Why does this keep happening?!

[JaamesVRS]

You guessed it...... another turbo, this one was still working .... just! But was going woooooo woooooooo and making very little power. My last CHRA failed at 500ish miles and this one has done the exact same!!! This was the same company sending a CHRA out on warranty. Is this bad CHRA causing the issue? As I’ve ordered a recon Garrett 1749VB which will be here tomorrow and obviously don’t want that to fail!!!! . In terms of the slight damage will I need to remove the FMIC again and flush it out? Or will it be okay as damage is fairly minimal 

Edited 28 March, 2018 by JaamesVRS

[JaamesVRS]

I’ve dropped the intercooler and hard pipes cleaned them out with petrol, filled intercooler couple of times dumped out, doesn’t sound like anything In there. The oil was changed 500 miles ago, is it necessary to change the oil again? Or will it be okay? 

[sepulchrave]

Oil should be fine since everything is still intact.

 

I can't explain that damage unless the turbo is overspeeding dramatically, the ECU should prevent overspeed (overboost) and flag a fault if it happens unless the map you're running has been programmed to ignore it.

 

I find it unlikely that you'd get two bad cartridges in a row, I'm starting to suspect a very bad map.

[JaamesVRS]

My friends Cartridge from the same company also failed, I’ve kept the car off Boost since it’s been fitted haven’t strained the turbo in the slightest. Not hit the limiter, not abused it full throttle or anything. That’s what I don’t understand, we had issues with the CHRA being difficult to spin once the housings were fitted back together, and took the turbo apart again and kept cleaning and sanding down any pitting marks til it spun freely, however there’s a possibility it contacted for .00000001 of a second causing the damage. What causes impeller damage like this? Seeing as my first tirbo failure did do the same thing, possibly faulty VNT and the impeller making contact with the VNT system? 

[sepulchrave]

VNT is on the hot side, we're looking at the cold side here so VNT not a factor. I'm obviously concerned that you had issues with impeller clearance, that suggests that it may have been damaged during assembly, the impeller is incredibly fragile and any contact would distort it causing it to run out of balance.

[JaamesVRS]

Of course it is, brain fart lol... is this damage from the impeller hitting the housing then? Okay so possibility it’s the turbo being put back together is what caused the failure? Obviously I don’t want my shiny new Garrett unit from Turboactive to fail! I’ve washed all the Boost pipes out with petrol, and filled the FMIC with petrol and dumped it out twice, then shook the intercooler listening for a metallic noise, the oil feed and return I blasted through with can brake cleaner until the cleaner the other end came out completely clear, is that sufficient? Obviously the other times when the turbo failed I have changed the oil filter air filter and oil 

[JaamesVRS]

Also I never got the VNT setup or the actuator, I used a feeler gauge on the CHRA stop screw until it was the same as standard CHRA that come out, granted it’s not the correct way to do it but all I had. This new turbo is fully setup according to the company, all on a special machine 

[sepulchrave]

Don't worry about debris, it can't get back to the turbo if it's on the high pressure side (which the intercooler is), the turbo can only suck debris in from the intake which is why there's a dirty great big paper air filter in the airbox.

[JaamesVRS]

Okay cool that’s reassuring! The other thing I noticed, on light throttle application, say when accelerating up a hill, or just increasing speed from say 30-50 the Boost gauge would climb to 25 psi, if I come off the throttle it would flutter/surge/chatter whTever you want to call it, and that was accompanied by a huge whooooooooooooosh hiss type sound (not Boost leak had the system pressure and smoke tested) like serious amounts of air rushing through the system, now I would expect 25psi on full throttle application, not 1/3 throttle? Is this a symptom of ovwrboost? Could these failures be due to me not getting the stop screw and actuator setup on the new CHRAs? 

 

The car never ever threw a code for over Boost or went into limp mode, only time t went into limp mode was when a boost pipe popped off, never had a code for over Boost like you said could of been mapped out. 

Edited 28 March, 2018 by JaamesVRS

[sepulchrave]

Boost is dependant on load, not throttle, full boost is available very early on turbo diesels with VNT turbos. Stop thinking like a petrolhead, you're a dervhead now.

[JaamesVRS]

I’m going back to petrol head in a couple of months! Had enough of this derv life already!! Could the stop screw or actuator rod being set incorrectly cause Overspin? Or is that an ecu controlled variable?

[sepulchrave]

Just now, JaamesVRS said:

I’m going back to petrol head in a couple of months! Had enough of this derv life already!! Could the stop screw or actuator rod being set incorrectly cause Overspin? Or is that an ecu controlled variable?

 

Yes, incorrect setting can indeed cause overspeed but the ECU should sense it and feather the VNT and flag a code for overboost.

[JaamesVRS]

Unless the values/tolerance to ping the code have been set stupidly high to stop the ecu throwing the car into limp mode? Is there a way to tell the car is overboosting? Any tell tale signs? Someone told me when I’m lifting off the throttle around 3k rpm the flutter sound I’m hearing (like a petrol with a cone filter) is overboost. Although mine has standard air box and OE filter 

[sepulchrave]

23 minutes ago, JaamesVRS said:

Unless the values/tolerance to ping the code have been set stupidly high to stop the ecu throwing the car into limp mode? Is there a way to tell the car is overboosting? Any tell tale signs? Someone told me when I’m lifting off the throttle around 3k rpm the flutter sound I’m hearing (like a petrol with a cone filter) is overboost. Although mine has standard air box and OE filter 

 

The sound you're hearing is the VNT feathering, jesus stop LISTENING to these ****ing idiots. In fact stop talking to them altogether, whenever someone you know starts talking rubbish you have to slap them hard, deal?

[JaamesVRS]

He’s Polish, owns a garage near here called Boost Factory, built some extremely powerful cars, Audi 8L S3 750bhp, Integra DC5 700bhp out of standard K20 etc! He does know his stuff but it could be language barrier. It never done it on my original turbo, but the VNT Feathering is that an overboost condition? As like I said never happened on my original turbo! Only since changing the CHRA

[sepulchrave]

16 minutes ago, JaamesVRS said:

He’s Polish, owns a garage near here called Boost Factory, built some extremely powerful cars, Audi 8L S3 750bhp, Integra DC5 700bhp out of standard K20 etc! He does know his stuff but it could be language barrier. It never done it on my original turbo, but the VNT Feathering is that an overboost condition? As like I said never happened on my original turbo! Only since changing the CHRA

 

So he knows how to get big power from PETROL engines, this is totally different, the VNT feathering hard means the ECU has sensed that you don't want boost because you've come off the loud pedal, the VNT will feather progressively as peak boost is reached to prevent overboost, you can't generally hear this happen, the engine just runs out of power.

I now suspect the VNT linkage has not been set up correctly and the map has been bodged to prevent ECL and limp mode engaging.

[JaamesVRS]

He’s built a few high spec 2260s PD engines are very popular in Poland apparently. He’s got a sponsor car on the ramps at the minute with 2260 and custom pipework etc loads of bits great project to follow to be honest. However I understand what your saying. In terms of Knowing I have overboost how can I do this? I don’t have a laptop to run VCDS 

[sepulchrave]

You can't, you need someone with VCDS to log requested and actual boost while doing in-gear pulls.

[JaamesVRS]

Okay cool before I bought the turbo I asked the company about the VNT etc being set up and they told me it’s all setup on a flow machine to the Factory spec so I’m theory I should be okay? 

[JaamesVRS]

What is th actual cause of overspin i know Boost leak is a factor however I know for a fact I haven’t got a Boost leak as that’s been pressure (30psi) and smoke tested with no leaks, so what else would be causing it? Is that why my original turbo failed? I’m going to link the photos of all 3 failed turbos the order they are posted in is

CHRA Replacement,

CHRA Replacement 2

Original

Edited 29 March, 2018 by JaamesVRS

[JaamesVRS]

Obviously this is all the same actual turbo as original, just the CHRA that was changed, is it possible it’s the VNT causing the issue? Say for example it’s sticking and causing overboost, as all 3 failed in the same core with the same impeller damage, the snapped shaft on the second turbo is that down to over speed? 

[JWvrs25]

I had a very bad remap on my car, caused massive overboost between 2000-3500 rpm, it ran fine for 8000k miles on an old turbo so doubt its your map causing the issue.

The vnt and stop screw aren't usually correctly setup unless a brand new turbo unit from kkk or garrett. My recon was 'flow tested' etc etc and still wasn't set correctly when fitted, had to get it set up whilst on the car doing 3rd gear WOT runs to check boost. 

Again, I don't think this would cause the turbo to fail as the ECU usually senses overboost and will put it into limp mode.

Sounds like the issue with how it was mounted in the housing, must be some slight difference in the sizes causing it not to sit correctly. Could the housing be distorted at all??

Did you clean the TIP thoroughly as well? they get all oily and some of the bits of the old turbo may have stuck in there and then been fed back through the new turbo. Just a thought as thats most likely how my 2nd turbo failed (previous garage not doing the job properly)

Its unlikely that the core is the issue as its the 2nd one and also you say the company has many good reviews which would suggest they do things properly.

 

[JaamesVRS]

Yeah I understand what you mean, I bought the car in june and got it remapped in July, and it ran fine up until January when the first turbo went. I’ll be honest I didn’t clean the TIP out until yesterday, rinsed it out with petrol sealed both ends gave it a shake dumped it out etc, so the issue could possibly be the CHRA not fitting correctly in the original casing? Hence the damage to the impeller. How and where can I get the VCDS logs done to check for Boost etc? Do you know anywhere in kent that will do it? My inlet manifold is all caked up with ****, is it worth cleaning that out (if so how) or just leave it? 

[JWvrs25]

VCDS is £80 for registered lite version, cable is about £10 and you can do all the diagnostics and scanning you will ever need for the fabia with that.

Otherwise any tuners or vw specialists should be able to log it for you.

Intake manifold can be cleaned by removing and soaking in mr muscle over cleaner overnight. Then scrub with (old) toothbrush and rinse out with carb cleaner or petrol until fairly clean. You wont get it all out but will get somewhere good.

What could have happened is the TIP got sprayed with aluminium bits from the old turbo and it all stuck in the oil residue which builds up. Then as you use the car the oil and bits of alloy get sucked in and damage the wheel. That could throw it out of balance and cause it to snap if the bits were big enough. It would seem though that your issue could be to do with 'we had issues with the CHRA being difficult to spin once the housings were fitted back together'. It doesn't sound great considering the turbo spins over 100,000 rpm and any slight contact would damage the blades

[JaamesVRS]

I’m not planning on keeping the car much longer, I’ve had enough issues with it now to want to burn it. Can’t wait to see the back of it! So not point spending on VCDS when it’s going soon. Just want it reliable as I couldn’t ever bring myself to sell a dodgy car to someone! I’m not that type of person. Yes the issue we had as soon as the bolts were tightened up on the housing the CHRA wouldn’t spin at all, not until the bolts were loosened off, we must of had the CHRA in and out the housing 30 times until we were “happy” with it