Boomba Racing Blow Off Valve (BOV) adapter; Vent to Atmosphere on BL 2.0

[Major Kong]

The source is watching a boost gauge while driving a 2L turbo for the last 10 years. For normal driving the system is not in boost, it’s in vacuum. Only under moderate acceleration does it even move from vacuum to boost. You really have to push pretty far down on the accelerator to get far into boost. The turbo is always going to be hot because all of the exhaust gasses are running through it. So what we are talking about is just how hot it is. I’ve read many times over the years the advice I gave above. If this was truly an issue to be concerned about on these small turbo engines, there would be turbo failures piling up. Do turbos fail, yes. Are they failing at a high rate, no. Most drivers pay no attention to this and never will, which would lead to a higher failure rate if it were an issue. Airplanes work pretty hard during landing so I can see where they would need a cool down period. Most cars are driven easy in the last minute or so before getting parked. It’s really only at the extreme that you need to consider this cool down. After all that, if you want to sit in the car and let it idle, and that makes you feel like the turbo is being taken better care of, then by all means.

full synthetics
low volatility
not an issue of debate
hot shutdowns was the focal point
spindle seal/bearing contact closest to the heat source
potential for residue hard to ignore
cool down just long enough to finish listening to "hey joe"

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[Meanderthal]

hot shutdowns was the focal point

In my mind the question becomes how hot is a "Hot Shutdown" and how would you know?

Probably the best gauge would be an oil temperature gauge but I don't think the BS has one.

 

[Major Kong]

Aircraft engines are air cooled, which means the only real cooling provided for the turbocharger bearings comes from the engine oil. The overwhelming majority of modern automotive turbochargers—including those used in Ford's EcoBoost engines—are protected by the engine's cooling system during operation. Using the engine's liquid coolant to cool the bearings affords several advantages over oil-only cooling, including lower/more consistent peak operating temperature under load and more rapid decrease from peak when not under load. These advantages are the primary reason auto manufacturers no longer recommend a cool down period for the turbocharger—it's simply not necessary under the operating conditions most daily drivers see.

Also, as mentioned by Eric, modern synthetic engine oils are not as susceptible to coking as their dino-base equivalents. This is one of the main reasons that Ford requires the use of oils that meet the new API SP/ILSAC GF-6 standards. Piston aviation engines are not compatible with synthetic oils.

Does it hurt anything to idle your engine for whatever time you decide is necessary to "cool down" the turbo bearings before shutting it down? Aside from the use of fuel and time, not at all. Nor does it hurt anything to wear garlic as a guard against vampires, witches, werewolves, and demons. Personally, I don't see a need to do either.

To go a bit off topic (indulge me), I've been involved in general aviation for nearly three decades, so I'm intimately familiar with the operation of piston aviation engines. The video you posted is taken directly from the engine manufacturer's recommended operating manual, but if you note when the presenter begins discussing procedures (@1:22) he says, "Always follow the POH for specific shut down procedures." The POH is the Pilot's Operating Handbook—the airplane equivalent of a car's Owner's Manual. While the engine manufacturer publishes its recommended operating procedures, it's up to the aircraft manufacturer to determine which of those recommended procedures are appropriate for an engine as installed in their aircraft.

The aircraft that's featured in this video is a Cirrus SR-22T, which is equipped with a Continental TSIO-55ON, a turbocharged, direct drive, fuel injected, air cooled, horizontally opposed 6 cylinder engine with 550 cubic inch displacement. You can read the POH for the aircraft here. When you do you'll find there is no requirement for a turbo cool-down period prior to engine shut down. This is mainly because flight testing showed the low power setting during approach and near idle power typically used during taxi afford adequate cooling time for the turbocharger.

POH/eng mfg/aircraft mfg
in comparison one could draw similarities to
Ford/engine maker/borg-warner
borg-warner? (think that's the turbo maker)
will Ford offer up anything towards proactive maintenance
yeah, sure the owners manual nailed that one
maybe a dig into borg-warner turbos will help
might be a good start

 

[Major Kong]

In my mind the question becomes how hot is a "Hot Shutdown" and how would you know?

Probably the best gauge would be an oil temperature gauge but I don't think the BS has one.

My own personal take on that one would be since the water jacketed coolant and oil journals throughout the engine are in proximity to each other they may share close temperature values. So coolant temps may be an indicator.

 

[Mark S.]

full synthetics
low volatility
not an issue of debate
hot shutdowns was the focal point

True, but the main reason you should be concerned about heat after shutdown is oil coking on the turbo bearings. Modern synthetics that meet API SP/ILSAC GF-6 require a great deal more heat/time to evaporate than non-synthetics.

maybe a dig into borg-warner turbos will help
might be a good start

Good idea. For its line of aftermarket turbochargers, BorgWarner says:

Water cooling is highly recommended, wherever possible. In cases where it is not possible, turbo-compassionate cool down procedures (idle time) should be used.

 

[Major Kong]

True, but the main reason you should be concerned about heat after shutdown is oil coking on the turbo bearings. Modern synthetics that meet API SP/ILSAC GF-6 require a great deal more heat/time to evaporate than non-synthetics.



Good idea. For its line of aftermarket turbochargers, BorgWarner says:

Now we're getting somewhere
let's address the oil recommended by Ford
2.0 liter eng per owners manual

as you can see no full synthetic
not unless you head into the extreme cold operating ranges

1.5 liter eng per owners manual

once again no full synthetic until extreme cold climate

so the average owner will most likely be running a blended oil at best
non-synthetics as you can see are recommended
*recall err on the side of caution*

turbo-compassionate
hard enough to recall anniversary dates here
now my turbo wants flowers

 

[Major Kong]

Good idea. For its line of aftermarket turbochargers, BorgWarner says:

appreciated the link
think I'll bookmark that one
shop drawings stamped "reviewed & approved"

 

[Mark S.]

so the average owner will most likely be running a blended oil at best
non-synthetics as you can see are recommended
*recall err on the side of caution*

turbo-compassionate
hard enough to recall anniversary dates here
now my turbo wants flowers

I was imprecise, and you caught me! I was using the term "full synthetic" as a proxy for "API SP." The important factor is the API quality rating. The only oils capable of meeting API SP (or ILSAC GF-6) standards are either full synthetic or synthetic blend oils. Either way, oils used in our engines (and most modern, small-displacement turbocharged engines) must meet the standard for NOACK volatility testing, which is a strong predictor of coking due to heat.

 

[Major Kong]

I was imprecise, and you caught me! I was using the term "full synthetic" as a proxy for "API SP." The important factor is the API quality rating. The only oils capable of meeting API SP (or ILSAC GF-6) standards are either full synthetic or synthetic blend oils. Either way, oils used in our engines (and most modern, small-displacement turbocharged engines) must meet the standard for NOACK volatility testing, which is a strong predictor of coking due to heat.

Of the 12 categories half show gains were accomplished for the GF-6 (A)
notably in the hi-temp deposits
and largest gain in chain wear

so does the chart boundary just terminate there
has hi-temp deposit met the final goal
somewhere I ran into a GF-6A comparison wheel to the GF-6B
boundary of the wheel expands outward indicating potential for improvement

I'll gladly acknowledge the improvements done in the last couple years

I'll still be wary of any hard shutdowns after a workout

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