Exhaust questions...
04-27-2008, 12:01 AM
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Exhaust questions...
Im gonna take a shot at making a tuned exhaust for my modified homlite. Making it from a couple of old baseball bats. I did a little research and im thinking about going with 7/8 ID inlet, 1/2" stinger, center of the pipe will bulge to 2" diameter and about 13" long overall. I cant really go any shorter then this due to the taper of the bats. May not work as great as a factory pipe i know, but it has to be better then the stock exhaust and its free, and its cool that im making it from scratch. I was thinking the longer length may be good for the homie anyway since it probably wont rev as high as a zen anyway. Probably going to start with 12.5-13" from the exhaust port to the weld, heard this is a good starting point. Should I start even longer since its not a zen were talking about?
Anyway main question is about headers. Has anybody made headers themselves? Whats a good material to use? What ID are the headers?
And what about cooling? Whats the advantage of a water cooled manifold and how important is it? Is it a good idea to inject the water leaving the cylinder into the pipe? I heard it changes it to a longer tune, any dissadvantages? Are there ever any problems with water going back the exhaust system and into the engine? How would i be sure to avoid this?
Anyway main question is about headers. Has anybody made headers themselves? Whats a good material to use? What ID are the headers?
And what about cooling? Whats the advantage of a water cooled manifold and how important is it? Is it a good idea to inject the water leaving the cylinder into the pipe? I heard it changes it to a longer tune, any dissadvantages? Are there ever any problems with water going back the exhaust system and into the engine? How would i be sure to avoid this?
..... Not longer
04-27-2008, 04:38 AM
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RE: Exhaust questions...
you dont need to cool the header or pipe unless its under the hatch?,also you dont want water in the pipe if you do cool the header or pipe just use a wrap such as brass tubing wrapped round the header?.I have one here that someone made themselves i never used it but its stainless steel but wont fit a weedy as the bolt spacings are for a zen.
04-27-2008, 10:46 AM
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RE: Exhaust questions...
Exhaust timing is pretty high actually, 170 degrees i think. So that should be compareable to a zen, i was just thinking that the revs will still end up being a little lower which would require a longer pipe.
So, what ID is common for headers, and whats the story with water cooling? I see from pics that almost everybody runs a wet pipe. Whats the differecne in injecting in the header or into the pipe, and how do you avoid haiving water running back into the engine?
So, what ID is common for headers, and whats the story with water cooling? I see from pics that almost everybody runs a wet pipe. Whats the differecne in injecting in the header or into the pipe, and how do you avoid haiving water running back into the engine?
04-27-2008, 05:02 PM
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RE: Exhaust questions...
I dont think most people run wet pipes? most run dry pipes with a water cooled manifold with o rings usually and they run cooling on the pipe more to save the o rings where the pipe joins the header than to actually cool the pipe itself.Iv never run a wet pipe so cant comment on them.Ext diam of header pipe is 7/8".
04-28-2008, 02:13 AM
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RE: Exhaust questions...
Thank for the help Mart, I think i'll leave it dry. Well I started to make my pipe and header today and got it all pretty much done. Turned out pretty good. Pipe was straight forward, chop up some baseball bats, weld them together and clean it all up. I was really stumped on how I would get a nice tight 90 degree bend in the manifold without kinking the pipe. Most pipe benders i've seen are a much larger radius and I wouldnt have room. So then it came to me, instead of trying to find a way to bend the tubing, try and find a piece thats already bent. So i looked at a bunch of things, snowmobile suspension arms, a lawnmower handle and finally i decided to use the leg of an old chair. Worked out perfectly. Welded it onto a piece of 3/8 plate (i wanted to go thick so i could blend the rectangular port to the round pipe) and I was good to go. One of the screws for the manifold was behind the bend, but i just slotted it so i can slide the manifold over the bolt and then tighten it after. Some pics below.
I started it up for a min or so just to see what it sounds like, and holy crap is it ever loud! I think i might need to make a silencer too. What are boat silencers like? Do they have baffles and stuff or are they just sraight through core with fiberglass around it?
I started it up for a min or so just to see what it sounds like, and holy crap is it ever loud! I think i might need to make a silencer too. What are boat silencers like? Do they have baffles and stuff or are they just sraight through core with fiberglass around it?
04-28-2008, 07:42 AM
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RE: Exhaust questions...
ORIGINAL: mmurray70
Thank for the help Mart, I think i'll leave it dry. Well I started to make my pipe and header today and got it all pretty much done. Turned out pretty good. Pipe was straight forward, chop up some baseball bats, weld them together and clean it all up. I was really stumped on how I would get a nice tight 90 degree bend in the manifold without kinking the pipe. Most pipe benders i've seen are a much larger radius and I wouldnt have room. So then it came to me, instead of trying to find a way to bend the tubing, try and find a piece thats already bent. So i looked at a bunch of things, snowmobile suspension arms, a lawnmower handle and finally i decided to use the leg of an old chair. Worked out perfectly. Welded it onto a piece of 3/8 plate (i wanted to go thick so i could blend the rectangular port to the round pipe) and I was good to go. One of the screws for the manifold was behind the bend, but i just slotted it so i can slide the manifold over the bolt and then tighten it after. Some pics below.
I started it up for a min or so just to see what it sounds like, and holy crap is it ever loud! I think i might need to make a silencer too. What are boat silencers like? Do they have baffles and stuff or are they just sraight through core with fiberglass around it?
Thank for the help Mart, I think i'll leave it dry. Well I started to make my pipe and header today and got it all pretty much done. Turned out pretty good. Pipe was straight forward, chop up some baseball bats, weld them together and clean it all up. I was really stumped on how I would get a nice tight 90 degree bend in the manifold without kinking the pipe. Most pipe benders i've seen are a much larger radius and I wouldnt have room. So then it came to me, instead of trying to find a way to bend the tubing, try and find a piece thats already bent. So i looked at a bunch of things, snowmobile suspension arms, a lawnmower handle and finally i decided to use the leg of an old chair. Worked out perfectly. Welded it onto a piece of 3/8 plate (i wanted to go thick so i could blend the rectangular port to the round pipe) and I was good to go. One of the screws for the manifold was behind the bend, but i just slotted it so i can slide the manifold over the bolt and then tighten it after. Some pics below.
I started it up for a min or so just to see what it sounds like, and holy crap is it ever loud! I think i might need to make a silencer too. What are boat silencers like? Do they have baffles and stuff or are they just sraight through core with fiberglass around it?
I know from experience that this makes a very quiet pipe, the stinger muffler type are still loud, not got experience of them but I understand that cooper also make a bolt on muffler that works well.
http://www.prestwich.ndirect.co.uk/silencin.htm
Glenn
04-28-2008, 07:52 AM
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RE: Exhaust questions...
Mark try one of these ,cheap easy and Patrik off the forum says they work well.Theres a thread on here somewhere about them,he used two small energy drink cans pics are pretty self explanetry.ill try to find the build thread.Look like fun to me ill be trying one too.Very similar to Glenns link in design [)].
mart
mart
04-28-2008, 11:48 AM
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RE: Exhaust questions...
I might try to make a stinger type silencer. I dont really mind if its a little loud to be honest, I wont be running in public areas. I just wasnt really expecting it to be as defening as it is! If a stinger silencer on a boat is anything similer to the way it is on bikes and sleds, somewhat quiet until you really open it up, that would be great.
Skoda I welded the pipe with a lincoln Mig-15 and a SG-100 spool gun. That spool gun is fairly new from lincoln and its great. Price is good and it works nice. I had to do some mods to get it to fit my welder but if you buy the new version of my welder (Mig-Pak 180 i think?) it plugs right in.
What diameter will I use for my stinger exhaust? Half inch again like the exit of the pipe?
Skoda I welded the pipe with a lincoln Mig-15 and a SG-100 spool gun. That spool gun is fairly new from lincoln and its great. Price is good and it works nice. I had to do some mods to get it to fit my welder but if you buy the new version of my welder (Mig-Pak 180 i think?) it plugs right in.
What diameter will I use for my stinger exhaust? Half inch again like the exit of the pipe?
