Your mod is phenomenal and I love your capsules. The engines are 100% broken though. With the biggest 11 kerbal capsule with only monoprop, 1 mrs 2.5 meter decoupler I made 3.75 with tweakscale, 1 S3-14400 tank (the big stock 3.75), and one 2800 kn Skywipe, I point straight up (relative to ksc and center of kerbin) and achieved an escape trajectory.
This seems like it should be fixed