Читать книгу Dodge Challenger & Charger - Randy Bolig - Страница 11
ОглавлениеIn the 1950s and 1960s, if you mentioned to someone that your car had a Hemi engine you immediately gained respect. The Hemi was known as a powerhouse, and in automotive circles, it was tough to beat. Sadly, the cost to build the Hemi and strangling insurance regulations led to the demise of the legend in 1972.
With the introduction of the 2003 model year, the legendary engine made a return. However, production of the engine actually began in June 2002 at the Saltillo plant in Mexico. In 2003, Chrysler showed a Hemi engine with a supercharger to the public. Using the 5.7 Hemi engine and a Whipple supercharger, that engine made 430 hp and 480 ft-lbs of torque. That doesn’t sound like a lot, but for a completely new engine design, it was a start. The engine initially found its way into Dodge trucks.
For this, its third, generation of design, Chrysler incorporated some new build processes and design features. The block, for instance, is precision cast and the connecting rods are powder metal.
The Gen III Hemi was designed with two spark plugs per cylinder. One coil pack was over each spark plug, and a plug wire also connected from that coil pack to a spark plug on another cylinder (each cylinder shares a coil pack with another cylinder). This means that a separate coil fires each of the two plugs on a given cylinder. One spark plug fires during the power stroke to begin the combustion process and the second spark plug fires during the down stroke of the piston to help burn any residual fuel and hydrocarbons that didn’t burn during combustion.
The 5.7-liter Hemi V-8 found in the new 2006 Charger Daytona featured 350 hp and 390 ft-lbs of torque. That’s 10 horses over the previous year’s 5.7-liter Hemi that came in the R/T Charger. Engineers at Chrysler say that the horsepower increase was accomplished by using a less restrictive intake system, and by moving to a straight-through muffler design instead of the previous years’ three-pass muffler. A styling enhancement meant that the Daytona also received a color-matched engine cover. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
Over the years, the third-generation Hemi has undergone many revisions, and when looking for an engine, some of these revisions can affect choices in aftermarket parts. Do you have an idea of how you want to build your Hemi? Are you looking for a max-performance monster, or do you want to just add some bolt-on parts to increase the performance? Either way, you need to know which late-model Hemi you actually have.
The 5.7-liter Hemi engine made its 2003 debut in the Dodge Ram as the standard engine. That first generation was capable of producing 330 hp at 4,800 rpm, and 375 ft-lbs of torque at 4,200 rpm. The 5.7-liter Hemi engine was also available in the Dodge Durango.
By the time the 2005 model year cars were introduced, the 5.7-liter Hemi had become a proven performer, so it was a natural fit to make its way under the hood of the new LX-platform cars, including the 300 and the Magnum (eventually the Charger, in 2006). The Hemi was smaller and cheaper to build than the older LA-series small-block that it replaced, but produced more power and torque.
When building the engine, designers incorporated a very strong deep-skirt design into the block. The deep-skirted block made it possible to create a stronger, four-bolt support system for the crankshaft. This means that supporting the crankshaft are four bolts at each main bearing (two that mount vertically through the bearing cap, and two that mount horizontally through the block into the bearing cap). The new Hemi block is precision cast, and this allows it to be much lighter than other engines of the same relative size.
The pistons are made using a cast eutectic alloy, and are relatively light (413 grams). It’s believed that using a relatively small cylinder bore and a long stroke can aid in reducing emissions, so the cylinder bores of the 5.7-liter Hemi were designed at 3.197 inches, and the crankshaft stroke comes in at 3.578 inches.
The connecting rod was also designed to minimize weight but keep some much-needed strength. The connecting rod is built using a powder metallurgy. This is the process of blending fine-powdered materials, and then compressing them into a desired shape or form. Once this “compacting” is complete, the connecting rod is then heated in a controlled atmosphere (called sintering) to bond the material/powder into the desired product.
The 5.7 Hemi used in cars from 2003 through 2008 used short blocks that interchange between car and truck engines. The difference is that all cars since 2005 are MDS equipped with the solenoids and lifters. In 2007 the Ram and Durango also benefited from the addition of MDS. With the exception of a few minor sensor changes these short blocks are identical. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
The 2003–2008 5.7-liter Ram with a 5.7-liter DR (truck) engine used a seven-rib front accessory drive; the front cover, water pump, and accessories do not interchange. This setup mounts the accessories high in front of the intake, prohibiting the use of car intake manifolds. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
The cylinder block of the new Hemi is precision cast. This process of making the block allows it to be lighter than other 5.7-liter engines. This is accomplished even though it has a taller deck height than GM’s equivalent V-8.
The use of powder-metal technology eliminates the need to manufacture the product by traditional forging and metal removal processes (casting and machining), thereby reducing costs. Also, instead of using a through-bolt with a nut, as with previous engine designs, Chrysler employed a cap bolt. The result is a 6.24-inch connecting rod that is more than sufficient in stock applications.
All 2008 and earlier 5.7- and all 6.1-liter engines have a 32-tooth reluctor wheel. All 2009 and later 5.7-liter engines have a 58-tooth reluctor wheel.
The crankshaft has large inner counterweights but doesn’t result in an unnecessarily heavy crankshaft. The crankshaft features radius leading-edge counterweights and is definitely performance oriented. The factory 5.7- and 6.1-liter Hemi V-8 crankshafts do interchange, but the reluctor wheel on the 5.7-liter uses three mounting bolts whereas the 6.1-liter uses four bolts.
The new Hemi also features a camshaft that is located considerably higher within the block than on previous V-8 designs to minimize the pushrod length required to operate the rocker arms. Shorter rocker arms deflect less, creating a more stable valvetrain. To help keep the weight down, the cam is a hollow-core billet piece. The stock 5.7-liter Hemi camshaft measures .477/.462–inch lift, and 255/236–degrees duration. As built, the stock valvetrain is good to around 6,200 rpm.
The Gen III Hemi uses a block with Siamese bores. Siamese cylinder bores are generally more stable than cylinder bores that are cast as part of the engine block. Siamese bores are often used with aluminum blocks because the steel cylinder inserts of the Siamese bores add rigidity.
The stock rocker arms in your Hemi engine are a cast design. Although they perform well in your production engine and are interchangeable from 5.7 and 6.1, they can be considered a weak link when valvespring pressures are increased.
You can identify a block that has the MDS by looking under the intake manifold. Four round solenoids are mounted in the block (one for each group of lifters); they receive electrical connectors from the harness. If you remove the MDS function, round nylon pieces, each with a retainer, are used to plug the holes.
This first version of the 5.7-liter cylinder head is found on all Dodge trucks and passenger cars (not SRT). That usage makes it the most common head in the family. The intake runner is 161 cc, and typically flows around 250 to 260 cfm at .600-inch lift. The exhaust port is unusually small at 50 cc, and again, the exhaust port flows around 155 to 165 cfm at .600-inch lift.
In 2004, Chrysler introduced MDS on 5.7 Hemi engines installed in cars; it was added to Hemi-powered trucks later. The MDS turns off the fuel in four opposing cylinders when power is not needed. Chrysler estimated that the MDS saved nearly 100 million gallons of gasoline between 2005 and 2009.
The MDS is designed to selectively deactivate cylinders 1, 4, 6, and 7 to improve the fuel economy of a Hemi engine. All deactivated cylinders have unique hydraulic lifters that collapse when the MDS is activated, to prevent the valves from opening. Pressurized engine oil is used to activate and deactivate the valves. The oil is delivered through special oil passages that are drilled into the cylinder block, and the MDS solenoid valves control the flow. When activated, pressurized oil pushes a latching pin on each MDS lifter, which then becomes a lost-motion link. This means that the base of the MDS lifter follows the camshaft while the top remains stationary. The MDS lifter is held in place against the pushrod by an internal light-pressure spring, but it is unable to move because of the much higher force of the valvespring.
When 2009 arrived, the 5.7-liter Hemi (now designated Eagle) was modified to increase both power and fuel mileage. These changes included a higher compression ratio (from 9.6:1 to 10.5:1), better-flowing heads, intake and exhaust, and the all-new Active Intake Manifold. This manifold incorporated new-for-the-time technology. This design allows the intake to switch between using long or short intake runners by simply moving a flapper door. The ability to switch runner length can create better torque at low RPM and higher horsepower as the RPM increases. The intake manifold integrates the manifold absolute pressure (MAP) sensor, fuel rails, and electronic throttle control.
Also new in 2009 was the variable valvet timing (VVT) system. The camshaft and timing sprocket used with the VVT system is completely different from that used on earlier engines. The VVT system is operated by hydraulic pressure via the engine’s pressurized oil to actuate cam phasing. The hydraulic-roller camshaft has oil passages machined in the front that direct the oil to “move” the cam phasing sprocket, and either advance or retard the engine’s timing as required.
The 5.7-liter Hemi has an oil control valve (OCV) that is mounted behind the timing cover. The OCV is an electro-hydraulic pulse-width-modulated solenoid that controls oil pressure to the camshaft phaser sprocket by taking engine oil and routing it to the two oil passages inside the valve. The newly designed camshaft phaser replaced the standard camshaft timing chain sprocket, and is attached to the camshaft by a single bolt. The phaser itself has internal vanes, and the OCV regulates the oil flow to either side of the vanes.
When the engineers started to make improvements to the 5.7-liter Hemi for 2009, they began by increasing the engine’s ability to breathe. One way to accomplish this was to incorporate a new technology, variable cam timing (VCT). The job of VCT is to boost power and torque levels throughout the entire engine RPM range. Other mechanical upgrades included structural upgrades to the crankshaft, inclusion of a dual-mass crankshaft dampener, and finally, the addition of floating wrist pins.
The combination resulted in a rating of 380 hp and 404 ft-lbs of torque. That’s an increase of 10 and 8 percent, respectively, over the previous 5.7-liter Hemi. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
Another big change in 2009 was with the Hemi’s throttle body. Until this time, a Continental Corporation VDO-design throttle body was used. In 2009, Mopar started using the Magnetti-Marelli throttle body on all of their Hemi cars.
The Hemi’s new VVT system improves fuel economy in two ways. First, it reduces the engine’s pumping effort by closing the intake valve later during the combustion cycle. Second, it increases the expansion process of the combustion event. This expansion allows more work to be transferred to the crankshaft instead of being released out of the exhaust port as wasted heat. Essentially, VVT improves engine breathing, which improves engine efficiency and power.
The VVT system does not keep the valves open longer; instead, it opens them later in the combustion cycle, and also closes them later in the cycle. This is done by oil pressure rotating the camshaft forward a few degrees. If the intake valves normally open at 10 degrees before top dead center (TDC) and close at 190 degrees after TDC, the total duration is 200 degrees. The opening and closing times can be shifted using the hydraulic mechanism that rotates the timing of the camshaft ahead a little as it spins. So the valve might open at 10 degrees after TDC and close at 210 degrees after TDC.
This oil flow to either side causes the phaser to rotate right or left and thus change the position of the camshaft’s orientation. One oil gallery supplies oil to the OCV and two separate oil galleries supply oil to the number-1 camshaft bearing for advancing and retarding timing via the camshaft phaser.
A newly redesigned piston-and-rod assembly this year allowed the pistons to use thinner walls with a stronger-alloy wrist pin that was now a floating-style pin. The crankshaft was also stronger, and the oil pump featured a higher flow capacity to help with the VVT system.
The use of the VVT system also meant that a new, deeper timing chain cover and water pump were used. The timing cover from 2008 and older engines does not fit on 2009 and later engines with the VVT.
The cylinder heads featured a few revisions, too. The intake and exhaust ports were redesigned with the exhaust-port floor raised and larger intake valves (2-mm larger) used. The Eagle cylinder head is found on 2009 and later non-SRT passenger cars and trucks with VVT. The intake manifold has been changed on all applications and is model specific.
In 2009 the 5.7-liter Hemi received an all-new piston and connecting rod assembly design. The new pistons were built with thinner walls to reduce weight, and the piston’s wrist pin was now a “floating” style instead of a press fit. You can see that the wrist pin on this assembly (upper left) has a different look to it. When a wrist pin is “floating” the fit of the piston to the wrist pin is not a press fit; the piston is able to move on the wrist pin. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
The water pumps also changed for 2009 and later engines. The face of the pulley on 2008 and earlier engines is flat, and the impeller fits in a recess in the timing chain cover. On 2009 and later models, the pulley is beveled, and the impeller is flush with the water pump housing, because the timing chain cover does not have a recess for water flow.
The oil pump in your third-generation Hemi differs significantly from the previous small-block (LA) design. The oil pump itself is driven by the crankshaft timing gear rather than by an intermediate shaft as on V-8s of the past. Notice the grooves in the center of the pump; these grooves mesh with the crankshaft timing gear.
Another small difference between 2008 and earlier water pumps (right) and 2009 and later units (left) is the boss that supports the belt tensioner pulley.
Note that 2009–2012 5.7-liter Hemi engines with the 6-speed manual transmission do not have MDS.
A comparison between 2008 and earlier cylinder heads and those used for the 2009 5.7-liter Hemi engines reveals big differences. The size and shape of the intake port are different, plus the 2009 cylinder head (bottom) uses 2.05-inch intake and 1.55-inch exhaust valves that are larger and have longer stems. The rocker arm support pedestals are taller, and the valveguide boss sits higher on the top side of the cylinder head, moving it out of the intake port. The 2009 head also has a “closed” combustion chamber (notice the circular ring around the chamber in the top head but not in the bottom head). (Photo Courtesy Fiat Chrysler Automobiles US LLC)
In 2005, engineers at SRT (Chrysler’s performance division) set out to create their own version of the third-generation Hemi. They developed a 6.1-liter version of the Hemi engine. They increased displacement by boring the 5.7-liter Hemi’s cylinders 3.5 mm larger.
The SRT group mandated that the engine must make more power than the standard 5.7-liter Hemi to be considered a success. They accomplished their goal with an increase of 25-percent more power (an additional 85 hp and 30 ft-lbs of torque).
The result of their work was a 425-hp Hemi with the highest specific output of any V-8 engine ever offered by Chrysler. Would you believe it developed 69.8 hp per liter? You should, because it does.
To meet their goal and also make the engine durable, SRT engineers modified and/or upgraded numerous standard 5.7-liter Hemi engine parts. The 6.1-liter Hemi and the 5.7-liter Hemi both have the same dimensional stroke (3.58 inches). The crankshaft dampener on the 6.1-liter was re-tuned to handle the higher engine speeds that the engine was designed to reach. The large-diameter flat-top pistons, which were rotated by the new forged-steel crankshaft, created higher-pressure loads. The deep-skirted engine block structure was redesigned with reinforced bulkheads to handle these higher-stress loads.
In 2012, Chrysler issued a recall for 5.7-liter Hemi-equipped Challengers, Chargers, and Chrysler 300C models that were built between 2009 and 2012. All cars recalled had the MDS feature with automatic transmission (MDS was not available with manual shift). A timing chain issue occurred whereby the car could realize sudden and catastrophic engine damage while in MDS mode if the timing chain broke.
For some reason, the timing chain on 5.7-liter Hemi cars suddenly failed without warning while driving at normal highway speed. This occurred while the engine was in 4-cylinder fuel-saving mode.
Technicians at the dealerships were authorized to perform only the recall service work to the timing chain. In other words, they were required to replace the chain, reassemble the car’s engine, and attempt to start it. If engine damage was confirmed when the engine was started, the technician could then tear the engine apart (again) to repair the more significant damage that had occurred.
The SRT group designed the 6.1-liter Hemi, introduced in 2005, to be the big brother to the 5.7-liter Hemi. The engine’s increased ability to breathe was achieved with the use of new high-flow cylinder heads, a specially designed intake manifold, and tube-style exhaust manifolds that closely resemble headers.
Also unique to the 2005 6.1-liter Hemi engine are larger-diameter valves and reshaped cylinder ports. These design improvements in the heads allow for maximized airflow. The intake manifold was designed with larger-diameter runners for higher-RPM tuning capabilities.
The 6.1-liter Hemi’s exhaust manifolds have individual primary tubes that are encased in a stainless steel shell. Swapping these manifolds with shorty headers will realize very little, if any, performance gain. (Photo Courtesy Modern Muscle Performance)
All 6.1-liter Hemi engines came with these oil squirters, which were located under the pistons. They connected to the underside of the cam, and oil was sprayed from them to help keep the pistons cooler, thereby helping decrease detonation. These were later adapted to other Hemi engines. When installing a stroker crankshaft these squirters need to be modified if retained (the tubes must be shortened).
The 6.1-liter Hemi was built with a higher compression ratio, which was increased from the 5.7-liter Hemi’s 9.6:1 to 10.3:1. The 6.125-inch connecting rod’s redesign used higher-strength powder-metal material. New floating wrist pins were used.
Oil squirters aimed at the underside of each piston were added to aid piston cooling for increased engine durability. A special oil pump pressure-relief valve was added to accommodate the pressure loss that was created for squirter oil flow.
Even the oil pan and windage tray were modified to manage oil return to the oil pan sump at high engine speeds for improved power.
The 6.1-liter Hemi cylinder head ports were designed with a larger cross-sectional area. This allowed for an 11-percent increase in flow for the intake ports and a 13-percent increase in flow for the exhaust ports. The camshaft featured more overlap and lift to help increase performance.
The 6.1 Hemi head is found only on SRT-equipped vehicles. The intake port measures around 185 cc, and depending on the flow bench, flows 310 to 320 cfm at .600-inch lift (using a 2.08-inch valve). The exhaust port is D-shaped and measures 57 cc in testing; again, depending on the flow bench, it flows 185 to 195 cfm at .600-inch lift with a 1.650-inch exhaust valve. The beehive-style spring that is used on the 6.1-liter head has proven to handle up to .580-inch cam lift. With its 74 cc, the open chamber is smaller than that of the 5.7-liter.
Although the valves are larger (2.00/1.55 inches to 2.08/1.650 inches), the 6.1-liter Hemi uses the same 1.65-ratio shaft-mounted rocker system and valve orientation as the 5.7-liter head. The 6.1-liter camshaft has .547/.541–inch lift and 283/286–degrees of duration.
6.4-Liter Hemi (392) 2011–2014
Although introduced in 2007 as a “crate engine,” the 392-inch 6.4-liter Hemi did not replace the 6.1-liter in production vehicles until 2011. With 470 hp and 470 ft-lbs of torque, the 6.4-liter Hemi provided an additional 90 ft-lbs of torque at 2,900 rpm over the 6.1-liter. This engine created just over 73 hp from each liter of displacement.
The block was made with the same high-strength iron and featured an increased bore of 4.06 inches. As with all Gen III Hemis, five main-bearing supports provide a rigid structure for the crankshaft, and each of the main-bearing caps is attached with four bolts (two vertical and two horizontal).
The forged-steel crankshaft with a stroke of 3.795 inches provides the basis for an extremely strong rotating and reciprocating assembly. The crankshaft is once again connected to powder-metal forged connecting rods, but now they measure 6.2 inches long.
The 6.4-liter Hemi still used cast pistons, but they have been optimized to reduce friction and noise under both hot and cold operating conditions. With the compression ratio of the 6.4-liter Hemi at 10.9:1, premium fuel with an octane rating of 93 is highly recommended. The camshaft has .577/.537–inch lift and 286/288–degrees duration, and again actuates by variable cam timing.
This latest engine is designated the Apache. You can find this head on 2011–present (as of this writing) SRT 6.4-liter Hemi Challengers, Chargers, and Grand Cherokee Jeeps. The combustion chamber volume is 73.4 cc and valve angles are 18 degrees on the intake and 16.5 degrees on the exhaust side. The Apache cylinder head uses the same rockers and bolt pattern as the 6.1-liter Hemi but the head uses larger 2.14-inch intake and 1.65-inch exhaust valves.
In 2011, the 392/6.4–liter Hemi came standard in the new Challenger and Charger SRT8s. When delivered, and in stock form, many owners have experienced impressive 12-second quarter-mile times at the dragstrip. Not bad for a car that weighs more than 4,000 pounds and has air conditioning and a sound system. The new 6.4-liter engine is a bored and stroked version of SRT’s 6.1-liter Hemi. As found in the 2011 Challenger, the 6.4-liter Hemi delivered 470 hp at 6,000 rpm and 470 ft-lbs of torque at 4,200. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
Supporting the rotating assembly of the Hemi engine is an impressively strong block and main cap structure. All five main caps are a four-bolt cross-bolted design. Cross-bolting the main cap has two distinct advantages. First, it connects the two sides of the engine block together, making it stiffer overall and less prone to flexing. Second, it helps to hold the bearing cap against the downward force created from the combustion process and the movement of the piston.
The intake ports are almost a perfectly square 2 × 2 inches, and the flow is in the 340-cfm range. To accommodate the larger valves and improved port design, the valveguide was moved. This means that the heads only fit a 6.4-liter Hemi engine or a head with at least a 4.06-inch bore and custom pistons.
The 6.4-liter Hemi engine is fitted with a cast-aluminum oil pan that is designed to provide better oil management characteristics and additional structural rigidity to the engine than previous designs. The pan was designed with special channels, baffles, and scrapers to help funnel engine oil back into the bottom of the pan and away from the crankshaft. Externally, strengthening ribs were cast into the oil pan. This improved oil pan fits all current Gen III Hemi engines and makes a good upgrade for earlier engines.
This 6.4-liter Hemi from an SRT8 Jeep Grand Cherokee uses a six-rib belt to drive the accessories. The power steering uses an attached reservoir and mounts to the cylinder head. The alternator on a Jeep fits tight to the engine and bolts in from the side with three bolts. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
The 6.4-liter Hemi uses an integral gasket and windage tray design that is fitted between the pan and engine block to reduce the amount of oil that comes in contact with the crankshaft. This helps prevent the possibility of horsepower loss because of engine oil aeration or sloshing.
Once again an Active Intake Manifold is used. The active intake system is designed to harness the pressure waves that exist in the intake runners to improve the volumetric efficiency of the engine. Depending on engine speed, the intake manifold switches between short and long runners. This allows greater tuning capabilities over a wider RPM range than a fixed runner intake.
In 2014, the 6.4-liter Hemi became available in Ram Trucks. The new 6.4-liter Hemi V-8 produced 410 hp at 5,600 rpm with 429 ft-lbs of torque. It also carried VVT and MDS fuel-saver cylinder deactivation. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
A major change to the engine in the 2014 Ram was that the new 6.4-liter’s throttle body was moved forward and angled to the passenger’s side of the vehicle. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
Note that 2011 and 2012 engines with the 6-speed manual transmission do not have MDS.
Maybe you’re looking for an engine that you can build for your car but don’t want to use the one that’s already under the hood. That’s not a problem; many owners do that so they can keep the original engine. When looking at an engine that is out of a car a few clues will help identify what engine you are actually looking at.
Below is a short list of some of the most notable differences that you can use to identify an engine.
LX is the standard car setup found on 300s, Chargers, Magnums, and Challengers.
DR is the standard truck setup found on all Dodge trucks equipped with a Hemi.
5.7-Liter Hemi (Truck) 2003–2008
DR engines use a seven-rib front accessory drive, and the front cover, water pump, and accessories do not interchange with other models. This setup mounts the accessories (alternator and air conditioner pump) high in front of the intake; this prohibits the use of stock passenger car intake manifolds. The front cover assembly/accessory drive can be changed to a car unit.
Hemi truck engines up to 2008 have a coil and plug wire for each cylinder. This is to accomplish the multiple sparks required for emissions.
After 2007, the coil is segregated by cylinder, and the multiple sparks required are controlled individually on each cylinder.
5.7- and 6.1-Liter Car and Jeep Hemi 2005–2008
These front covers interchange; the only difference is the location of the alternator and power steering pump. These are all six-rib belt units.
The car-style power steering uses a remote reservoir and mounts to the cylinder head. The Jeep unit attaches the same way but has an attached reservoir.
The car alternator bolts to the engine from the side, utilizing three bolts. The Jeep alternator mounts the same, but fits a little tighter to the engine.
5.7-Liter Hemi (Truck) 2009–2012
With the introduction of the Eagle engine, the front cover was redesigned to accept the VCT and new block. Although these do not interchange with earlier Dodge Rams, they also use a seven-rib serpentine drive system. Mounting of the air conditioner compressor and alternator is the same as on previous Ram trucks: up high.
Truck engines like this one from a 2009 Ram feature an intake system that is entirely different from both the car and Jeep Hemi engines. The truck intake features a throttle body that points upward from the front of the intake. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
Earlier truck engines featured a small engine cover that was positioned over the throttle body. The throttle body on these engines also pointed upward (and a little forward) but was located at the center of the intake. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
5.7-Liter Eagle 2009–2012 and 6.4-Liter Apache 2011–2012
These engines share the same front cover, which does not interchange with earlier models. The alternator and power steering fit earlier engines, but care should be taken to ensure correct interchange as there are concerns other than physical fitment, such as electrical.
Until the 1990s, most automotive intake manifolds were made of cast iron or aluminum. Manufacturers eventually made them of a composite or plastic material that was durable enough to survive engine use. The benefits of both lower weight and cost made them popular.
5.7-Liter Hemi (Truck/Durango) 2003–2008
These intake manifolds are made of a composite material and place the throttle body in the middle of the engine facing forward. They fit correctly only on pre-2009 5.7-liter heads. The MAP sensor is located at the front of the intake.
5.7-Liter Hemi (Car and Jeep) 2005–2008
This intake manifold is also composite but places the throttle body directly above the front accessory cover, parallel to the ground. This intake fits only pre–2009 5.7-liter heads. The MAP sensor is located at the rear of the intake.
5.7-Liter (Truck) 2009–2012
As with previous versions, this intake manifold is composite. It fits all square-port heads. Unlike previous truck intakes, this one places the throttle body at the front of the intake, at a 90-degree angle (facing upward).
These stock 5.7 car manifolds are barely adequate for a stock Charger, Challenger, Magnum, or 300, but you can add aftermarket bolt-on goodies, and forget it.
All Gen III Hemi intakes (except for the 6.1-liter) are of a composite design. This reduces weight and helps reduce intake-charge heat. This intake is for a 2008 or earlier passenger car. The passenger car intake varies from the truck intake, which typically has the throttle body in a different location and pointed upward.
5.7-Liter (Car and Jeep) 2009–2012
This intake is composite but looks and performs like that of the 6.1-liter intake manifold. The throttle body is located horizontally at the front of the intake, above the timing cover. This intake fits all square-port intake heads and the MAP sensor is located at the rear of the intake.
6.1-Liter Hemi 2005–2010
All applications use this aluminum intake. It is designed for square-port heads. It is a two-piece design with a removable plenum cover. This removable cover makes porting and polishing easy. The throttle body is located horizontally at the front of the intake above the accessory drive cover. This intake fits both 5.7- and 6.1-liter blocks, making it a great choice.
6.4-Liter Hemi 2011–2012
In all applications, this intake is composite. It features a variable-length runner design that is RPM controlled. The throttle body is located horizontally at the front of the engine, above the accessory drive cover, but is angled toward the driver’s side of the car. This intake fits all square-port heads, but may require the use of spacers.
Many companies offer transmissions for Hemi-powered cars. The following are the most popular among Hemi car owners.
NAG1/A580 2005–2014
With the merger of Chrysler and Daimler/Benz, it wasn’t long before some of the Benz parts began to appear in Chrysler vehicles. Enter the NAG1 automatic transmission. The NAG1/A580 transmission had advantages over existing Chrysler automatic transmissions. For example, it was more efficient than the previous 4-speed automatic that was used with less-powerful LX cars. Compared with the 545RFE 5-speed automatic transmission that Chrysler was using in their trucks, the NAG1/A580 had a wider gear range, was considerably smaller, and weighed less.
MAP Sensor
A 1-BAR MAP sensor reports barometric pressure, which is approximately 14.7 psi or 30 in Hg (inches of Mercury). As an example, a typical three-wire MAP sensor has 5 volts and ground to power the circuit. The signal circuit, or return voltage to the computer, is about 4.5 volts at a barometric pressure of 14.7 psi; this measurement is taken at key on, engine off. The sensor can withstand about 1.5 BAR of pressure, but the return voltage peaks at about 4.8 volts.
This type of sensor is designed for a normally aspirated engine to read a negative pressure, or vacuum, at a typical barometric pressure. A reading of 2 or 3 BAR simply means two or three times above barometric pressure.
Common MAP sensor readings are:
• 1 BAR is for a normally aspirated engine
• 2 BAR handles a forced induction up to 14.5 psi of boost
• 3 BAR handles a forced induction up to 29.0 psi of boost
A MAP sensor measures both vacuum and pressure. (Photo Courtesy Fiat Chrysler Automobiles US LLC)
If you ordered an automatic-equipped Hemi car, your shifting duties were handled by the Mercedes-Benz–derived NAG1 transmission. The NAG is an electronically-controlled 5-speed transmission that has a lock-up clutch inside the torque converter. A large 13-pin electronic connector located on the passenger’s side of the transmission (just above the fluid pan near the bellhousing area) identifies the transmission.
All rear-wheel-drive LX cars from 2005 to 2012 use an aluminum oil pan with a front sump. All 2003–2012 two-wheel-drive Ram trucks use a stamped steel rear sump pan (shown). Jeeps use a unique cast-aluminum rear sump oil pan.
The NAG1/A580 automatic transmission is an electronically-controlled 5-speed transmission that uses a lock-up clutch encased inside the torque converter. Fifth gear is an overdrive with a high-speed ratio, and the different ratios are actually selected by three planetary-gear sets.
The NAG1/WA580 was used in different cars, starting with the 2005 Chrysler 300 and Dodge Magnum with Hemi V-8 engines. Later, it was put into service in the Jeep Liberty, Grand Cherokee, Charger, Challenger, and eventually, the Ram truck. The NAG1/WA580 was built at Chrysler’s Transmission Plant II, in Kokomo, Indiana. Plant I built the 45RFE and 545RFE electronically-controlled transmissions starting in 1998.
Gear Ratios
Visually, the NAG1/A580 transmission can be identified by the round 13-pin connector located on the passenger’s side of the transmission near the front corner of the transmission’s oil pan.
The torque converter and transmission housings are made from a light alloy and are sealed and bolted together with a coated intermediate plate. The fluid pump and the outer disc carrier are then bolted to the torque converter housing. The stator shaft is pressed into the housing and is positioned with splines, which prevent it from rotating. The electronic control unit is bolted underneath the oil pan.
On early models (2003–2005), some owners experienced transmission “shudder.” At that time, Technical Service Bulletin 21-011-05 was issued; it was later superseded by 21-003-06. This bulletin applied to LX and LE vehicles equipped with an NAG1 transmission (sales code DGJ) built prior to December 2005 with a transmission build date of July 8, 2005.
The shudder condition may have been because of the torque converter clutch continually sticking and slipping because of contaminated transmission fluid. The transmission fluid contamination was thought to be caused by water getting past the transmission filler-tube (dipstick tube) seal. Depending on the amount of water in the transmission oil, car owners experienced a transmission shudder or vibration and/or an audible high-frequency buzz-like sound.
If you wanted a car that allowed you to row-your-own in the shifting department, you didn’t order a Charger. All manually-shifted Challengers (manual not available in Charger), came with the TR-6060. The Tremec-sourced TR-6060 6-speed manual transmission is derived from Tremec’s T-56 6-speed manual transmission. It’s a stout piece that is rated to handle 700 ft-lbs of torque. The T-6060 is a “double overdrive” transmission, with .74 fifth-gear and .50 sixth-gear overdrives. (Photo Courtesy Tremec)
The shudder/vibration or buzz-like sound was most noticeable during light driving (cruising) in 3rd, 4th, or 5th gear. The fix was to flush the transmission thoroughly (Chrysler recommended three times) and install a new filler-tube seal. Some owners flushed the transmission and simply applied RTV to the seal area.
A popular and simple modification to the NAG1 is to replace the OEM-supplied brown-top solenoids with AMG blue-top solenoids as on the stock valve body. The blue-top solenoids have larger ports and provide firmer and faster shifts over the OEM brown-top units. If you are looking for even firmer shifts, a shift improver kit is also available but requires a little more work to install.
Tremec TR-6060 2008–2014
The 6-speed Tremec TR-6060 manual transmission was derived from its predecessor, the T-56. Dimensionally, they fit within the same location, but the T-56 was never used in the Challenger.
Upgrades from the T-56 include reduced friction while shifting, thanks to a new cam and antifriction plunger to control the side loading of the shift detents. The forward and rearward shift-detent grooves are broached on the front of the main-shaft with a spring-loaded anti-friction roller. This gives a more positive shift feel. In addition, anti-friction ball struts, sintered hubs, and fine-pitch splines on all synchronizers also help reduce friction between the components. The two-piece gears are wider and have machined teeth for more precise gear engagement and reduced potential for gear block-outs and missed shifts.
To use a manually-shifted transmission in the Challenger, Dodge looked to the already proven TR-6060 that was used in the Viper. Internally, the TR-6060 comes with triple cone synchronizers for first and second gears, and then twin cone synchronizers for third through sixth gears. These multi-cone synchronizers greatly reduce shifting effort.
The clutch chosen for use in the Challenger was also sourced from the Viper. It is a 250-mm twin-disc design that is capable of delivering great torque-handling capacity and clutch life. The TR-6060 features a first- through fourth-gear skip-shift property, reverse inhibit solenoids, and a 5:1–ratio shifter.
TR-6060 Gear Ratios
As usual, the helical-cut forward gears are synchronized, but the reverse gear operates through a fully synchronized constant-mesh system. The TR-6060 contains removable wear pads on the shift forks and uses an aluminum alloy for the main case, extension housing, and clutch housing. In stock form it is rated for 600 ft-lbs of torque.
When the LX cars were released in 2005 (and the Challenger in 2008), Chrysler needed to find a rear end that would hold up to the performance demands of the new Hemi but still deliver uncompromising ride quality. For years before the introduction of the LX cars, a solid, or “live,” axle was used. A live axle is a rigid rear end that connects the two rear wheels. The axle shafts are within tubes that are connected to the differential housing.
The rear suspension and differential on Chargers and Challengers is one complete module that is isolated from the body via bushings. It was initially designed to be compatible with parts from Mercedes-Benz. The five-link rear suspension offers a better ride quality than a traditional solid or live rear axle. The multiple suspension links maintain independent control of each rear wheel’s camber and toe angle during suspension movement. The entire rear suspension module is mounted to the body with bushings and can be removed as a complete unit.
Because this type of axle is solid, when making a turn under severe cornering the wheel on the inside of the corner tends to lift. At the very least, the tire’s angle to the asphalt changes, minimizing the tire’s contact patch with the road surface. Also, when a wheel on the passenger’s side of the vehicle hits a bump, it channels that energy to the wheel on the other side of the vehicle.
The differential on an IRS is rigidly mounted to the body, and the axles are connected to the differential and wheels via constant velocity (CV) joints. With the differential rigidly mounted and the wheels “suspended” individually they can move independently of one another. So, when energy is created as one wheel hits a bump, it is isolated only to the wheel that has to travel over the bump. Suspension travel of an independent suspension system also allows the tire to remain perpendicular to the road surface, maximizing tire contact with the road during hard cornering.
Although the Charger and Challenger use IRS, solid-axle suspension systems aren’t all bad. They are significantly less expensive to build than an independent suspension because they’re less complex. By design, they require fewer moving parts. Depending on what you use your vehicle for, a solid axle might work just fine.
