I have been searching for some results for what happened when I hit the bottle. I installed a sport comp nos dry setup on my 99 si. I checked and re checked everything before hitting wot in 3rd for the first time. mind you this is only a 50hp shot. I get into 3rd and hit wot at about 4500. I feel a hit of nitrous and everything feels good. I look at my a/f gauge and its reading ok. then my check engine light comes on. so I shut the nitrous off and turn the car off. my bottle pressure was at about 850. I pop the hood and everything seems ok. then I start the car and I drop cyclinder 2. so I get back home and find that cyclinder 2 has a plug with a melted end and the other plugs look a little lean but nothing to cause them to melt. so to make a long story short I now have no compression on cyclinder 2 but no blow by or air leaks when I hook a hose up to the cyclinder. now with the valves on both the intake and exhaust closed you hear all the air going out the exhaust. my question is , is this a sign of burnt exhaust valves.... plugs and timing were stock. need help.... pulling head as we speak.... thanks in advance

 

It obvious to me that the melted plug was from the nitrous.
What kind of fuel was it on?
Nitrous could have deffinitely melted an exhaust valve, even though it seems unlikely with only a 50 shot, i used to run a dry 50 shot all day on my bone stock b16 and never had an issue
Deffinitly try a step colder plug next time, and maby retard you overall timing a lil

 

I was on 93 octane. I just do understand what happened... and nos said I shouldn't have to do any timing or plug change with just the 50 shot. but the plugs were cheap... I didn't change them for only a 3rd gear pass....
I will have the head off and let you know what it looks like. thanks for posting!

 

like i said i never had a problem with the stock plugs or ign timing either, but your engine is completely dfferent.
maby you had the wrong jet just a long shot