Junkyard Ram 5.7L Hemi Engine Makes 496 HP and 530 LB-FT of Torque
A Nitrous Express Single Fogger and a few rebuilt parts get this used Hemi making good power
There it sat, alone and forgotten, open to the elements, enduring endless dust and rainstorms, and without so much as a valve cover, oil pan, or intake for protection. Such was the fate of our 5.7L Hemi, or at least the remaining part of what was once the proud and powerful motivational force for a 2006 Dodge Ram 1500 truck. So long had it sat, we forgot its original purpose, or even why it was lacking such a vast array of critical components. Had this Hemi been relegated to donor duty? Was it a prior Dulcich test engine? Perhaps it was picked over to provide the necessary components to complete other, more important builds?
We know from experience that it was certainly more expensive to piece-meal the missing components on this motor than it would be to simply purchase another complete junkyard motor. Still, we couldn't help but be intrigued by the mystery motor, and like any good mystery this one needed to be solved. By solved, we mean it needed to become whole once again. Then, once complete, it needed what every motor needs—more power!
Our orphaned baby elephant began life as a 2006 Ram truck engine, but we can't for the life of us remember where it came from or why it was in its current configuration. Undaunted, we opened up the homeless shelter and ordered up everything needed to make it whole again. The list of bare necessities included an oil pan, front cover, valve covers, a single set of rockers and shaft, cam and crank sensors, and the entire induction system, including intake manifold, throttle body, and fuel injectors. The intake is a story in itself, as the used Hemi intakes often come with excess baggage in the form of piston parts.
The random, unexpected dropping of valve seats is very common in 5.7L Hemis, and the resulting failure causes extreme piston damage. The intake receives more than its fair share of the unwanted debris and ours was no exception. It took no less than five thorough cleanings with gas, water, and air to finally get the nylon intake clear of the broken piston parts. Sometimes the broken piston and rings will imbed themselves in the plastic intake, coming loose only after you apply heat and vibration from running the engine—fun stuff! New intakes are a safer choice but are certainly more expensive—just not more expensive than rebuilding an engine after you dislodge the debris in that used intake!
In addition to replacing the missing components, we also took the liberty of replacing the MDS lifters with their conventional counterparts. This allowed us to run the engine without the hefty variable displacement lifters. The conversion also required use of stock galley plugs to replace the MDS solenoids. In anticipation of our nitrous testing and future boost (yes, there will be a turbo test!), we also tore into the engine to increase the factory ring gap. Though the stock Hemi pistons have a reputation of being weak, most of the damage (under boost) comes from a combination of extra heat and a lack of ring gap. Heat causes the rings to butt together, they momentarily seize in the bore, and boom, off goes the ring land. The problem isn't the weak piston but rather insufficient ring gap.
We also installed a fresh set of Fel-Pro MLS head gaskets and treated the stock fuel injectors (which came with the intake) to a thorough cleaning and flow testing on the ASNU injector machine. Since we ran the factory Ram truck cam, we elected to keep the stock valvesprings in place. The one major modification to the 5.7L was to convert the electronic DBW throttle body to a manual (cable) version with a little destruction and welding. We don't like asking the computer to open the throttle body, we like telling it!
The goal for the mystery motor in Part 1 is simply to find out if it runs, and if so, add a little spice in the form of a nitrous kit from Nitrous Express. After adding a set of Hooker long-tube headers, a Meziere electric water pump, and the Holley HP management system, the first of our questions was quickly answered. After tuning, the 5.7L Hemi pumped out 367 hp and 414 lb-ft of torque. Note that this output betters the factory rating of 345 hp, but the factory horsepower rating is achieved with all the factory accessories, full exhaust, full air intake, and with the conservative factory tune. We've run stock Ram Hemis in the past that made 10 to 15 hp more, so possibly our Mystery motor was not 100 percent perfect, but it was alive and well, and most importantly, ready for some nitrous. To complete Part 2 of our mission, we installed a wet fogger nozzle from Nitrous Express. The Shark nozzle combined the nitrous and fuel, then injected them into the intake tube before the throttle body. Run with a 52/28 jet combination, the NX nitrous kit took the mystery out of power gains and improved the power output to 495 hp and 530 lb-ft. Imagine how much fun the Homeless Hemi could have in your neighborhood with a 500hp Hemi! Check back with us for the next episode when we give this engine a new cam.
5.7L Hemi Dyno Test: Stock vs. Nitrous
Run in all-motor trim, the 5.7L mystery Hemi produced 367 hp and 414 lb-ft of torque. After installation of the NX single-fogger nozzle, the power output jumped to 495 hp and 530 lb-ft of torque, though the activation spike exceeded 500 hp. That's one heck of punch for a Hemi without a home!