This will cover 'every' type of engine to use in differing environments: these being ATM and VAC and both. Doing research on each engine in desired situations is important, and with most runs Runners use either (Mammoth or Vector engines). To layout the foundation for which engines to use I confirmed the Mammoths to be best in terms of T/KT in comparison to other engines, the next higher performance engine is actually not the Vector, but the Skipper and Mainsail engines. Present Info on the Vector engine and the two other better engines, it is important to identify 3 values [ATM(A), VAC(V) and AAV] value. ATM is Atmospheric T/KT performance, VAC is Vaccum T/KT performance and AAV which is AvgAtmoVac which is used in environments evolving both Atmosphere and Vaccum.

The Vector Engine has an (A) value of (192.25), (V) Value of (212.5) with an (AAV) value of (202.375) performance when in atmospheric conditions.

The Mainsail Engine has an (A) value of (230.18), (V) Value of (266.66) with an (AAV) value of (248.42) performance when in atmospheric conditions.

The Rhino Engine has an (A) value of (191.83), (V) Value of (218.75) with an (AAV) value of (204.29) performance when in atmospheric conditions.

The Mammoth Engine has an (A) value of (246.77), (V) Value of (283.33) with an (AAV) value of (265) performance when in atmospheric conditions.

To conclude Vector is a hybrid of the Rhino Engine Better at ATM but worst at VAC. The Vector AAV performs worst than Rhino. This means the Rhino is better when changing ATM and when in a vacuum it is still better than the vector making the Rhino better overall it scores 2/3. What will surprise most people is the [Mainsail engine's] performance is near to the Mammoth engine and is 20%~ better than Vector and Rhino. Mainsail scores 3/3 compared to Vector and Rhino. However, it should be noted it doesn't make the Mainsail better it should be used in consideration as a second choice for landers and such. The values do not change with additional engines (all of the engines have been ratioed 1:1). Finally to state you should only use Mammoth engines if you want performance but the Mammoth will have much lower stability and in a future post I will discuss stability to elaborate on better engines to choose. Order of Engine Power [Mammoth, Mainsail, Rhino, Vector]

This post is in reference primarily to Kerban Death% since you need to balance this value with, TWR and many other variables instead of overall. Just to clarify.