R32 Gtst Turbo Noise

[RBnub]

I own a r32 Gts-t standard rb20DET with a rebuilt r34 highflowed turbo. After letting the car warm up for a couple minutes I start driving and the turbo makes a screaching noise just as boost comes in then stops after it reaches over 2 psi roughly. After the car warms up more the noise becomes obsolete. Just wondering if this is a sign of problems to come.

[SargeRX8]

Pretty sure its not the turbo but a leak somewhere. Check your BOV gasket, exhaust and all the other seals. When metal heats, it expands which *could* seal the problem.

Also pay attention to whats really happening. Is it on 2psi of boost or is it at a certain RPM with certain throttle. I'm guessing it happens between 1800 - 2400rpm.

Edited March 3, 2011 by SargeRX8

[RBnub]

The only way to describe the sound is like a drop saw cutting metal. It's not a very nice sound at all. I will check all my seals tomorrow.

[SargeRX8]

Does it sound like a squeal or a grinding sound? You make it sound quite harsh and if it actually does sound like a drop saw cutting metal, your bearings or shaft could be really f**ked. Its weird though that after its warmed up it subsides. Is it a faint sound or very loud?

If you really do think its the turbo I suggest you check over it. Check the shaft play, back and forward, side to side. If it has too much play, the wheels could be hitting the housing and that could be giving you the metal on metal sound. If thats happening, I suggest you don't drive the car or you'll shatter the turbo or get pieces of metal in the intake which will probably destroy your piston rings.

There's no quick check to see whats what. If it is the seals its gonna be a pain in the arse narrowing it down. I only found out it was my BOV because I used my old BOV replacing a atmo BOV. The symptom came as soon as I fitted my stock BOV. I bought another standard BOV and the problem was still there. I used a paper kind of gasket rather than the metal one and the problem is gone. Single layer pieces of metal as a gasket is a shit idea.

[RBnub]

It's quite loud grinding noise. If you put your foot down you can only hear for a second as it hits boost and then again when the boost comes back down on 0psi. The boost gain is quite long so it's very noticeable when just sitting on 0-1 psi. But other then that at higher boosts it sounds like a dream.

[Trozzle]

Can you hear the induction sound of the turbo even AFTER the boost stops trying to climb? That would suggest it's still sucking air, but it's getting out somewhere.

I'd think it could be a leak somewhere with a metal gasket, say BOV flange or even intake manifold. Do you have AFM or MAP sensor? If AFM, of course black smoke would pour out if you have an AFM....if no black smoke, then yeah you're not even sucking air IN, let alone losing it.

[RBnub]

I have a AFM from a 300zx I'll check the smoke this afternoon along with my BOV flange. I will isolate the noise aswell so I know where it's coming from. I dont understand why the noise only occurs just at the start of boost and then disappears and comes back as boost drops when changing gears or letting off the throttle. Between the range of around 1-18 psi it makes no strange noise at all. Just to try and describe it a little more In depth, say I was going down the road I'n 3rd gear climbing slowly. The initial wind of the turbo is fine between the range of -8 psi and -1 psi on the boost gauge. As soon as it hits the 0 psi mark the whistle of the turbo turns into a clean ginding noise (like an old ceiling fan on high speed). The noise plays out until boost starts to climb then it's gone. change into 4th and I hear the noise again for a split second as the turbo winds down past the 0-1 psi mark.