Red Rocket

Recently dyno tuned my 396 LT1. Above 5600 RPM's the car really started to lean out and did not respond to more fuel plus the fuel pressure dropped to 40 PSI.

Replaced the Walboro GSS 307 this week which was installed ten years ago. The filter sock was pretty dirty and partially clogged. Went with the Walboro GSS 340M pump this time which is suppose to pump alittle more at higher pressure. The shop did not feel comfortable putting in the pump hot wire kit to the alternator. They felt it would not make any difference anyway. We did get 457RWHP at the dyno tune.

Has anyone else noticed a big change replacing their Walboro fuel pumps? Should the hot wire harness kit upgrade be installed?

leesvet

I think that hot-wire kit is for people without an existing intank system from the factory. I can;t see how the pump would need that much more amperage than the harness can supply...unless its so much bigger or a totally different type of motor...

powerpigz-51

Measure the voltage drop (bat voltage vs. pump) at the pump under load. The voltage from long, skinny, old wires may be much less than new, thicker wires.

pr0zac

i have a hot wire kit and a 255lph pump and we had to bump the rail pressure for the afr to get richer after surpassing 450rwhp. the pump is older but it doesn't have more then 20000 miles on it.

rodj

A datalog will regularly show the pump voltage 1/2 - 1V lower than the batt voltage and that is measured at the pump relay on the firewall ; not way back at the pump itself