"Thinking Caps" on Guyz - 'Dusted' Compressor Whee

[ENGINR]

OK - like the subject line says - I need everybody to put their "Thinking Caps" on and try to help me find the root-cause of my 'dusted' compressor wheel problem.

In short:
* Am running K&N pod filter in an enclosed custom air-box with A/F meter, a 3" inlet pipe plumb-back E8MR BOV.
* Car has NEVER been run without the pod filter in place or the piping plumbed up properly.
* I have damaged compressor wheel blades (not destroyed or smashed to bits - but pitted and with bits taken out of them)
*I've checked the pod filter - there are no holes, tears or visible signs of damage to it. The inside of the filter looks spotless.
* There's no damage to the honeycomb structure of the A/F meter
*I've pulled off the intercooler and flushed it a couple of times with petrol and no visible crap has fallen out of it.
* I've pulled off the intercooler piping and checked that and flushed it with petrol and no visible crap has come out of them either.

HOW ELSE COULD I HAVE DAMAGED MY COMPRESSOR WHEEL BLADES?!?!?!

* Could some crap from my first turbo blow-up have lodged in the core and over time worked its way through the core into the BOV re-circ?
*Or could it have been lodged in the hot-side of the intercooler and been sucked back into the compressor housing?

I'm at a loss here fellas and short of replacing the intercooler to be sure that it's completely free of shit, cleaning and re-cleaning the pod filter and flushing the cooler piping time and time again I'm not sure what I need to do to find out how this damage was caused and ensure it doesn't happen again when I put my rebuilt turbo back on.

Help/experience/comments would be appreciated.

Cheers

 

[BMGTZ]

is it possible water could do this?

bm

 

[ENGINR]

I've thought the same thing Brian, that a fluid of sort could have caused the damage - I've got ALOT of oil in the system at the moment as I haven't got a catch-can on the thing. But I'm trying to work out how anything except oil could have gotten in there.

 

[BMGTZ]

I bought another gsr the other day for my daughter,pod filter as well. anyway I was doing a coolant change yesterday along with a new thermostat as some one had "chopped" the old one when it failed.

the whole thing is filthy from an oil leak under the little d shaped grommet that goes under the cam cover so I took it all to bits and cleaned her up. while I was there I it occurred to me that the guy has removed the inner guard behind the std intercooler......allowing spray from the front wheel to be throw around in that area.......with no air box.....sucked into the pod filter.

possible do you think?

brian

 

[shadow]

Could also be tiny broken bits of welding from the intercooler piping. You might not have found any after flushing it as the damage is already done.
Did you check for any shaft play?

Perhaps low oil pressure? or did u crank the motor over a bit to get some pressure before you first started it? The low oil pressure could have caused the bearings to go, and the turbine shaft to get slightly unbalanced, allowing the compressor wheel to scrape the housing.
Check for scratch marks on the housing.

But most times i've heard of this happening its been from welding.

 

[SIVART]

if your still running a AFM check the honey comb inside the AFM

or a bad balance job could cause it to hit against itself,

or the rubber ring that goes around the turbo before you fit the air intake pipe.

 

[CLuTZ]

or a bad balance job could cause it to hit against itself,

Didnt it just get rebuilt?

 

[shadow]

Off memory he bought it new.

 

[ENGINR]

Didnt it just get rebuilt?

Yep - rebuilt about 800km ago. I purchased the comp wheel and got it assembled and balanced by a crowd here in Melb. New bearings and seals in it - the works. I'm very very pissed off but until I find out how it happened I just have to get over it and move on with getting it back on the road.

I've thought about the welds breaking inside the air-intake pipe and can't see any jagged edges or such which would indicate that sort of failure. It is something that is playing on my mind though so I might get the welds redone and purge welded to make sure they're out of the equation when the new/rebuilt turbo goes in.

Bryce - No shaft play whatsoever - the rotating assy feels solid as a rock. There's marks on the inside of the housing but I'm not sure if they're from where my mate machined it out on his lathe when he opened it up a bit to fit the 20G comp wheel. The outer tips of the blades seem OK in the sense that they're not shaved down or smashed, it's the middle portion of the forward face that is damaged on all of them.

Brian - Good point re the crap spraying up. I don't have guard liners on my car atm. I've checked the airbox and it's got a bit of grit and crap in it which I would expect to see, I've got a 4" duct from the front bumper which runs up under the guard into an inlet on the air-box. The inside of the filter is clean and there's no dust or grit in there either.

Trav - checked the A/F honeycomb - it's all good. If anything got through it would have been very small or just somehow passed through the A/F meter. I don't have the rubber O-ring seal that sits over the comp opening - I destroyed it when I sucked it into the Big16G just before Christmas. That was what drove the 20G upgrade and rebuild. I got a better silicone joiner when I got the air-intake pipe made up and didn't trust getting a replacement!!

Thanks for the suggestions/comments guyz - very much appreciated. I'll keep you posted how the investigation goes.

 

[brisvr4]

I would say that it is very unlikely to be bits of weld hitting the blades as that would have destroyed them.
Try to picture throwing a bit of metal into a fan blade spinning at 120000 RPM. :shock:
From the pitting and minor marks I would guess at it being water droplets being sucked in, they would have a similar effect on the blades as a mild sand blasting.

 

[ENGINR]

Hmm. Hadn't thought of water. How could that have gotten into the comp housing though? I'm running the standard re-circ hoses etc as per the factory arrangement, they don't mix with any water lines. Maybe the core has a leak in it somewhere and some of the cooling water got in there?

This is doing my head in.

 

[BMGTZ]

I am thinking that if you have that 4" pipe kind of ramming air into the box
then any airborne water such as rain droplets and wheel spray from puddles etc has no where else to go but into the filter. where it will form droplets and eventually make its way through. on my 4wd triton I have a snorkel with an air ram....but it has a drain a t the back of it so that any any droplets will run out through these slots
can you put a swirl in the pipe to spin the air causing the water to hit the outside of the pipe. then have a couple of slots to let it out?

bm

 

[shadow]

I have actually seen the damage from welds to turbo's, which resulted in minor chips on a few blades of the compressor wheel.
It doesn't have to be big pieces of weld, but infact think of extremely small bits. You've gotta remember there is quite a bit of pressure in the intercooler piping, which could cause that tiny, exaggerating 'microscopic', bit of weld that snaps off, and hits the wheel that is traveling at insane revs. Enough to nick the wheel and continue through the turbo.

With saying that, i can't really see water causing it bit i'll talk to the mechs. here at work tomorrow, and bounce some ideas off them for ya.

 

[Missile]

you could drill a few holes in to the underside of the 4" piping which leads in to the air box... but this isnt helping you solve your issue right now...

have you thort of the possibility of compressor surge..?

 

[Liberoz]

It you have custom bro intercooler pipes I'd bet a grey one on that its from internal slag from the welded pipes making its way to the blades