A few months back I replaced the manifold gasket on my engine, whilst I had the manifold and turbo off I decided that I would wind the wastegate down to stop myself from being tempted to turn the boost up until I got a controller. Now when the boost gets to a certain level, there is a screetching noise which I am presuming is the wastegate letting off the extra pressure. Or is it a boost leak? I have never had a boost leak that sounds that loud before so I am hoping it is just the effect of the wastegate but I've renewed the intercooler seal just to be sure, it's still doing it.
Sound like metallic screeching? If so the compressor is trimming itself!
Compressor trimming itself? You mean the blades catching on the inside of the housing? Why would that happen? It is something I've never heard before now, it sounds somewhat similar to a belt slipping.
If the turbo's f*cked there will be lateral movement in the bearings allowing the turbines to contact the housings which will get worse as turbine speed increases.
I did this my my last turbo, started sounding like a police siren
What psi and what turbo are you running?
Heh, taken it out today again. I am pretty sure the blades are catching. I am running a K14 at 14.5 psi (standard pressure). I had taken the turbo off to replace the manifold gasket so I don't know if that might have caused it. It was running 22psi before though. I don't know if it is because I didn't change the oil for a couple years, but then I had only done about 6k the last couple years anyway.
oil should be changed every year or whatever miles your service intervals are
Due you get a kick out of stating the obvious?
Whoa whoa whoa only being helpful :p
Heh, I was talking to Daniel306. So this is definately not just the wastegate letting air out then?
So does anyone know what's causing this?
with out more information / pictures / videos we can't really help much more,
I'd suggest that it's your cars way of telling you your turbo is on its way out
Have you been running de filter?
No I've always had the whole intake ducting on. The only thing I can think of is not changing the oil for two years; but then I hardly ever drove it during that period either.
Sounds to me like turbos shafted. (broken) lol.... Im pretty sure you've described the exact noise mine makes
Heh, this was actually the result of putting the LDA pin diaphram on the wrong way around. When I had the missfire and shaking at low revs problem I thought that perhaps I was wrong assuming that what looked like the right way round was actually the right way round so put it the wrong way around to see if that would solve the shaking in gear.