I'm new to this forum and also new evo x owner... Only had the car for 3 months I'm second owner.. Just installed cobb evo x stage 1 lwr v403 and and I did a couple pulls and my max boost is less then 13psi on 4th gear... Prior owner seem to have bolts ons and decided to put everything back to stock to trade it in... Any ways my opinion might be oem boost controler lines not on right... Any one else wants to give me some pointers where and what to look for???

 

v400+ requires the OEM boost pill to be put back in.

The original owner probably didn't put it back. Locate it using the cobb documentation and ensure it's there.

No boost pill on v403 will result in lower boost pressure.

 

That's exactly what I think is the problem... I check yesterday and car has no restrictor pills what so ever.. I will have to go to dealer to buy vacuum lines with all restrictor pills in them.. Thanks a lot men