Ford 5.4L Engine Upgrades

It seems that everything nowadays is large-scale. We’ve got super-macho-grande tacos, the bucket o’ fountain drink, and vehicles that come from the factory with up to twice as much horsepower as their counterparts of a decade ago. Yet, we still want more!

The Mission

We were interested in discovering how much more power we could muster from a 1999 Ford F-150 in just one afternoon of bolting on parts, so we gave Russ Jacobs of RV Performance Connection a call. We explained that we needed these improvements to be smog legal, compliant with the manufacturer’s warranty, and easy enough to install so that the average truck owner possessing decent mechanical skills could perform the installation. He suggested one of his package deals consisting of a K&N Filtercharger kit, a JET Performance Products chip, and a Gibson after-cat exhaust. With all the leg work done for us, we loaded up the parts and headed out.

Jet Performance Products was kind enough to let us flog this 20,000-mile Ford on their dyno for the afternoon to generate our before and after horsepower numbers. Before performing any modifications we strapped the bone-stock 5.4L Ford to the dyno to establish our baseline. We were very surprised to learn that the 5.4L belted out 241 peak horsepower at 5,000 rpm.

The truck was then taken to South Coast Muffler, Hitch, & Welding where Edward Nuno of South Coast and Israel Lopez of RV Performance installed the parts in about four hours using common tools that most enthusiasts would have in their tool arsenal.

With the installation complete we motored back to JET to see how much horsepower we had gained.

The Parts

An engine is nothing more than a glorified air pump. The more air and fuel you can cycle through the cylinders, the more power you are able to generate. The parts supplied by RV Performance simply helped the Ford 5.4L breathe in and out better.

The K&N Filtercharger replaces the factory paper element and plastic housing with an oil-impregnated gauze element and high-flow intake tube that K&N says provides a 30 to 50 percent increase in airflow. All sensors and connections from the stock assembly are transferred to the K&N unit to retain emissions legality.

The Gibson after-cat exhaust uses mandrel-bent 3-inch pipes and Gibson's high-flow muffler. The system increases mid and upper rpm power and allows the engine to work easier, thus freeing up more horsepower to the rear wheels. We were pleasantly surprised to find that the Gibson exhaust provides a more muscular sound, without a drastic increase in loudness.

With the increased airflow afforded by the K&N and Gibson parts, the engine was in need of more fuel. The JET Performance Products module plugs into the factory ECU diagnostic test port to alter the engine’s management of timing and fuel delivery. Since the test port is used only at the factory during assembly, there is no need to remove the JET module during servicing. The JET module does nothing to alter the engine’s performance at low rpm, but from about 2,500 rpm and up the chip advances the ignition timing and increases fuel input.

The Results

Are we happy? You bet! The dyno told us what we suspected from the seat-of-the-pants feel. We saw an increase of about 20 hp across the entire test range with the peak horsepower climbing from 241 to 267 at 5,000 rpm. That’s power you can feel during everyday driving or blasting across the dunes. Not bad for an afternoon of bolting on parts.