Hi all, I'm new to the forum & i'm after some help/advice please bear with my descriptions & the answer to my issue maybe at the end but i just want to double check im not missing something before i bite the bullet.
2006 BWA. Ram air oversize induction kit. Down pipe/De-cat. Stage 1.
Parts replaced in the last 2 weeks, Revision G valve, Brand new intake manifold (original cracked) & digital boost gauge installed.
Background - The Ram air induction system is extremely loud and the boost release sound (excuse the description) is very distinctive & loud, i was driving an A road a few weeks a go and i noticed a distinct change in the noise of the diverter valve releasing the boost pressure, it sounded much weaker than normal & i had also been noticing a gradual performance loss over a week or so of driving as well as an occassional lumpy idle. I had the diverter valve checked & sure enough it was torn so i had it replaced for a Rev G thinking this would solve the issue, the car gained some performance back but still no where near where it should be & still the "weaker boost pressure sound". Took the car back in & had it smoke tested, garage found the inlet manifold had a crack in which they showed me & sure enough there was a big crack £400 + Labour later a cured occasional rough idle & better mpg but, nope, boost pressure sound still "weaker" and car lacking in performance. Checked the PCV by removing dip stick, car ran roughly for the 2 seconds the dipstick was removed, switched it off & double checked the PCV by blowing in to it, no air going through so i would guess the PCV is good.
Installed digital boost gauge, used forge fitting kit, all secured nice & tight no leaks. Boost gauge is reading -10 Vac, i believe it should be -20 so Vac leak? Boost spikes 16psi but struggles to hold 11-14. So that would surely be a boost leak? I have been reading up and on stage 1 i should be expecting 19-21Psi. So i have a possible vac leak & a boost leak.
I have since been back to the garage and the Turbo manifold has a crack which i have seen for myself & upon looking at google have found lots of images of cracks on the ko3 that look very similar, the car doesnt suffer with any blue smoke. So just because there is a crack will it definitley cause any or all of the issues im suffering? And would a cracked turbo housing cause a Vac leak? Boost leak? And be the reason why the boost pressure noise is much weaker?
I know it will need replacing, i just wonder if there is anything else that could be causing/contributing to the issues before i bite the bullet.
Any advice would be appreciated.
Thanks
