Squad did a bit of adjusting to most of the upperstage rocket engines too. LV-909 among them, has a whopping 15 kN max thrust at sea level. They did increase the max vacuum thrust to 60 kN though. For realism, they nerfed vacuum efficient rocket engines to the point of making them next to worthless on planets with atmospheres. I found out when I cratered my moon lander, returning to Kerbin on her maiden voyage. I needed those LV-909s to assist the parachutes when landing.
Looking into the files I notice the ASL = 85 for the 909. What caught my eye was that 85 ASL showed up in several other engines. It may just be a coincidence. But there are inconsistencies with the other engines that are similar in use.
The Ant inline LV-1 vs the Ant radial LV-1R. The inline ASL is 85 but the radial ASL is 260. Quite a difference for very similar engines wouldn't you say?
Now lets compare the Rockomax 48-7S inline vs the 28-77 radial. The inline is ASL is 270. Thrust got nerfed to 18 though. The radial ASL is 250. Thrust 16. So why do the Ants get an atmos nerf (not that they were of any use) but the rockomax duo does not (other than a thrust nerf)?
Where else does 85 ASL show up? In the Poodle engine too. Which brings me to the only other engine that sucks at sea level. The LV-N nuke. ASL of 185! What there is a 1 in front of an 85! This is purely conjecture on my part but could it be that it is possible someone forgot to put a 1 in front of the other 85 values as well?
Why are they so similar? Would it be that easy? Change the 85 into a 185 gives a much needed boost at landing without the ability to take off again. Sqaud claims those engines were overpowered to begin with and needed to reflect reality.
The exception to the rule is the Aerospike. It's thrust got hit with the nerf bat too at 180 kN. It matches the RAPIER with liitle variance between atmo and space.
Let me get this straight. There is a tiny solar system with very tiny planets. On one of those planets live Kerbals. This planet is only 600 km in diameter yet has gravity and atmospheric pressure equal to Earth's. Kerbin's water is a super-dense medium that is nearly impenetrable. And Squad want's to make rockets realistic.