Building a steam pipe manifold???

[wasfishing]

As there aren't many off the shelf turbo manifold options for the aw11 I thought it would be a good idea to make my own custom one. I have access to mills and a few good welders at work so the actual construction of the manifold shouldn't be a problem. I'm just not to sure on the actual design of manifold I should go for, is it worth trying to make a equal length runner design or is it more trouble than it's worth? What's the best type of bend to use I was looking at this on eBay

WRX SKYLINE VL XR6 sr20 TURBO MAKE YOUR own "STEAM PIPE" extractors/manifold


What sort of a weld is better tig or arc?

Any help that anyone can give me would be great

Cheers shane

[TERRA Operative]

Forget arc for this application, it's a toss up between MIG and TIG, basically whatever your welder is better at, but TIG would give better control and better finish.

[ajansen]

I went to a local metal wholesaler and bought heaps of 90 degree bends and some 45 degree bends and 2 meters of straight pipe. I tig welded as much i could and stick welded the rest. The tig welds are nicer and none of them leaked when Heavily sandblasted.

[Supra967]

Mig, tig is too slow. Steam pipe is thick as so easy to weld.

If you're work has mills and welders chances you have an account with blackwoods or a steel supplier? Go through them, it should end up much cheaper than the common man supplies on ebay. Buy something over 2mm thick, whatever schedule that is. Thicker will hold heat nicely but you'll loose I.D and cost more.

Keep design simple. Equal length not so important for a turbo, they seem to care more about getting the exhaust out than getting it in. If you bother with equal length you're best off going through the whole exhaust theory to work out what RPM you want to work best, otherwise it's just a guess and get you no further than a simple design.

[wasfishing]

yeah we hav an account at blackwoods ect so that might be the way to go, would it be better to arc weld flanges and then tig the rest of the joins? wot size pipe do people usually go for?
My mate is going to water jet me the flanges out of 10mm plate.

[Supra967]

get 12 if they have it, bit of extra strength won't hurt. Make sure you bolt the flange to something flat before pumping heat at it, minimise warping. Ideally you have a chamfer on the engine side of the flange and insert the pipe all the way through, weld the engine side and mill flat. A couple of extra strength welds on the o/s of the flange and you're right.

I'd mig the lot, anything over 2mm. TIG is great for control on thin stuff but you can throw a bit of heat at the bigger pipe. Don't weld yourself into trouble, make sure you can reach the last couple of spots when you're putting it all together. Mig is a bit friendlier in that regard. Don't use stick, you'll end up will porosity which will really love heat.

[Indelible]

you want the smallest inside diameter steam pipe that will support the power your after to keep velocity up.
for my vvti 1jz i had a manifold made in 32nb steam pipe (actual inside diameter was around 33mm) was good manifold but
my manifold guy wanted to do some testing and made another manifold same design out of 25nb steam pipe ,which had 28mm inside diameter,
around 2.8mm wall thickness i think on both sizes

(vvti 1jz exhaust ports are tiny 29mm round ports so closest to their size)
and i gained about 250 rpm quicker spool and around 20hp more throughout the whole rev range
made the car much nicer to drive

anyway here is the 32nb mani



and this is the 25nb one



and dyno results red line is 25nb , green line is 32nb

[the_random_hero]

Mig, tig is too slow. Steam pipe is thick as so easy to weld.

If you're work has mills and welders chances you have an account with blackwoods or a steel supplier? Go through them, it should end up much cheaper than the common man supplies on ebay. Buy something over 2mm thick, whatever schedule that is. Thicker will hold heat nicely but you'll loose I.D and cost more.

Keep design simple. Equal length not so important for a turbo, they seem to care more about getting the exhaust out than getting it in. If you bother with equal length you're best off going through the whole exhaust theory to work out what RPM you want to work best, otherwise it's just a guess and get you no further than a simple design.

Whaaa? I've never seen a good, well designed manifold that didn't have the majority of welds done with a TIG (and I used to help build them).
Equal length is not important, in fact unless you've done a considerable amount of testing to get lengths right a mixed-length (within reason) manifold will perform better. The whole process of building a manifold is pretty easy, it's just a bit time consuming.

[The Witzl]

I agree with random hero. All the fabricators I've EVER spoken to use tig when welding up manifolds. Maybe you just need a better tig welding machine, or a better welder.

[Supra967]

yeah i can't tig that well, but it's well slower than MIG. Not saying MIG is a better weld, looks nicer or whatever, but if the guy is here asking what type of weld to use he probably isn't the sort of pro fabby that you guys are thinking of, or ever helped build manifolds. Apologies if assumtion not correct, by all means TIG if you can, MIG if you can't. Result will be the same (apart from looks)

Great info on the pipe size up there too.

[e30-323ti]

you want the smallest inside diameter steam pipe that will support the power your after to keep velocity up.
for my vvti 1jz i had a manifold made in 32nb steam pipe (actual inside diameter was around 33mm) was good manifold but
my manifold guy wanted to do some testing and made another manifold same design out of 25nb steam pipe ,which had 28mm inside diameter,
around 2.8mm wall thickness i think on both sizes

(vvti 1jz exhaust ports are tiny 29mm round ports so closest to their size)
and i gained about 250 rpm quicker spool and around 20hp more throughout the whole rev range
made the car much nicer to drive

anyway here is the 32nb mani

and this is the 25nb one

and dyno results red line is 25nb , green line is 32nb

Great info on the pipe size up there too.

+1

Glad to hear 25nb worked well in a 1JZ as I've built my manifold (6-2) with 25nb primaries & 32nb to the turbo.
25nb worked well on the TT head also, as you can angle the outer runners to match the ports (with a fair bit of die grinding on the water cut manifold flange)

[Commotion]

e30 i like what you have done there. I tried some ideas, doing something similar with the runners matching the ports but couldnt get it to work with 32 pipe. obviously it works well with 25.

Here is one i'm building for myself, still havent finished yet. The rust repairs on the 28 has taken most my spare time. I copied a full race design and used DN32 pipe and elbows purchased from Onesteel or affiliates. Its meant for a GT42 but im thinking of going to a smaller turbo, t04z or gt40 to run smaller ic pipework as to do less body mods.



also for reference T3 1j & T4 rb manifolds.