# Instructions to make your own turbo manifold.



## Chuck (Nov 19, 2003)

Ok.. im going to make a documented walkthrough on how to make your own manifold for turbo application..

The current test prototype manifold is goign to be for my GA16DEt project...

Parts needed : 
1 - manifold flange
2 - turbo inlet flange
3 - 6-7 weld-els 40 gauge (i got 6-90° bends)
4 - Some straight pipe (still 40 gauge)
5 - recipricating saw, to cut through metal
6 - Mig / Tig Welder

Here goes..

1 : Start out with your flange for the manifold.. the flange that attaches to your head..










2: get a good idea of how you want your turbo to be mounted.. and then you can get a pipe layout of how it should look... now me, My piping is going to be 1.5" in diameter, so ironically enough, i found a hose that would match that size, a Vaccum cleaner suction hose (for attachements and what not on you vaccum cleaner..), well i placed them against the manifold, for a good idea of how long each one should be.. and i came up with this.










3: After getting a measurement of piping size/length, cut the piping, so that they will merge into 1 nice collector.. you can always cut and weld the real pipe so that it will work better.. 

















4: Duct Tape the piping to the manifold, to get a relative idea of how the metal pipes will have to be bent.... note, due to the piping not Completly being solid, like metal, this is only a rough draft.. 


















*Please stay posted, I will be updating this with more information, as i have more information to post.. im waiting for metal exhaust piping right now..

Coming soon : Making your own Downpipe, intercooler piping, and Turbo installation*


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## javierb14 (Jul 9, 2002)

i usually just test out a bunch of different designs by tacking and test fitting.....but that's definately a different way to mock things up, might save some time  *hint* you might want to try those PVC pipes/bends from a hardware store. they come in different IDs and radii, and are a little more stable .

as for your pipe diameter.....1.5 in. ID is quite large.....you may want to consider a smaller dia. ID for a tubular manifold that will power a T25 turbine. also, you can save considerable time and $ by using pre-bent mandrel bends instead of bending your own.


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## chimmike (Oct 17, 2002)

Chuck....this is great! However, I feel most of the people that are about to turbo their 1.6 don't have the skills or knowledge required to do something like this, or, well, to do it properly. I'd still suggest a tried and tested manifold simply because an average joe making a manifold may not produce postive results. Flow patterns need to be maintained


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## Chuck (Nov 19, 2003)

lol.. an average chuck you mean...

well i considered buying mandrell bends. but, im looking over the long run, plus its hard as heck to find smaller piping.. i ordered 7ft of pipign of JCwhitney.. for like.. 19$ shipped.. and not only that, i measured the holes on the exhaust manifold, and they are a peachy 1.375... the same as the interior of the exhaust pipe..

BTW: my BRAND NEW T25 turbo is coming in the mail today.. oh joy


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## Chillboy (Oct 8, 2003)

Yes guy!!! I have a machist meeting with me tomorrow to discuss making all new intercooler piping and dp (he has access to cnc machines, mandrel bender, sandblasting, powdercoating...) and he is def going to see this thread. Thank-you!!
So if I wanted a nice equal length manifold, there's nothing more to that than having the same length pc's with curves that will fit in underhood space I have? I may as well ditch the log manifold since I need a dp and have a guy to do it without killing the pocket book. I just hadn't thought about it, thanks again.


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## chimmike (Oct 17, 2002)

damn man, your guy has a mandrel bend machine too!! DAMN YOU!!!!


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## Chuck (Nov 19, 2003)

for real.. im going to have access to a cheap pipe bender.. but.. it will do the job.. like i said.. i will update as i have something to update.. but id love to see other people share the passion in making there own.


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## morepower2 (Apr 19, 2002)

Chuck said:


> lol.. an average chuck you mean...
> 
> well i considered buying mandrell bends. but, im looking over the long run, plus its hard as heck to find smaller piping.. i ordered 7ft of pipign of JCwhitney.. for like.. 19$ shipped.. and not only that, i measured the holes on the exhaust manifold, and they are a peachy 1.375... the same as the interior of the exhaust pipe..
> 
> BTW: my BRAND NEW T25 turbo is coming in the mail today.. oh joy


Better watch the tubing thickness as well, just any "tubes" from JC whitney is probably going to crack apart real quick. I would recomend scedual 40 weld-els or at least some thick 12 gauge tubing. A turbo manifold has to support the turbo so it has to be strong.

Mike


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## Chuck (Nov 19, 2003)

true that.. i may search out some thicker tubing..


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## dave_f (Dec 11, 2002)

chuck, its good that you are laying out your exhaust manifold, but keep in mind the minimum bend radius of your bender. I used prebent weld-els (I believe they had about a 1.25" radius) and I still found myself cramped for space in some spots. How are you planning to make the collector to merging the 4 pipes together?
-dave


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## Chuck (Nov 19, 2003)

alot of cursing, welding, and cutting.. thats how..

no, im going to get about 4 pieces of 2" piping. and cut them up, so they will merge into one piece, and have 4 pipe outlets still.. if that makes any sense.. just like any collector.. only hard part will be making precise cuts.. we shall see.. im goin to document it as best i can


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## javierb14 (Jul 9, 2002)

stainless 16 or 18 gauge tubing on the left, stainless 8 gauge aka schedule 40 weldel on the right


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## Chuck (Nov 19, 2003)

holy god.. where the hell can i get that kinda tubing?.. Lol. does that stuff even bend?


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## dave_f (Dec 11, 2002)

you buy the weld els pre bent in 90/45/180 degrees... I used schedule 40 els. I think that's what's on the right in Javier's picture. I added a picture of my manifold during the mock up stages.










-dave


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## Chuck (Nov 19, 2003)

Lol.. notice the big bottle of vadka on the left.. 

thats pretty nice... where do you get the weld el's from?


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## morepower2 (Apr 19, 2002)

Chuck said:


> holy god.. where the hell can i get that kinda tubing?.. Lol. does that stuff even bend?


A hydralic supply company usualy has them. Listen to Javier, stainless weld-el is the s--- for making a really nice street manifold that will last forever. As another tip, you might want to put cuts in the flange sperating the two paired ports or makes these two separate pieces to reduce the stress on the manifold once completed. It will be less likely to crack.

Mike


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## Chuck (Nov 19, 2003)

wow, thats a tad pricey!! like 9 bucks a bend.. I have a feeling if i go to the local hardware stores, i can find the same stuff for the same price.. just save on shippin


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## javierb14 (Jul 9, 2002)

dave_f said:


> you buy the weld els pre bent in 90/45/180 degrees... I used schedule 40 els. I think that's what's on the right in Javier's picture.
> -dave


yup


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## dave_f (Dec 11, 2002)

I got the weld els from McMaster Carr, they come in mild steel and stainless. I went with the mild steel because it was my first attempt at a manifold and I was worried about stressing the head ...plus it was a cheaper. I made the collector out of four 45 degree fitting cut and welded together.
-dave


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## NotAnotherHonda (Aug 7, 2003)

morepower2 said:


> As another tip, you might want to put cuts in the flange sperating the two paired ports or makes these two separate pieces to reduce the stress on the manifold once completed. It will be less likely to crack.


thats how javier made the one i have...


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## Chuck (Nov 19, 2003)

ok got my weld-els and some piping, and flanges.. all ready, heres an updated pic of the ingrediants










8- 45° bends, and 4 couplers, then 2x12" piping for misc bending.. this is 1/2cm thick.. i dont know what it constitues as far as "gauge" but.. i doubt it will break.. hehe


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## Chuck (Nov 19, 2003)

well heres some updated pics of the manifold in progress... im working from the inside out.. i figure the inside is easier to work with.. plus if you work on like.. the right side only, it will be a tad harder to get welding access


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## James (Apr 29, 2002)

did you make that flange yourself chuck? Maybe its just the lighting but the holes for the studs look HUGE! and they seem too close to the holes for the runners...


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## Chuck (Nov 19, 2003)

its just lighting.. ive test fitted it.. it fits grrreat, its hard to explain without a nice digi cam.. lol.. let me get a pic of the back of the flange to give you a better idea.


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## James (Apr 29, 2002)

ok that's good because those last two pictures look like you cut the flange out of an old pot and bent it straight! :crazy:


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## Chuck (Nov 19, 2003)

thats an old gasket just for refference..

well, My moms cast iron pot was the best thing i could find for the flange!!!!  (jk) lol..


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## James (Apr 29, 2002)

Chuck said:


> thats an old gasket just for refference..
> 
> well, My moms cast iron pot was the best thing i could find for the flange!!!!  (jk) lol..


much better picture. i was watching some tv and they were building a set of headers for a old domestic motor (really cool process btw, they have these CNC machines that can design a flange by locating the centers of the holes and plotting them in 3d) then they have this program that can basically show all the trouble areas for clearance! 

anyways, they said you should take the piece of the runner that goes into the flange and expand it a bit and weld it from the inside to avoid cracks, don't know if that is an old skool domestic theory or what but you might look into it.


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## Chuck (Nov 19, 2003)

Hmm.. Im not sure, Im thinking of a name for this kinda manifold...

im thinking something like

Poorboy manifold..
Frankensteins Mistake manifold...
Trashcan manifold..

I dunno.. we shall see when its done.


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## NotAnotherHonda (Aug 7, 2003)

chuck! isnt that flange upside down??? it might not matter, but wouldnt it make for some clearance issues with your dipstick, and possible other things?

heres mine....










and yours...










i hope your test fit has the dipstick accounted for too...just a thought


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## Chuck (Nov 19, 2003)

Lol, no my flange's bottom straight line is the bottom of the manifold. its going to clear the dipstick.. cause after i get done welding it.. im goign to cut that middle bar off. to resist crackin


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## James (Apr 29, 2002)

i wouldn't cut it off... it will allow more room for the dipstick but the flange will warp so much more easily... cut some slots into the holes where the bolts go to help reduce warping like Javier did to his old manifold, you can probably find some pictures of it around here somewhere.


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## Chuck (Nov 19, 2003)

Oooh, is that what they were saying?...

and i just test fitted it really quick.. adn it clears the dipstick.. so im thinking of leaving it as is, for structural integrity


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## James (Apr 29, 2002)

who? well its just that if you cut the center the two flanges will be floating around and eventually won't rest flat against the head...


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## Chuck (Nov 19, 2003)

yeah, thats what i was under the impression of the whole time.. but.. Maybe I missinterpreted a previous statement.. after test fitting.. it gives me a really good idea of how its going to turn out.. i am considering getting more bends.. i believe i will need more.. possibly 3-4 per runner.. i only have 8 total..... and holy shit, let me tell you, the collector is a MAJOR FREAKIN PITA!!!!!!! lol.. i hate collectors already, and ive barely scratched the start of it.. but i know the hard work, and cussing is going to end up with something good.. 

Im just trying to build my arch... and i gotta get all my animals... then ill be cruisin .. right now im workin on the lion.. and let me tell you. the lion is a vigourous creature. Damnit if noa could do it, i will too!


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## James (Apr 29, 2002)

You know while you're doing this you may want to stop and reconsider the design... if you're creative enoguh I'm sure you can find a location to mount and external wastegate and then you'd be set!!!


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## James (Apr 29, 2002)

Ok, I read all the posts above and Mike said to cut the middle piece out to keep it from cracking... so I'd listen to him. I'm looking at it like this, you have two manifolds that aren't connected to each other anymore and with a couple heat cycles of the manifold it will move the two flanges just enough so that they're either not flat with the head or the bolt pattern no longer lines up... where as if you left that center piece in you can ensure that the flange will remain together.

But... I'd listen to Mike!


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## Chuck (Nov 19, 2003)

HAHHA, external wastegate!!!.. now see, i plan on using it for my OWN use, not to sell it.. .. i dont need an external wastegate.

Well, i got time to decide.. no hurry..


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## dave_f (Dec 11, 2002)

James said:


> anyways, they said you should take the piece of the runner that goes into the flange and expand it a bit and weld it from the inside to avoid cracks, don't know if that is an old skool domestic theory or what but you might look into it.



I welded my runners to the flange from the head side, actually it was easier than trying to weld all around with the runners especially when they are so close together.

Chuck, 
Are those weld style pipe fittings or threaded... They look like threaded pipe fittings, but the picture is a little blurry. 
Be very careful when you cut the flange in two... there is a very high possibility that it wont fit on your head once you cut it. The stresses in the manifold from all the welding will cause it to move. I used a two piece flange design and I had some trouble with this. If I were to do it again I would use a one piece flange design.


-dave


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## James (Apr 29, 2002)

You could take a fly cutter across the surface of the flange (the side that bolts onto the head) to make sure its flat now right? Well then again you'd have varying thicknesses in the flange....


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## Chuck (Nov 19, 2003)

its smooth, just the pictures suck butt.like i said, if i had a better camera, i would have better pics.. i may make another manifold later on to complete this.. because my next step i wont have any pics except the finished project.. lol.. I can try to see if i can get pics up though.. ill try.. i never knew how hard it was to cut through scheduale 40 steel until today.. omg, id KILL for a die cutter (exhaust shop cutting thing).. 

as far as the flange is concerned, im leaving it 1 piece, and constantly checking the level on it, throughout its creation. to make sure its not warping..


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## NotAnotherHonda (Aug 7, 2003)

James said:


> cut some slots into the holes where the bolts go to help reduce warping like Javier did to his old manifold, you can probably find some pictures of it around here somewhere.



this is his old manifold...you can see the "expansion slots" here


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## Chuck (Nov 19, 2003)

i noticed that.. hmm it seems like a fail-safe method, i may have to go ahead and do it as well..


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## James (Apr 29, 2002)

NotAnotherHonda said:


> this is his old manifold...you can see the "expansion slots" here


why is that bottom stud not there?


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## wes (Apr 30, 2002)

FWIW my manifold has not been cut and it came off just as easily as it went on after some serious heat cycling. Although I have considered placeinga single cut in the center.


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## Chuck (Nov 19, 2003)

Man, I just went and got my manifold started.. totally different than what i expected.. wow.. Its still at matts house.. so i cant take pictures.. But the second i get it home, pictures will be taken.. lol. i dont know how i can contribute a How to.. but i can post total ingrediants used


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## NotAnotherHonda (Aug 7, 2003)

James said:


> why is that bottom stud not there?


yea, i know. i need to get that huh...theres no leak, but i still should get it fixed


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## Chuck (Nov 19, 2003)

on my old OBX headers, i couldnt get a wrench to fit the 2 inner bolts, so i never had 2 bolts on the bottom inner holes.. i didnt have any problems... but... your dealing with boost.. .. and if i have learned anything from years of reading.. Boost doesnt play


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## Chuck (Nov 19, 2003)

Making a write up.. right now.. on how this was done.. its almost finished..


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## Chuck (Nov 19, 2003)

http://chuck.nissanpower.com/photo2.html


Go there to see it (paint format.. lol)


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## javierb14 (Jul 9, 2002)

Paint is awesome :cheers:

side note.....you will want to clamp or bolt the head flange and turbine flange to a large mass when you finish weld it. this will help prevent the flanges from warping.


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## NotAnotherHonda (Aug 7, 2003)

did you tig weld all of this chuck?


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## Chuck (Nov 19, 2003)

I didnt weld, but it is still in process of being built. its only tac welded. (like 1 or 2 dots of weld, just to hold the pipe there) the demonstration super pimp show of the paint version is only for show, the actual manifold is still being constructed, its just under construction. lol. 

and javier, what do you suggest, some sort of bracket, attaching the turbo to the block? or the manifold/turbo flanges to the block?


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