the setup is a 2000 gsr with a drag turbo kit. recently ive been experienceing loss of boost when i shift between gears. it just happened out of no where. heres what it does:

i give it full throttle and i get full boost (8psi) at about 4k like normal all the way to redline. but when i shft the boost would drop to about 5psi. and it slowlys rises but barely reaches 8 psi by redline in that gear.

this also happens when i down shift...it would reach 8psi quckly and stays there but when i shift it does the same thing and drops to about 5 psi.

it doesnt matter what gear i start the initial boost at...i lose boost when i shift.

this just happened rescenlty..and i dont know what the cause is because i didnt mess with anything. i checked everything i could and everything seems normal. i assumed it was my blow off valve letting too much out but i checked and it wasnt loose or anythng. by the way i have an hks ssq blow off valve that came with the kit. any suggestion on what it might be?

 

anything, anyone?