Originally Posted By: 440Magnum
Originally Posted By: Cujet
Downsized, turbocharged, high output engines have been around for over 30 years. I drove 1987 Thunderbird Turbo Coupe, with 2.3L engine. It was a heavy car, that's for sure. And the little turbo engine, with increased boost (by me) held up perfectly over the long haul. Albeit on a diet of Mobil 1, 15W-50. The demise of that car was not the engine wearing out a 180,000 miles, but an underhood fire, related to old, plastic, fuel line connectors.
The technology is not in question, nor is longevity. It's been proven. New model "mistakes" are another story.
The big difference is the duty cycle. Turbo sports cars and even turbo luxury sedans are sprinters- the boost is less than a few PSI 90% of the time, even if it peaks over 20 PSI. Most of the time, the engine is operating at a tiny fraction of its peak power- and thats true for normally aspirated engines as well.
Trucks are different- when towing that thing's going to run boosted for hours on end. No big deal for a diesel to do that, VERY big deal for a spark-ignition engine to do the same. Structurally, I'm sure its up to it- all it takes is a stout block, fasteners, rods, piston, and crank. Its the exhaust-gas temp on a spark-ignitied engine under sustained boost that would have me worried. Cylinder crown and exhaust valve temperatures can get out of hand pretty easily, but modern electronics can probably keep that in check OK.
The thermal loads are not a problem. Nor are turbine inlet temperatures. I contend that a smaller engine, running, intercooled, under modest boost, has less stress, than a normally aspirated engine, screaming at higher RPM, under large throttle openings, while struggling to pull that trailer. Robust in much the same manner as turbo diesels. By proper design, application and engineering.