I now have a b20z and i sold my old b18a motor to some guy that wants to do a full rebuilt for a turbo. He ripped the block appart yesterday night and he sent me those pix.
they have about 120,000 miles and they’ve been abused with nitrous a little bit. I was running a 50 shot single fogger wet on the stock b18a and also stock fuel pressure. I did detonate once on the highway, i was racing my friend wit his b16 hatch and i was spanking him pretty bad but one of the wires on my fuel solenoid disconnected !! So i was only spraying nitrous, no fuel…it was pinging but before i could realise what was happening, it was too late and i melted a plug and then stop right away when i saw i was running on 3 cylinders. I open the hood and the engine was VERY hot…obviouls, it didn’t have enough fuel…
The engine was running fine after i replaced the plug tho but look at the piston in the middle…i consider myself very lucky i didn’t melt it. This was in may and the engine didn’t show any other problems until october (when i had my b20)…after about 5 or 6 refills. Not bad.
I’ll make sure that all the wires are fine before i start spraying again on my new set up 
My bad tho…
Lots of carbon (high milleage motor)
a little bit of detonation
Feel free to comment 
Later