greenmeanh1
Member
I bought my hmc4 back in 2000. The first lift pump lasted 70k miles. Since then i have gone through 4 in half as many miles. I put it down to cheap manufacturing with cheap materials. Having recently completed the FTB mod the search has been on now for a better HO pump for the truck.
I chose the Raptor RP150. I actually wanted the RP100 being better suited for what i was doing but i found a good deal on the 150 and could not pass it up. I have read a lot of the install threads and it seemed the Raptor although expensive seemed to have less failures than other pumps. I was just about to order the Walboro FRB5 and changed my mind because of a few threads here on it shortcomings and failures in some cases. Hopefully the Raptor lives up to its price and the hype.
Then i got to thinking about our spikey 12v battery power supply and i realized you can't blame everything on the pump. I came to the conclusion that the same issue killing PMDs was killing pumps as well. Battery voltages can be descibed as spikey at best with wild fluxuations. Motors don't like it and niether do logic circuits. How can i install the expensive Raptor knowing this and the potential risks??
Answer I can't so a solution must be found and the answer is.,, Pulse Width Modulation!
Pulse width modulation will do several things. It will prolong the life of a DC motor by minimizing heat and spike stress with higher frequency switching and regulation. Also it uses less power than a direct connection and most importantly the load can be accurately controlled with a programmable digital gauge and a single potentiometer.
The Raptor was clearly overkill and even with the Raptors internal pressure regulation 8-10 psi was the average minimum you can get. Some would say its still too high. What i decided to do was set the pump pressure to 16 psi which is the maximun DS4 pump pressure tolerated and use the PWM to dial down the speed of the motor to control pressure in a precise way from in the cab on the fly.
So with all that in mind!!! I built a box!!
I will explain the box a little better.
The red and green wires out the top go to the raptor pump.
There is a 3 wire mini connector you cant see that comes out the top for the control knob input from the cab.
In the bottom is the stock pump connector that is fed from the stock plug on the truck. The red wire is the battery feed wire and it is fused at 15 amps inside the box.
On the right side bottom is a neg and pos buss connection. The Black is ground. This wire must be connected for the priming feature or negatively switched pumps to operate properly.
The pos contact is hot when the vehicle is off unles the logic switch is in the center position in which case the contact is hot when the vehicle is running. I have a plan for this connection.
The 3 way switch when in the center position direct the flow through the PWM. If something should happen to the PWM the switch can be put to the right to bypass the PWM and DIRECT INPUT to the pump motor.
With the vehicle off the switch an be turned to the left to run the pump for priming the fuel system from under the hood.
The two green leds on the side are power indicators for the trigger side and batt+ side of the switch and will be helpful for quick diagnostics of the fuel system if any,,, ever
A few pics
I chose the Raptor RP150. I actually wanted the RP100 being better suited for what i was doing but i found a good deal on the 150 and could not pass it up. I have read a lot of the install threads and it seemed the Raptor although expensive seemed to have less failures than other pumps. I was just about to order the Walboro FRB5 and changed my mind because of a few threads here on it shortcomings and failures in some cases. Hopefully the Raptor lives up to its price and the hype.
Then i got to thinking about our spikey 12v battery power supply and i realized you can't blame everything on the pump. I came to the conclusion that the same issue killing PMDs was killing pumps as well. Battery voltages can be descibed as spikey at best with wild fluxuations. Motors don't like it and niether do logic circuits. How can i install the expensive Raptor knowing this and the potential risks??
Answer I can't so a solution must be found and the answer is.,, Pulse Width Modulation!
Pulse width modulation will do several things. It will prolong the life of a DC motor by minimizing heat and spike stress with higher frequency switching and regulation. Also it uses less power than a direct connection and most importantly the load can be accurately controlled with a programmable digital gauge and a single potentiometer.
The Raptor was clearly overkill and even with the Raptors internal pressure regulation 8-10 psi was the average minimum you can get. Some would say its still too high. What i decided to do was set the pump pressure to 16 psi which is the maximun DS4 pump pressure tolerated and use the PWM to dial down the speed of the motor to control pressure in a precise way from in the cab on the fly.
So with all that in mind!!! I built a box!!
I will explain the box a little better.
The red and green wires out the top go to the raptor pump.
There is a 3 wire mini connector you cant see that comes out the top for the control knob input from the cab.
In the bottom is the stock pump connector that is fed from the stock plug on the truck. The red wire is the battery feed wire and it is fused at 15 amps inside the box.
On the right side bottom is a neg and pos buss connection. The Black is ground. This wire must be connected for the priming feature or negatively switched pumps to operate properly.
The pos contact is hot when the vehicle is off unles the logic switch is in the center position in which case the contact is hot when the vehicle is running. I have a plan for this connection.
The 3 way switch when in the center position direct the flow through the PWM. If something should happen to the PWM the switch can be put to the right to bypass the PWM and DIRECT INPUT to the pump motor.
With the vehicle off the switch an be turned to the left to run the pump for priming the fuel system from under the hood.
The two green leds on the side are power indicators for the trigger side and batt+ side of the switch and will be helpful for quick diagnostics of the fuel system if any,,, ever
A few pics
at: This is a major violation of KISS! It is made worse by disregarding the fact that electronics are what is killing the runner up pumps, Walbro. 
