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The entire problem with this is that all turbos are defective, but they don't fail catastrophically. Willing to be dollars to donuts that if some who posted on here went to the dealership complaining of a turbo noise and the techs did a full inspection (turbine and compressor side), at least some would be getting new turbos. The design is flawed. Some don't just have unicorn turbos.
 

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2014 Q50 Sport Deluxe technology pkg takeda stage 2 intake custom axel-back 3inch resonated exhaust
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I saw a really nice RS for sale,,2016-91,000 miles very attractive price,,BUT SORRY NO WAY,,BEING HONEST..
 

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I normally don't buy any vehicles with 70k miles unless they are quite old/rare, etc. Unless it was a superultrablowoutdeluxe price and I knew the history (say all highways mileage, adult owner that took care of it) and was in excellent shape, then no wouldn't buy a Q50 with 70k miles.
 

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2014 Q50 Sport Deluxe technology pkg takeda stage 2 intake custom axel-back 3inch resonated exhaust
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Sure I understand,,buying one with 35k has a degree of risk,,the higher mileage you go, the risk just becomes unacceptable,,,
 

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I spent all 10 years of Legacy GT ownership waiting for the turbo to fail. I suspect it will be the same with my Q50.
Have you crossed 10k miles on your Q50 yet Pill?
 

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2018 Q50 Red Sport 400 AWD
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Again, don't be afraid of a VR30 with 75K on the clock. The chances of the OEM turbos failing at that point is basically non-existent or the turbos have already been replaced. I'd say that a higher mileage Q50 is probably safer to but than one at 30-50K miles.
 

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2021 Q50 RedSport, ARK Cat-Back. HKS BOV, AMS LDP, Mishimoto Catch Can
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We had a 2018 Luxe for sale that had 120k miles, no turbo failures, it sat for a bit, not for the mileage but because of the color, mocha almond RWD. Car drove fine and eventually did sell
 

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If I end up really liking my Q50 I can see keeping it to at least 70k miles.
You just got the car at 35k miles and you only think you MIGHT keep it until 70k?
 

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Discussion Starter · #32 · (Edited)
You just got the car at 35k miles and you only think you MIGHT keep it until 70k?
I should rephrase that - I hope to keep it to 70k and beyond. I generally keep my cars for a while. I still have a Toyota Venza, that I just gave to my daughter, that is a 2009 with 179k miles! I also have 2 summer only cars - a 1991 MR2 Turbo and a 2008 BMW 335 convertible.
 

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The entire problem with this is that all turbos are defective, but they don't fail catastrophically. Willing to be dollars to donuts that if some who posted on here went to the dealership complaining of a turbo noise and the techs did a full inspection (turbine and compressor side), at least some would be getting new turbos. The design is flawed. Some don't just have unicorn turbos.
If this is true, why would they expand the use of the engine into the Z? I thought someone said it was going into an SUV too, but maybe that was just a rumor. Seems it would hurt the sales of the Z if turbo failure was considered imminent. For those that do sell, the failures would tarnish the Z's reputation.

What is the actual design flaw? My sense from reading posts here is that about 2/3 have bearing noise and 1/3 have oil leaking into charge pipe...are these both caused by the same issue?
 

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Yes, both issues are caused by bearing failure. The sound is caused by the compressor wheel rubbing the housing and the burning oil is usually from a failed turbine housing seal. The failing rear seal usually leads to excessive play which allows the wear on the compressor side which eats the thrust bearing and compressor wheel.

The bearing in the mgt1446 is a semi floating single bearing unit that combines a thrust bearing surface on the end instead of using a separate piece. This is supposed to cut down on stack errors due to less parts and easier assembly. It looks ok enough from what I've seen online but who knows.

I really wish an Infiniti tech could crack open a failed turbo for inspection so we could see the failure mode. Alas, they get sent back to Garrett for rebuild so there's no incentive for disassembly.

The turbo itself could be fine but the application might not be great. Maybe these turbos don't get sufficient lubrication at low rpm from the engine when they're under boost at 1,600-2,000rpm. Maybe some of these wheel assemblies aren't properly balanced or go out of spec. Maybe the thrust surface isn't large enough and collapses at high load/low rpm.

The world may never know.™
 
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Interesting,,sounds like your on to possible answer if any cared to solve this,,,
 

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Discussion Starter · #36 ·

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If this is true, why would they expand the use of the engine into the Z? I thought someone said it was going into an SUV too, but maybe that was just a rumor. Seems it would hurt the sales of the Z if turbo failure was considered imminent. For those that do sell, the failures would tarnish the Z's reputation.

What is the actual design flaw? My sense from reading posts here is that about 2/3 have bearing noise and 1/3 have oil leaking into charge pipe...are these both caused by the same issue?
I think you're misreading my message. There's nothing wrong with the engine. The turbos are defective. They're not STILL defective in a 22/23MY. Anything prior to the real fix, say 19 or 20 is defective in design.
 

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2018 Q50 Red Sport 400 AWD
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I think you're misreading my message. There's nothing wrong with the engine. The turbos are defective. They're not STILL defective in a 22/23MY. Anything prior to the real fix, say 19 or 20 is defective in design.
Thanks.

As if I didn't have enough issues in my life keeping me awake at night.
 
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@Ddnspider has anyone actually been able to confirm a change to the turbo outside of a part number change?

While I'll agree that part number changes often signify a revision, they often change due to batches as well. Those two could happen at the same time of course but I've never seen anything that suggests actual improvements were made. I would hate to think that the new turbos are different when they're not, and the reason we don't see failures on newer turbos is because, well, they're just new.

I've looked on this site and not found anything. If my google-fu has failed me then that's fine. Do you have any concrete evidence? Hell, I think if take anyone's word for it as long as they've physically compared the old vs new turbskis.
 
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