I have learned a lot from this forum.. bad and good... and I feel like I need to give something back.

One of the things I needed to make and could not find an answer any where, was a 3 to 1 merge collector for my header project. So I decided to make my own, after some thinking and trial and error this is the method that works best for me.... may not work best way (or be even close to the best way), but works really well for me and I hope it will help someone also.

Step 1: Get your pipes together, for this I was using 3 about 6" 15 degree bend pips. (Pipes are from http://www.mazzurisuper.com great prices on great mandrel bends)



Step 2: You need to figure out the center line of the bend, on the outside of the bend (the side you won't be cutting). You can use a ruler, but I just eyeball it.



Step 3: You need to figure out how to cut out 240 degrees out of the pipe, because to make a 3 to 1 collector you would need 3 120 degree sections of the pipes so they fit nice and work. I use a simple round protractor, marked to only leave 60 degree of it showing.



Step 4: Line up the center line with the 30 degree mark and mark 30 degree -/+ from the center line, the reason behind this is you basically are cutting 30 degrees off from both sides to end up with 120.



When marked it should look like this:



Step 5: Clamp the **** to your band saw. I made a metal "jig" to hold the pipe in place with a line at the center, line up the 2 marks you made in step 4 with the center line to cut the angle you need.









When you are done cutting you should have 3 pipes that look like this



Step 6: Line up the pipes, if you did everything right they should line up really nice and weld them up



Step 7: Trim everything to the right size, expand the ends to what ever you need and you have your self a collector!



Again this is not the best way to do it, I am sure there are easier ways, but this works out for me and I hope it helps you confused guys out!

 

What about a 4 to 1 or 2 to 1? What angle should those be at?

Very nice 3 to 1

 

What about a 4 to 1 or 2 to 1? What angle should those be at?
Very nice 3 to 1

X2

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by coronadrinker &raquo;</TD></TR><TR><TD CLASS="quote">What about a 4 to 1 or 2 to 1? What angle should those be at?
Very nice 3 to 1

X2</TD></TR></TABLE>

for a 4 to 1 you would make the marks at 67.5 degrees instead of 30, for 2 to 1 you would just cut it rigth down the middle that one is easy.

 

bear with me while i try to explain my question

if im cutting two 2" pipes going into a 2.5" pipe would you suggest cutting them a little off center(at 1.25" not 1") that way when they are welded up it will be 2.5" across (like a 8 on its side) then when the muffler shop expands it they only stretch it out up and down not side to side? would this benefit me or is it just more work?

 

Very nice, thanks for sharing!

It looks like you have a pretty hefty tubing expander also, correct?

 

Damn, i just ordered collectors for 3-1 and they are splayed, not parallel like yours..Thanks for such a nice tutorial! How did you get the collection end to mate so nicely with the larger single pipe?
-Michael-

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by coronadrinker &raquo;</TD></TR><TR><TD CLASS="quote">bear with me while i try to explain my question

if im cutting two 2" pipes going into a 2.5" pipe would you suggest cutting them a little off center(at 1.25" not 1") that way when they are welded up it will be 2.5" across (like a 8 on its side) then when the muffler shop expands it they only stretch it out up and down not side to side? would this benefit me or is it just more work?</TD></TR></TABLE>

You can do it that way, but it will still have to be expanded either way, so what ever is easier for you do that. No point in doing more work when you don't have to.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Motorhead_AZ &raquo;</TD></TR><TR><TD CLASS="quote">Very nice, thanks for sharing!

It looks like you have a pretty hefty tubing expander also, correct? </TD></TR></TABLE>

A while ago I was looking to buy an expander and had those ebay ones that work manually and wow they suck, with some other honda-tech members I was able to find a hydraulic one for 1000 shipped. Here is the thread about it https://honda-tech.com/zerothread?id=1548889

 

If you guys need collectors like that made, PM me I will gladly make some up for you guys and it won't cost much at all. I charge $75(shipped) for a merge collector in 304 stainless steel doesn't matter what kind... 3 to 1, 4 to 1, 75 to 1

 

I'll take one of those 75-1 collectors.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by k24em2 &raquo;</TD></TR><TR><TD CLASS="quote">I'll take one of those 75-1 collectors. </TD></TR></TABLE>

lol, x2.

75 shipped... watch out you'll probably get a million PM's once word gets out

 

Like I said, I do this stuff all day, so I have no problem making what ever you guys need. Just let me know.

 

what size pipe is that there?

 

yay! I'll be doing a supra turbo manifold here shortly... I'll do my 3-1 parallel, not symmetric.

great job.


TIP: for welding 16 gauge stainless...go buy some .035 stainless MIG wire...straighten it out... = filler rod.

 

danielm3 is the man

 

Any pics of the inside?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dragline &raquo;</TD></TR><TR><TD CLASS="quote">Any pics of the inside?</TD></TR></TABLE>

I did take one but it didn't come out that well.. but the insides line up very well, it's all in the cut if the cut is right, they line up perfectly. Also, I didn't back purge on this one so the inside has some bird poop.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Eric@HorsepowerFreaks &raquo;</TD></TR><TR><TD CLASS="quote">yay! I'll be doing a supra turbo manifold here shortly... I'll do my 3-1 parallel, not symmetric.

great job.


TIP: for welding 16 gauge stainless...go buy some .035 stainless MIG wire...straighten it out... = filler rod. </TD></TR></TABLE>

Or buy .035 tig wire.

 

$$$$$ its cheaper to get the mig wire.

 

Yes it is, especially if you buy a 40lb roll of it. But I already have 10lb of .035 so i'll use that up first.

 

I guess i'm just lazy. I like grabbing a STRAIGHT piece of .035 filler from my box and not having to deal with unwinding and straightening mig wire. lol

10lbs of .035 filler will last quite a while!

 

once you use the curved ish...its kind of nice...you dont have to hold your hand up in the air you can rest it on the table and use the arc of the wire to get in there perfectly.

btw...love my mag lense. Made a huge difference. Time to go buy tons of cup/lense combinations with a trail cup.

 

Step 3: You need to figure out how to cut out 240 degrees out of the pipe, because to make a 3 to 1 collector you would need 3 120 degree sections of the pipes so they fit nice and work. I use a simple round protractor, marked to only leave 60 degree of it showing.

Step 4: Line up the center line with the 30 degree mark and mark 30 degree -/+ from the center line, the reason behind this is you basically are cutting 30 degrees off from both sides to end up with 120.


Maybe i'm missing something here, but if youre marks are at +/- 30 degrees would'nt you end up with only a 60 degrees section of the pipe left?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike626t &raquo;</TD></TR><TR><TD CLASS="quote">
Step 3: You need to figure out how to cut out 240 degrees out of the pipe, because to make a 3 to 1 collector you would need 3 120 degree sections of the pipes so they fit nice and work. I use a simple round protractor, marked to only leave 60 degree of it showing.

Step 4: Line up the center line with the 30 degree mark and mark 30 degree -/+ from the center line, the reason behind this is you basically are cutting 30 degrees off from both sides to end up with 120.


Maybe i'm missing something here, but if youre marks are at +/- 30 degrees would'nt you end up with only a 60 degrees section of the pipe left?</TD></TR></TABLE>

It's hard to understand i, it took me a while too, but here is a picture to help you understand it some more (not exact of course).



You are basically cutting away 30 degrees from the middle/center line on both sides leaving you with 120 after.