Fractured K04 Compressor Vane

[MSMS3]

Title says it all, but a little context may be helpful. Photo attached. I've been off of this board for a while due to trying to chase down a problem with my stock K04. Power has been objectively down about 20-30 whp for several months. I chased everything. No boost leaks. Compression is fantastic at 108,000 miles. Leak down test is good. It just felt sluggish. I thought maybe it was time to clean the intake valves again, but g/s absolute max was fine.

What I was seeing on logs was that boost was slower to build and was not quite hitting expected targets, maybe 1-2 psi low and coming on slower and taking longer. I also use separately measured (accelerometer and stopwatch) 60-100 mph times as an independent validation of what logs are showing. Knowing that the 60-100 mph times were a full second slower suggested my logs were not lying.

When I pulled the battery and all the intake plumbing out of the way and got a good light on the compressor wheel, I found that it spun freely, but there were clear signs of excessive shaft wear and that the compressor was beginning to strike the housing. I thought I saw a broken vane, but was not sure.

I decided it was time to go ahead and pull the K04 and take a good look and at 108k on the speedo, probably time to replace it. I like the stock K04 and did not want to go big turbo, so I found a good company (more later, if anyone's interested) that could do a rebuild exchange with a completely new but stock CHRA. That's what I did.

Well, when I pulled the turbo and took a look at the compressor wheel, I saw that one of the vanes was actually fractured and a piece of it was missing! My guess is that under boost the worn shaft and bearings were letting the wheel touch the housing (I can see scrape marks) and at some point it hit with sufficient force to fracture that vane. This has probably put the compressor, which spins at well over 100,000 rpm, out of balance, all combining to significantly affect power.

I am lucky. I still don't know where that vane fragment went. Obviously it went through the IC, IM and intake valve into the cylinder and ultimately out an exhaust valve, and out the exhaust. How it avoided doing any downstream damage is probably a small miracle.

Lesson to those of us with old turbos with lots of miles -- take the time to not only inspect for shaft play, but visually inspect for damage.

All is good now with exchange turbo with new CHRA. Power is back. Life is good.

I don't know how rare this experience is, so I thought I'd share it. This is my fourth turbo car. Others were Saabs and a Volvo. I've never seen a vane fracture before. Here is one. Has anyone else experienced this and had the engine live with no evidence of damage?

[sheston]

Do you think something got past the filter and hit it?

[MSMS3]

It is possible, but I don't think so. The drag marks on the housing are pretty tell-tale that the wheel probably struck the housing and fractured the vane. I have a Mazdaspeed CAI intake (rebranded AEM) and don't see how anything could have gone through.

I actually did have a little Fiat 1100 car when I was in high school. Carbureted. A small nut in the carb vibrated loose and was sucked in. It wedged between the piston and cylinder head and locked up the motor -- like hydrolock! It left a nice little hexagonal imprint in the top of the piston. The little engine made such low horsepower than nothing bent or broke. I pulled the head, removed the nut, put it back together and rolled on!

No, I don't think anything foreign entered the compressor wheel side. I think it simply developed too much shaft and bearing wear, the wheel sagged, scraped the housing and then fractured the vane. If you look closely at the top right of the photo next to that vane, you can actually see the scrape marks on the housing.

I'm just lucky that there seems to be absolutely no harm downstream. With a remanufactured turbo and new CHRA, the engine is now as strong as before.

[maisonvi]

you sure its not stuck in the IC somewhere?

[Novej]

Clearly this is the fault of the Hypertech..........














Im kidding!!! I had to after all the posts you've jumped in bashing the AP.......LOL!

[Tokay444]

Pull intake mani and make sure it's not on the back of a valve.

[helmetface]

Yea, I would pull everything apart and give her a look see. I'd bet it's stuck somewhere.

[scubasteve711]

my money is on the IC...

[MSMS3]

Will check IM. Due for a valve cleaning anyway. Already pulled the IC and shook the hell out of it and nothing there.

Thanks for the suggestion. It is small enough to pass through an intake valve. But if it is still there disaster lurks.

[Tokay444]

If there isn't any damage on that turbine wheels, I'd wager it hasn't made it out of the combustion chamber yet.

[MSMS3]

Originally Posted by Tokay444 If there isn't any damage on that turbine wheels, I'd wager it hasn't made it out of the combustion chamber yet.

No damage visible on the turbine side.