Quote:
Originally Posted by celek
I would like to point out that the Rod bearing journal is the same Diameter as the K24 Honda, SR20 Nissan 1AZ Toyota and EJ20 Subaru. Additionally I will not be using factory bearings which are designed for non spirited driving.
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Good point, but the only one that you directly compare to is the EJ20. The crankshaft loading on the rod pins in an I4 are very different and would not be directly applicable to a boxer. Even then, it would be difficult to use the EJ20 as comparison as it only made ~150hp and spun up to 7200rpm (aftermarket tune), so the rod pin never saw the same level of stress the FA20 does that has higher combustion pressures. Not to mention the EJ20 is oversquare so it can spin faster without spinning a large amount of mass (92mm bore, 75mm stroke), as long as there is sufficient oil flow rate from the oil pump.
/tangent (pressure isn't as important as flow rate since your pressure will change depending on your cross sectional area of the oil passage. I've performed an actual engine flow analysis before and your bearings don't care about pressure, they live off of oil flow. The only reason why we use pressure is because no one, OEM's or race groups, can realistically install a flow meter in the main oil gallery before the bearings)
/tangent
Also, aftermarket or racing bearings are only useful when you do not have a film thickness to float the bearing. If the system is designed properly, where you want the engine to live, the crank, rod, cam bearing or any other bearing using oil are completely floated by oil.
Either way, even if what I have said may seem harsh, I'm hoping what you put together works for you. I just want to give you some information that
might help you create a badass NA FA20 that won't try and fling itself apart at 9000+rpm due to all the inertia you will have with a 94mm stroke crankshaft, because I would love to see this succeed.
