Who Here Has Blown Their Turbo?

[MANWHORE]

I would like to say firstly, I have seen the pistons that wrxhoon was referring to. I agree with him about the exhaust wheel going on the rb26 motors.

In some situations, the exhaust wheel might shit itself and not travel into the cylinder. However, when the exhaust wheel shits itself, it unbalances the shaft, which is still travelling at tens of thousands of rpm when it happens.

I recently helped a friend pull the turbo off his rb25. The exhaust wheel had crapped itself, and smashed into the cat. I don't know whether it went back up into the engine. It doesn't seem like this happens on rb25s very often based on the manifold and turbo design. However, the shaft had unbalanced itself when the exhaust wheel went causing the inlet wheel to eat the inlet housing.

The engine has not been inspected or pulled down yet. The engine was switched off immediately (however, that's still a while after. e.g. you realise the turbo has blown, you're still travelling at speed, you have to slow down, pull over, turn it off).

After pulling off the turbo, there was metal everywhere and it was in the piping ahead of the turbo too. Therefore, i would hazard a guess that it has also gotten intot he engine.

Therefore, you basically face the risk of double trouble.

[Taso84]

Fine then, dont believe me. I spoke to him bout it again 2day over coffee. He reconfirmed that theres basically 0 chance of turbobits being blown back into the engine from the exhaust side, however....

When the turbo craps itself, what can happen is that the exhaust wheels unbalances the compressor wheel, causing it to hit the housing and also snap. If this breaks, u can be in a bit of trouble since the bits will get sucked through the piping and into ur intake manifold. Altho the cooler should be able to block the larger bits from entering, the smaller bits will flow through. Since they are very small bits, they prob wont do alot of damage, but there is certainly a chance that it will severly damage the engine.

[Taso84]

P.S for all u making fun of my mate... this guy gets paid more than 50g p.a to work on the design of the new XR6T, whilst u guys are the internet mechanics not getting paid, and knowing close to nothing compared to him... think b4 u ridicule

[R31Nismoid]

P.S for all u making fun of my mate... this guy gets paid more than 50g p.a to work on the design of the new XR6T, whilst u guys are the internet mechanics not getting paid, and knowing close to nothing compared to him... think b4 u ridicule

and i get paid 55k a year to know a lot about nothing.

But im still classed as an expert @ my company

You cant excuse the fact that cermic dust is found in and around the piston and the piston rings

Come on, use some common sense

How does it get there if its impossible?

It doesnt just "appear" because it feels like it. You cant argue with proven fact for one second based on some persons thoughts that are not proven or backed up by real life example

[wrxhoon]

P.S for all u making fun of my mate... this guy gets paid more than 50g p.a to work on the design of the new XR6T, whilst u guys are the internet mechanics not getting paid, and knowing close to nothing compared to him... think b4 u ridicule

I don't know what you or your mate knows about RB26's and ceramic turbo wheels ( by the look of it stuff all).

I'm not an internet mechanic, i speak from experience and i have posted the evidence above ( post 12) if you care to have a look. I guess if you have no idea about engines you won't know/believe how the pistons are like that they are .

As you can see in the pics there is no ringland damage or broken rings there, the pistons are scored badly and you can see on the top of the pistons the pits from the ceramic/pieces, some are still embeded in there.

Ceramic pieces were also embeded in the cyl head, the cyl bore was scored just like the pistons are .

I have seen several more RB26's after one of the turbos has spat the exhaust wheel ( most of the times the rear for some reason) and there is always some damage to the bore /pistons, most of the time not as bad as the ones in the pic though.

I know of one RB 26 that spat a turbo, they replaced both turbos and the engine was going fine but with a little more blowby than before the turbo went. A compression test was done and it was fairly normal, down a little on a cyl 4+5 ( from memory 10psi), a leakdown test was done and she was 20-30% on the rear 3 cyls, the front 3 were all under 10%. When the engine was stripped you could see the bore and pistons scored by the ceramic dust in the rear 3 cyls.

The pistons i have in the above pic are scored very bad and compression on the the rear 3 cylinders was very low (30-60psi ) the front 3 had some damage as well but still had 160 psi comp.

I still have the damaged turbo if you want to see a pic of it just say so and i'll put it up, only the exhaust wheel is missing, the compressor wheel is still there intact . How would you explain the ceramic dust from the exhaust side will go in the inlet ? The only way back in the engine is sucked back through the exhaust valves.

I have my theories how it happans on RB 26's and not on RB 25's but i'll leave that for now.

Just think for a minute, i'm not the only one that has stripped an RB26 and found ceramic dust damage, there is a few others here as well. Do you think we are all iddiots? Tell me how manny RB 26's you ar your mate have stripped?

[GTRgeoff]

Taso, I was also reluctant to accept that the ceramic ingests into the engine on a TT setup. A couple of my Engineering specialities are fluid/aerodynamics and impulse mechanics and first impressions led me to think it was just compressor contact but believe me it does happen. I have some extensive theories on this phenomenas' occurance but proof is always difficult to establish in the how department. That it happens is fact. I'm also a mechanic from days long past and I bring in well over $100K a year in my engineering, so I'd assess your mate as being a recent undergrad. Perhaps he could hop on here and learn a few things.

[Abo Bob]

I remember this argument has been had on this forum a few years ago and a couple of highly respected forum members (not naming names but I remember ) didn't believe it was possible but the proof exists.

All it means is that it's difficult for people to definitively figure it out with the limited resources all of us have here. Once the theories have been proven or disproven and sufficiently published some of us will understand it but right now we have proof of the phenomenon but none of the reasons.

[T04GTR]

Fine then, dont believe me. I spoke to him bout it again 2day over coffee. He reconfirmed that theres basically 0 chance of turbobits being blown back into the engine from the exhaust side, however....

When the turbo craps itself, what can happen is that the exhaust wheels unbalances the compressor wheel, causing it to hit the housing and also snap. If this breaks, u can be in a bit of trouble since the bits will get sucked through the piping and into ur intake manifold. Altho the cooler should be able to block the larger bits from entering, the smaller bits will flow through. Since they are very small bits, they prob wont do alot of damage, but there is certainly a chance that it will severly damage the engine.

well it hapent to me you silly duffer

[T04GTR]

my engine shop said it was like someone threw a handfull of sand into the engine at full noise.

how do i know.

1..not many particals in the cat

2..i ruined his head surfacing machine. (ceramics dont like getting "skimmed" and brobe the tool bit a few times.

3.. pieces of turbine wheel in the intake balance chamber.

4..pieces of turbine imbeded in the piston crowns.

5..pieces of turbine imbeded under the intake. ,yes intake!!!valve seats

this may be hard to grasp but some strange things happen to a motor at 8 grand when they pop.

for example our cace civic (b16a v-tecyo) broke a exhaust valve retainer on number 1 cyl. at around 9000rpm.

i pulled it apart and found the missing exhaust valve head in the intake port of number 4!!! amongst all the other carnage lol

[AndrewD]

Its funny how this discussion has almost become about how big your d!ck is

Im an engineering graduate, and i have not worked on XR6T or RB26TT engines before, not that it makes any difference the principles are the same (you cant tell me an XR6T works on a different cycle than an RB26TT now can you)

Its elementary fluid mechanics. He should have atleast learnt that by 2nd year. And if hes is only on around 55 he is like said previously most likely a recent graduate. Like myself. That or he has no aspirations. Unlike myself

Fact is the damage could be caused by many reasons, and just because the turbine is post cylinder doesnt mean it can be excused. Engines are not steady state machines at even any far reach of the meaning. Especially the gas flow throughout them.

And as far as small particles not damaging pistons you can think that again, the acceleration of the piston itself throughout the cycle is enough to make minute particles worthy of doing damage. Why do you think most pistons fail at TDC? High inertia forces resulting from high acceleration! Even though they weigh very little. 100's to 1000s of gs can do that.

[T04GTR]

ok.. the reason the 26 is suseptable to this damage is theres two turbos not one.

theres not a constant flow of air comeing out the cllinders. rather pulses. and theres also a fair amout of presure in the exhaust manifolds. generalaly at least twice the boost pressure.

now when they break off theres roughly 20 pounds of presure tryiny to push everything back into the exhaust ports during valve overlap.

thats why all the bits can get inside the rest of the engine.

all the black shit on the intake ports is exaust deposits. mixed with oil from the breathers. it only seems to happen on these engines at hi rpm. if the wheels drop off at relativly low revs it doesnt seem to matter.

[T04GTR]

WRXHOON it took me alot of convincing to the place i got the engine from to believe what happend.

there like nup detonation ect ect. at the end of the day. i spent 7 grand on a rb26 that lasted two weeks. at .8bar.

so yeah. not happy jan lol. im still spewing that i didnt get a red cent of compensation.

[Taso84]

ok, i have had a think about it, and after reading all ur posts, i have my own opinion on the matter.

For single turbo engines such as XR6T and RB25DET, what i posted previously still holds... that it is highly unlikely that turbo bits will get sucked back into the engine since the airflow is going outwards. I myself have done abit of fluid mechanics and if this exhaust flow was laminar then we would expect this result. On the other hand if it were turbulent flow then yes it could get sucked through. From wat i can remember, i think my mate said that up to the turbo is laminar and the turbulence starts at the dump pipe, but i will reconfirm with him.

What happens with TT cars such as the GTR (in my opinion), is that when 1 of the turbos blow, the air in the engine will take the easiest path out and go through the non-blown turbo. This will cause the air-pressure from the blown port to reverse and for theengine to begin sucking air in from the blown turbo, enough pressure that is, to send tubo bits back in.

I think this is what u were saying t04GTR.

This phenomenon would obviously not be a problem in single turbo cars since there is no other way the air can escape.

Plz correct me ne1 if what im saying is full of shit... but to me it makes sense.

P.S. I said my mate makes over 55K, that doesnt mean he's not making 100gs, I just don't want to post his exact salary up on a public forum

[AndrewD]

ok, i have had a think about it, and after reading all ur posts, i have my own opinion on the matter.

For single turbo engines such as XR6T and RB25DET, what i posted previously still holds... that it is highly unlikely that turbo bits will get sucked back into the engine since the airflow is going outwards. I myself have done abit of fluid mechanics and if this exhaust flow was laminar then we would expect this result. On the other hand if it were turbulent flow then yes it could get sucked through. From wat i can remember, i think my mate said that up to the turbo is laminar and the turbulence starts at the dump pipe, but i will reconfirm with him.

What happens with TT cars such as the GTR (in my opinion), is that when 1 of the turbos blow, the air in the engine will take the easiest path out and go through the non-blown turbo. This will cause the air-pressure from the blown port to reverse and for theengine to begin sucking air in from the blown turbo, enough pressure that is, to send tubo bits back in.

I think this is what u were saying t04GTR.

This phenomenon would obviously not be a problem in single turbo cars since there is no other way the air can escape.

Plz correct me ne1 if what im saying is full of shit... but to me it makes sense.

P.S. I said my mate makes over 55K, that doesnt mean he's not making 100gs, I just don't want to post his exact salary up on a public forum

AHAHAHAHAHAHAHAHAHAHAHA

there is no way the exhaust flow at any stage is laminar

Edited October 21, 2006 by AndrewD

[khunjeng]

mate who cares what his salary is? 55k or similar is hardly impressive, but if u work for ford its not that bad cos form what I have seen, THEY pay shit. totally off topic? yeah cos this point is totally irrelevant.

[R31Nismoid]

What happens with TT cars such as the GTR (in my opinion), is that when 1 of the turbos blow, the air in the engine will take the easiest path out and go through the non-blown turbo. This will cause the air-pressure from the blown port to reverse and for theengine to begin sucking air in from the blown turbo, enough pressure that is, to send tubo bits back in.

P.S. I said my mate makes over 55K, that doesnt mean he's not making 100gs, I just don't want to post his exact salary up on a public forum

How can the air go out the other turbo when the manifolds are separate to each other.

1-2-3 & 4-5-6

If the 4-5-6 turbo dies, the air just doesnt "magically" jump to cyclinders 1-2-3 because it simple CANT. They are not connected.

So basically your saying the combusted goodies are going back out the plenum and back down to cyc 1-2-3 to go out that side? Because thats the only way they can get there in the RB26.

Do you have an idea what your talking about? I mean, seriously. Im not expert at all, im just using my basic common sense here

Not trying to be nasty here but your just coming out with more incorrect points each time you post.

100g, 10g, pfft. Doesnt mean a lot when its clear your dont know what is going on.

[Taso84]

How can the air go out the other turbo when the manifolds are separate to each other.

1-2-3 & 4-5-6

If the 4-5-6 turbo dies, the air just doesnt "magically" jump to cyclinders 1-2-3 because it simple CANT. They are not connected.

So basically your saying the combusted goodies are going back out the plenum and back down to cyc 1-2-3 to go out that side? Because thats the only way they can get there in the RB26.

Do you have an idea what your talking about? I mean, seriously. Im not expert at all, im just using my basic common sense here

Not trying to be nasty here but your just coming out with more incorrect points each time you post.

100g, 10g, pfft. Doesnt mean a lot when its clear your dont know what is going on.

It was just an idea i had, didnt realise they had seperate manifolds

[StockyMcStock]

well i feel dumber after having read all of the posts since mine. i'll stick with my idea until i hear something better.

[R31Nismoid]

It was just an idea i had, didnt realise they had seperate manifolds

[AndrewD]

well i feel dumber after having read all of the posts since mine. i'll stick with my idea until i hear something better.

Maybe you should read yours again. It was nothing special either.