Overbore on the factory ECU?

[Ca_Silvia]

If you were to bore out the cylinders can you still run factory tuning or do you have to go to a stand alone system?

[BEST1TUNING.COM]

not standalone necessarily, but an over bore would require a retune of the factory ECU most likely. Even If you didnt %100 need a retune because of the overbore, it would be best in order to get the full potential power increase of the modification.

[float_6969]

The car would probabaly run and drive OK, but I'd be a bit worried about timing as boring increases compression. I would think the stock ECU could handle the extra air volume.

Regardless it would still be best to have the ROM tuned to make the most of the increase in bore.