Saving Fuel, Our Strategies
Increased economy is the result of a more efficient intake, higher air density, better fuel atomization and increased exhaust efficiency during the combustion/exhaust cycle.
Air intake efficiency, coupled with air density (oxygen content), is the key to proper combustion. Air density, simply put, is the number of oxygen molecules in a given space. Air temperature effects air density and as air temperature is increased, the oxygen content is reduced. For this reason, air that is drawn or pushed into the engine needs to be as cool as possible. Upgrades that provide diesel engines with more oxygen content are products such as intercoolers, less restrictive intake manifolds, higher flowing turbo chargers, pulse flow exhaust manifolds and free flowing exhaust systems.
Other upgrades can also provide lower air intake temperatures, such as water injection systems. As water is injected into the engine, it cools the intake charge providing denser air that allows for more oxygen content in a given space.
Propane injection is another great source for increasing engine efficiency. Huge gains can be achieved with the proper injection of propane because it provides more oxygen content during the combustion process. This allows the fuel to start burning earlier during the combustion process. This small head start in combustion gives the atomized diesel fuel longer burn durations that push the piston down while absorbing more mechanical energy and providing more torque.
Fuel atomization is an important aspect of increased fuel economy and performance. Increased atomization is achieved by maintaining minute droplets of fuel as it’s injected into the cylinder. In factory systems, the pressure at the injectors drops as the injector is turned on. This cannot be seen with a diagnostic tool because the injector nozzle is down stream of the injector flow orifice. The only way to increase fuel pressure reliably is with an additional pump, such as a Twin CP3 System. Many trucks will benefit from higher volume lift pumps as well because the lift pump helps supply fuel to the high-pressure injector pump.
Airflow out of the motor through the exhaust system of a diesel is equally important. A high flow, well-tuned exhaust manifold, as well as the turbine section of the turbo, is crucial to overall fuel economy increases. Relieving exhaust pressure in the exhaust manifold, turbine section of the turbo and exhaust system will provide gains equal to an efficient intake system. Don’t be mislead; a big turbo is not the key to reduced back pressure and increased airflow. The turbine and compressor section of the turbo must be perfectly matched to the volumetrics of the engine for maximum efficiency. A volumetrically matched turbo means the compressor will run at the apex efficiency with the air temperature at it’s lowest, and air density at it’s highest, for efficient combustion.
An important factor in economy is the exhaust turbine or the turbo. The exhaust turbine uses exhaust gas flow to transfer energy through the turbine to power the compressor-side of the turbo. Wasted exhaust flow yields a decrease in both performance and fuel economy; this is why you will not find a waste-gate on better turbos. A non-waste-gated turbo will use as much energy as possible from the exiting exhaust gas to then transfer energy to the compressor-side of the turbo, increasing air density back into the intake system.
In summary, the best way to increase performance and economy is to provide a cool, dense airflow into the combustion chamber, as well using water or propane injected into the intake to provide more cooling. Couple this with an efficient turbo for increased compressor and turbine performance, and a free-flowing exhaust system, and you’ll increase the economy and the performance of your diesel truck.