N75 backing off the boost

[gti_shaun]

right been having boot problems for a while now, i can stick my foot down and it goes to 21psi then as revs rise the boost drops off sometime worse than others, ive had it leak checked etc and even made a tester and put 21psi in my system and its all air tight, anyway i rigger a camera up to watch my actuator as it had to be throwing my boost(turn your volume down!) http://www.youtube.com/watch?v=Xjmg8qk3gYU

the audio is to slow(youtube for you) but as you can see it is moving as the revs rise, so the n75 is doing this, i have a (F)version (New one aswell) it had (C) version when mapped(when it was rapid.lol)  i have ko3s so should i have the (J) version, my head is a mess with this weird fault, im thinking it must need a diffrent valve to keep the boost there to redline?? HELP ANYONE!!!

[jimmyGIT]

Hello.Mines the same m8. aum stage 1 r tech.jus not like wen it wa mapped.First few days,AWERSOME.Today i have changed my n75f for a new 1!!Didnt even bother with h,j,k versions.It was mapped on f so in opinion stick with the original from what i have read.TBH theres no difference  runs super smooth,not as rapid though!Just maybe needs a service after the mapping? mines was mapped 6 months ago .still pulls well but like you say not as rapid  :undecided:let e know if you get any results cheers.

[Hulmie]

Im running a R-Tech map on a AGU engine fitted with a K03s Turbo

Boost peaks at 22psi but the drops off to 18psi and holds. This is how it should be.

[topher]

have you tried taking the n75 out of the equation to eliminate a weak actuator spring?

[gti_shaun]

yeah if i clamp off the actuator pipe it boosts like fook, what can cause the n75 decide to back off the boost? pinking or engine knock or if it was pinking would it give nearly no boost?

[ggggolfgti]

i have the same issue, stage 1 rtech gen4 map, but my turbo is blown so dont drive with foot down, im doin a k04 upgrade very soon so im hoping after its complete the problem will be gone, my boost drops as the revs increase so i just assumed as my turbo's blow it was just struggling to create more boost to feed the engine as the revs increase

[gti_shaun]

when you say your turbos blown, is your car smoking? or do you have excess play in shaft?

[ggggolfgti]

smoking when ticking over for a while, like when im at traffic lights or traffic

[ggggolfgti]

you say you clamp off the actuator pipe?? have you floored it at high revs when clamped?? did it still hold boost?

do you have a boost gauge?? what boost did it hit when clamped off just curious

[gti_shaun]

i cant remember if it holds when clampted, i hope so or else id say my turbo was at fault, i will go do some testing in a bit if i can.