Ceramic turbine damage to engine - what did yours do?

[Erelyes]

Long time no see, I haven't posted since 14 years ago...

To cut to the chase, R32 GTR. dead stock. Split wastegate hose = stock turbos were overboosting = front turbo's exhaust wheel has shattered.

Have done a compression test following this and the results are (dry, cold) - 120 / 60 / 75 / 110 / 150 / 150. Haven't bothered with a wet test or leakdown test. The results definitely support front turbo failure (on 1-3) however the low compression on #4 is concerning too.

Can anyone share their experience of when their turbine wheel shattered and damaged their motor - and what work needed to be done afterwards? Pistons? Rings? Valves? Throwing in the bin or salvageable? Motor is 100% stock. Will be getting it looked at further soon - I don't have a borescope and head hasn't come off (yet).

[GTSBoy]

It will be salvageable.

It really doesn't matter what is damaged. Opening up a 30+ year old motor for a rebuild immediately means a complete rebuild of the head anyway. Damaged valves just means an opportunity to put in some nice new ones.

And in the modern day, why would you not throw at least a nice set of pistons at something. And if you're doing that, why not rods, and ARP fasteners, and so on.

[Duncan]

It will mostly be bad scoring on the bores, which you can almost certainly fix by machining for oversize pistons.

I have to say, I am super surprised that any standard turbos made it 35 years down the track before exploding!

[GTSBoy]

1 hour ago, Duncan said:

I have to say, I am super surprised that any standard turbos made it 35 years down the track before exploding!

My Neo turbo only went last year. Not 35 years old, to be sure - closer to 25. But still.

[hypergear]

The overboost could be more of a cause. Broken turbines usually ends up in the cat, time to engine rebuild. Blown stock turbos can be high flowed with bigger and modern wheels for greater power goals.    

Edited 23 hours ago by hypergear

[GTSBoy]

37 minutes ago, hypergear said:

The overboost could be more of a cause. Broken turbines usually ends up in the cat, time to engine rebuild. Blown stock turbos can be high flowed with bigger and modern wheels for greater power goals. 

Hi Tao,

It seems that turbine fragments entering the engine is more of a thing with the twins. The theory is that because there is much more of a straight shot from the turbine housing directly at exhaust ports, they seem to cop it where the single turbo cars don't do it so often. It is definitely something that we hear about on GTRs far far more often than the others.

[Erelyes]

8 hours ago, Duncan said:

It will mostly be bad scoring on the bores, which you can almost certainly fix by machining for oversize pistons.

I have to say, I am super surprised that any standard turbos made it 35 years down the track before exploding!

Yeah car has 110 on the clock. That said the front turbo (that exploded) doesn't seem to be the original, it has a S1 part number but the car is a series 3.

4 hours ago, hypergear said:

The overboost could be more of a cause. Broken turbines usually ends up in the cat, time to engine rebuild. Blown stock turbos can be high flowed with bigger and modern wheels for greater power goals.    

Yep, in the cat is where I first found the turbine wheel pieces - a couple decent sized ones, then a whole lot of fragments. 

9 hours ago, GTSBoy said:

It really doesn't matter what is damaged. Opening up a 30+ year old motor for a rebuild immediately means a complete rebuild of the head anyway. Damaged valves just means an opportunity to put in some nice new ones.

I agree, probably makes sense to upgrade parts that are being replaced. Things like rods would be 'nice' but realistically it seems unlikely they would need replacing.

I was hoping that it was a case that they generally f**k up the valves but not the bore, or vice versa. Is it generally the scour damage rather than ceramic bits getting mashed into the piston tops / valves? I tried a search but couldn't find any threads with pics from the guts of a motor that's had this happen. 

[GTSBoy]

As @Duncan said - the bores are most likely to cop it. But anything can and does happen.

Rods are cheap. Rods are good. The work to rebuild the motor will be 30x the price of rods. You won't notice it.

[Lithium]

On 26/01/2025 at 8:01 AM, Erelyes said:

Long time no see, I haven't posted since 14 years ago...

Will be getting it looked at further soon - I don't have a borescope and head hasn't come off (yet).

Whoa, that's a name I've not see for a long time!

Sorry to hear about the engine / turbo damage.  Fwiw with any engine problems it often really a case of just seeing what happens when it's apart, ymmv - I wouldn't rule out the possibility that the damage isn't even from the turbo failure, or possibly from a combination.  The airflow between cylinders isn't dead even, injectors can go off over time as well, with the turbos overboosting if you didn't have upgraded fuel system there could have possibly been a bit of leaning out - stock triggering is often a bit unreliable by this age too.  Basically its an old engine and a few things could have been going on, and you won't know how much work is needed until the engine is apart.

 

[Erelyes]

Cheers Lith! You're right, it's entirely possible that there's other reasons for the low compression. It's off to the shop soon, skipping borescoping etc and just getting it out and apart, we'll see what it looks like then.