Hey guys I have 89 T2, has a full exhaust, 3" downpipe, RTEK 1.5 ecu with OMP delete and premix, air pump and smog delete, no cats. Other than than that its completely stock. Couple years ago I got a pop on the highway while doing a partial throttle acceleration and the rear iron cracked, pumped out all the oil and dumped all the coolant. Engine still runs perfect but I need to get the iron replaced. Ive been told that the reason for the pop might have been detonation and that I dont have any fuel system upgrades/changes with the few mods I have. Just looking for ideas. Currently pulling the engine to replace the rear iron but want to fix what could have caused the original issue.

 

More than likely detonation, really the only thing that can make the engine twist enough to crack irons.

Did you port the waste gate at all? Installing a free flowing exhaust can without porting the waste gate can bump up boost pressure/creep pretty high.
Stock fuel pump as well? Fuel pressure drop due to voltage drops in OEM wiring could also be possible.

 

Wastegate and fuel pump/wiring is stock. I did have boost creep, i think it would spike to 12-13psi then come back down to around 10psi.
I know it has the fuel pump resistor in it and the rtek chip reduces timing over 9psi.

 

i would look at the ignition system very very carefully, to break an iron at that power level something must be really wrong. if it was lean, it might detonate and chip a seal, not break the block.