i happened on this thread searching boosted-hybrids site…a very imformative thread on side load being cause more on R/S then actual Psi running…im still trying to soak what all was said but here is the link
i think it’s because you can run x:1 low compression and the resulting peak pressures, loading, or final whp can be different. imagine 14:1 n/a making 220whp vs 7:1 + 10psi making 175whp. the n/a motor probably has greater cylinder pressures. now imagine 13:1 + 5psi vs 7:1 + 10psi. the first one probably has greater peak pressures. so it’s not enough to say “x” amount of psi since there are so many other variables.
of course in reality the majority of us run similar setups so we usually just spout out typical numbers instead of explaining how, what, and why.