So that's my problem until 4500 rpm i got 8 psi and then i got 5 psi that's about 1 week (around 15 hours)that i'm seeking why

at the beginning that was happening only in first gear and sometimes in second too but now it's always

 

what do you mean one week and then around 15 hours?

 

Look for leaks in the rubber parts starting at the turbos, going to the intercooler, and throttle elbow. Take them off the car, remove any shields, and stretch them to show any cracks. Also check the hoses leading to each blow-off valve, again looking for leaks. Again, remove them from the car to inspect them.

After you've exhaustively searched for boost leaks, then look around the UIM and pressure tank for loose hoses or broken check valves.

 

Check for vacuum leaks, a vacuum gauge will be your best friend. Replace all of the stock check valves, this can be done for around 20 dollars. Just check everything.

All you really have to do is follow the instructions on this site.

http://www.autosportracetech.com/RX-7/rx7stuff.htm

 

I mean that's doingit for one week now and i worked on to find the trouble for 15 hours