I was reading a book i have about building small block chevys on a budget. I am sure everyone has read about how hypereutectic pistons are bad for nitrous and how they are prone to cracking. Here is a blurb from the article, let me know what you guys think:

"It has been found that using 18% silicone to make a hypereutectic alloy has improved the material for high performance pistons while keeping costs nearer that of regular cast pistons.

The only drawback to producing hypereutectic pistons is that the free silicon in the aluminum wears out regular carbide machine tools much faster than non-hypereutectic alloys and mandates the use of diamond tools. As far as use in a performance engine is concerned these alloys are really what the high performance street engine builder was looking for. Because casting allows metal to be put exactly where it is believed to be required, hypereutectic-cast pistons need not give away any real strength advantage to a forged piston. With forged pistons the forging die must be removed from the forging so undercuts in pin bosses cannot be directly formed. To make a forged piston significantly lighter than a cast piston requires much more machining. Because of the process and material involved, hypereutectic pistons are just about as strong as forged pistons but can be run with mcuh tighter initial clearances and wear much slower. Just before Sealed power introduced its first Chevy hypereutectic piston I was sent a set to use in one of my street nitrous motors. About 50 pulls on nitrous at levels wtween 530 and 560 hp had no visible effect on them. Since then, several other companies have produced such pistons. The most notable is Silvolite with the Keith Black signature series. Although a little heavier than some of the lighter forgings, these pistons are proving to be race tough. I have used them up to almost 600 hp and there are racers with blown motors making several hundred more than this who are making it through several seasons on the same pistns. However, for this kind of reliability with cast pistons, I recommend modifying the block so the pistons are oil cooled... Without the aid of oil cooling, I limit the amount of nitrouspower augmentation to 150 horsepower when using hypereutectic pistons."

I would never put a hypereutectic piston in a motor i was building, but this makes me feel a lot better about the hypereutectic pistons that are in my 350HO crate engine when it comes time for spray .

 

I think that a 150 shot with hypereutectic pistons is fine, provided the A/F ratio is ok. A forged pistons gives more leeway if things go bad, but forged is not an absolute necessity. I know there are some guys pushing 175-200 shots on hypers without a problem.

 

With progressives or dual stages, you could put a shock on those hypereutechtics around 200. Add, either one or both and you can push 175-200.

The issue comes with the crushed ring land. Once the cylinder pressures build past the hyper-piston threshold, the ring land will crush and either tear into the cylinder wall or disintegrating with the rod going through the side of the block.

Forged pistons will deform, but not disintegrate (at these levels). Yes, I've got a Top Fuel Ceramic Coated Piston on my desk with a crack on the side (free pen holder). So forged is not impervious to damage.

Cylinder pressures have a lot to do with Dynamic Compression Ratio. If you've done any head, cam, block work... even the head gasket to the Cc'd valve reliefs in the piston heads, they will affect cylinder pressure and DCR. Sooo, if you are already on the threshold of 8.5, then it will not be forgiving if there is a small "glitch". If you are closer to 8.25, then you'll have a chance to survive a "glitch".

So, the hypereutechtic survivability has a lot to do with your desired RPMs, DCR, and quantity of N2O.