hi guys & gals,

i have a question regarding the relationship between increasing the amount of boost versus the stress place on a turbo and the average life span of the turbo.

Is this relationship linear or exponential, or both. By both i mean, for examples sake, linear between 0 - 1bar, then exponential from 1bar onwards.

I also noticed that my turbo at 0.9bar in my 1998 wrx, when i accelerate (but not fully flooring it) the noise from the turbo spooling up is a loud whining sound (something like a jet engine starting up, but not as loud). this sound was not really loud when my boost was set at 0.8 bar. Is this safe for the turbo to be making this noise, or am i pushing my stock turbo too much.

For those wondering why i said my boost was at 0.8 bar before, my ECU is running in safe mode, thus stock boost at the moment is 0.5bar, however i had up the boost using a maunal boost controller for the time being.