Clearly you are a ford fan, Im not sure why you are here. I think you belong on f150forum, with all the other "ecoboost is god" people.
Actually I am an every truck fan. I don't limit myself to liking just one brand and I think doing so is silly. There are things from every brand that I like and dislike. For example, while I like Ram HD diesel trucks better, I don't think Ram makes the best half ton out there from my personal experiences.
You talk about high rpm being an engine killer, but dont consider that high boost at low rpm with a big trailer generates A LOT of load on the motor and trans in your towing example. Good way to pop that little **** motor, similar to what happens with all those blown head gasket diesels (that you also love so much).
Yes, high rpm is one of the major factors of decreasing the life of an engine. Moving parts cause wear, and the faster they move the more they wear. Although your high boost scenario that you are speaking of is not a killer IF the engine is built to handle said pressure. Just like a diesel is "over built" to handle the pressures of turbocharged compression ignition, so can gas motors which is clearly the case with the Ecoboost being that it has beefier internals than the average engine with steel cylinder sleeves rather than iron, and six bolt mains where most are only four.
Of course if you increase boost too much then yes you can blow a head gasket especially if it isn't designed to handle that much pressure just like the guys who increased the boost 50 psi on their diesels and were blowing head gaskets left and right. However, going back to what I said above of things being designed to handle the stress, an aftermarket head gasket made to handle that much stress over the OE head gasket that was only designed to handle up to 40 psi. My towing tune on my Ecoboost was at 410 hp and 530 lb-ft and the boost never spiked over 20 psi which is only 5 psi over stock. That is not much. I also know for a fact that the 6R80 transmission in the F150 was designed to handle 590 lb-ft which my 530 lb-ft was well below that.
Blown head gaskets and burnt trannies are due to dumb****s back in the day who just bought a tuner to increase engine power only and did not do anything to beef up the rest of the truck to handle said power. They did nothing to increase the line pressure on the transmission to keep it from slipping from all that extra power or defuel the engine to keep the EGTs in check. If you build the transmission to handle the added power, then you would have no problems. This is why ATS and other trans manufacturers sell transmission stages because they are built to handle the added power depending on how much you want to add.
So it depends if said engine or transmission is built to handle said stress. If it is build to handle it then there should not be any issue with longevity.
People, including ford, have been selling/driving turbo vehicles since the 80s. Turbocoupes, SVO mustangs, etc. The whole "ecoboost" scam is silly, just a ploy to play on noobs who dont understand anything about automobiles. Its just a turbo motor. Plain and simple.
Older oil cooled turbos with port injection are a lot different than the modern oil-water cooled turbos with direct injection so yes the combination of both in newer trucks makes a BIG difference.
Older turbos only relied on oil to cool down the bearings which is fine when the engine is running, but the real killer is when the engine gets turned off and all the heat from the exhaust will soak into the turbo housing. Since the engine was not running and there was no oil going through the turbo housing to cool the bearings down, then turbo housing gets hotter than what it would with the engine running. This would burn the existing oil in the bearing housing or "coke" it into the housing which is bad for a turbo. This is why it was recommended for people to let the engine idle for a few minutes before shutting it off to let the turbos and exhaust to cool down. Problem was, most people with these vehicles did not abide by this.
Another thing is the port injection. Port injection does not allow for precise timing of fuel delivery and fuel can only be added on the intake stroke. This causes a problem with fuel pre-detonation which is why most turbo engines back then required premium fuel and had a high compression ratio.
Modern turbos are oil and water cooled which not only is an added cooling when the engine is on, but also keeps the turbos cooled when the engine is off. If arranged correctly, the system creates a "thermal siphon" so that there is a continuous stream of coolant flowing through the turbo until it is cool enough where "coking" will not occur. Add the precise fueling of direct injection to the mix and it does not require you to have such high compression ratios or higher octane fuel requirement as the older turbo vehicle you spoke of.
There are other things that modern engines like the Ecoboost use to cool down the engine like injecting fuel on the exhaust stroke or utilising oil squirters on pistons.
I wouldnt hold your breathe on a ecoboost 3/4 ton, trying to tune something like that so that your average noob, driving along in the 105 degree heat WOT in the hills with a 18klb load, doesnt blow it up is going to be almost impossible.
I don't have to hold my breath because I know it is coming. Although, even the 6.4L or my Cummins in my 2500 is rated for 18k so why would you put that kind of weight on the Ecoboost? Remember what I said about being within it's designs earlier.
Thats why there is sooo much room on diesel tunes (and ecoboost)... not because the factory engineers are morons, because they have to support EVERY buyer out there. Most of which arent very bright.
Modern engines are tuned for emissions first, and diesel and Ecoboost engines have turbos. This is why you can get so much out of them while still being safe.
On the Interwebs all is possible. I've seen lots of Cummins owners claim 30mpg on the highway.
