This weekend's project was rewiring the stock fuel pump with 10ga wire straight off the battery and adding a 8ga ground. I have always heard this is a worth while mod but never read what kind of gains should be expected. Take a guess at what my results were.

*Note: Pulls were three days apart with very similar intake and coolant temps(aka no fuel trim alterations). In fact I found a portion of the log where I was in the same gear with the same intake temp, and the exact coolant temp~freaky~.

According to RRE... you should see almost 40% gains in volume at the same pressure.


Taken from RRE's website for the stock pump -

100 lph @43psi @12v
140 lph @43psi @14v

My Observation: I am running O2 feedback on the wideband. The corrections that I was seeing after the rewire on average were 5%. That is, to meet the target air/fuel ratio the ecu was pulling 5% fuel from the stock fuel map.

Now after thinking about this... I am still running the stock FPR. If rewiring increased the fuel flow, but I did not change the tune to allow more fuel through the injectors, wouldn't I just be returning more fuel to the tank? Maybe my 5% increase was from slightly overflowing the FPR resulting in a pressure increase.

I guess it is time to slowly crank the boost until the AFR falls off

Or rather, until you start knocking and then back it off some.

On the contrary, dial in the AFR, add timing until it knocks, then back it off some