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New for 2012 Charger Pursuit

Written by Law and Order Staff

The 2011 model year was a very short one for Dodge, running from just March to July. As such, you would expect the changes for 2012 to be few in number. Not so! A bunch of upgrades – all important to law enforcement – were made for 2012.

For 2012, the 5.7L HEMI V8 in the Charger Pursuit comes from the factory with 100,000 mile spark plugs. The best kept powertrain secret in all of law enforcement is that the spark plugs in the 5.7L HEMI need to be replaced every 30,000 miles – all 16 of them. For 2012, all that changes. On the V6, the plugs on the 3.5L V6 have been good for 100K miles for a number of years now, as are the plugs on the new 3.6L Pentastar V6.

New for 2012, the Charger Pursuit has police-specific front seats, both driver and passenger. The new seat has heavier duty fabric and better reinforced seams. The extra-durable fabric is from the Ram and Durango lines. The entry and exit are improved by seat bottom and seat back bolsters with more clearance.

Of course, the seat back has been sculpted, relieved and contoured to make room for the fully-loaded duty belt. The driver’s seat remains a power, 6-way adjustable. As for daylong comfort, Dodge really did benchmark the Lexus 460 seat. The seat change will also include longer seat belts.

The 2012 Charger Pursuit will also get the Gen 3, redesigned front hubs (knuckle-bearing) that have stiffer bearings. With less deflection, this should lessened judder and vibration, while also improving durability.

Longer Life Brakes

Responsive to requests for even longer brake pad life, Dodge upgraded friction materials for the 2012 Charger Pursuit. The V6 and V8 Chargers tested by the Michigan State Police had this new compound. These 2012 OE brakes are backward compatible with all earlier Charger Pursuits. The new brakes also include high-temp silicon caliper boots.

In spending a full year in developing the new brake pads, Chrysler focused on two of the most realistic and widely accepted brake tests: the Huron-Detroit Metro Traffic (HDMT) and the Los Angeles City Traffic (LACT) protocols. HDMT is the standard test for brake vibration, jerkiness or pulsation. This testing confirmed a 50% improvement in roughness performance.

LACT is the standard test for brake noise and pad wear. The testing takes 20 days in a vehicle loaded to its Gross Vehicle Weight Rating. In this testing, the noise went from “noticeable” on the older pads to “not noticeable” with the new compounds. Most importantly, this street-realistic test confirmed that pad life has been increased by a full 35%!

Stronger Steel Wheels

For 2012, the Charger Pursuit comes with very different steel wheels. These are a bit heavier and much stronger than the earlier generation wheels. The new wheels have thicker ribs (spokes) to pass the tougher FIAT-mandated corporate durability standards. Due to changes in the weight of the new wheel, the new wheels are NOT INTERCHANGEABLE with older generation wheels.

Also new for 2012 are solid steel lug nuts. These replace the troublesome lug nuts with chrome caps. These new lug nuts can be used on any year of Charger Pursuit. Maintenance tip – on the old chrome capped lug nuts, be sure to use the correct 21mm socket when removing them. Not everyone has this metric size, and 7/8-inch (.875-inch) is very close to 21mm (.827-inch). However, using this 7/8-inch socket is part of the lug nut rounding problem. And 13/16-inch (.812-inch) is not 21mm, either. Until your entire fleet is converted to the solid lug nuts, be sure to use the 21mm socket.

Mopar Upfitting

New for 2012, Chrysler Fleet is offering factory-based upfitting using Mopar brand components. Their police equipment packages feature emergency lighting, audible warning, communications and safety equipment. Upfit packages are available for the police package Dodge Charger and for the Special Service package Dodge Durango and Ram 1500.

Industry-leading suppliers were involved in the development including Whelen Engineering, Setina Manufacturing and Havis. Vehicles will be ready-for-duty right from the manufacturer. Mopar equipment carries a standard 3-year/36,000-mile warranty. For more details, see the Nov-Dec 2011 issue of Police Fleet Manager, in print or online. The 2012 Charger also comes with a 220 amp alternator and 800 CCA battery. For 2012, spotlights with LED bulbs (emitters) will be an option to the standard halogen bulb.

New Axle Ratio for V6

New for 2012, the Charger with the 3.6L Pentastar V6 is available with an optional rear axle ratio. The standard gears are the economy-oriented 2.65:1 ratio. The optional gears are the performance-oriented 3.07:1 ratio. For departments wanting the maximum fuel economy, the 2.65 gears are the clear choice. And most departments select the 3.6L V6 over the 5.7L V8 specifically for the better fuel economy.

However, for a variety of political or operating cost reasons, some departments that really want the 5.7L V8 are required to buy a V6, period. For those who want the V8 but get the V6, the optional 3.07 rear gear in the V6 produces more bottom end punch – better throttle response – than the standard 2.65 gears.

This lower gear ratio improves the acceleration from any vehicle, i.e., cars with a pushrod valvetrain. However, it is especially helpful on a car with a single or double overhead cam engine. (The new Pentastar V6 is a DOHC engine.) The faster these kinds of engines wind up to higher rpms, the better the acceleration.

With the 2.65 axle, the 3.6L V6 Charger is already the fastest V6 sedan around the road course. The 3.07 axle does not turn the 3.6L Charger into a HEMI Charger, of course. But the 3.07 gear will further improve that pursuit and emergency response performance. Compared to the Charger V6 with 2.65 axle, the Charger V6 with the 3.07 axle is ½ second faster to 60 mph and a full second faster to 100 mph. That is a big deal.

Decel Fuel Shut-Off

The driver information center on the 2011-2012 Charger has a display that lights up with the term “ECO.” This means the engine is operating in some sort of lean, fuel efficient manner. On the 5.7L HEMI V8, it means that both the Multi Displacement System (cylinder deactivation) and the Interactive Decel Fuel Shut-Off (iDFSO) may be activated. On the 3.6L Pentastar V6, it may mean the iDFSO has been activated.

Regardless of what software controllers are acting on the engine, the ECO light means that the throttle is below a certain threshold and that the torque required from the engine is below a certain level, even if neither MDS or iDFSO are activated. For example, in 5th gear on a level road and cruising below 2000 rpm at a relatively steady throttle, the ECO light will be lit.

The iDFSO system is one of the ways to improve the fuel economy from both police engines. With iDFSO, the engine controller shuts off the flow of fuel during vehicle deceleration. The fuel is shut off completely under two basic scenarios. First, lifting your foot off the gas pedal when the engine was running at higher rpms, for example, 3500 rpm. The fuel is cut to prevent high catalyst temperatures, and the fuel will resume as the rpm drops to about 1200 rpm.

Second, during a normal lift foot from a steady state where the transmission torque convertor is in slip control. The fuel is completely cut off after a short delay from closed pedal when the transmission is not shifting and the torque convertor is holding the engine rpm. The transmission will downshift with the fuel off as the vehicle speed decreases. The fuel turns back on as the rpm approaches 950 rpm and/or the torque convertor unlocks.

In typical drive cycles, the fuel will be off approximately 5 to 8% of the time the vehicle is moving with improvements to both fuel economy and brake pad life. The vehicle may feel like it is not "coasting" as far on decel as the previous model years did because fuel is not being used to propel the vehicle at closed pedal.

As the pedal is lifted to coast to a stop on a MDS-equipped engine, the iDFSO (fuel shutoff) and the MDS (cylinder deactivation) work in combination with one another. The fuel will shut off or turn on in either MDS mode (8 cylinder or 4 cylinder). MDS may also activate during a fuel shut off, but the activations will not happen at the same time. The vehicle deceleration will be milder while in 4 cylinder mode. Light pedal tip-ins will stay in 4 cylinder mode as the fuel is turned back on. When coasting to a stop, 8 cylinder mode is re-enabled after the fuel turns on.

So, “ECO on” illuminated on the dash can mean either iDFSO or MDS is activated, or the vehicle is just being driven easily. However, the two ECO methods (MDS, iDFSO) are disabled at idle in both Park and Drive. As the sedan coasts to a stop, as soon as the gas pedal is backed off, the ECO is activated. As the sedan nears a full stop, as the engine speed gets below 950 rpm, the ECO is off, MDS-iDFSO are disengaged. (Most V8 engines do not idle smoothly enough for cylinder deactivation at idle.)

Published in Police Fleet Manager, Jan/Feb 2012

Rating : 10.0


Comments

Comment on This Article

Spark Plugs

By Tom Laquidara

Why wouldn't the civilian version of the 2012, 5.7L HEMI V8 Charger have the 100,000 mile plugs as well. Why or are they limited to the Pursuit?

Submitted Sep 14 at 7:04 PM

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