H&S Motorsports LML Dual High Pressure Fuel Kit w/o CP3 | 2011-2016 GM Duramax 6.6L

The H&S Motorsports dual high pressure fuel kit w/o CP3 is the ultimate in high pressure fuel supply. With over a year in development and testing H&S Motorsports has pushed this kit to the extreme and it still performs in even the most demanding conditions. Our friends over at H&S Performance have been testing this kit on their 2011 Denali HD for over 6 months. This is the same truck that made 1086 horsepower and 1911 ft/lb of torque on a Mustang 1100SE dyno during the "Breaking Point 2" live feed in which they intentionally set out to find the limits (or breaking point) of the factory LML bottom end. Prior to the "Breaking Point 2" event, the truck was driven regularly by not only the engineers at H&S Performance, but also the members of the race team. Needless to say, they were (and still are) impressed with the ability of the kit to maintain rail pressure, even in the most demanding conditions.

Just as a quick reference for you diesel nuts out there, the engineers at H&S Performance were able to run 3800us (not recommended) of main injection duration on stock injectors without a drop in rail pressure. So what does that mean? Well, think about it this way; their off-the-shelf HOT tune commands around 1400us and is on the verge of draining the rail on a stock CP4-equipped truck. At 3800us, that is a 270% increase in fuel demand from their HOT tune and limit of the stock CP4. The H&S Motorsports Dual High Pressure Fuel Kit was able to maintain the commanded 29,000 PSI rail pressure without skipping a beat.

This product MUST be used in conjunction with custom tuning calibrations for an H&S Performance tuning device. Calibrations and information found here. Failure to install the correct calibrations can result in engine damage.

You must use an aftermarket lift pump with this product. AirDog and FASS are the two most commonly used.

So what's wrong with the factory CP4 fuel system?

Nothing is necessarily WRONG with it, but the factory CP4 fuel pump by itself is only capable of providing enough fuel to safely produce around a maximum of 480-500 horsepower. Once your power goals exceed that 480-500 HP range, more fuel is an absolute requirement. Assuming your factory CP4 pump is in good condition, this kit is easily capable of producing 900+ HP worth of high pressure fuel supply.

Will the CP3 pump ever wear out or deteriorate over time?

The CP3 pump we include with the kit is a brand new OEM unit from Bosch. That's right, BRAND NEW, not a remanufactured unit like many shops include. The key to ensuring the longevity of any high pressure fuel pump is by providing the high pressure fuel system with clean, waterless diesel fuel. Any fuel contamination that reaches the high pressure fuel system can be detrimental to reliability and performance. We highly recommend using AirDog or similar lift pump for proper filtration and water-separation.

Why do we use a CP3 in instead of a CP4?

There are a few reasons we chose the CP3 over the CP4:

The CP3 pump has been proven to be reliable. This pump technology has been used on the Cummins and Duramax platform for years. While the CP4 has the capability of delivering higher pressures, it lacks the volume of the CP3. With both pumps installed, you get the best of both worlds - high pressure and high volume. Price. With the CP4 being a newer pump, it is obviously more expensive. By saving on the pumps included with the kit, we can pass that savings directly on to the customer. If your fueling demands exceed what the stock CP3 and CP4 are capable of providing, one of our 6.7L Cummins 10MM Stroker pumps can easily be used as a replacement while still being able to re-use all fittings and lines included with the kit.