Exhaust systems, cold-air intake systems and other similar components are typically the first steps enthusiasts take to boost performance of their vehicles and for this story, that’s exactly what we did with a shiny, Hemi-powered Dodge Ram. We enlisted the help of Corsa Performance Exhaust, K&N and ASP to supply the parts, while Medina, Ohio’s Back Street Performance (www.backstreetper.com) provided the wrenches and the dyno to complete and evaluate the project.
Of course, the logical question surrounding most bolt-on projects is: If a bolt-on part is so effective, why doesn’t the factory simply produce their vehicles with it? The answer lies in some side effects that come with power-enhancing parts. Cold-air intake systems, for example, generally produce a notable increase in sound under wide-open throttle. To performance enthusiasts, this is a welcome sound, but for the remaining 99.5 percent of the car-buying public, it’s considered noise. The open-element air filter of most cold-air systems can be exposed to water ingestion in certain conditions – conditions enthusiasts would be careful to avoid, but not so with the general public.
That’s not to say that bolt-on parts necessarily bring compromises to drivability. Carefully selected bolt-on parts often provide years of trouble-free service, along with the benefit of increased performance over the stock configuration. Bolt-on parts also serve as the foundation for more serious engine upgrades. Long tube headers, for example, won’t do much for an otherwise stock engine, but they would be helpful with a supercharger.
Here’s what we added to our Ram project vehicle: A K&N cold-air system, a Corsa cat-back exhaust system and ASP’s underdrive crank pulley. Versions of these products also are available for the Hemi LX cars – Magnum, Charger and 300C. Each component offers a performance increase, but they work well together as a package to provide a noticeably improvement in seat-of-the-pants performance. In fact, we recorded 8 percent gains in overall rear-wheel horsepower and torque when all parts were installed.
CORSA CAT-BACK EXHAUST
The Dodge Ram – as well as the Dodge Durango, Chrysler Aspen and Jeep Grand Cherokee – has a single-outlet exhaust system. A “Y” pipe located after the catalytic converters merges the exhaust of both cylinder banks and sends it through a large-diameter, single-outlet system. To accommodate MDS – the cylinder deactivation system – there are two mufflers and a resonator in the system.
Despite the seeming performance handicap of a single-outlet system, the Hemi-powered Ram’s exhaust tubing from the Y-pipe rearward measures 3 inches in diameter. The biggest kink in the stock system is a pinch of the tubing where the left-hand and right-hand sections meet. Daimler Chrysler’s Mopar Performance accessories division offers a freer-flowing. After the Y-pipe, the exhaust system flows through the mufflers and, arcs over the rear axle to the resonator/outlet.
Removing and replacing the stock system is, for the most part, an easy project. There is plenty of room beneath the Ram to maneuver and it is probably not necessary to raise the vehicle off the ground – especially if the vehicle has 4WD.
The Corsa system used for this project was installed in about an hour, thanks to the aid of a lift and impact tools. The do-it-yourself enthusiast could perform the same project in the driveway with only a little more time. The Corsa system’s fit was excellent and its sound quality was a quiet burble at idle and a more throaty growl under hard acceleration. Also, the kit’s polished tips are a great complement.
The system also performed well. It was worth 13.7 horsepower and 17.4 lb.-ft. of torque at the rear wheels, compared to the stock configuration.
K&N AIR FILTER
The K&N Ram Aircharger, part number 63-1533, is similar in design and installation to systems for a variety of vendors, although some manufacturers’ kits have a longer intake tube to draw air from the bottom of the engine compartment. It retails for around $275, but can often be found for less.
K&N Engineering claims the Aircharger is worth more than 10 horsepower over the stock configuration. However, as the test vehicle already was wearing a high-flow exhaust system, the Aircharger did not add 10 horsepower. Tests on a DynoJet 248 revealed that, with the exhaust already in place, the cold-air system was worth about 2.5 horsepower at the tires. It seems like a statistically insignificant result, but a higher number likely would have been recorded with a stock exhaust system. K&N’s published tests for the Aircharger also were performed on a DynoJet dynamometer.
If anything, the intake system proved that bolt-on horsepower isn’t stackable – performance gains are incremental as more bolt-on items are employed. Still, a cold-air intake system is easy to install and can provide added benefit if more serious engine modifications are made. It also improves the underhood appearance of the vehicle.
Installation of the Aircharger kit is simple, requiring only a few hand tools and little more than an hour’s time. Enthusiasts who are inexperienced with tools can perform the installation and expect excellent results.
ASP UNDERDRIVE PULLEY
ASP’s Ram balancer/pulley (#ASP501360) replaces the stock 7-3/16-inch-diameter crankshaft balancer/pulley with a 20-percent reduction in diameter. While turning the accessories a little slower, it nonetheless provides full charging capability for the alternator at 850 rpm. ASP’s list price is approximately $286.
Installation difficulty straddles the line between simple bolt-on and a more challenging project. If the installer has little or no experience with tools, particularly pulley pullers, it’s a job that is probably best left to more experienced hands. It’s a job that any competent dyno/tuning shop can perform in an hour or two.
Installation procedures are similar for cars and trucks; in a nutshell, they involve removing the stock crank pulley/balancer and installing the underdrive pulley. The serpentine accessory drive belt also must be replaced, as the stock belt won’t fit with the smaller-diameter pulley. The ground clearance on a Ram allows the installation to be performed with the vehicle on the ground. Installing a pulley on a car is much easier on a lift.
Auto Specialties Performance (ASP)
13408 Redfish Lane
Stafford, Texas 77477
Back Street Performance
650 W. Smith Rd. Unit 12
Medina, Ohio 44256
149 Blaze Industrial Pkwy.
Berea, Ohio 44017
P.O. Box 1329
1455 Citrus St.
Riverside, Calif. 92502
DODGE RAM BOLT-ON COMPARISON (2006 Ram 1500 4WD with 5.7L)*
Configuration Rear Wheel HP Rear Wheel TQ (lb-ft)
Stock exhaust and air intake 239.6 @ 5600 rpm 261 @ 3500 rpm
Corsa exhaust and stock air intake 253.3 @ 5700 rpm 378.4 @ 3500 rpm
Corsa exhaust and K&N Aircharger 255.9 @ 5600 rpm 276.1 @ 3500 rpm
Corsa exhaust, Aircharger and ASP pulley 264 @ 5800 rpm 283.5 @ 3500 rpm
Total gain 21.4 22.5
Percent gain 8% 8%