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Thread: Daydreaming about making headers - what tools and fabrication method?

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    Daydreaming about making headers - what tools and fabrication method?

    So I was thinking of making some headers for the BA because I'm 90% certain none of the commercial manufacturers have done testing worth a damn, as none of them could tell me a collector length before muffler/cat/cutoff/tuning point, so I'm going to throw engine specs at an American company that will spit out ideal calculations for my setup. If it's much different I'll (depending on the differences) I'll have to modify what I can get, or make a new set. I have a set of hurricanes on the racecar at the moment, simply because they were cheap and probably better than the factory manifold.

    I have most hand tools, a MIG, drill press, vice, and a few other things like die grinders.

    What other tools would I need to build a set of headers from scratch?
    Is it better to butt weld or expand & slip over?
    How the does one make a merge collector? Are they measurably superior to normal collectors? How do you make *those* look presentable?

    I'm looking at a set of those $200 Lisle exhaust expanders (the ones that take an impact gun, and if you're really keen, a hydraulic ram can be attached, they seem to work well on the youtubes). I have a port-a-power already, so the hydraulic upgrade would be a $50-80 addition.
    I don't *have* a press, but I have access to one. Dies I do not have, nor do I have access to a lathe to make them.

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    log + disco potato is always the correct answer.

    Some of those that work forces are the same that burn crosses.


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    Maybe for my Echo, but a Disco Potato on a Barra would struggle to keep up past 4500rpm. I'd use two, but... racing class says no forced induction

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    That's Sir Cunt to you... krisr's Avatar
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    I made these at home with a cheap shitter ozito drop saw, a multitool attachment on my bench grinder so I can deburr the pipe with a linishing belt, butted the bends and tacked with a MIG and fused them together with the TIG. The head flanges I drew up in cad and had laser cut, that was the most complicated bit. Just be prepared for a huge headfuck as making pipes suuuucccckkks!

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    Last edited by krisr; 07-02-18 at 06:49 PM.
    Quote Originally Posted by Motherfucker Jones View Post
    If you can't appreciate that then you are more narrow minded than the most mulleted, flanno, thong wearing, thong slapping, 253 owning, southern cross tatted, fuck off
    we're full stickered, VB drinking bogan you'll ever meet

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    And the collectors?

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    Unregistered User Permit Roadsailing's Avatar
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    *not an expert, but

    Quote Originally Posted by BLSTIC View Post
    What other tools would I need to build a set of headers from scratch?
    that should do it, you will probably figure out what else you need when you run into a problem.

    Quote Originally Posted by BLSTIC View Post
    How the does one make a merge collector? Are they measurably superior to normal collectors? How do you make *those* look presentable?
    you just buy them? are you planning on doing 6-1, 6-2-3-1, or 6-3-2-1 (dunno if that is even a thing)?

    stainless or mild?

    from memory this looked like an OK way to do it, search for "July 20-21" to get to the relevant bit on the page. http://www.kimini.com/Diaries/2003Late/

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    I was *intending* on fabricating them myself, but I do see 3-1 merge collectors available commercially. 2-1 don't look at all hard to make, but I'll need at least one 3-1 collector. Depends on the design that the program spits out is optimal for my goals of "screw everything below 3000rpm give me as much torque at 5000rpm as you can". 6-1 collector would be nigh-on-impossible for me to fabricate. My skills aren't l33t (or however kids these days say it) enough for that and I don't think I have the room anyway

    6-3-1 is the way 4495's are for peak power
    6-2-1 is the 4490 and hurricanes that supposedly give better low-rpm performance.

    Personally I think either design can go either way, depending on the tube length & diameter
    Last edited by BLSTIC; 07-02-18 at 07:06 PM.

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    Look behind you... Milkman Don's Avatar
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    Oh mate this thread has come at right time. Iíve been pondering making my own equal length for my m10 build in the e21.

    I need to read up a bit more on it but have no clue what length to make them, collector etc. The making part I am good for.
    Quote Originally Posted by Faux Forg View Post
    I agree with Rdyno

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    A jig to square cut the mandrill bends is also worthwhile.

    If anyone wants formulas and links for calculating primary and secondary lengths, diameters etc LMK. You need to know cam timing and a few other engine parameters.

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    And no one answered your question on slip joints vs butt joints, so Iíll make a comment. As you are building these for a race car you should be making the primaries and secondaries equal length. Achieving equal lengths and only making your joints on straight sections to suit slip joints, plus juggling the packaging, would make the project way harder than it would be if you were butt joining the tubes at the most convenient points, which may be on a bend. If you are not confident in your welding, tack the butt joints and give them to someone to weld up with a TIG.

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    Edit: and just buy the collectors off the shelf, you will find this project will be time consuming, itís good to eliminate one item from the fabrication list.

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    You will need a drop saw or vertical bandsaw, MIG or TIG welder, a box of felt tip markers, some acetone and rags, and some way of finishing the tube, I use a belt grinder/disk sander combo from hazard fraught tools.

    If you give us your cam specs, displacement per cylinder, and desired power band, we can work out the math for tube diameter and length. If you know where you want peak torque to fall, then we need intake runner length and intake runner diameter as well.

    For a N/A inline six, you will want a 6 into 2 setup for best midrange and a 6 into 1 setup for maximum high rpm horsepower. Full race 8000rpm monster will like a 6 into 1, etc.

    There is a bit of juggling to do with the numbers but it's not too bad.

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    It would be an extravagance for one-off fab, but cheaper than a mill, slitting saws, etc to make a collector...


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    Non Compos Mentos Gammaboy's Avatar
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    This is the way you want to do it:
    "Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."

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    Defective Faux Forg's Avatar
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    Quote Originally Posted by Marlin
    Chickens will slip under water in the cover of darkness like a seal team and FUCK YOU UP.

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    Registered User gtrboyy's Avatar
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    Saw my cousin make a set for his 383 bb into vh charger...cunt of a job.

    Took him 6 months on/off after spitting the dummy numerous times...did an awsome job though haha
    an easy fix is get a mate to drive in front of you at 60 then 80 then 100 and mark in on your speedo with some liquid paper.

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    Non Compos Mentos Gammaboy's Avatar
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    Quote Originally Posted by Faux Forg View Post
    Fuck working with all that lead!
    It would be an epic amount of lead in a larger tubing size.
    Last edited by Gammaboy; 08-02-18 at 10:54 AM.
    "Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."

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    That's Sir Cunt to you... krisr's Avatar
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    Fuck making collectors. Just buy them.

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    Quote Originally Posted by Motherfucker Jones View Post
    If you can't appreciate that then you are more narrow minded than the most mulleted, flanno, thong wearing, thong slapping, 253 owning, southern cross tatted, fuck off
    we're full stickered, VB drinking bogan you'll ever meet

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    Registered User Ke26 Wagon's Avatar
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    Drop saw, grinder, marker and lot and lots of beer

    Its a cunt of a job but nothing major that cant be done without some thinking

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    I don't know that it would be a massive PITA it would take some skill but it doesn't look to hard I've made an exhaust out of mandrel bends before and what I can say is gaps is what makes it hard. After watching this I came away with some tips of how not to get gaps.


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    Also this one is cool.


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    I made LS turbo kits for work for a few months on end, all merge collector type deal. I used make the collectors with just a drop saw that was lightly modified to go out to approximately 70 degrees of cut angle.

    Bang a pipe in, make a cut, spin the pipe 90 degrees, make second cut. This left you with one quarter of a merge collector.

    In your case, if you can set up your drop saw at approximately 70 degrees of cut angle, make your first cut, rotate the pipe 120 degrees and make the second cut.

    As for merge collector vs open style, almost all commercially available extractors for just about any car use an open style collector, I honestly don't think there will be a huge gain in making a merge collector but it certainly couldn't hurt!

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    Regarding collectors, I've seen one hybrid style collector. I mean it was an open collector, but rather then weld in a star between the four points, they heated it up til it was glowing pretty brightly, then stretched the inside bits til they touched, i.e. there was no gap between the pipes at the end. That doesn't seem that technically difficult, would it be worth it to save making merges?

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    That's how Doug Thorley headers have been made since inception.

    Also there are conical merges that are stamped from sheet and have you weld up an internal "spike" to weld to your pipes, I've used these and they show no losses to a proper merge collector either. Much easier to assemble if all you have is a MIG welder too.

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    Quote Originally Posted by Gammaboy View Post
    Fuck working with all that lead!
    It would be an epic amount of lead in a larger tubing size.
    Much more convenient to use Wood's metal, can't remember the local trade name, was commonly used in plumbing - and probably banned now. Still available over there I believe, it'll just turn your children stupid from the lead content, big plus, it melts with boiling water.

    One of the jobs it did here a long time ago, was a water cooled exhaust on a bridge to bridge racer, forming both the inner and outer tube at the same time.

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    GTFO of my ED doctor ed's Avatar
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    Pipe max
    Mit freundlichen GrŁŖe

    Quote Originally Posted by Keith Duckworth View Post
    "I think that in a racing engine, the closer it is to disintegrating, in general the better its performance will be "

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    Quote Originally Posted by gxxr View Post
    One of the jobs it did here a long time ago, was a water cooled exhaust on a bridge to bridge racer, forming both the inner and outer tube at the same time.
    That's a cool way to use it.
    "Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."

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    I have 4lbs of Wood's metal here, and I use it for small diameter tubes-never tried to bend large tubing with it, although the alloy I have is supposed to be good to 1.5" tubes.

    Old Yoshimura up there has the skills. Sand bending is "easy" conceptually but takes more practice than I've got to get multiple tubes where you want them.

  30. #30
    Non Compos Mentos Gammaboy's Avatar
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    I'm not convinced there's sand in the pipe in the yosh vid... would love a set of those hand bent Ti pipes for the Kat.
    "Where can we get hold of a Vincent Black Shadow?" "Whats that?" "A fantastic bike," I said. "The new model is something like two thousand cubic inches, developing two hundred brake-horsepower at four thousand revolutions per minute on a magnesium frame with two styrofoam seats and a total curb weight of exactly two hundred pounds."

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