I am going to be building a motor using 198 rods and 2.2 turbo pistons. How much nitrous will these be able to take before failing?

Which 2.2 piston are you planning to use? (these come in cast, hypereutectic and forged)

The most common are the cast hypereutectnic pistions from Silvolite / KB.
These will take a 100 HP shot and even more if you use the Silvolite pistons with the lower ring lands.

If you use a hypereutectic piston, use large ring gaps. Butting rings are a problem with these.
DD

If I were to get a custom piston instead, when would the 198 rod fail?