I saw someone on another thread express surprise that I had an auxiliary fuel pressure regulator with the MSPNP. As far as I understand, the AFPR just makes sure there's enough pressure on the line and wouldn't affect how much fuel is squirted. Am I wrong?

Cheers, Jon

 

The AFPR clamps down the return line to raise fuel pressure when it sees positive pressure (aka boost). So it does add more fuel to each squirt because of increased pressure.

The reason people are surprised is because AFPRs aren't usually used with programmable ECUs since you can just throw on bigger injectors and aren't working with a stock ECU's limitations. I don't see why it wouldn't work, it make might initially dialing in the VE table a little more annoying, but that's it.

 

Thanks.

Do you think I could safely ditch the AFPR with the MSPNP, the Greddy at 5 psi, and stock injectors? It's a limitation of the stock ECU that requires the AFPR?