After years of being the underdog, the diesel engine is ready to take the crown as the king of power-and it won't ever give it back. We know that you, our Diesel Power readers, agree, but the guy down the street with the gasoline V-8 truck may be harder to convince. Bench racing-arguing about which engine makes the most power-is fun, but it rarely settles disagreements. So we decided to let a dyno do the talking.
We got in touch with Granatelli Motor Sports (GMS) because the company makes power parts for gas and diesel engines and there's a big Mustang Dyno in the middle of the shop. Owner J.R. Granatelli set up a real-world version of a gas versus diesel bench race by obtaining a brand-new '07 F-150 with the 5.4L gasoline V-8 and pitting it against an '06 F-250 Super Duty with the 6.0L Power Stroke. Here's what happened.
Gas
GMS is well-known for its gasoline power tricks that include helping an engine breathe, spark, and fuel to its full potential. The '07 F-150 FX4 in our test was fitted with a stock three-valve 5.4L Triton V-8 engine. Before the GMS team started upgrading parts, they obtained a baseline dyno rating of 192 hp and 230 lb-ft of torque at the rear wheels.
The first part to be replaced was the nasty factory intake full of baffles, elbows, and expansion chambers. It was swapped for Granatelli's high-performance intake with a fully enclosed airbox and a custom programmed mass airflow sensor. A spin on the dyno revealed a power increase to 216 hp and 264 lb-ft of torque-an improvement of 24 hp and 34 lb-ft of torque for just under $400.
The next power-adders were eight coil-on-plug packs for powerful and accurate firing of the spark plugs. After the factory coil packs were removed, it wasn't hard to tell why the Granatelli parts work better. The connectors are much better than stock, and the voltage built in the packs is significantly higher. This $500 upgrade was good for 227 hp and 269 lb-ft of torque, which is an 11 hp and 5 lb-ft of torque gain along with better throttle response and fuel mileage.
 This was the first '07 F-150...  This was the first '07 F-150 to enter the shop, so after the restrictive factory intake was removed, the Granatelli staff immediately strapped it to the flow bench. The measurements taken were used to program the mass airflow sensor to maximize the effectiveness of the intake charge. |  The intake for the 5.4L gas...  The intake for the 5.4L gas engine comes with a fully enclosed airbox, a reusable high-flow air filter, and silicone connection boots. It also includes the Granatelli Motor Sports slotted MAF that's calibrated in-house and designed to improve throttle response and mileage without voiding the factory warranty. |  One look at the 60,000-volt...  One look at the 60,000-volt Granatelli coil packs almost made us wish for a truck with spark plugs-almost. In addition to providing three times the stock voltage to the spark plugs, the coil packs feature a superior connection between the pack and the plugs. Instead of the factory "Slinky" connector, Granatelli uses braided cable with connectors that click when the plug is attached securely. Each unit also has a patented ceramic ring to eliminate radio interference. |
The final gas upgrade was a blast of programming from the Fuego flash tuner designed by Granatelli. The $325 Fuego provided the biggest bump in power output. It brought the truck up to 246 hp and 289 lb-ft of torque for a total improvement of 54 hp and 59 lb-ft of torque. The total retail cost of these upgrades is $1,223.
Diesel
Sorry about that, but we have to write a little about gasoline products when the article is titled "Gas vs. Diesel." Don't worry, it's a Diesel Power-fest from this point. The first upgrade Granatelli made to the Super Duty was adding the GMS $189 cold air intake kit. A dance on the dyno showed the stock rating of 236 hp and 369 lb-ft of torque was raised to 241 hp and 383 lb-ft of torque-a nice little bump.
Next, the Big G module was wired into the Super Duty and mounted behind the dash. The Big G costs $315-or $599 when equipped with the in-cab display that provides tons of control and watches your back when temperatures get out of hand. The Big G Mileage Miser setting is designed to add 3 mpg, and the dyno showed it was still able to increase the power to 296 hp and 481 lb-ft of torque-and that was just the beginning. The Big G high-performance setting was measured at 373 hp and 554 lb-ft of torque. That's 137 hp and 185 lb-ft of torque over stock.
The $325 Fuego flash tuner was next to be unleashed on the 6.0L. After a couple of minutes loading the program into the engine computer through the port under the dash, the Power Stroke was ready to beat on the dyno. The Fuego was set to "Race," and the dyno registered an incredible 459 hp and 726 lb-ft of torque-229 hp and 357 lb-ft of torque more than stock. But, wait, there's more.
The Fuego and Big G can be stacked to maximize the output of your diesel engine. The first dyno run fell short of expectations, but it turned out the Big G was playing nanny and cutting back the power due to a high EGT spike. Using the in-cab monitor, Granatelli told the Big G to mind its own business during the next pass. With the nanny on break, our diesel posted an awesome 485 hp and 789 lb-ft of torque...for just $1,113!