General Challenger

  • Engine Dyno vs. Chassis Dyno

    What's the difference between running an engine on an engine-dyno, or, as installed in the car, on a chassis-dyno? Most chassis dynos extrapolate an engine's power and torque based on vehicle inertia. Many variables can affect chassis dyno results. It's a great convenient tuning aid, but you can't directly equate the reported torque and power numbers back to engine dyno results, or even the results obtained from two different chassis dynos. Operator experience is critical for obtaining...
  • Camshafts

    Camshafts are used to operate poppet valves. It consists of a cylindrical rod running the length of the cylinder bank with a number of oblong lobes protruding from it, one for each valve. The cam lobes force the valves open by pressing on the valve, or on some intermediate mechanism, as they rotate. Camshafts can be made out of several types of material. These include: Chilled iron castings: Commonly used in high volume production, chilled iron camshafts have good wear resistance since the...
  • Crumple Zones

    Crumple zones, crush zones, or crash zones, are a structural safety feature used in automobiles, to absorb the kinetic energy from the impact during a collision by controlled deformation. This energy is much greater than is commonly realized. A 4,409 lb. car traveling at 37 mph.,before crashing into a thick concrete wall, is subject to the same impact force as a front-down drop from a height of 47 ft. crashing on to a solid concrete surface. Increasing that speed by 50% to 56 mph. compares...
  • Fuel Delivery Systems

    A carburetor was the common method of fuel delivery for most US-made gasoline engines until the late 1980s, when fuel injection became the preferred method. This change was dictated by the requirements of catalytic converters and not due to an inherent inefficiency of carburation. Basically, a carburetor consists of an open pipe through which the air passes into the inlet manifold of the engine. The pipe is in the form of a venture- it narrows in section and then widens again, causing the...
  1. The Origin of Scat Pack

    The Dodge Scat Pack was originally introduced in 1968 with the Charger R/T, Coronet R/T, Dart GTS, and Super Bee. In 1969, the Charger Daytona joined the Pack. In order for a car to enter the Scat Pack it had to be capable of running the quarter mile in the 14s (14.99 sec. or faster). Mainly a marketing term, Scat Pack cars got twin bumblebee stripes and special decals. It became legendary in the enthusiast community and symbolized one of the most feared groups of street machines every to...
  2. Why Do Hemi Engines Have Dual Sparkplugs?

    Each cylinder on a Hemi engine has an ignition coil pack over one spark plug, and a regular plug wire connected to the other spark plug. Further, the coil pack also has a plug wire attached to it that extends to the opposite cylinder bank. Each cylinder shares a coil pack with another cylinder. Each of the two plugs on a given cylinder is fired by a separate coil. One plug has a coil directly attached, and the other is fired via an ignition wire connected to a coil located on another...
  3. Featured

    Axle Ratios

    An axle ratio is the number of revolutions the output shaft or driveshaft needs to make in order to spin the axle one complete turn. The number is expressed in a ratio, which represents the number of teeth on the ring gear divided by the number of teeth on the pinion. For example, a vehicle with a 3.73:1 gear ratio means that the driveshaft will turn 3.73 times for each complete wheel spin. Many people simply refer to the axle ratio as 3.73, rather than express it as the ratio 3.73:1....
  4. Featured

    Active Exhaust

    It’s a fact of life- cars make noise. Inexplicably, there are those in this world who build houses next to major freeways and then complain about the speed of the vehicles going past. There are those who build houses next to airports and complain about the excessive noise. Just as there are those people, there were those who decided that cars were too loud and needed to shut up! This presented car companies with a problem. Their engineers were telling them that for maximum efficiency,...
  5. How Do Navigation Systems Work?

    Getting lost while driving, or stopping at a gas station to ask for directions, has become a thing of the past. With GPS in your car’s navigation system, in the portable navigation device on your dashboard, or in your smartphone, it is easy to pull up a map and see where you are, or get directions to where you are going. GPS makes you safer, routes you around traffic delays and helps you find nearby services. GPS (Global Positioning System), a technology we now take for granted, started...
  6. Featured

    Line Lock

    A line lock is a device that allows the front brakes to lock independently of the rear brakes, via a switch. The device is an electric solenoid that controls a valve which allows the brakes to be controlled individually. This allows the front brakes to be locked and the rear brakes to be open, and allows the driver to spin the rear wheels without wasting the rear brakes. This method is referred to as line lock and is popular among drag racers. Cars with manual transmissions allow drivers to...
  7. Ronnie Sox- A Tribute to "Mr. Four Speed"

    Ronnie Sox is one of the greatest Mopar drag racers. Like many who eventually became professional racers, "The Boss," grew up around cars, raised in the shadow of his family’s Sinclair service station. As soon as he was old enough to drive, Sox began competing in drag races, sponsored by the Police Club of Burlington, NC, at a local airport. In the early days, Sox didn’t even own a car and used his father’s 1949 Olds. From these humble beginnings, Sox would go on to become what many...
  8. High Impact Paint

    In the late 60s/early 70s, Dodge was already offering some of the hottest cars of the muscle car era- awesome machines like the Hemi Challenger and 440 Six-Pack Super Bee. Designers, however, decided to rev up the cars’ visuals to match, creating a far-out assortment of vibrant exterior paint colors. These special colors (a $15 option) generated a big buzz in the showrooms and launched an industry trend. The color palettes used by all the automakers were opened up, giving paint designers...
  9. Development of Airbags

    Airbags, like lap belts/shoulder belts, are a type of automobile safety restraint system designed to mitigate injury in the event of an accident. These gas-inflated cushions, built into the steering wheel, dashboard, door, roof, and/or seat of your car, use a crash sensor to trigger a rapid expansion of nitrogen gas contained inside a cushion, that pops out on impact to put a protective barrier between passengers and hard surfaces. The National Highway Traffic Safety Administration (NHTSA)...
  10. Evolution of Hood Scoops

    Back in middle school science class, we learned that in order to make fire, you need three ingredients: fuel, ignition and air- or, more specifically, oxygen. You’ll also remember that cold air is denser than hot air, putting more oxygen in the same amount of volume. While the modern internal combustion engine does a fine job of delivering fuel and ignition, that cold air part becomes tricky as you try to route fresh air from outside through a hot engine compartment. In response, in the late...
  11. Nitrous Oxide

    Juice. Squeeze. Laughing gas. Nitrous oxide has many aliases. It can inject a healthy dose of horsepower into an engine, via direct port, carburetor/throttle body plate, air intake tube or, air cleaner injection, to give a race car the winning edge at the track. In racing, nitrous oxide (often referred to as just "nitrous") allows an engine to burn more fuel by providing more oxygen than air alone, resulting in a more powerful combustion. The gas is not flammable at a low...
  12. Featured

    Rear Window Louvers

    The rear window louvers that were original equipment on some 60s and 70s muscle cars were first and foremost, styling statements. They were part of an appearance package that was created to set these cars apart from lower performance plain Jane versions and were usually combined with features like stripes, spoilers and vinyl roofs. In addition, while they did not improve the aerodynamics of the vehicle, they created a dead air zone that helped traction by reducing rear lift. Some pony...
  13. 3.6L Pentastar Engine

    A popular cost-conscious alternative for Challenger owners to the 5.7L and 6.4L Hemi engines is the 3.6L Pentastar engine. It replaced the 3.5L engine, in 2012, and is rated at an impressive 305 horsepower and 270 lb.-ft. of torque, with 90% of its torque available from 1,800 to 6,350 rpm. Performance from this modern 6-cylinder engine actually exceeds some small blocks from the first muscle car era. Before the first aluminum block was cast, the new Pentastar V-6 benefited from more than...
  14. Engine Dyno vs. Chassis Dyno

    What's the difference between running an engine on an engine-dyno, or, as installed in the car, on a chassis-dyno? Most chassis dynos extrapolate an engine's power and torque based on vehicle inertia. Many variables can affect chassis dyno results. It's a great convenient tuning aid, but you can't directly equate the reported torque and power numbers back to engine dyno results, or even the results obtained from two different chassis dynos. Operator experience is critical for obtaining...
  15. Limited Slip Differentials

    A limited-slip differential (LSD), or “anti-spin” differential is a type of differential that allows the rear wheels on a vehicle to turn at different speeds when executing a turn. They are widely used in high performance and four-wheel-drive vehicles because they provide superior traction abilities. Various types of differentials can be classified as "anti-spin." These include limited slip, locking and spool differentials. Each performs differently on and off the road. Generally, only...
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