Since this topic seems to be a hot one right now I thought it would be wise to further elaborate a little bit on things.
After seeing numerous questions in regards to the power capabilities of the stock OEM engine, along with other questions in regards to other facets of the OE engine it seems like we should delve a little further into this topic.
A quick item that was noticed was the discussion of the OE rod, crank and piston assemblies from the F-150 and the SHO. The parts between these engines are somewhat similar. The crankshaft is the same for the F-150 and the SHO, and the same goes for the connecting rods. This applies to every engine we've seen or taken apart, as well as the part numbers direct from Ford. The crankshaft is forged steel, the rods are forged, though technically that might be a misuse of the word as it's more commonly known because the rods are powdered metal. The process in ways is similar to forging in that pressure is used, but there are other aspects that are different.
Depending on the combination of elements used in the process, and the process itself to some extent, the powdered metal rods can be superior in strength to a forging. But there are sometimes trade-offs, the powdered metal rod might be stiffer than a forging, but might be more brittle. The design specifics of the rods are very much so controlled by the OE for the application. From the OE's side of the game (Ford) they will determine a specific part requirement for the application. This will be based on calculations, computer models, real world testing, etc. All of these things will drive what the final finished component needs to look like. As mentioned other places, the design requirements are all that the OE cares about. They don't concern themselves with making components stronger than they need to be beyond what the safety factor that they've already accounted for ahead of time.
The pistons in both the SHO and F150 are different, they have different designs. Besides the bowl shape being different the struts, skirts, supports are different between the two. From a materials standpoint I don't think either piston really stands out as beefy. But from an OE perspective they perfectly fit their application.
When we discuss power ratings with engines it's always an estimate. No two engines are alike, especially at the OE level where the parts need to just meet the requirements specified. This means some parts will exceed that specification and other parts will be marginal and just meet them. When pushed hard the part that is marginal will be the one that fails. So it's important to keep in mind that a power estimate is a rough approximation of power supported before failure. Some engines will fail under that power, others will support more power. But for those engines that support more power with OE parts, it's important to remember that because the parts are operating at the outer limits of their capacity, that most likely at some point, they will fail.
There is more that goes into the Ecoboost rod & piston upgrade than the component upgrade. From our perspective when we do one of these engines with the upgraded parts there are many other aspects of the build that increase the durability. The purpose of building an upgraded engine with better parts is to support more power, whether that be in the immediate, or in the future with other upgrades (in this case boost/fuel most likely). So when we build one of these engines the upgraded rod and piston are just one element of improving the total package. Other components are upgraded, main studs are added in place of factory bolts. Head studs as well. The changes to the engine from a machining standpoint are too numerous to list, but things like tightened clearance tolerances, revised piston to wall, different ring end gaps, block honing with deck plates, torque distortion simulated machine work, modifications of oil passages, modification of block stress points, oil pump modifications, balance work changes, etc. etc.
The rod and piston upgrade do offer a substantial increase in power capacity over the stock components, but because they are part of a complete engine build, or shortblock build, there are so many other aspects of the engine that get upgraded at the same time to meet the much higher demands of the application. All of these changes are what makes the engine capable of supporting much higher power levels. This allows for higher capacity, better performance and the ability to support much higher power levels going forward.
We've been working with Ecoboost engines for years now, and in that time we've seen a lot, and we've also worked with the OE manufacturers often on this platform. This time spent seeing the engines, building and upgrading the engines, working with the OEs, developing components and testing has all given us a ton of data to work with and build on moving forward. We've got a lot of things in the pipeline too right now, some pretty exciting ones.
So yes, some engines will fail, some won't fail. But we will always err on the side of caution when it comes to advising customers. This means trying to give the best possible information and data as we can upfront and then working with the customer to come to a decision that works for them. If the customer wants to push their stock engine hard and completely understands the risks involved in doing so, then more power to them. And if they plan to push the power and want a solid foundation to work with as they do so, then we'll definitely work with them in building a package that fits their needs exactly.
