Turbocharger Longevity?

[Cujet]

Just an FYI.

Today's turbochargers use water cooled housings, which helps to reduce coking.

However, the water cooling does not eliminate coking, as the turbine hot side is still red hot, as are the seals, and the shaft is still welded to the turbine. The shaft transfers heat right into the hot side seals and bearing(s) . It's not unusual for a turbine to be 1650 degrees F and the shaft a few degrees less.

What is different is the design of modern turbochargers. They are designed to operate properly with some coke buildup and are tolerant of it.

This is why people can "get away" with using lower quality oils on turbocharged engines without failures. However, at some point, the use of inferior oils coupled with high temperatures will result in significant buildup. Probably to the point of failure. Put another way, "that guy" who claims to use non synthetic with great results is likely unaware of the condition of the turbocharger.

Please use a quality synthetic in your turbocharged gasoline engine, AND change it regularly. It eliminates many potential problems.

NOTE: many diesel engines have EGT's that do not exceed 1200 deg F on a regular basis and larger diesel engines do not get the turbochargers anywhere near as hot as a high performance gas engine. Plus diesel engines have downright cool EGT's under light loads due to excess air. This lowers stress on diesel turbochargers.

 

[paoester]

Originally Posted by Cujet
Today's turbochargers use water cooled housings, which helps to reduce coking.
Don't forget oil cooling too. Key is today's variable displacement oil pumps that increase oil pressure (and flow rate for more cooling) basically proportional to throttle position and/or turbo pressure and/or turbo temperature; computer controlled.
A lot of engines use these special oil pumps these days.
This is probably why thin 0w20 oils are able to be used in a lot of small highly stressed turbo engines currently.

Also, remember the oil flowing past turbo bearings is not exposed to much oxygen. Its part of the reason why GM put additional aeration (foaming) tests in dexos1 Gen2 specs so that oxygen doesn't get up next to the hot turbo parts excessively.

Originally Posted by Cujet
Please use a quality synthetic in your turbocharged gasoline engine, AND change it regularly. It eliminates many potential problems.
It's often repeated that base oil is super important, but its not completely true. Again, as long as aeration is low, base oil isn't a big factor at all.
Base oil has far less to do with it than the additive chemistry. See starting at the 17:00 point in https://www.youtube.com/watch?v=0B6SHa4qv60 for engine studies on that. They found some additives can't take the turbo heat without decomposing in some way.
Let's go with actually what happens instead of conjecture.
The only way to be sure is to make certain your oil passes ACEA or dexos1 turbocharger deposit tests, and maybe the older Honda HTO-06 test. Why guess with all that proof available?

 

[ctechbob]

Just like anything, depends on many variables.

Several years back (early 2010's) I was riding with a kid, when I was still doing track day instructing, who was driving his fairly new twin turbo car. As we were chatting in the pits I was telling him how impressed I was with the car, it really pulled like a giant V8 coming out of the corners from low speeds. He remarked how much he liked the car and how he planned on keeping it a long time, but was saving for new turbos.

'Ohh, are you planning on upgrading?'

'No, they just break around 60k miles and have to be replaced'

'ok then'

Sure enough, I went home and did some research and that particular car, and yep, fails turbo's at what most people would consider an obscene rate.

At the same time, my brother had an old mid 80's Mazda 626 turbo that had over 200k on it when it got totaled by a truck. Ran like a top, didn't burn oil, and boosted like it was supposed to. All that on 'old technology'

With as many mines as the OP has, I'd say, if they were going to break or have a short life, they'd have done so by now. With good maintenance you should be good for some time.

 

[LeoStrop]

I believe it depends on the situation. The amount of boost, what type of engine it is attached to, and even the driver can affect the turbo longevity. Today's turbos are immensely better, but also has to work harder.

Like others said, letting it cool down is a good move. I also heard that modulating the throttle under high load/boost it's not the best practice.

Sometimes just a rebuild can solve the problem of a faulty turbo.

 

[Andrew1972]

Our old 2005 Legacy Turbo with a WRX engine has 250k on original turbo. My wife changed oil every 4K with conventional since new sold last year.

 

[wemay]

200k on our Hyundai Santa Fe Sport 2.0T. The turbo feed line was replaced through a TSB but never has had a turbo issue. It's used mostly Synthetic but the occasional VWB too.

I used to own a modified EVO VIII that was fed 15W-40 conventional every 3k miles. I sold it with 188k hard use miles.

I've owned others as well. Never had to replace a turbo.

 

[Cujet]

Originally Posted by paoester

Also, remember the oil flowing past turbo bearings is not exposed to much oxygen. Its part of the reason why GM put additional aeration (foaming) tests in dexos1 Gen2 specs so that oxygen doesn't get up next to the hot turbo parts excessively.

It's often repeated that base oil is super important, but its not completely true. Again, as long as aeration is low, base oil isn't a big factor at all.
Base oil has far less to do with it than the additive chemistry
The only way to be sure is to make certain your oil passes ACEA or dexos1 turbocharger deposit tests, and maybe the older Honda HTO-06 test. Why guess with all that proof available?



https://www.fuelsandlubes.com/fli-a...rtant-in-preventing-turbocharger-coking/

I dispute the claim that base oil matters little. It matters immensely (possibly due to the elevated temperature that a oil/fuel mix cokes at with better base stocks) as does the oil change interval due to fuel contamination and particulate accumulation in the oil. The good news is that there are many great oils available today, and that fact certainly prevents many problems.

In a past life, I was involved as a tech in just a little (not a lot) of HTS (high thermal stability) oil and grease testing. It's also good to remember that not just the oil carbons up a turbocharger's hot side. Fuel byproducts carried by the oil can also turn to hard carbon on the hot parts.

Amazingly, some oil escapes beyond the hot side seal and is exposed to plenty of oxygen. Yet either side of the seals will often be equally coked.

 

[antonmnster]

213,000 on the Mitsubishis in the BMW. I expect the front, smaller turbo to go fist, since it works a lot more than the larger, rear one. They still work great. If I'm out on a hot, high speed interstate run, I'll let the engine idle and lock the doors if I run in somewhere to keep the oil moving. Otherwise it's very common to hear the water pump running 5-15 minutes after shutdown.

 

[The motor guy]

Originally Posted by JohnnyJohnson
An acquaintance had his Turbo go out on his Duramax with only a little over 70K miles.


What failed? Sometimes the veins get stuck and you just need to drive it harder.

 

[PimTac]

Originally Posted by motor_oil_madman
Originally Posted by JohnnyJohnson
An acquaintance had his Turbo go out on his Duramax with only a little over 70K miles.


What failed? Sometimes the veins get stuck and you just need to drive it harder.




I think you meant vanes. If they are getting stuck then that turbo is doomed anyway.

 

[bdcardinal]

Originally Posted by PimTac
Originally Posted by motor_oil_madman
Originally Posted by JohnnyJohnson
An acquaintance had his Turbo go out on his Duramax with only a little over 70K miles.


What failed? Sometimes the veins get stuck and you just need to drive it harder.




I think you meant vanes. If they are getting stuck then that turbo is doomed anyway.


The 6.0 Powerstroke turbos would get coked up, but there was a procedure for cleaning them. Even then some would get to the point where you had to replace them.