So, I have seen alot of misinformation on other forums about the differences and which is best to use for what application. Some forums have members that believe the 2618 is the only choice for any FI, and 4032 is for N/a; which is not close to the truth.

Basically in a nut shell, 4032 has higher silicon content which makes it harder and expands less under heat-meaning you can run tighter piston to wall clearances, better wear and less noise, longer life. However, the tensile strength is not as strong as 2618 which means 2618 can handle detonation better. THis is where the misinformation comes from. The reality is that a 4032 piston is actually very strong and will hold up to detonation much much better than a stock cast piston. They are good for turbo applications, but if max power is what you are after, then 2618 is probably the better choice. So where is the point that you should choose 2618 over 4032? That is debated everywhere, but with about a 12% less tensile strength, it is likely only around 12% less power than 2618. So, If a 2618 piston is rated at 1200hp, the 4032 should be able to hold 1000 hp with the same effectiveness. But no matter what, any piston has the chance to melt down/crack/break apart with a bad tune.

The 4032 alloy has a higher silicon content which translates into less thermal expansion and therefore a more snug fit, which means a quieter piston that is more smog friendly as compared to 2618. The tradeoff is that it's less ductile and brings reduced ability to withstand detonation. The 4032 alloy is great for OEM applications, and its better service life is a more appropriate fit for long term warranties.