Ive got a GSR swap i bought, its a 99 GSR USDM OBDI converted motor. The ECU is a Mugen chipped p28. I could have sworn p28's were h22 computers, this seems likely beacues vtec engages at 5800 rpm. Should i keep this ECU? Whats the code for a OBDI GSR ECU? And is there a ECU i could get that would increase perforamnce? like a pr3 or an ITR ECU?

 

GSR ECU is P72
92-95 Civic EX/Si SOHC VTEC ECU is P28
H22 ECU is P13
89-91 B16A1 SiR1 ECU is PR3 (or PW0)
ITR ECU is P73

Sounds like you have the Mugen program in your P28, with 5700 VTEC x-over and 9500 rev-limit. It works, and works actually pretty good, on a stock GSR motor, but the only downfall is that VTEC is set too high for that setup, and you'll better advantage with the VTEC dropped (either another chip or a VTEC controller) to 48-4900.

 

Ill probably get a VAFC. Is the motor getin enough fuel with the sohc ECU runin the show? and is the timing curve affected? b18c are 17 degrees advanced arent they?

 

If you have the Mugen program or a close copy, you are getting plenty of fuel. The timing and fuel maps in this program are setup for DOHC VTEC motors, so not to worry. With the VAFC you can fine tune your fuel and VTEC, so you should be good to go.