Originally Posted by
mewantkouki
It might also be tuned for different injectors...
My thoughts as well, probably S15 Injectors
I had a customer that had 550's on his engine set, we thought the ECU was tuned for them since it came with the set but it wasnt.
Started up and drove but ran rich
EDIT:
But then again that would probably make it run lean.
seeing that due to bigger injectors the Fuel Inj, Duty Cycle will be lower due to higher flowing injectors