Turbo manifold fabrication☺ trying to build my own..
 

Hello, I'm trying to fabricate my first manifold. Need a little guidance please. I need the dimensions for the flange as well as the tubing. If anyone has experience with this please share. I'm trying to go for a short runner type of manifold and it will be used with a BW 7670 EFR most likely. I'm not trying to copy by any means but these pictures are the closest reference to what I want. Any info will help please. From steel, thickness, flanges both sides, tubing, length, etc.... If I had the ability to buy one of these fine products I would. Believe me.BTW this will go on a 88fc t2.

There are many options as far as metal type, I'd say one of the cheapest and strongest is scheduled 40 pipe, you'd want to use 2 1/4 diameter. The turbo flange and engine flange can be bought from many vendors, one place is racing beat, another ebay or just google it.

the 3 rotor volvo build thread has a couple posts about machining this flange and the material he used.

look up Aaron cake as well he did a vid on fabricating a manifold on his cosmo build

I have always made my own. So heres some info fwiw.
I have always used mild steel flanges as its harder to warp them from what i was told but its still a good idea to have the flanges resurfaced flat.
I have always used 11ga (.120) 2" od stainless steel mandral bends from columbia. All tig welded and back purged.
For a 2 rotor its best to run 2 wastegates but you can get away with running 1 if your transistions are smooth with the flow and your gate is a good size.
Bolt on your flange to the block and position your turbo with the flange bolted to the turbo. You then can use some 1/4 rod to connect your flanges/ turbo in the spot you want. Then you can pull it all off and work off the bench.
On the first pic you can see how i mocked up the 20b's bw s480.
The very last manifold pic i attached is my very first and wouldnt hold anything lower than 14psi but that was on a 38mm wastegate.
The middle manifold picture i used a 50mm on that if i recall and it held 7psi with no creep and had it up to 30psi with no issues. But again dual wastegates is the best. And adding bracing never hurts.
I hope this helps its just what I have personally learned over the years.

Thank you very much for the info. Appreciate the pictures. Just a qs, where did you get the flange to the block? I wanted to fabricate my own, but I don't know the measurements. Anyone knows what are the diameters for the flange?

I have a extra sitting here for a 2 rotor and i suppose i can measure what you need. Or you could just buy a new one from racing beat, mazdatrix or off ebay and save the hassel of having to make one.

I'm not sure it's worthwhile trying to make your own flange, especially of you are only making 1.
RB's gorgeous 1/2" stainless flange is only $57.
https://www.mazdatrix.com/e3.htm

I prefer 2" piping on a 2 rotor. You will get faster spool and it flows more than enough. 316 or 318 stainless. I prefer mild steel to stainless flanges because they are more resilient against warping. The most important thing is wastegate placement. You want the wastegate runner to be as straight a shot as possible from the main runner. There are a ton of poorly designed manifolds that ask the exhaust to make a 180 degree turn or worse to get to the wategate. They have issues controlling boost.

Best design I cold come up with. Thanks for the hook up BTW to IRPerformance on the Wastegate and turbo Vband parts.:nod:

I just want to bring up a point about the use of bracing when fabricating manifolds.

I read an article linked from a welding forum (can't find it now though) about how just throwing in a brace can actually create a problem.

The premise of the article was that a properly designed and welded joint spreads the load over a sizable area and is very strong. Welding in a brace can actually concentrate the load into a much smaller area and promote cracking.

Another thing to consider is expansion from heat, a brace across a span of a pipe that gets up to or above 1300degF will have a greatly varying expansion and create stress/strain.

Now I don't want to condemn the use of bracing, it just should be analyzed and used judiciously. If you look at examples of manifolds from the top builders, you'll find bracing is pretty rare.

your welcome:icon_tup:

A properly built manifold shouldn't need bracing. The key is to use quality material and have good penetration. We have 10 years plus on one of our manifolds with a ton of track events and no cracking.

Thanks for all the input. Black mamba, with that flange can I just bore it to use 2 inch piping? I have access to CNC machines so that would be there only reason I would create my own. I would be running a BW 7670 so Im not worried at the waste gate placement.

2" id?

That's fine. The piping I use is actually closer to 1.9" id because it is thicker walled but its not that critical.

Would it be best to use mild steel or stainless? Anyone? For tubing and flanges.

For durability, stainless is better. However stainless is much harder, and if you don't have the proper tools and equipment, working with stainless can be a pain in the butt. Also, you need to TIG weld stainless, to get it right back-purging is necessary. Because stainless doesn't conduct heat well it tends to get more distortion/warping when welding.

I prefer stainless for all the piping. Either 316 or 318. The flanges I like to use mild steel because it is more resistant to warping. People get away with stainless flanges but then they make them super thick and it negates the weight savings.

Just curious if your annealing the manifold when using stainless or not? I posted a picture of my manifold and someone suggested I better anneal it. Thoughts?

If the welding is done properly I don't see why any heat treatment would be necessary.

Its not needed. The trick is to weld a little at a time so you don't overheat the metal. I also back purge. Although its overkill, I also have the flanges securely clamped to a flat metal bench. Either way I have every manifold faced before it goes out.

I'll just get it faced and leter EAT! Thanks for the words of wisdom very helpful.

Rxpower, I am currently building the same manifold that u are. I have the efr8374 IWG. The manifold you have pictured is from turbosource or turblown. Your flanges should be 1/2" thick and you should use either schedule 10 or 40 2" pipe. 2" pipe is all 2-3/8" OD. As the schedule goes up the wall thickness is increased. So the ID gets smaller. Turblown uses schedule 10 which is .109 wall. I will be using schedule 40 because I got a good deal on it. The hard part will be transitioning from the round to the rectangle. the ID of the round is.44 square inches bigger than the T4 port. Then you have to make room for the wall thickness in addition too. I worked in a fab shop for several years and can tell you it is best to stay with alike metals.Your welds will have less chance of cracking.I am building mine out of all 304 stainless. 316 is harder to machine and doesn't weld quite as nice. 304 will hold up fine.