Making a exhaust manifold???

[4g63telantra]

I was thinking of making my own exhaust manifold for my T4 set up.

Just wanted to know if anyone has ever tried making one and if so what problems did you run into and also what stuff should I look for before making one.

Is a Mild steel set up good?

 

[thjones3]

I haven't made a manifold, but I can tell you from general welding experience, you will have a problem with the flange on the engine side warping (and thus possibly causing exhaust leaks). You will either have to find a way to fix it to something (like a jig) to minimize warping, have it machined flat after you weld it, or both.

 

[awdrst]

Make sure you use thick flanges at least 1/2 inch. ALso i'd suggest going with mild steel flanges as the ss ones tend to expand and rip studs off at the head. You can go with stainless steel sch 10 pipe from McMaster carr they are cheaper than the mild steel versions. From my experience with making manifolds its easier to measure for clearance and make a jig to hold both of your flanges in place. This will reduce warping and make it easier to tack all of the piping together for fitment.

Are you planning on making the merge collector yourself or buy one premade? I'd suggest if you are going to make it yourself go with a equal length or as close as possible. It should help spool up a touch.

Are you planning on mig or tig welding it? Both will work I usually make all of my tacks with the mig and then tig them for the final weld. Make sure you backpurge so you don't get any sugaring that can flake off and take out a turbo, this will also make the weld stronger.

 

[GVR4592]

I haven't made a manifold, but I can tell you from general welding experience, you will have a problem with the flange on the engine side warping (and thus possibly causing exhaust leaks). You will either have to find a way to fix it to something (like a jig) to minimize warping, have it machined flat after you weld it, or both.

Bolting the flange to a jig is a good idea, a 5/8" piece of steel works well. Just drill the holes and bolt it down before welding

ALso i'd suggest going with mild steel flanges as the ss ones tend to expand and rip studs off at the head.

If you drill the holes progressively larger, the farther you get from the center of the manifold, you won't have any problems with shearing studs.