650cc injectors require more fueling than stock?

[bigbenty]

Hey.  Im new to this stuff but would like to get some info.
I have 650cc power enterprise injectors in my jspec supra.  They are high impedance.  We are tuning the car right now.  My fuel map is requiring a large duty cycle from my injectors.  Apparently about 30% more than what we figure is normal to keep from leaning out.  We are wondering what the cause is of this.

Could it be due to differences between the low impedance and high impedance?  Do high impedance injectors require more output from the ECU? 

Throw some theories out there for me.

Thanx

[Bender]

Did you change the latency to properly reflect the bigger injectors?