Factorio Forums

I did some experiments using molten metals instead of metal plates on the bus.

I found that a single pipe can transport about 80% more than a single express belt, it can go underground so can be braided with non-metals that may be on your bus and it should be better for performance (from what I've heard).
You can see the output from the express belt on the top and the pipe on the bottom. The lamps read out how many items are on the belts, although you can't see them flicker in a still image the 80% is bit of a guess.
(Both input lines had more than enough input to overload them.)

What's the equivalent of one pipe of fluid metal to blue belts throughput-wise?

With pumps 1 pipe can carry about 120 fluid /s ~3blue. More realistic are 80/s =2 blue

IIRC it took 3 regular vanilla-pumps to fill an iron pipe. What pumps, how many per pipe and what type of pipes did you compare with?

The actual maximum flow through the pipe is determined by piecewise decay functions and the length of the pipe, as well as the fluid values defined in the Lua prototypes. At a flow of 60/0.59 units/sec (~= 101 units/sec), the graph has a discontinuity where the two piecewise functions join, and is followed by an immense drop-off in value: at 100 units/sec, you're looking at about 200 lengths of iron pipe; by 120 units/sec, merely 14 lengths of pipe. This WolframAlpha graph should show you the graph (note that the x axis is in units/tick, not units/sec).

I'd give the maximum flow in the pipe at 60/0.59 units/sec, given that said unit provides the inflection point on the graph, and the flow is pretty good. Note that this only applies for the pipes with "normal" capacity--although you'd best stick to those pipes anyways (larger pipes actually admit less fluid flow, and smaller pipes end up exhibiting very odd behavior at low fluid rates, and have lower maximum lengths at high flow rates).