hany

how can i calculate the safe boost for any engine ?

Dweezil

There's no way to calculate it how much, it's trial and error. It's much easier if someones done it before you and saves you the trouble.

idiot-stick

keep turning it up until something breaks, then back it off a bit.

hany

its the perfect answer i hear at all lol

hany

i know it depend on the C R. but is there any equation to calculate it ?

St.Taint

It does not depend on compression ratio, it depends entirely on tuning. Otherwise there would only be one compression ratio used for every application. Generally speaking, almost all engines can handle some positive boost pressure over ambient (atmospheric). A majority of decently designed stock engines can at least handle a half an atmosphere of positive boost pressure which would be 6-8 psi since atmopheric pressure is 14.7 psi as is.