The term "OP" is too OP because it renders anything OP. Therefore we should nerf the term OP. Greg, get on that.
Wow. If you can get 4X's your energy from using crummy combustion engines I wonder what kind of energy multiplication you could get using a liquid fueled boiler?
As someone above said, this is due to how I derived the math. The problem is that because there's like 20 different ways to assign "equality" between any two mods' power systems, that means there's 20 ways where somebody might do things different and wind up with an unbalanced ratio (in the sense of "too heavy on one side", not OP/UP). There isn't a lot I can really do about this, but that's why the ratios are configurable - if you as an admin (or pack creator) are worried about one of the infinite power loop exploits, just run the ratios downward until the conversion is lossy enough that it doesn't work anymore.
Or just slap your players if they build one of those things.
Honestly, if the oil fabricator DIDN'T generate a positive energy loop, what would be the point? Oil is only ever useful as a form of energy. Creating a system with multiple machines (fabricator -> refinery -> engines e.t.c.) that burns energy to create exactly the same amount of energy is the definition of futility. While setting up a system that increases your yield due to time and effort spent setting up the build make a great deal of sense.
what I read so far:
1. energy storage (something that isn't quite possible with buildcraft alone, and expensive with TE)
2. energy conversion (set up a nuclear reactor and watch the system producing oil out of EU)
and the system is (as energystorage) more powerfull than a MFSU. 1,5 million EU for 1 bucket of oil, one standard BC-tank stores 16 buckets... 24 million EU in just one block with 8 glass...