Thread: DIY Turbo Manifold

The only thing about stainless is you have to back purge it when you weld it. I don't know if I have another tank or a spliter to do that.

there is a pasty kind of chemicle you can get and you apply it with a brush on the inside of the pipes before you weld and it helps to make sure you welds penitrate good and seal everything up , major purpose behind back purging is to keep the area nice and clean and ensure good clean welds and less splatter on the inside of the construction.

Happen to know what its called? lol So I can technically weld Stainless without anything on the backside it just wont be as clean?

321 is a waste of money. Too expensive. I used 304SS SCH40 and it holds up amazing. If you want a SCH10, go for the more expensive stuff, but overall the SCH40 is stronger. The ID is a bit smaller, but perfect for up to 800whp. Just my opinion, of course.

When I was looking into 321 it was going to be a lot more expensive to make my mani from that stuff. It handles heat really well though.

So I took a look over ASP's website, all he sells on there is 16 gauge tubing... is this what he uses on all of his products? Seems way to thin to me.

You will get little mountain looking things (forget the technical term) from the lack of shielding gas (back purging) when you go to weld it. Not good for airflow.

Looks like this inside the pipe:

On a small, tight manifold I would use stainless sch10 pipe in 1.5" or slightly smaller diameter (bigger is not necessarily better or will even fit). I would not recommend a mild steel manifold. Where to get pipe? Ask danmartin, he'll know.
I reserve sch40 for larger (longer) manifolds that will hold a large turbo (lots of weight). Thin wall manifolds are great but you need to be a good welder and you need to heavily brace the flange with supports. Choose wisely.

blairellis posted a perfect picture showing what happens when you don't back-purge stainless. If you're willing to build the manifold in such a way that you can grind down those protrusions then you can avoid back-purging. I don't know the name of the paste that you can use instead, but danmartin has some and he'll know what it's called. I'm sure a quick Google search would find it as well.

read that honda tech section i posted. it has everything you will need to know and than some

I would start off with welding small things before doing a turbo manifold

Yeah that looks like crap. I've made a manifold in my fab class I had, even though it was just a little 2 cylinder lol, I know what to do just need the materials and what I can't do my brother is a certified welder So it's all good.

I will get the name of the stuff I was refering to, and I will try and get pics of a manifold a friend of mine built using this stuff, 1 of many actually with no problems. I understand the prupose of back purging and all that jibba jabba but it can be done nicely and correctly without.

321 ss materials may be mor expensive but for 5-7$ a weld el is not too bad in my book, and can withstand a lot of weight as well. in any case you
ay be better off with mild because it does not expand as much as ss when heated.