TeamSwift

How to build a G10 header

first you will need to cut the flange off the existing manifold if your feeling cheap.
or get one cut out of 1/4 plate steel at any shop that does milling or machining.
next go to home depot and get some 90 degree angle bent 1 1/4" electrical conduit.
cut approximatly 1-1.5" off the conduot at one of the ends. a hacksaw will do nicely for this.
allign the conduit so that it will collect as follows: cylinder 1 and 3 on top side by side and cylinder #2 in the middle below the other two. tack weld the 3 pipes together where they collect as so they dont moove too much. allign the pipes with the flange ports and weld them to the flange. be sure to tack them all in place first and check the allignment before welding completely. now go to a muffler shop (thruway or minekee shold have it) and get a piece of 3.5" exhaust tubing approimatly 3" long. get them to reduce this pipe down as far as it will go. i have gotten it down to 2" pipe. now you will also have to get them make you another 90 degree bend to go underneath the car. now take the 3.5" pipe and slide it over where the 3 pipes come together and tack it on the outside where it touches the pipes. get a torch and heat up the metal where there is gaps. get a ballpine hammer and use it to bend and strech the metal into where the gaps are. once all the pieces are tight fitting together weld it completely on the outside. now there will be a small triangular gap where the 3 pipes come together in the middle. you must carefully weld this shut and be sure not to weld too hot to avoid burning through the conduit. now weld the 90 degree ouece that is supposted to curve under the car to the header. install the header and check for any leaks in it. if you find any leaks weld them shut.

make sure you take your time and be careful when welding and use propper ventalation when welding galvanized steel and always use a mask.

pics are in the my gallery for all to view

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rip my poor baby sept 1994-apr 2008
91 sidekick, 4x4 2" lift 30" swampers, winch,
to come ..... performance bits.... body lift, custom bumpers

There are only 5 pictures in your personal gallery.

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1994 Metro - MPH project (getting a DOHC G13B)
1994 Metro - MPG project (getting an XFi G10)
1992 Swift - Parts car (gone)
1991 Swift - Parts car (gone)
1990 Swift - Parts car
1997 Metro - Parts car (gone)
1993 Metro - Parts car
1989 Swift GTi - Parts car
1998 Metro - Parts car

i have no clue it wont let me upload more pics i tried its because alot of posts i put out had pics attached.

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rip my poor baby sept 1994-apr 2008
91 sidekick, 4x4 2" lift 30" swampers, winch,
to come ..... performance bits.... body lift, custom bumpers

did you notice any power difference with this?

http://www.lowes.com/lowes/lkn?action=productDetail&productId=19623-15527-02-55544PE&lpage=none

is that the right item?

Now I don't doubt that a header built like this will breathe better than the cast iron collector that the car comes with, but I am curious, is there an easy way to determine what the optimum pipe size and length should be?

Also - since my application would be for the 4 cylinder SOHC motor - what's best an equal length 4-1, or a 4-2-1, and which cylinders would/should I pair on a 4-2-1?

One more question - is thin wall electrical conduit really the best material for a header, won't it burn up relatively quickly?

That information is locked away securely in Jard's head, probably.
My dad says there's this header wizard guy that sells a book on how to build your own header, determined mostly (I think) by the intended RPM range. I'll ask him who it was. I think he also sold a kit with elbows and different sized pipes and all that online somewhere.


I thought I was the only doubter! Maybe Jomo sprayed it with header paint...

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That would be Ed Henneman in Minnesota.
If you can get him on the phone, hes a riot.
If you want dimensions, PM me with your application, and I'll figure it out for you with my magical formulae

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Contact 3tech: [email protected]

what the heck do you expect? it cost me a whole $18 canadian to do mine if i get 6 months out of it im happy!



and in awnser to your other questions i have no clue i own a 3 cylinder and no i dont know what power gains will come from this as it has not yet been installed. i will tell you whats goin on when i do install it.

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rip my poor baby sept 1994-apr 2008
91 sidekick, 4x4 2" lift 30" swampers, winch,
to come ..... performance bits.... body lift, custom bumpers

The conduit is probably 16ga., which most headers would be anyway.
Nothing wrong with a little home-made ingenuity.
After all, I've seen your car, and I, too would think twice before sinking $18 into it

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Contact 3tech: [email protected]

GO BONDO!!!!!!

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rip my poor baby sept 1994-apr 2008
91 sidekick, 4x4 2" lift 30" swampers, winch,
to come ..... performance bits.... body lift, custom bumpers

now thats funny

Or sad, depending on who you are

I did my calculations based on a 3cyl making ~65 hp at 6000RPM with a bias toward street drivability, and good low, and midrange(3-6K) power.
1.25" OD primaries 35" long with a 1 7/8" collector at 12 1/8 long.
For the 8V 4cyl, making ~85hp, I came up with almost exactly the same numbers.
Hope that helps.
To calculate your exh. size,
The combined cross-sectional area of tailpipes on an engine should not exceed the combined cross-sectional area of primary header pipes, even for race engines. For light-throttle economy applications this ratio should be about 45%. For street performance cars this ratio should be about 50%. For street-strip applications, this ratio should be about 60%.
Remember to use ID, and area when calculating it
Hope that helps.

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Contact 3tech: [email protected]

Slick. Thanks for the numbers Superf1y. Should make Home Depot header building that much more easier.

The only bad thing about using conduit, is the softer metal compared to say... stainless. Guess how I know that? Stupid Home Depot exhaust system....

The best part? It's cheap. Cheaper if you find a chain link fence.

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Rice: Race Inspired Cosmetic Enhancement

I am building my own header, I am using 304 SS 90 degree elbows that I found on ebay for $3 each! Which is a steal when compared to 16 gauge mandrel bent steel 180 degree bend going for $20. The shipping was vary fair too, costing me $4 for the first pipe, and $1 for each additional one. I just paid $25 to have 20 of them shipped from California to Van Canada.

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Nowadays driving an 85 GMC SIERRA is painful... maybe thats why I'm currently working on an 87 Sprint Turbo!

any pics of your build ?

No, Haven't started yet, I am all over the place on finishing up my 85 chev, cleaning up my garage (getting rid of a 88 ranger) and scrounging up parts for my 87 turbo build. I still need to buy some material to make the flanges before i can start welding. I wanna use stainless steel, but i might opt out into using regular steel plate if i can't find any in small amounts.

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Nowadays driving an 85 GMC SIERRA is painful... maybe thats why I'm currently working on an 87 Sprint Turbo!

Most welders won't touch galvanized metal (conduit) because when heated it give of a poison gas (can't remember just what).
If you want to do it yourself either do it in a WELL ventelated area or send me you personal data so that I can take out a life insurance policy on you (payable to me).
Another way to go would be have a muffler shop bend up regular exhaust tubing for you. With all the small cars on the road today, they should have the size you need.
Either way, good luck. Post a photo for us if you build a header.

Hmmm... I've been welding galvanised stuff at my work these past couple of weeks... Thats some good info you posted, thx.

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Nowadays driving an 85 GMC SIERRA is painful... maybe thats why I'm currently working on an 87 Sprint Turbo!

Drink a tall glass of milk before you weld the galvy,it will help.Nothing replaces a good resperator though.