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Duramax Lift Pumps
This section is divided into 3 categories:
Complete kits - This is just like it sounds, kits with all that you should need. These kits are based on a standard pickup truck, but easily adaptable to most any vehicle.
Misc. Fuel Supply - This is the supporting hardware for mounting, plumbing, wiring, etc.
Pumps only - This is just the pump(s) with no supporting hardware.
Pump or Kit Selection
The Kennedy lift pump is a high volume, low pressure unit. Each pump produces approximately 3-4 psi on an idling Duramax. The added pressure of the second pump will never hurt you and will help overcome loss of flow as your filter(s) begin to take on load. My standard line regarding single versus twin is "Single is adequate, twin makes good and darn sure you have enough".
My recommendations based on application
Street driven trucks looking for a budget minded setup: Single Pump deluxe kit
Street driven trucks looking for the best setup: Twin pump deluxe kit
Kodiak Medium duty trucks and those facing fuel supply/low psi issues: Twin pump deluxe kit
HP and race applications: Twin pump everything kit (includes billet pickup and larger supply line)
Pump HP ratings
Without a doubt, the most common questions that I receive regarding lift pumps are "How many GPH do they flow?" and "How much HP will they support?" It seems that many are of the belief that the lift pump sizing needs to be tied directly to the ultimate HP level. While there is a connection, it is not as critical as one would think. HP capacity (fuel flow) is based on the capacity of the CP pump. The lift pump is there to ensure that the CP pump receives a constant supply of fuel without starvation. While there is some truth to the fact that adding a high pressure supply to the inlet of the CP pump will improve output in the upper RPM ranges, this is more of a race thing. In addition, it is my opinion that if you need to try to squeeze that last little bit of flow out of your CP pump you need a bigger one or a second one.
My 2012 LML and 2007 LBZ street trucks run my Twin pump deluxe kits in the 400 RWHP range. My 2002 LB7 runs my Twin pump everything kit. This truck has dual CP3's and produces well in excess of 1000 RWHP. No shortage of fuel supply there.