Turbo diagnosis (with pics)

[cwspellowe]

Right started a new thread as this will contain a lot of information. Hoping those more experienced than me with turbo stresses will be able to contribute.

Turns out the turbo shat itself, shaft snapped clean in two and the turbine wheel and half the shaft are somewhere down the motorway as they're not in the exhaust anywhere. Oh dear.

Right here's what i'm faced with. We'll start compressor side seen as that's the only side of the turbo left

One bent shaft and trimmed compressor wheel anyone?



And for Ruan, shaft size is roughly 4.5mm



Shaft seems to have snapped in a concave conical shape, doesn't look twisted from what I can see. Pretty sure it's a solid shaft so not sure why it looks like this







More of the compressor side and internals







This little bugger's taken a bit of a beating







And towards the hotside



Finally some sizes of various pieces. Ruan said over whatsapp he was interested to know a few dimensions.

Oil drain diameter ~12mm



Inlet size ~49mm



T2 manifold port size ~46mm



Turbine inlet size ~36mm



As you can see here, there's a good 5mm or so ring of coke around the turbine inlet, indicating the T2 mani outlet is much larger. Could possibly have been a factor, accelerating gas flow in the turbo. Seems strange the turbine inlet on both GT2056's have been like this.



Also for comparison, the castings and serial numbers are different on the two compressor housings, for what SHOULD have been the same turbo. Curious.

First the original GT2056 that I killed by not bolting the compressor housing down properly





Also looks to me like it says the A/R is 0.53 on this. And another casting next to the .53 that says either 06 or 90, not sure what this is for.

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And the second GT that i've just removed





And again, 0.53A/R but 80 or 08 in the casting next to it, along with different serial numbers.

If anyone can tell me what's wrong and why it died please do enlighten me. The way it's snapped, tells me it probably isn't shrapnel damage, but it doesn't look to have snapped under torsional load either, the shaft is still straight.

One theory me and Ruan considered was that the hotside was in fact too small and the pressure ratio to the compressor side is what snapped the shaft, but again isn't consistent with the damage. The power band for a Vivaro/Movano/whatever is only up to about 3.5krpm tops so me taking it up to 5krpm at much higher flow than it's application COULD be what killed it. The compressor maps seem to indicated it SHOULD be ok with that flow though. My concern is the inlet to the turbine housing being so small even compared to a T2 mani.

There's no coking or scoring of the bearing, it still looks in decent nick and certainly hasn't starved of oil. There was shrapnel in the CHRA housing but tbh that could have been anything, including the shaft/wheels grinding themselves away when failing, so that's inconclusive.

Oil and filter were changed after the last failure, intercooler and pipes were flushed too. Don't think anything was left in the oil that could have damaged any seals but you never know.

[darrenjlobb]

Looks like an overspeed to me.

What boost were you running / was wastegate holding it? or was it just making wat it could?

[cwspellowe]

Just making what it could. Didn't surge so much as gradually build pressure through the rev range.

Quick glance at the gauge while accelerating showed just over 30psi, but could have been up to 35. Was the first time it had made that speed.

Wastegate.. i'm not telling you about as you'll shout at me.

[Toms306]

Oh shit! You done that well Chris...again!

[cwspellowe]

I know Tom, i'm getting good at this now

[Jonny81191]

Oh dear..

[darrenjlobb]

35psi + GT series theres your problem... gate them at 26psi tops.

You just overspeeded the crap out of it, The GT series are epic turbos, but its no td04 / t series, you cant abuse them as they will just shit it, the shaft is like a match stick compared to other blowers...

[Ruan]

If it went off the end of the gauge, guaranteed that's why...

35psi is simply too high for it... Will have been overspeeding like a mofo at 5k making 35lbs of boost.

[cwspellowe]

Ah, then I have killed it in a moment of epical fun-ness.

I shall buy another. And use an actuator this time.

Shut up.

[Ruan]

Your location is very apt this time!!!

[cwspellowe]

Ha, it's been apt since the first GT died.

So what's the thinking? Go again with another one but actually run an actuator instead of trying to be a boss?

[Ruan]

Run an actuator and it'll be fine I'd bet....

And keep it ON the gauge this time...

[cwspellowe]

Mmm. Ok, only because it's almost as expensive as a mild coke habit at the minute

Got a T2 actuator you want to send me? Or should i plump for my lovely billet kinugawa one? I'm a tart, but not a rich one

Just said to Max there on Facebook, think the GT is ideal tbh as it will haul ass without being on the limit, which i'm happy with. I don't need a world beater, just something that will hold its own against more modern machinery while being cheap as hell to run.

[darrenjlobb]

Which it will do at 26psi

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Itl probs be just as quick / quicker at 26psi than off the gauge like it was!

[cwspellowe]

OK so I killed this one. But it shall be back soon with a proper setup

[David]

Oh dear. Sorry to hear mate.

[cwspellowe]

f*ck just checked the bank, not this month. And still need to tax it. Will be a couple of months by the looks of things

[Jonny81191]

If you want, I have a K14 you could use while you wait? I'll give it you on the manifold, just cover postage?

[Piggy]

oh dear...
sorry to hear bad news

[ash240970]

The turbo-slayer strikes again

[darrenjlobb]

Tempary nad'state im thinking!

[Piggy]

I gota T2 off a 2.1 going cheap if you need? Not sure on fitment though

[Jake]

I gota T2 off a 2.1 going cheap if you need? Not sure on fitment though

Different mani' isn't it ?

[Piggy]

I duno, probably....just trying to help

[cwspellowe]

S'ok i'm not in any rush, it's untaxed anyway as i'm still waiting for my V5 back.

[Piggy]

can you use a manual boost control with one of these...no?

[cwspellowe]

Yup, it just fits inline to the actuator, reduces lag too as it stops early creep of the wastegate under partial boost pressure.

Basically, set it to 25psi or whatever, and the wastegate ONLY opens when the MBC allows it to see that 25psi. Without an MBC, the wastegate may creep open early as the psi rises, so may be partially opening at say 10psi making the turbo less efficient. With the MBC it will see no pressure at all until the MBC allows it.

You can fit an MBC to any internally wastegated turbo really, just plumbs between the boost pipes and the actuator. I have mine set to read boost from the neck of the inlet manifold for as true a boost pressure reading as possible.

[Piggy]

thats what I was also thinking....

instead of taking the boost from the turbo to MBC then actuator...go from inlet manifold...true read etc


Have you looked into the K16 KkK turbo?? map looks good. or is 'KKK' a swear word here?!?

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PS I guess you were not using a MBC on this GT turbo....??

[cwspellowe]

Nah i'm plumping for one last GT2056 as I already have the manifold and elbow made up...

[Piggy]

has anyone gone down the K16 route...maybe even the hybrid K16/16g?!

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PS fair enough...good point....what vehicles have you found them on so far?! I will keep an eye out down the scraps