If you're a big fan of spicy food, you check out somebody like Guy Fieri on the Food Network to watch him cook up all kinds of hot habineros. But if you want to feel the heat from a Hemi, Vortech serves up a centrifugal supercharger that'll smoke 'em. Try one little taste of this chile-green Charger, and you'll be howling for more. As with any gourmet dish, quality is more important than quantity, so instead of a rotund Roots blower piled high on the hood, the centrifugal type packs its punch in a compact unit right under the hood.
Force-feeding more air and fuel into a Hemi has a long and storied history dating back to the Mopar muscle cars of the '60s. Those hemispherical heads are real heavy breathers, and open their nostrils quicker than stuffing your face with a mouthful of hot peppers.
The major components of the Vortech package include a compressor, Power Cooler, pulley bracket, belts, hoses, air filter and water tank. Either satin or chrome finish is available. (Not shown is the Diablo programmer for recalibrating the engine computer.) The system shown here was installed on a 5.7 Hemi, and the basic steps are fairly similar across all Dodge and Chrysler models, with only a few minor variations, which are highlighted below.
Of course, increasing the respiration rate on today's computer-controlled Hemi isn't all that easy. But Vortech is already all over that one, having introduced a new system that simplifies installation. Designed to fit either the 5.7 or 6.1-liter Hemi V-8s ('05-'09), it doesn't require routing of oil lines, nor drilling into the oil pan, since it has an internal oil reservoir for self-lubrication. (Note, though, that the oil in the compressor should be changed every 7,500 miles, and Vortech provides three pre-measured bottles of the special oil that's required. All you have to do is pull a plug, drain the compressor, and then refill.)
The major steps of the installation on the engine bay consist of adding a new pulley bracket, air compressor, bypass valve, high-flow air filter, and Power Cooler. To prevent a lean-out condition and keep up with the increased airflow pumped out by Vortech's over-achieving, internally lubricated V-3 Si-Trim centrifugal supercharger, the fuel management requires some attention as well. This aspect requires adding high-flow Mopar fuel injectors and a two-bar Map sensor (procedures vary slightly between the 5.7L the 6.1L, which includes a fuel-pump voltage booster assembly as well).
On the stock Hemi, first make sure that your ECM does not need to be updated. (The Diablo programmer can indicate if this extra step is needed.) If not, begin by disconnecting the negative cable of the battery, and removing the plastic engine cover. Also remove the breather hose, air filter, and intake ducting up to the throttle body, and unplug the IAT (Inlet Air Temp) sensor. The front bumper will need to come off as well, along with the electric radiator fan assembly and the accessory drive belt. You also might need to remove the upper radiator hose. If your vehicle has more than 15,000 miles on it, change the spark plugs as well.
A DiabloSport Predator hand-held programmer is used to change the ignition timing and fuel enrichment. Before proceeding with these latter steps, though, be sure to let the engine cool down before relieving pressure on the fuel system. Also, do not attempt to reuse the factory retaining clips on the new injectors.
One item we weren't able to show is the dowel pin install on the harmonic damper, which acts as a fail-safe to prevent it from spinning on the crankshaft. This step requires removing the electric radiator fan assembly and crankshaft damper bolt. Vortech supplies a drill guide for precise location of the pilot hole for the 1/4-inch dowel pin.
It's no secret that compressing extra air into a Hemi creates heat, which can impede power production. That's why cooling the induction is so important, as it improves the oxygen density of the charge density while reducing the risk of detonation. To that end, Vortec includes an integrated dual-pass air/water charge cooler that utilizes a closed-loop water-cooling configuration with a stand-alone pump, tank and front mounted heat exchanger.
Taking all these mods together, expect to give up the better part of your weekend fitting on the system, but if you know your way around a rollaway (fitted with standard shop tools, such as a socket set, wrenches, screwdriver and drill), you probably can pull into your garage on Friday evening and be test-driving your Hemi-powered Dodge (or Chrysler) by Sunday afternoon. (Vortech also has a network of professional installers if you'd rather pay somebody to do the wrench work, and offers a three-year, 36,000-mile warranty.)
How much heat can you expect from a bite of this hot chili pepper? Running a streetable 5.5 pounds of boost and 91-octane fuel, you can figure on spiking the output of a 5.7L to 432 hp, about 102 horses more than stock. And the 6.1 Hemi, force-fed with a max of 6.5 pounds, jumps to 560 hp, a gain of 135 horses. Torque output goes from 420 to 510 lb/ft.
Those numbers look great on paper, but what's it feel like in your mouth, er, behind the wheel? This type of blower, essentially a belt-driven turbo, requires getting up a head of steam first, but unlike a positive-displacement Roots or twin-screw system, there's no limit to how fast it can spin. That means the power delivery is very linear--in most cases. It really all comes down to how hard you hit the loud pedal.
If you stomp on it, spiking the revs and popping the clutch, you can fry the hides like a hot rod with a Jimmy blower sticking through the hood. Problem is, when you don't hook up the tires, the acceleration time might be only a tick or so quicker than that of a stock Hemi.
But if you drive smarter, not harder, and roll on the throttle, you can let the Vortech build up the boost in a steady fashion. Using this approach, the Charger feels like a fighter jet on takeoff, hurled off a carrier deck by a steam catapult. The horizon zooms up so quick, you might find yourself saying, "We have liftoff!" And that's way hotter excitement than anything you'll ever see on the Food Network.
