I’ve been trying to better understand fuel management in my near stock ITR for quite some time now; to no avail.
I was pleased to learn that leaning the upper RPM with a V-AFC on a stock motor will yield a worthwhile increase.
I’m also using a wideband O2 to learn more about how the ECU operates in conjunction with the V-AFC in turn leaning the mix a bit further. –this I get.
..But, I’m interested to understand why a fuel pressure regulator does anything beneficial to a stock motor; when most run too rich at WOT anyway.
Am I wrong? –don’t Honda’s generally dump too much fuel in open loop, only to serve an overly paranoid ECU?
Is not the job of an FPR to increase the fuel pressure above stock. –and if this is done, wouldn’t this rich’n the mix even more, further away from stoic?
I don’t picture myself using any plus values on my V-AFC until something major is asking for it, i.e. cams, FI, etc.

Just trying to understand… thanks.

 

A lot of people actually lower fuel pressure and tune out the lean/rich spots via a VAFC

 

this is true, most when tuning with a VAFC, will bump up fuel pressure and only remove rich points on the fuel curve with the vafc. remember once the stock injectors hit 80% duty cycle they are maxed anyway.

 

yeah, but why bump the pressure then lean it out?
I don't get it.

 

General VAFC tuning rule: You shouldn't add positive values through the VAFC for fear of exceeding the MAP sensor ECU input voltage...thus triggering a MAP sensor out-of-norm voltage code.

You can add MAP voltage using the VAFC, but that's generally not the way to do it when you have a FPR and the VAFC.

 

this info is very helpful to me as well. i will be tuning with a fpr and vafc in the near future. threads like this help educate a novice like me