2500km Old Gcg Highflow Turbo Died, Possible Cause Of Failure?

[Rolls]

I had a brand spankers gcg highflow on my rebuilt rb25det. Now it had a series1 rb25det rear housing that was milled out and a rb20det front cover. The car occasionally blew some smoke on cold start if you accidentally boosted it but I never found the cause.

Was running about 10psi and making roughly 200kw as it was waiting for a full power tune. I was driving it one night and it suddenly made a VERY loud whirring noise so I immediately throttled off, I then drove home slowly, at one point the noise went away so I reved it to about 3k and I believe the bearing seized as it made no boost, the car refused to rev and it had no power. Once again I throttled off and babied it home around 1500 rpm. About 30 seconds later it un-seized and started making the horrid whiring noise.

Once home I removed the turbo, upon inspection the shaft was twisted/bent and the compressor blades had made very slight contact with the housing, there was no oil to be seen in the front or rear of the turbo, however plenty came out of the oil feed along with coolant from the coolant feed.

I started the motor with no exhaust and did an oil flow test, got about 400ml out the oil feed in approx 15 seconds at idle so thats about 1.6L per minute of oil the turbo was getting, ample according to Adelaide Turbo Services.

Now there was zero sign of foreign material ingestion and the bearing still seemed ok and it would spin alright, I'm not sure if it was the blades touching the housing that stopped it free spinning for more than a second or the bearings were shot. Now I am sending the turbo off to GCG for inspection and to see if it will be covered under warranty. I would open it up and look at the bearings to see if they are blue and cooked from oil starvation but I don't want to void my warranty.

What could cause a problem like this? Providing it was getting adequate water and oil and it had a good tune, how could the shaft warp itself and cause the impeller to hit the housing? The only things I can think of are an impossibly small manufacturer defect (if it lasted 2500kms theres no way their balancing machines would pick it up) which caused the shaft to slowly get worse and worse over 2500kms or contaminated oil making the bearing f**k out.

Oh also the car had had an oil change about 800kms prior to the failure with fully synthetic mobil 1 oil and there was zero (visual) evidence of bearing material in the oil.

It is being sent off to brett at gcg tomorrow for a full inspection and report, I really hope it is covered under warranty as a new shaft, impeller and bearing will be at least $1500.

Also the use of a the rb20det front cover, will that restrict the top end power much? Is it just a smaller inlet or a smaller overall cross sectional area?

Cheers guys and wish me luck

[T04GTR]

was it a bush turbo or ball bearing?

did it have the standard oil lines going to it? if so then that why its gone. if its ball bearing then one of the oil passages is blocked in the turbo.. thread tape, silastic etc etc.

if you grab the comp wheel, does it pull in and out?

[Rolls]

Ball bearing turbo and oil seems to pass through it with no problems. No shaft play, its just warped and off centre. It was set up exactly as the manufacturer specified. If thread tape had blocked the oil feed surely it wouldn't have lasted more than a few hours let alone 2500kms ?

Edited October 20, 2009 by Rolls

[Simon-S14]

thread tape has a tendency to work loose or deteriorate over time, it should never be used for oil feed anyway as the banjo washers is what seals it, or if your using dash fittings use a liquid pipe sealant instead.

as for what caused the prob, i dont think we're going to know until its stripped down so maybe wait and see what GCG have to say.

hopefully they are more helpful then ATS who i might add, are a bunch of dickheads, a mate of mine had a turbo rebuilt by them, and it didnt last one track day. they then refused to repair ir under warrenty as they suspected there was an oil supply issue, where there was not.

[Rolls]

Yeah there was copper washers on my oil feed and oil drain, no thread tape anyway. The blokes down at gcg have always been very friends/helpful and nice on the phone so I'm confident they will find the problem and help me out.

[Simon-S14]

let us know how it all pans out

[Rolls]

Will do, I took it to Adelaide Turbo Services so I could get a quick opinion before sending it off as the bloke there knows his stuff and he was fairly stumped, he seemed to think that either the shaft was bent the tiniest bit from day one or something else strange had happened.

It left today so should get to them sometime this week. Hopefully hear back from them early next week.

[femno]

Details of intake setup?

[Rolls]

Details of intake setup?

Apexi super induction pod, standard AFM (not hooked up) with stock bendy piping, rb20 elbow going to rb20 compressor cover.

Rb20 bov attached to r33 intake pipe venting back to intake via a rubber hose. Bov nipple attached to the standard location.

Hybrid FMIC.

Vented catch can

Here is the only picture I can find, doesn't really show much.

Edited October 20, 2009 by Rolls

[Rolls]

gcg are pulling turbo apart as we speak.

[Shiraz200SX]

brett at GCG is a good guy anyway... hopefully something gets sorted for you.

[Rolls]

brett at GCG is a good guy anyway... hopefully something gets sorted for you.

Yep he was very helpful on the phone and seemed like a nice guy. I'm confident it will get sorted out, I've only ever heard good things about their turbos before, who knows it could be an exterior fault that caused it anyway.

[discopotato03]

The RB20 compressor housing is smaller than the RB25 one so it may limit airflow a little on an RB25 . I'm a bit surprised they didn't ask about that if they knew it was going on an RB25 . It may be worth trying to find the right housing if you want all 43 beans out of it .

If you can't PM me as I think I still have a VG30 BB one which from memory is the same casting as an RB25 one . I'll possibly be back at GCG on Monday so could drop it off .

Cheers Adrian .

[Rolls]

Wont it have to be machined etc? what is that likely to cost?

[discopotato03]

I'm not sure but Brett or Michael would be able to tell you , just thought it was a good opportunity .

A .

[Rolls]

whups double post

Edited October 28, 2009 by Rolls

[Rolls]

Apparently the balance something drooped which caused everything to spin out of balance and eventually eat the bearings and the compressor wheel. He said the cause was excessive exhaust gas temperatures as everything was blue.

My dyno sheet says the afrs are around 12:1 and the cat, middle exhaust and rear cannon aren't blocked so what could cause this? I am going to get a complete re tune when the turbo goes back on the car but I don't want a repeat performance.

Was quoted $1200 for new bearings, front wheel, shaft and balance weights, quite cheap as he said he would do it minus the labour charges which I really appreciated. Basically an entire new turbo with new warranty minus the housings obviously.

[Rolls]

Spoke to the guy who originally looked at it (adelaide turbo services) and he said they it looked like nut on the front of the wheel had been ground all the way around and had huge chunks taken out of it which he said suggests they struggled to balance it in the first place, also at 8psi even with a blocked cat nothing should melt and droop from heat.

Oh well live and learn, I can't really argue with them and it is a cheap price considering it is 1 year out of warranty and I am essentially getting a new turbo.

Edited October 28, 2009 by Rolls

[Crans]

For $1200 id be talking to hypergear about a brand new turbo

Try the ART28G4 including internal gate kit oil line and dump pipe its costing me $1330 delivered will flow over 300rwkw

[Rolls]

For $1200 id be talking to hypergear about a brand new turbo

Try the ART28G4 including internal gate kit oil line and dump pipe its costing me $1330 delivered will flow over 300rwkw

It won't be ball bearing though and if its good for 300 it will have bigger wheels so it will be laggier for two reasons. I liked the gcg one because it reached my target of 250kw and is ball bearing so has response almost as good as that of the stock turbo. I'd imagine that turbo wouldn't come on hard until 4k+ where as the gcg one comes on pretty strong by 3-3.5k.

It is a street car so I want the smallest laggiest turbo possible for my target power. For $1200 nothing else is going to go to that, If I was starting from scratch I'd go pay bill at Adelaide turbo services $2k and get him to set me up one with garret wheels and bearing core in the standard housings.

edit: I had a look at their website and a comparable turbo is this one:

http://www.digi-hardware.com/tr28gt.html

The G2 450hp model which is $1500 not including delivery or GST so it would be more like $1700+ and $1200 is already stretching my budget as I didn't plan on a turbo failure.

I still need to get this thing tuned and through a regency inspection which is another good $700 I don't have.

Edited October 28, 2009 by Rolls