please help on this topic

hi this is what im doing i have a 200tdi fitted in a rangerover classic bobtail. now i have rebuilt the engine and i have staged the turbo by putting a bigger compressor wheel in. now im told i need a dump valve to release turbo build up pressure. so ive brought one for a td5 off ebay as the guy doing the turbo recons i need one or it risks damageing my conrods because of build up of boost. now i got another friend who looked today and said because i dont have a throttle body i wont need one buy did say i could fit a manual pressure realease valve. so do i need one or not as im told people fit turbos off 330 tdi on 200tdi and the 200 runs at o.8 bar and 300 runs at 1bar .now my friend said my turbo is out putting 12psi and he is putting it up to 20psi. .im confused of what i need to do can some one help me out plz.

your turbo already has an adjustable waste gate to limit max pressure ,and you havent got a throttle butterfly to stall turbo when throttle closed so why would you need dump valve

hi martyn . idont know i know nothing on how boost works. i now how to rebuild them which ive done and the idea was a friend who recommended to up grade turbo boost. as he said it would give more power but said i need a dump valve. this is y im on here asking the question for the right advice as i dont want to damage my engine after all the work ive put into it. so your saying i will beable to bolt it straight on and the vacume actator will deal with any excess build up of boost.

sorry the waste gate will deal with excess build up of pressure.

if you fit a boost guage you can see and set max boost ,how are you going to drive it ,flat out up and down motor ways or ?

i do a lot of off roading and just want more pick up from stand still. also to help when towing my car trailer. ive done all the pump adjustments and altered the waste gate adjustable bar. did that sometime ago and made a great diffrence.