Exhaust manifold design

[zx_volcane]

There's guys out there making 1200hp+ on log Manifolds... There's not much point IMHO in going for equal length and I just never trust tubular Manifolds, they always crack unless you spend an insane amount of money on them...

As piggy said, check out SteedSpeed - that's the sort of idea I'd be going for, two halves of machined steel and then just welded together, no issues with cracking, strong, you know what the internals look like... Perfect, there's people making insane amounts of power with them and they aren't massively expensive and with some work you could design one yourself, no point in worrying about primary lengths, the cam profile of a diesel and the fact they don't spin that fast means that it has little effect, especially on the exhaust side..

That's my opinion anyway...

Have been discussing this with Paul for my next turbo, prob going for a log manifold if he can knock one up

Know all too well about cracking though, my current gearbox manifold has cracked twice which is annoying, but its under all sorts of heat cycle and vibration stress.

But for something you can do in your garage with a welder and some scraps of metal its a great way to go.

CNC machined mani looks amazing, its just getting access to the tech or having know how to design one and knowing someone that would put it on their machine for cheap rather than having to pay a company setup just for one run.