Thoughts On Turbo Failure

[steve_gts4]

ive just had the 2nd rear 2860-7 turbo fail in my gtr in 6 months. both failures have happened at track days. the turbos have been running 20psi with a good tune.

the turbo shop said the first failure was due to an overspeed. there were no signs of oil starvation.. just the shaft was bent. this was a 4 year old turbo with about 6000km on it.

i havent pulled it apart after this second failure, but i can hear wheels scraping on housings. this turbo had done 600km.

both times the engine has escaped unscathed.

the only thing i can link between the 2 failures is the boost gauge hose popping off the fitting at the back of the throttles.

is it possible that that little fitting could be leaking enough air to overspeed the turbo? this is frustrating

Steve.

[GTScotT]

If you had a reasonable boost leak you could have possibly over boosted the turbos, although I doubt one event would kill it so quick.

I would be going over as much as I can. What dumps/exhaust are you running?

[hypergear]

Well I don't think they can over speed on 20psi. How ever can fail due to oil contamination which wears bearings, increase tolerance, resulting in shaft play and vibration at high speed. Wheel contact occurs once shaft movement exceed its housing clearance. At high speed it breaks both wheels and bend turbine shaft.

Or if you don't have a BOV high surge pressure can also twist the shaft.

[MrStabby]

Are you sure both actuators are good and moving in unison? If they're not you could be spinning one turbo a lot harder. Even if they appear to be ok, swap the front and rear so if it goes again it will be interesting if the failure moves with the actuator or not.

[steve_gts4]

Are you sure both actuators are good and moving in unison? If they're not you could be spinning one turbo a lot harder. Even if they appear to be ok, swap the front and rear so if it goes again it will be interesting if the failure moves with the actuator or not.

good advice.. i will check this closely

[steve_gts4]

If you had a reasonable boost leak you could have possibly over boosted the turbos, although I doubt one event would kill it so quick.

I would be going over as much as I can. What dumps/exhaust are you running?

trust split dump/front pipes.. high flow cat, and a greddy PEII exhaust.. no blockages.

no other leaks in the intake that im aware of.. it was holding 20psi very nicely before the incident.

[lotsalag]

What sort of power is ur gtr making?

U sure ur not just pushing them too hard and hence durability is suffering?

Seen a pair of -7s last barely 5000km on a gtr making 330+awkw, and yes this was at about 20psi or so as well. But im talking just getting smokey and losing efficiency, not physically bent shafts or anything of that nature, well nothing easily audible anyway.

[steve_gts4]

What sort of power is ur gtr making?

U sure ur not just pushing them too hard and hence durability is suffering?

Seen a pair of -7s last barely 5000km on a gtr making 330+awkw, and yes this was at about 20psi or so as well. But im talking just getting smokey and losing efficiency, not physically bent shafts or anything of that nature, well nothing easily audible anyway.

last time it was dynoed was several years ago.. it made about 300rwkw (4wd disabled)

and, ive just pulled the intakes off.. looks like both of them are failed. the front is worse than the rear. the bearings are noisy as hell, and the wheel is hitting the housing on the front one

Edited June 28, 2010 by steve_gts4

[DVS JEZ]

U running a catch can?

I agree with Stao oil contamination. Might be due to a little bit of blow bye letting fuel into the oil and breaking the oil down

did the new turbo come with a new actuator?

[R31Nismoid]

If there was oil contamination and lack of flow the bearings should be burnt, and have blue markings on them.

I would get them looked at before going further.

Where is you boost reference being taken from? Turbo or plenum?

Could be you have an intake restriction or similar and the turbos are thumping 25psi+ while you are only seeing 20psi @ the intake

[N1GTR]

Sorry to hear Steve, you finally get it all on the road and this happens

[steve_gts4]

U running a catch can?

I agree with Stao oil contamination. Might be due to a little bit of blow bye letting fuel into the oil and breaking the oil down

did the new turbo come with a new actuator?

the engine is pretty new and the rings have sealed well.. it has a catch can which is still empty after 4 years

one actuator was replaced last time.. it had a small leak, and the other inspected and declared ok.

If there was oil contamination and lack of flow the bearings should be burnt, and have blue markings on them.

I would get them looked at before going further.

Where is you boost reference being taken from? Turbo or plenum?

Could be you have an intake restriction or similar and the turbos are thumping 25psi+ while you are only seeing 20psi @ the intake

good point.. boost reference is off the plenum. i might move that around the other side closer to the turbos.. would make sense.

i will strip the turbos down myself this time and see what they look like inside.

Sorry to hear Steve, you finally get it all on the road and this happens

thanks for the sympathy hehe thats life i guess.. ill work it out eventually