Its not a secret. Piston rings wont last long over 25psi.
Rods bend around 600ftlb.
Any knock event, hot ambients, lean fuel all help to shorten the engine life.
This is nonsense. I've run well over 25 psi for 3 years on GC turbos and 23 psi on stockers for many years before that.
Firstly 25 psi tells you nothing but the restriction air flow is encountering at the TMAP.
Secondly 25 psi at 13 degrees of timing is very different to 25 psi at 3 degrees. You can run pump gas on that.
Thirdly 25 psi on a stock turbo is very different to on a 19T or a single.
Also it makes no account for the charge temps. An intercooler thats too small, bad fuelling etc will all make two cars running the same 'boost' very different.
Rods will bend at high torque but they will be alot more likely to bend if running high torque at low rpms.
So people shouldn't assume over 25 psi will mean a dead engine soon...