Hi all

Question here, my setup is Greddy Turbo kit, HKS SSQV, TP and HKS hi power exhaust. recently I replaced the cracked Greddy manifold with new Pfab manifold and replaced TP with OEM CAT (Inspection time) Afterward I notice every time when the car is under boost, I can hear a hissing sound coming either from the right side of the car which I didn't notice before. the sound can best be describe as a jet taking off. It wasn't doing this before. I am thinking could it be either a boost leak? or bearing going bad on the turbo? or could the sound just be from having the Pfab manifold? furthermore, after the pfab manifold and OEM cat, the stock boost just gone from 6.x to 8.x is that normal?

Thanks

 

I have almost the exact same setup as you (greddy kit, hks bov and exhaust), but still have the TP and I have a custom manifold. I'm right a 8psi under wot/full boost. I notice that under hard acceleration it sounds kinda like a jet maybe. I wouldn't say it is a hissing as much as a whooshing or suction sound though. I have dyno'd my setup and I'm making full boost, so I don't think it is a leak or failing turbo, I just thought that was the combination of the turbo spooling and air getting sucked in to the manifold. Is your car operating strangely, or is it just the sound that has you worried?

 

Leak out the BOV or manifold?

 

Just the sound, the car runs fine, no oil leak, no CEL, I am scared that the sound might be a bearing gone bad or something. But come to think of it. replacing the TP with OEM does dampen the exhaust note a little bit so maybe the "jet" sound is always there just been cover up by the exhaust note. btw, I know that it's been recommend to run Greddy with 5-40W synthetic oil. any harm running Mobil One 10-30w? I live in NC and its getting cooler now. my car is sorted like a daily drive, not a hardcore track car.

 

30 maybe be too thin when up to temp. 5 flows best for cold. If I had to make a compromise id go with a 10/40

 

Anyway to test these? the manifold is new from PFab, and I didn't notice the sound w/cracked Greddy manifold. BOV, again didn't notice before the manifold and not sure why it leak all the sudden. I am running the AEM tru boost controller but again, the only thing change is the manifold. I notice that the Pfab manifold is make out of the different material than the original greddy (Cast Iron?) could the different manifold material transmit turbo wheel differently? That is just a wild guess.

 

Actually now that I think about it, could also be the wastegate. My friend has the Pfab manifold and we thought it was leaking, turns out there was a stud missing and some loose nuts, but that wasn't where the sound was coming from actually, the wastgate came loose and was about to fall off. Apparently this shit vibrates and comes loose. Id just go over the whole set up and make sure things are tight.

 

It would be extremely coincidental for you to happen to have a bad bearing or something else seeing as how you didn't have this sound the day before you made the changes, but then had the sound immediately after. I remember being a little surprised by the sound of my Greddy kit when I had it installed, especially under boost. I actually watched some videos on youtube of other greddy's getting dyno'd though, and realized that my car sounded pretty much the same as theirs.

 

agree, and the car seems to drives fine. thanks, next month on the meet, I'll see what other think when they hear it

Thanks

 

If you really are concerned with the noise the best thing to do would be to post a video of the sound. That way people can better assist you as there are quite a few hissing type noises on a FI car.