Originally Posted by
cobaltssoverbooster
if the turbo is bone stock then it wont appreciate more than ~24 psi for more than a couple of months. some people do get away with it but its not going to have customer longevity if that's important to you. the shaft overspeed will eventually kill it. the k04+ unit has a larger compressor wheel and died super fast for me at 26 psi. once the bearings started to deteriorate the heavier wheel expedited the process according to my turbo refurbisher. it was kind of disappointing but i recognize its an expendable unit and was beating the absolute hell out of that particular unit.
i did successfully run a 24 psi max boost for a year and a half. i tuned it to hold 24 psi for as long as the turbo flow would let me and then let it settle to 21-22 psi at high rpm where it just couldnt physically keep up. I know a lot of other tuners that tune for 20-21 psi and just let it rock out with a flat boost curve through the whole rpm range. doesnt peak torque as hard around 3200 rpm and save clutches/gearboxes. keeps intake heat build down a tad which is nice for cars that get beat for extended time periods such as auto-x or full circuit cars.
to go with that, i tuned my neighbors car for use at some hot desert tracks like seca and sedona. it was set at 18 psi because we wanted the endurance and it made iat a little bit easier to manage.
honestly just need to look at all the factors that come into play when you strain the turbo unit out and decide what you are willing to deal with and accept.