how to make a turbo manifold

[john]

was gonna throw this in the fab thread but figured it would end up getting lost. bunch of shitty pics of a manifold i made yesterday, took about 17 hours not including the collector which i made a few days ago. the purpose of this is just to show the people who dont know and to kind of document it a little because i want to try to write an article for a mag. also will help people learning to fab/weld because when i was learning there really wasnt much help out there so the initial curve was very steep.

first few steps i didnt take pics of but kind of goes like this:

* weld up a collector
* fit it to whatever turbo flange you are using
* weld the flange while its bolted down (i usually just bolt it to a spare exhaust housing)
* brace the collector to the head flange in the location you want the turbo (i have just made an L - bracket that bolts to the t3 flange that is reusable then just bolt a piece to that and weld a rod to the flange. very easy to do and easy to clean up when done

* start on the first runner. doesnt really matter which one just make sure you have an idea of how everythings going to look in your head before you start

heres my first runner ready to weld. it is very important to bevel all the pieces at least 3/4 of the way down to make sure you have good penetration. it is also important to have all of your bevels consistant in width and depth as this will make the welding look much more consistant when finished.

also a few pics of my purge T and kind of how i purge when im welding the runners. also a pic of the champagne nozzel i use on the torch. the wide nozzel really helps on pipe to get more gas coverage during each pass. each pass i make in pipe is sually about an inch as a time.








oh, also a pics of the pipe before and after wire wheeling. i do this after mockup of the runner right before its welded.



then on to the next runner until all 4 are done and tacked to the collector and head flange.








on longer runners where i know there will be a tendency to warp i will actually weld half od the runner before completing the other half. this help to reduce making changes after welding.



another post....

[john]

[john]

after the four runners are tecked on just throw it back in the car and double check everything to make sure nothing moved.






next step is to decide which runner would potentially be the most difficult to weld at the collector, and which would be the easiest. obviously do the hardest first and the easiest last. i usually start with leaving two runners on after braking off the brace just incase anything happens you dont lose the flange location. i also put a few VERY solid tacks at the head flange for each runner before completely welding to the collector.

i also usually switch to a smaller nozzel for around the collector as the space is usually much tighter.







after the runners are welded to the collector the head flange is bolted down to a plate for final welding.



after it cools i remove it then weld the inside of the runners at the head flange.

on cars like this where space is abundant i wll sometimes actually make the downpipe before the wastegate. also when the wastegate reroutes into the downpipe this helps for have accurate wastegate placement.




then add wastegate







im sure is skipped some important parts for begginers so just let me know if theres anything else you need covered. i was also thinking about doing a simple welding post to show what welds look like in different conditions to help identify problems. ie: too hot, too cold, not enough gas coverage, contamination etc.

[john]

[CJ]

is that a rwd 4g63?

[CJ]

[john]

yeah eclipse motor, evo intake, in a starion. built motor should make around 550-600.

[john]

[zach from NY]

Can I just come live next to your garbage cans like a raccoon and you can teach me to do this insanely awesome shit?

[zach from NY]

[Stevieg]

thanks john, some awesome info in there. some examples of "wrong" welds would be excellent!

steve

[mmmjesse]

Id like to know reccomended pipe size/quality for manifolds.  Also, say you only have access to a mig welder, any suggestions for welding a manifold with  mig?

[mmmjesse]

[john]

The industry standard is sc10/40 304 pipe. The biggest problem with welding stainless steel with a mig is the lack of post flow control. This would cause the welds to become slightly contaminated right after you release the trigger. If you only have access to a mig then I'd reccomend using mild steel pipe instead of stainless. Or find access to a tig.

[john]

[mmmjesse]

I have access to a tig.  its a newer miller machine but its a lower model so i dont know how well it would do or if it could do the sc10/40 pipe.

[mmmjesse]

[Ash]

I have a HUGE boner right now.

[Ash]

[Primo]

Just stopping by to say you're rad at what you do.

[Primo]

[ECDA]

I'm gonna sticky this, and if anyone wants to do any more cool how-to fab posts, i'll sticky that too. ya heard?

[ECDA]

[john]

I have access to a tig.  its a newer miller machine but its a lower model so i dont know how well it would do or if it could do the sc10/40 pipe.

 the runners usually take about 60-70 amps to weld because of the bevelling, the flanges require a bit more, usually about 120-160 and ill usually make about 3 passes around the turbo flange to kind of preheat as im welding. so maybe a 60 amp pass, then 90 then full heat. the head flange just gets one heavy pass because i actually dont want to put too much heat into it to reduce the warping and stresses. the turbo flange is where cracking is most likely to happen so to me it is the most important weld on the manifold.

oh also to reduce warpage on the turbo flange i actually tack a few spots on the outside, then completely weld the inside. then let it cool and bolt it down, then weld the outside retorquing the bolts between each pass. ive found this gives the flattest surface after finish welding. most of the time it wont require and surfacing or belt sanding.

[john]

[mattycakes]

my jsp manifold is one of my favorite things on my car

[ThrwnSprkz]

wow, this thread kinda made my day.
& Id love to see a bit about right and wrong welds.

love your work

[ThrwnSprkz]