synapse

I've been doing some R&D and found something interesting. If you run the Walbro 255 pump at lower fuel pressures than max you actually get more flow through the injectors and result in richer air fuel ratios.

Comptech's website states the following about the pump: Rated at 55 gph @ 50 psi and 48 gph @ 70 psi.

So they're saying that it flows more at lower fuel pressures. Didn't make sense to me at first, but if you think about how a pump works, the lower the operating pressure that it has to pump against, the less the pump has to work, so it can actually move more volume, per unit time.

So I tried it by lowering my rising rate ratio on my Synchronic fuel pressure regulator from 10:1 down to 7:1 and I was actually able to drop my afr from 12.5 to 12.3 and felt more torque and better power. At 7 psi of boost, I dropped peak fuel pressure from 102 psi to 84 psi.

Intuitively, it doesn't make sense because how could you flow more through the injector at lower fuel pressures when the pulsewidth is the same? But really, that only applies if the fuel was moving through the injector at sonic. I really doubt that the fuel is moving through the injector anything remotely close to sonic let alone supersonic. So until you go sonic, you really aren't breaking Bernoullian principles.

Something you guys may also want to try.