Now, I know that mixing lightweight pistons and boost is not recommended...
But at least they are forged and JE Pistons tech support told me over the phone that 15 psi is the maximum recommended (or 125-150 nitrous, whereas 200hp nitrous "would be pushing it").
Are any of you by any chance using the JE Pistons part number 138103 400g pistons in a boosted application? If yes, how much boost are you running?
Thank you very much!

 

JE should know their own pistons. But no piston is designed to operate with any severe or prolonged detonation. And the bottom line on cars run with boost and pump fuel is that they do experience detonation. That's why they eat pistons. I would put nitrous in a lsightly different category in that I don't think it predisposes to detonation to the extent that boost does - provided the setup is right as far as timing and fuel (in both cases).

There is a (good) reason why JE and other hihg end poiston manufacturers make specific psitons for boost.

Rich