Screaming On Boost!!

[drifto]

My turbo is screaming when it reaches the set boost level.

Makes normal spool up sound while getting there but makes a horrible sound on full boost.

I've varied boost from 10psi to 18psi and the sound is only there when it has reached this level.

Power has not been lost, oil pressure/level and quality are good.

A local workshop suggested that the shaft bearing may be loose or worn and the exhaust wheel is touching the housing????? Either that or it's a blockage in the oil feed line and the noise is from the bearings running dry.

To anyone with knowledge does that sound right or should my turbo have blown up by now???

Could it be something to do with air getting in or out of somewhere it aint supposed to?

The Turbo is an old HKS T3G with an internal wastegate.

[adam 32]

balancing

happened to me

get it VPS balanced at your local turbo shop

[Dawzey]

yeah happened to me and it ended up losing boost and the flow out the end stopped.

i just high flowed the trurbo and it works fine now

but there was not much movment inside the turbo and it looked fine from outside.

but get it looked at and rebuilt.... but do it before u start losing boost. cos it wil happen if the same prob as mine

at first it would only happen at high boost but then slowly worked it way down and then boost would come down with it.

cheers

[adam 32]

you dont need to rebuild the turbo neccessarily. its simply out of balance, whether this has caused damage or not is another issue

[Doctor]

Have you ruled out a loose belt?

[adam 32]

a belt would squeal all the time, not only on full boost...

[Doctor]

I dont know mine ony screams at 10-11psi and its turbo of a R34 never been boosted over 11psi. At least Im pretty sure its the belt.

[drifto]

Thanks to all for your replies.

Doesn't sound good. This may be the start of some serious rebuilding.

It's definately not a belt. Time to rip the Turbo off I guess. Maybe I'll find out now what a HKS T3G is. I now it's been good for over 200 rwkw so a bit of rebuilding might see more.

Cheers fellas

[Lozza150]

Could it be your exhaust manifold. Mine schreeches at 6,000 rpm (not bad) just noisy. The guy's said some manifolds come lose after time, so the air escapes and makes that noise.

It might not be the problem, but it's one to keep in mind....

Cheers

Loz

[matlowth]

Lozza150's right on the ball. The screaming noise you're hearing is air escaping from between either the exhaust manifold and the block or the exhaust manifold and the turbo. My car did the same thing, you'll probably need to unbolt it, replace the gasket and re-bolt it back up.

Cheers,

matt

[adam 32]

mine made this same noise, took it to a turbo shop an took the guy there for a drive. instantly he said it was a balance noise

so it could be either

[matlowth]

Adam,

Yeah but his car doesn't seem to have any problems making boost, which would indicate that there isn't any damage to the turbo...

I've had a busted thrust bearing on a different turbo which caused the compressor wheel to grind itself into the housing... This didn't even make any noise, the car just wouldn't make the same amount of boost!

matt

[matlowth]

Easiest way to tell, is to have a look around the manifold, and if there is a leak, there'll probably be a grotty section where the air is leaking out.

Cheers,

matt

[adam 32]

mine didnt have any loss in repsonse or boost either

the way it was balanced caused the blades to cut through the air in a way that causes noise...

[turbomad]

I agree that it sounds like an exhaust gas leak, a friends VL turbo made a similar noise, he took it to a so called turbo mechanic who said it's rebuild time, before that he thought he'd check it over himself and discovered that the bolts from the turbo to the manifold were loose, I believe the turbo shop would have thought that all along and would have recieved $800+ for simply tightening a few bolts.

[Lozza150]

the worst part is most of the cost is to take off all the bits to get to the manifold.... you may as well Hi flow or rebuild the turbo while it's off.

Well that's what I'd do... Hence why i'm not going to fix the exhaust leak till i can afford to hi flow the stock turbo...or fit a HKS gt2540.... (Yeah right)

Loz

[drifto]

Cheers again for your replies. I believe it is more along the lines of a gasket leak too.

I'll have a good look Saturday and post back what I find for any other people curious.

By the way my Turbo aint stock and I don't think HKS would approve of someone going to their handy work with an air grinder.

A rebuild maybe, but if it comes off I'm hoping it can go straight back on again.

I'm getting really toey running around town without letting it build any boost.

The slightest hint of waistgate chatter is enough to get me going. ch ch ch ch ch to to tooo.

[46n2]

Check that none of the studs that bolt the manifold to your head have snapped off. I had 3 snapped - causing my leak...because a new gasket isn't going to do much if you're missing those studs...

46n2

[Doctor]

How did you get that fixed?

[Mr Rb20]

Lets assume it is the exhaust manifold gasket for a moment.

How much would that be to replace and also, would there be a noticable power loss ??