Maulin’ Magnum Made Meaner By Magnuson - A Power Adder Primer

If you’ve been following project Maulin’ Magnum in these pages, then you know we addressed the late model weak link, its Achilles heel, the factory rear end. We used parts by the Driveshaft Shop, Richmond Gears, and OS Giken to upgrade the rear end to be an anvil against which we can experiment. Experiment with what? Why, more power of course!

Before we get into the specifics, let’s start with the basics. An internal combustion engine at its most fun damental is an energy conversion device. Potential chemical energy in the form of fuel is introduced into the engine along with oxygen (contained in air). The fuel/air mix is oxidized (burns) and the chemical energy is converted into thermal energy. The thermal energy pressurizes one side of the engine’s pistons causing them to move and turn the crankshaft, thus converting the thermal energy into mechanical energy and movement.

To increase the power a given engine produces, you can improve the efficiency with which it uses its chemical fuel potential. In modern EFI engines, there’s not much room for improvement here, the engines are already highly optimized. If your engine is already highly efficient, the only way to increase power is to pump more fuel through the engine.  Of course, you can’t just pour more fuel into the engine without more oxygen with which to burn that fuel, so you have to provide both more fuel and more oxygen.

There are a few different roads we can travel to get our engines to pump and convert more fuel and air. A power adder such as a nitrous oxide system, turbocharger, or supercharger can force feed more air into the engine. Without a power adder, a normally aspirated engine can be larger (more air and fuel per cycle) and/or revved to higher RPM (more power cycles per time unit). If you stay normally aspirated (which means no power adder device) to take maximum advantage of the increased displacement and higher redline you have to modify the cylinder heads and change the camshaft and valve train components.

The cylinder heads are modified—usually by increasing the size of the intake and exhaust ports and optimizing their shape and cross section—or replaced with aftermarket pieces that feature such optimization. In order to take advantage of the changes, the camshaft is swapped to one with a profile with higher lift and changed duration and overlap to match the needs of the higher flowing heads. Valve train parts such as rocker arms and the valves themselves are often changed as well.

We already explored one power adder path last year with our three part series on nitrous oxide. Nitrous systems have two main components, a pressure bottle holding nitrous oxide—a high oxygen content gas—and plumbing to introduce the nitrous oxide and more fuel into the engine. When activated, a nitrous system introduces pressurized oxygen (contained within the nitrous oxide gas) and additional fuel (gasoline in our case) into the engine’s intake manifold.

How much extra power you produce is directly related to how much nitrous oxide and fuel you introduce. The upside to nitrous is that it is inexpensive to install (you can purchase basic systems for under $500) and can add 100+ horsepower to a late model Hemi. Downsides include the cost of nitrous refills ($5 a pound in Southern California and a bottle typically holds ten pounds) and the limited time you can make the added power before the bottle is empty.

Another way to get more air into an engine is to force it in using a mechanical device to pressurize atmospheric air and introduce it into the engine. These devices will themselves consume some power as the source of the energy needed to pressurize the incoming air. If the source of this power is from the exhaust system, then you have a turbocharger.

If the source of this power is mechanical belting or gearing to the engine, then you have a supercharger.

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