Compact Efficient 3x3 Fuel Engines 2023

I wanted to share a fortress with four different high efficiency, high power density 3x3 fuel engines that I came up with, two of which have a variation for a different orientation of exhaust. Also includes two small example engines that form the basis of these. All four of my engines - and the variants - are sort of hybrids in that they combine high power density engines with high efficiency engines through exhaust-sharing. That is, each "engine" is made up of multiple engine blocks and is effectively more than one engine mashed together. Through my experiments, it seems having the exhaust of a high power density engine pass into the input of a high efficiency engine results in higher than normal efficiency and power density. CALCULATING THE VALUES Because each of my engines are made up of multiple engine blocks, the way to determine values like Power Per Material and even Power is not at all straightforward. Unlike with engines with only 1 engine block, you can't just, say, look at the 'Fuel engine overview' window to find such. Nor can you just take an average of the Power Per Material for each part. Moreover, I've discovered that the "Volume (cells occupied)" in the 'Fuel engine overview' is unreliable and buggy - at least with engines that have multiple engine blocks. Here are my calculations: Fuel 5559horiz 3x3x13 5559pwr 52ppv 474ppm 4x horizonal exhaust 4140. 9pwr + 709. 1pwr + 709. 1pwr = 5559. 1 total power 9. 6 material/sec + 1. 06 material/sec + 1. 06 material/sec = 11. 72 material/sec total 5559. 1pwr / 11. 72 material/sec = 474. 3 Power Per Material 26 blocks + 7 blocks + 9 blocks + 7 blocks + 9 blocks + 7 blocks + 9 blocks + 9 blocks + 24 blocks = 107 total volume 5559. 1pwr / 107 blocks = 51. 95 Power Per Volume Fuel 5559vert 3x3x13 5559pwr 52ppv 474ppm 4x vertical exhaust 4140. 9pwr + 709. 1pwr + 709. 1pwr = 5559. 1 total power 9. 6 material/sec + 1. 06 material/sec + 1. 06 material/sec = 11. 72 material/sec total 5559. 1pwr / 11. 72 material/sec = 474. 3 Power Per Materia