Since the beginning of time, as it pertains to automobiles, people have been changing and modifying these mechanical wonders in the quest for more power, better handling, and simply making their car better than the next guy. But over the years, the mechanical wizardry has taken on advancements that at one time were the things of science fiction. Cars, quite literally, are more computer-controlled wonders than mechanical ones these days.
But has that made the hot rodder extinct? Not by a long shot. It seems that no matter what kind of advancement, be it mechanical or electrical, the aftermarket suppliers will come up with a way to improve upon the O.E.'s basic design. It used to be as simple as changing an intake and carb, slapping on a set of headers, or installing a set of numerically higher gears, and, presto, improved performance. Is it still that simple? When it comes to the 21st century Hemi, almost.
Sure, the engine is computer controlled. Sure, it's fuel injected. Sure, there are a lot of accessory items mounted all over the engine, but underneath it all, it's still an internal combustion powerplant. So, theoretically, a few bolt-on upgrades would be an improvement, right? Well, keep in mind, since the engine's functions are computer controlled, that computer has set parameters for the functions the engine does. So, if we add a cold-air intake system, theoretically, the calibrations will change in the computer in regards to the fuel mixture. Now, with this simple modification, the change will not violate the parameter, and the result is usually a slightly leaner condition, resulting in an increase of horsepower.
Let's get deeper into the modifications. What if we add a cold-air kit, headers, and perform a cam and head swap? these are some above-average modifications, especially to an engine as new as the 5.7 Hemi. the computer will realize the increase in cylinder pressure (depending on the new cam specs, and the head's chamber volume), and the more efficient movement of the air and fuel mixture (resulting from the ported heads). This will require a special tuning be applied to the computer to compensate for the changes, correct? O.k., maybe we are thinking too deeply into the modification realm, and some of you just want to get a little more oomph out of your Hemi. Luckily, the modifications that have been going on for centuries still have merit today.
 Comp Cams is now manufacturing...  Comp Cams is now manufacturing three different cams for the 5.7 Hemi. Their new XFI (Xtreme Fuel Injection) series of camshafts for Hemi-powered Chrysler vehicles, according to them, "dramatically increase engine horsepower and torque, yet retain compatibility with all OEM vehicle computer systems." The cams are available in three different profiles: XFI 260, 268, and 273. These three new camshafts are application-specific, with designs for street, street performance, and towing. We decided we would take a small step and choose the 260 version of these new cams. The XFI 260 cam features a .522/.525-inch valve lift, with 208/212-degrees of duration at .050-inch lift, and a 113-degree lobe separation. Since we were doing a cam swap, we thought it wise to also install a set of Comp's valvesprings to go along with their cam. Fortunately, these springs are the same as GM's LS-1, and readily available. Yes, it's a fairly small cam, but Comp tells us this particular cam needs no computer modifications. The large XFI 273 cam may require some computer reprogramming. |  The Plan At first, we thought...  The Plan
At first, we thought we could simply throw a bunch of parts at our '03 Hemi-powered Ram, and see what stuck. Well, common sense got the best of us, and we realized that wouldn't work. What we did do, however, was find out about some aftermarket manufacturers that are producing performance items for the new Hemi. But would we be able to tackle the work? We decided we needed to find a shop that was capable of working on newer computer-controlled vehicles and able to undertake the task we were throwing at them. Fortunately for us, we found KRC Performance in Cocoa, Florida. KRC Performance is the kind of place that will pick up your truck from anywhere in the continental U.S. and perform all the work. Whether it's a wild stroker motor or a show truck, KRC can handle it. |  Normally, a torque converter...  Normally, a torque converter is swapped in favor of a performance piece that allows the engine to reach a higher rpm before engaging. The reason for this is usually for racing, where you need the engine to reach a certain rpm where more performance is available from the engine. In our case, we found that TCI has developed a truck torque converter they tell us increases power, efficiency, and fuel mileage. We also hear they are more durable than OE converters equipped with plastic stators. The new TCI converters for 5-45RFE transmissions feature an aluminum stator for increased torque multiplication and heavy-duty furnace-brazed components. they also tell us their converter delivers better power throughout the entire rpm range. So let's see, better performance and fuel economy, yep, that's what we need. |