I recently had a b20vtec built, stock bottom end, gsr head, ctr cams, stock fuel system and chipped p72 ecu. compression is about 10.8. My question is could i run a stock p72 ecu and not run too lean to hurt anything if i kept the rpms under like 4000. The engine is basically stock so i dont see why it wouldnt. Im gonna try to pass smog, (not the visual of course. ) other option is maybe trying to tune it with a vafc and wideband.

Any input would be great, thanks.

 

If you have a way to turn up the fuel pressure, you will be ok. Otherwise I might be concerned with a bit of detonation, and lower RPMs have more of a tendancy to detonate, in fact. The wideband is a great idea, and the VAFC will work in a pinch, although it can't replace really tuning the ecu.

 

The chipped ecu is running extremely rich right now. i dont have an fpr to tune fuel pressure though.

Does anybody know what generates better smog results, perfect stoich, a lil rich or a lil lean?