At these power levels, the Duramax's Bosch injection pump will not consistently suck enough diesel from the factory fuel tank. To cure this problem, TTS Power Systems has engineered a stand-alone lift pump system that will work on any Duramax truck. When the engine is keyed on, the TTS lift pump will activate and prime the fuel system before start-up. The pump will then run continuously and supply fuel as long as there is engine oil pressure. For trucks making more than 350 hp, the TTS Stage II lift pump system (shown) is recommended. Its function is the same as the Stage I (single pump) kit, but under high-load situations (referenced from the engine oil and turbo boost pressure) the Stage II system will turn on a second lift pump that will continuously supply a 450hp Duramax. And as our testing clearly shows, it will handle much more than that for short periods.
To survive under extreme use, the 12-volt TTS lift pumps feature brushless electric motors rated for 40,000 hours (that's 1,666 days!) of continuous use. The pumps feature stainless steel and brass construction, and no fuel ever comes in contact with the electronics.
 The pumps mount back near...  The pumps mount back near the fuel tank, just ahead of the factory fuel cooler. All of the necessary fittings, hoses, and wiring are included with the kit. The TTS lift pump will work regardless of whose power programmer, box, or chip you are using. |  Our test vehicle is a '04...  Our test vehicle is a '04 GMC with 29,000 miles on it. We ran all of our TTS Power Loader III testing with the original air filter in place. Look at all that dirt! |  Naturally, we wanted to see...  Naturally, we wanted to see if we could free up some air and make a little more power. But, we wanted to retain the stock engine look, so we didn't want to run one of the popular open-air cleaners. |
 We decided to give the VaraRam...  We decided to give the VaraRam Industries VR-D1 lower airbox a try. This inexpensive upgrade replaces the lower half of the factory airbox with a new piece that directs air in from the bottom of the box. To install the VR-D1, you remove the factory airbox and the metal tray that it mounts to. The VR-D1 piece then bolts in with sheetmetal screws to direct air in from under the front bumper. |  HORSEPOWER On the dyno, this...  HORSEPOWER
On the dyno, this system did make a little more power, but it could be because the original filter was so dirty. Even with the optional Green air filter element, the before and after dyno results were almost the same. |  TORQUE We'll admit, it is...  TORQUE
We'll admit, it is hard to replicate the amount of airflow a truck sees on the open road with a chassis dyno. There could be more potential in the VR-D1 than our testing shows. |
We knew the engine could deliver plenty of fuel in the TTS Race mode. We also knew the engine wanted more air. But, instead of a complex turbo swap (that would surely give our intensions away), we decided to turn to nitrous oxide. If you look closely, you can see the solenoids under the VaraRam airbox, and the two nitrous jets in the intake tube (arrows). Commonly used in drag racing applications, nitrous can be thought of as a chemical turbocharger for diesel engines. With the extra oxygen delivered by the nitrous, power levels spiked to 527 hp and just about 1,000 lb-ft of torque. And remember, those numbers are at the rear wheels, and the engine still looks completely stock.
 The 10-pound nitrous bottle...  The 10-pound nitrous bottle could have been mounted in the pickup's bed. But, keeping with our stock truck look, we chose to slip the bottle under the bed, just in front of the rear tire. | 
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