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moar cowbell
Trailblazer
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6,426 Posts
Discussion Starter #1
Well, to make a long story not so long I'll skim through the "best" parts....

Back in January I slapped on an alky control setup as well as a ported intake and upped the boost from 7 to 9lbs on my frankensteined STS kit for just a lil more oomph. While at the dyno we couldn't get the boost over 6lbs... weird...

Not only that but while on the dyno we saw what looked like valve float... great.

To remedy the possible valve float situation I ordered up some ls7 lifters, ls6 springs and an ls2 cam among other bits and pieces so I could remove the weak link in my truck... the DOD system (did I mention mines a 5.3l lh6?)

A month or so later I was back on the dyno with a MBC thinking the boost problem was perhaps a faulty spring.... NOPE! After twiddling with it for a while and basically setting the boost to kill we still couldn't push it over 6 lbs.

Tuner thought that I might have clogged up the cats and couldn't get enough exhaust pressure to spin the turbo.... so I took it home and gutted the cats.... they were clean as could be.

Next up was the ported intake. Didn't see anything wrong with it on the truck but I was out of ideas and swapped it back out to the stock one and lo and behold I find I had cracked the seam on the drivers side on the manifold from end to end. lol.

Took it out for a spin with the stock intake back on and it ran much better. Although it had a clicking sound under throttle that I thought was perhaps an exhaust leak... I had just pulled the y-pipe so it made sense.

Got the ported intake fixed up and today (7 months later) I set about swapping it back in. While switching things over I noticed that a small piece of metal had taken a nick out of the butterfly on the throttle body.

After buttoning things up and fearing the worst I pulled the turbo.......

What. The. Fuck.

 

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trailer park living.
TrailblazerSS
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16,328 Posts
Must of been some thick air.:biggrin2:

That sucks. Did you ever run with out a filter.
 

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Premium Member
Trailblazer SS
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5,208 Posts
Thats far more damage than running without a filter would ever cause....


Maybe a chunk from the crack on the mani? You still running cats? One may have broken and things went south from there.....idk. Theres tons of posibilities. Take it apart and see if the compressor housing is fucked. Wheels are cheap.....well, cheaper than a new turbo lol
 

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moar cowbell
Trailblazer
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6,426 Posts
Discussion Starter #4
nope. filter always on.

I pulled the turbo to inspect it when I did the cats. It was fine. I's been around the block only a couple times since.

Today when I pulled it I did notice that I was missing one lock washer on the exhaust flange when I unbolted it.

My only guess is this was caused by the missing washer
 

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Premium Member
Trailblazer SS
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5,208 Posts
Like I said, I would take it apart and inspect the damage further. The turbo may be salvageable.

Anywho....how would a lock washer make its way into the exhaust stream from the Y pipe? It sounds kinda ilogical to me....
 

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Premium Member
Trailblazer SS
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5,208 Posts
I know....I can see that lol. I misspoke in my last post. :doh:

I guess I am confused by how a washer goes missing from the exhaust....and makes its way into the compressor housing if you always had a filter on. IDK. Maybe I need to stop thinking aloud. I'll shut up now.
 

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Premium Member
08 Black Granite
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4,004 Posts
Any play in the shaft? End play or radial play would cause this. Do you have a turbo timer? Insufficient cool time after runs.....

Sucks man.
 

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Premium Member
07 2WD TrailblazerSS
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10,061 Posts
The only way damage like that happens with a filter, is when the turbo is over spinning and or the blow off valve is not doing its job!
 

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secret squirrel
TrailblazerSS
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1,280 Posts
couple of things that may have cause that....1) debris. 2)overspinning the turbo itself. 3)compressor surge.

if that is a cast compressor wheel and you over spin it, it can and will come apart. compressor surge plays havoc on compressor wheels. if it started to come apart because you wanted to go from 7-9psi, it may have been over spinning the wheel to achieve that amount of boost.

my guess is that it happened because of overspinning and causing its own debris. if it was a larger piece of debris, it would have caused MORE damage to the compressor wheel. alot more damage on the second set of blades.

are you intercooled?? if you are, good thing because these little pieces would stop at the intercooler and not be ingested into the engine.:burp:
 

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Premium Member
Trailblazer SS
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Damn man that stinks
 

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moar cowbell
Trailblazer
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6,426 Posts
Discussion Starter #12
couple of things that may have cause that....1) debris. 2)overspinning the turbo itself. 3)compressor surge.

if that is a cast compressor wheel and you over spin it, it can and will come apart. compressor surge plays havoc on compressor wheels. if it started to come apart because you wanted to go from 7-9psi, it may have been over spinning the wheel to achieve that amount of boost.

my guess is that it happened because of overspinning and causing its own debris. if it was a larger piece of debris, it would have caused MORE damage to the compressor wheel. alot more damage on the second set of blades.

are you intercooled?? if you are, good thing because these little pieces would stop at the intercooler and not be ingested into the engine.:burp:
Yes its got an intercooler. I'm gonna pull all the charge piping and clean it out.

I'm unfamiliar with compressor surge. Its a garrett ball bearing and the owner before me ran 12 lbs. I didn't think I was pushing it anywhere near its limit.
 

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moar cowbell
Trailblazer
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6,426 Posts
Discussion Starter #14
That's kind of what i was thinking Matt. Weird thing is I took it off after that and it looked fine. 10 miles later I have this... guess it was ready to go, I just couldn't see it.
 

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trailer park living.
TrailblazerSS
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16,328 Posts
how big was that turbo? Guess its time for a bigger one.
 

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secret squirrel
TrailblazerSS
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1,280 Posts
Problem is you werent building boost because of the Crack so you spun the Snot out of the thing to wring out the little boost you created....It never hit its target boost so it never opened the wastegate so it spun FOREVER...

I am gonna have to say this was likely the detrimental factor that took out the wheel.
i agree also that it was probably way past its safe rpm level of a bazillion rpm, and he wanted to make more boost, so lets try a gazillion rpm spool rate!!!hahhaa!!!! it happens......not his fault. ive had a turbo failure myself, but mine was from a hard right turn, no oil on the shaft of the turbo, burnt the bearings and whallah.......funny sounds from under the hood..car ran normal, just NO boost and a funny bbbzzzzzzzz from under hood. pulled apart turbo compressor side, and lookie there...problem found.


compressor surge video

what it looks like on a gauge..
:burp:
 

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Premium Member
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1,146 Posts
Damn sorry to hear about this Eric, I hope it all gets worked-out for the better. Just imagine how great it will run when at it's full potential!

Weird summer, a lot of us dropping like flies around here....
 
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