I wanna build a manifold. Help?

[Gamble97]

So I think urbansmokers build has inspired me to build a turbo manifold. I've been wanting to do it for a long time and think it will help me with welding stainless.
So questions/comments/concerns.

I should use sch 10?
What size runners, 1.5"? 304 or 321?
What type of bends? No idea on a design just yet, something simple for my first attempt, but I want someone to run it since I don't have a dsm.

What's the major difference between these 2 head flanges
Mitsu 4g63 CNC Machined Exhaust Head Flange | eBay

4g63 Exhaust Manifold Head Flange 1 1 2" Pipe | eBay

Does that piece in the middle help with anything?

Probably going to start with this collector to start.
OBX Turbo Collector Merge 4 to 1 w T4 Flange | eBay

On a headflange that has the stock size opening, how do you form the piping to fit? I'm guessing a hammer and some heat?

Best place to buy some sch10 piping? And best way to cut them into small sections if needed? Don't want to hold them down that close to a saw blade and they aren't very long to begin with.


Thinking parts (depending on where I find to buy piping) should be $250-$300. And maybe if it comes out well I can sell it for a small profit.

Since I'm pretty new with stainless, how do I ensure no cracking will happen? And how do I know how many passes to make? You guys make your bevel after a cut with just a belt sander?

I know it's a shit ton of questions, but any help in the right direction would be key.

Not sure which machine I'm going to use for this, probably the HTP 221 and some 1/16th tungsten and 1/16th filler. Should i use 308L or 309 filler?

 

[bastarddsm]

AMS used to have some killer flanges that were investment cast 321 with the transitions already in place.

Stainless is pretty resilient to heat, so I wouldn't worry to much about cracking as long as the materials are decently thick.

 

[Slow95gsx]

Sch. 10 1.5" is the most commonly used. Ace stainless is where I get all mine from. Making a merge collector is not hard, can be done with a simple chop saw or a decent bandsaw. There are how to's on Honda tech to give you am idea on making a jig. I've always used my Syncrowave 200, but I recently switch to a htp 221. Nothing but good things with it so far.

 

[Gamble97]

I was just using my htp 221 to do my friends intercooler pipes actually. Love this thing!
Ordered the flange and 1.5" 90 bends from ace stainless. Only thing that sucked was $25 in shipping WTF
Just need a collector now. Nobody makes one all welded up for less than $100. I hate my chop saw also. But maybe it's worth a shot.

 

[silvreclips]

I used a band saw to cut the pipes for the collector. It was a pretty big PITA. Also just used a cut off wheel on an angle grinder to cut the pipes to length for the runners and then beveled the ends a little bit.

 

[Gamble97]

Any pics of your jig that you used to hold it on a bandsaw?

 

[2gdanny]

hey i came across this page last year when i was trying to make a friend of mine a manifold for his Honda, i was going to make a jig like this, get it cut and tacked with a mig welder and get it tig welded by a friend.

we ended up just buying one as i didn't have time for fab work.
this thread is very helpful
VWVortex.com - Building A Turbo Manifold...Step By Step