3.5 turbo let run ?

[Gros Ventre]

How long does it take the turbo to cool after a long hot pull? I bet the answer will surprise you.

The common practice for aircraft turbos for spin down & cooling is 5 minutes at engine idle. Aircraft turbos can get glowing red hot during extended power runs. So I use 5 minutes. What I do when going to that coffee & snacks place at the top of the climb is to shift to manual then downshift to get a high enough engine rpm to stay off the turbos. I find about 2000-2200 rpm in 4th shows no boost.

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[TheGoatman]

The common practice for aircraft turbos for spin down & cooling is 5 minutes at engine idle. Aircraft turbos can get glowing red hot during extended power runs. So I use 5 minutes. What I do when going to that coffee & snacks place at the top of the climb is to shift to manual then downshift to get a high enough engine rpm to stay off the turbos. I find about 2000-2200 rpm in 4th shows no boost.

I’m sure. Like mentioned, old cars without coolant, cars with huge aftermarket turbos still a good idea to run turbo timers.

 

[Gros Ventre]

I’m sure. Like mentioned, old cars without coolant, cars with huge aftermarket turbos still a good idea to run turbo timers.

I agree. The core issue I face is that with a PowerBoost, I have to outthink the engine off cycling when cresting a slope. If you stay at power it'll be no problem. But if you reduce power for some reason, like for my coffee place, then you need to plan ahead since the engine will cycle off.

 

[TheGoatman]

I live in a really hilly area. My trucks been turned off hot after a big climb daily. There’s no way around it for me, My wife uses my truck and I’m not waiting around at this frequency. So there’s no point for me and like you said the powerboost programming is happy to turn it off. For me It is what it is. If I have to alter my behavior, I’ll go to a ‘27 GM na v8…I’m at sea level

 

[Goldeneye36]

The common practice for aircraft turbos for spin down & cooling is 5 minutes at engine idle. Aircraft turbos can get glowing red hot during extended power runs. So I use 5 minutes. What I do when going to that coffee & snacks place at the top of the climb is to shift to manual then downshift to get a high enough engine rpm to stay off the turbos. I find about 2000-2200 rpm in 4th shows no boost.

The thing is that aircraft and car engines operate in very different ways. Cars vary their power load throughout different speed and acceleration regimes and spend very little time at maximum output. Aircraft engines operate at max power for several minutes during takeoff and initial climb then stay at 80-90% power during cruise for potentially hours on end. To me that's not really an apples to apples comparison. If it was driving my truck at full or almost full throttle for 3 hours straight then I would definitely consider a cool down period. In reality, my normal driving barely touches the boost outside of accelerating from a stop or merging on the highway so the amount of positive boost I see during a typical 30 minute drive is minimal.

 

[Gros Ventre]

The thing is that aircraft and car engines operate in very different ways. Cars vary their power load throughout different speed and acceleration regimes and spend very little time at maximum output. Aircraft engines operate at max power for several minutes during takeoff and initial climb then stay at 80-90% power during cruise for potentially hours on end. To me that's not really an apples to apples comparison. If it was driving my truck at full or almost full throttle for 3 hours straight then I would definitely consider a cool down period. In reality, my normal driving barely touches the boost outside of accelerating from a stop or merging on the highway so the amount of positive boost I see during a typical 30 minute drive is minimal.

You miss the point... It only takes a few minutes at high power to get the rpm up and temps up. Once that's reached it is irrelevant how long you stay there.

 

[XLT22]

He's ignorant because he doesn't understand the lubrication issue for a shaft spinning as much as 100,000 rpms that is involved.

I only worked on them for their entire production run up until recently. I can assure you every use case has been thought of by now. These small turbos have very little inertia and slow down almost immediately with the wastegates open. I've seen various turbo failure modes over the years but not a single one ever had a thing to do with being shut down hot.

 

[Goldeneye36]

You miss the point... It only takes a few minutes at high power to get the rpm up and temps up. Once that's reached it is irrelevant how long you stay there.

Maybe not completely. Heat soak is a thing and a handful of seconds at full throttle, which is what most engines will see at a time, won't heat soak the block or the turbo housings. How many people are running their engines at high or max load for minutes at a time then immediately shutting them off? Maybe drag racing comes close but even that is measured in tens of seconds at most and if you are towing something heavy enough to need minutes of full throttle with these 400HP+ engines then something isn't right.

If someone is towing or doing spirited driving IRL the amount of time spent at or near 100% load is minimal and there is most likely at least a short period of low throttle or idling afterwards before shutting off the engine where things could cool off to some extent.

 

[XLT22]

You miss the point... It only takes a few minutes at high power to get the rpm up and temps up. Once that's reached it is irrelevant how long you stay there.

With the cooling modules these trucks combined with the emissions strategy they just aren't going to let you get them hot enough to damage anything unless there's some sort of component failure or tampering.

You really can't compare gasoline turbocharged engines to aircraft turbines. The mode of operation is totally different. The Ecoboost turbochargers being both oil and liquid cooled operate within a relatively narrow temperature range because there's a catalyst downstream that can't tolerate excessively high exhaust gas temperatures.

 

[XLT22]

Maybe not completely. Heat soak is a thing and a handful of seconds at full throttle, which is what most engines will see at a time, won't heat soak the block or the turbo housings. How many people are running their engines at high or max load for minutes at a time then immediately shutting them off? Maybe drag racing comes close but even that is measured in tens of seconds at most and if you are towing something heavy enough to need minutes of full throttle with these 400HP+ engines then something isn't right.

If someone is towing or doing spirited driving IRL the amount of time spent at or near 100% load is minimal and there is most likely at least a short period of low throttle or idling afterwards before shutting off the engine where things could cool off to some extent.

Our fleet drivers would challenge the notion of not running full throttle for minutes at a time.

The amount of XL trim 2.7s running around since 2015 on the cheapest synblend oil getting changed at 10k miles while loaded above max payload every single day would make your head spin. When they get enough miles the older style mechanical wastegates crap out before the shaft bushing ever get worn.

 

[v8440]

Wait, are you telling us that ford actually thought about the powerboost shutting off? You really don't have to outsmart the pcm strategy? I dunno, trusting them to have considered that sounds, kinda, I dunno, ignorant.

 

[F-150_Fan]

You don't need to worry about cooling the turbos by idling. They are still spinning even while idling, though boost is minimal, so not generating any more heat to dissipate. I believe Powerboost have an aux electric pump to force coolant through the turbo bearing casing, and non Powerboost turbo are designed to use the temp differential to siphon cool the bearings.

I had a 2013 Ecoboost and never any issues with the turbos or the engine, for that matter, in over 140K miles and it is still running fine for the new owner. Don't worry about it, Ford engineered the engine to live a normal everyday driving life.

Google it up and you can read all about it

 

[Billflangjr]

Hi folks , heard something today and just wanted to ask on here about it. My 2022 3.5 Ecoboost , should I let the engine run for a couple minutes after I park before shutting off because of the turbos? I normally give it a descent enough warm up from cold before driving anywhere and that’s about it . Thanks

I do , if I was using the turbos or driving hard. And I always warm my truck up from a cold start always. The turbos do get extremely hot and it will cook the oil in them. So letting it idle cools them down. But I change the oil so often in my truck that is always good oil in it every 3000 miles to 2500. Oil is cheap compared to an engine repair. Yes warm your truck up on a cold start. Cool down the turbos just a bit and you’ll be good.!!

 

[Gros Ventre]

I only worked on them for their entire production run up until recently. I can assure you every use case has been thought of by now. These small turbos have very little inertia and slow down almost immediately with the wastegates open. I've seen various turbo failure modes over the years but not a single one ever had a thing to do with being shut down hot.

On similar sized aircraft engines with similar sized turbos, the issue of coking and scoring of the bearings is a known problem. Unless there is a designed in feature to provide lubrication during shutdown there is a real risk of damage. I'm sure they spin down quickly... but when you start from 100,000 rpm it can still take a measurable amount of time. Appreciate your assurances but they don't ring true.

 

[Gros Ventre]

With the cooling modules these trucks combined with the emissions strategy they just aren't going to let you get them hot enough to damage anything unless there's some sort of component failure or tampering.

You really can't compare gasoline turbocharged engines to aircraft turbines. The mode of operation is totally different. The Ecoboost turbochargers being both oil and liquid cooled operate within a relatively narrow temperature range because there's a catalyst downstream that can't tolerate excessively high exhaust gas temperatures.

Was speaking of aircraft turbo charged piston engines... not gas turbines.

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