Hey guys, I am doing a turbo G13b and was just wondering what material everyone made their custom manifolds out of. I was thinking i might have to do a log, is there much difference in lag between having the turbo as early as possible to being say 50-60cm away from the head? I'd suppose you would want it as early as possible??

If you want it to last forever and hold up the turbo with no other brackets then buy steam pipe and steam pipe bends. These are mild steel, thick and with ends chamfered for welding.

If you plant to hold the turbo up with some sort of bracket then you can make the manifold out of normal steel tube and mandrel bends (from any decent exhaust shop, truck muffler suppliers are best). This will be far lighter but it won't last forever and you may need to coat it inside & out with HPC ceramic. You'll also need your turbos bracket to allow for the expansion of the manifold and the consequent movement. Restrict this and it will break.

Don't go stainless unless you carefully research the correct grade and use the exactly right welding wire/gas combo. It will just crack on you.

Don't expect any noticeable lag increase with a 50 cm distance and a sensible diameter manifold. The volume will be about 2.5 to 4 litres. A 1.3 litre engine spinning at even 2,000 rpm will fill that volume in a very small fraction of a second.

M