The newest LT-series of GM engines and engine control systems are some of the greatest technology available today. But, like all gearheads, we usually want more, right? Well, the GM Fuel Pump Pressure Modules (FPPM) included in the GM wiring harnesses, leaves a bit to be desired when more fuel is needed.
The Gen5 and Gen6 ZL1 fuel pumps are a great fit for a stock LT4. Though GM lists the same fuel requirements for LT4 and LT5 crate engines, it is believed that the Gen5/6 fuel pumps will not be enough for the LT5’s 750hp. Plus, what if you want more power out of an LT4 and need more gas? The best way would be to use two ZL1 fuel modules, but the GM Fuel Pump Pressure Module (FPPM) may leave the pumping system electrically underpowered, lacking sufficient power to drive both ZL1 fuel pumps to their full potential.
So, what to do? VaporWorx has developed an “Ally”, or follower, system that uses the GM FPPM output to the primary fuel pump to tell it what to do. In other words, as the FPPM ramps up/down in pump power output, so does the VaporWorx Ally controller. When used this way there is sufficient power for both fuel modules while maintaining the FPPM full CAN feedback and diagnostics.
With just a single 20ga wire to attach to the FPPM fuel pump + grey wire to tell the VaporWorx Ally what to do, hookup is super easy. With that done, it’s just battery power in, and fuel pump power out. Done. No on/off switch, etc. It just follows the FPPM. No pressure adjustments, no ECM tuning changes, etc. are required.
As with all VaporWorx fuel module controller, features such as full output short circuit protection, overheat protection, UL94 materials, etc. are used to help protect the system.
If you’re thinking of future power upgrades for your LT4, or doing a fresh LT5 installation, dual ZL1 fuel modules are a great way to do the job once and be ready to go.