the center of the boat and down. It may be that it is screwing up the airflow past the nipples and not causing a suction. I am gonna try
re-installing again maybe a little deeper this time to get them in the flow better. It puzzles everyone who looks at them because they should work. Airflow is a funny thing though and sometimes the slightest thing will cause dead spots and maybe I just got lucky. LOL

 

[Ron Miller]

To test the air flow just tie or tape some 6" to 12" pieces of YARN to the area you want to check. Then take pictures and a video at different RPM'S. You will be amazed at what you see.

 

[cntry141iq]

I would love to do that but the problem is the flow I want to check is inside my exhaust pipe and around a corner LOL.

 

[Anonymous]

Plumb a fuel gauge into the exhaust system (run a length of tubing to the gauge)

Low end of the pressure range is what you're looking for (2 or 3 PSI maybe)

If it is pegged out at 10 psi, you need a better system.

I will probably pull this trick on my boat. I like gauges.

I have a 3500 RPM tach, water temp, oil temp, vacuum, amps, inline fuel pressure and, of course, oil pressure

 

[jdotson]

With the new requirement apparently passed how do they plan on inspecting for automotive mufflers? I am assuming it will be a visual check? If so then I may have a few solutions to my evac question. :idea:
Laws and rules may require a "muffler" but I can operate quietly if I have too without them!