Recently, I have rebuilt a b18c engine and run with power fc.

I had tuned the engine before rebuilt. but at the time I tuned for it , the engine not in perfect condition, just 150psi compression across 4 cylinder.

I rebuilt the engine with 1mm+ oversize piston, same camshaft as before. In this situation , Do I need to retune?

For now, the engine with no issue and I dun have to air/fuel ratio to monitor. So, I dont know does the map fit for my rebuilt engine.
Or any way to know the map is good or bad for my engine.

Thanks.

 

Yes, you need a re-tune.

 

 

If the tune was based on a weakened/compromised engine, a healthy engine will make more power... and this means that your current tune will be lean. Lean is dangerous. Get a re-tune.