PC1P's TJ Hemi Swap Adventures - Part III
References & Helpful Links (in random order):
-
https://wranglertjforum.com/threads/hemi-swap-resource-thread.37529/
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https://www.enginebuildermag.com/2019/08/unlocking-the-mysteries-of-the-5-7l-gen-iii-hemi/
Downloads (see attached files):
- NGC Pinout (Excel file)
- More to come as available
Gas Pedals
- All Hemis utilize a DBW (drive by wire) throttle body, though the early ones use what is known as a "bell crank" to generate the throttle position signal. There are two styles of connector that I've been able to find: Early (2003-2007 cars, 2002-2006 trucks) and Late (08+ cars, 07+ trucks). Functionally and physically they are similar but the connectors are different:
View attachment 224854
[Early and late style connectors - https://www.redline-motorsports.com/products/hly-558-418]
Transmission Info
- Most Hemi Ram and Jeep applications utilize the 545RFE 5-speed transmission. Following the traditional Dodge naming convention, the 545RFE is a 5-speed, 4-power rated, Rear-wheel drive, Fully Electronic transmission. Despite actually having six forward gear ratios, the transmission used only five forward gears in normal acceleration. A different 2nd gear was used for kickdown acceleration (often referred to as 2' or "two prime").
- In 2012, the 65RFE was introduced, although it was nothing more than a 545RFE with slightly modified gear ratios and different programming that allows the use of all available gear ratios in "autostick mode". The programming changes also allow use of the TCC (torque converter clutch) in all forward gears except first to help efficiency.
- Although all Gen III Hemis use an electronic throttle body, the 2003-2004 Ram trucks utilized a bellcrank (see photo above) and traditional throttle cable (Mopar # 53032456). This was likely due to the fact that the 4.7L motor still utilized the 45RFE transmission and thus needed a TV cable. Rather than have two different cables and two different firewall holes/configuration, they used what they had left to work through the change.
View attachment 223014
[Early Hemi Bellcrank assembly]
- The cable went to the bellcrank assembly that housed the TPS (throttle position sensor) as well as the mechanical linkage to work with the early transmission throttle valve assemblies. For those looking to utilize a TF-727 or perhaps an A518 transmission, this is one of the few ways to get OEM-reliability with a modern Hemi swap.
DIYHemi has a great video about the factory bellcrank assemblies:
- More to be added as I find it!
ECM Differences:
The reason the LS was so popular was because the ECM's were more quickly cracked and there weren't as many variants to understand. Over time however, the factory Hemi ECM options were more understood and now many aftermarket companies are developing standalone units.
There are two major iterations of G3 Hemi ECMs: NGC and GPEC. Note that these are generic terms and there are many sub variants (e.g. NGC4 vs NGC4A)
All NGC (Next Generation Controller) variants utilize 4 plug connectors at the ECM: C1 thru C4. These ECM's are found on 2003-2010 cars and 2003-2012 trucks. Note that individual model year changes vary, so you'll need to physically check what ECM your donor vehicle has if you're buying a transition year rig. Truck ECM's are "standalone" and the case is designed to be installed in an open environment. The car NGC ECMs are designed to be flush or near-flush mounted.
C1: power/CANBUS/SCI/grounds
C2: engine controls (coils, sensors, injectors, TB, etc)
C3: cabin/chassis interface (gas pedals, auto trans user control, etc)
C4: transmission controls (this will be blank on ECMs that came with a manual transmission or with a NAG Auto trans)
View attachment 223019
[Rebuilt NGC controller for a 5.7L Ram - note the blank C4 port, suggesting this was for a manual trans truck]
On the GPEC (Global Powertrain Engine Controller), there are now only two 96-pin connectors rather than the 4-connectors of the NGC.
C1: cabin controls (power, grounds, CANBUS, starter-sense, communications, etc)
C2: ECM/Transmission
View attachment 223030
[example of a GPEC ECM - note the consolidation of 4-ports to now just 2-ports]
DIYHemi has another great video here:
2015+ GPEC EMC Considerations:
2015+ GPEC ECM's are difficult to work with and at the time of this posting, are generally referred to as being "locked" (although many places can unlock). These require removal of some factory systems and also require some circuitry manipulation and circuitry emulators (such as starter-signal from what would be a factory BCM unit). I won't be dealing with a 2015+ ECM for the foreseeable future but will include any links or info as I run across it.
View attachment 223284
Standalone ECM Options:
The Holley Terminator series of standalone can now work with the 2009+ Eagle Hemis, plus they can control MSD, VCT and the SRV (short ram valve) on the active intake models. With nothing more than bolt-on headers, the 5.7L Eagle Hemis will consistently make 420-425 hp on the stock Holley tune.
- More to come...
Exhaust Manifolds & Factory Short Tube Headers:
Similar to the front timing covers and accessories, the exhaust manifolds are generally broken down into the following: LX/Car, Jeep and Truck. Within the LX/Car as well as the Jeep segments, there are also SRT versions.
View attachment 227571
[Visual differences of the various manifolds available on the Gen III Hemi vehicles]
The early non-Eagle 5.7L heads have a standard square exhaust port. The early 6.X SRT motors had D-shaped exhaust windows that the later 2009+ Eagle 5.7L motors moved to. As a result, the later Eagle-style exhaust manifolds and headers typically fit just fine on early 6.X motors.
View attachment 227573
[Factory Jeep SRT 6.4L tubular manifold on left; Kooks long-tube header on right]
The SRT manifolds are excellent and flow very well. However, the car SRT manifolds (as well as the car 5.7L log manifolds) point the collector at the frame rails. The SRT tubular manifolds are very similar to the SRT car tubular manifolds, but work well in Jeep and other swaps. As you can see in the image above, the SRT Jeep manifolds are similar to the car version, but the front two ports are siamesed together to provide clearance for the mounts. The exit port is also in better position for most swaps.
View attachment 227576
[Mopar Performance 6.4L Manifold Kit, PN 77072462AB, which sells for ~$335 for the complete set as of the time of this writing (Feb 2021)]
The SRT 6.4L Jeep tubular manifolds have been out of production for a long while. However, you can get a newer cast-style manifold directly from Mopar Performance that actually outflows the earlier tubular manifold and is less prone to cracking. The Mopar# is 77072462AB. I got a set from
WholesaleMopar.com...
Another excellent DIYHemi video:
TJ Specific Information & Considerations (in random order):
*** Thanks to @StevieRT and @Wildman for catching an error; information has been edited as of 3/4/21 to reflect the updated and correct information
Instrument Cluster
Prior to the TJ, the Wrangler used analog signals for the gauges and lamp-drivers (typically a grounding switch) for the idiot lights. This means that each gauge had its own wire going from the gauge, thru the firewall, to its respective sending unit. By the time the TJ rolled out, there were new ways of communicating between the ECM/engine, the dashboard and other networks in the vehicle.
The concept, known as a "bus", used a modulated single or twisted pair(s) of wires to communicate via a digital protocol to the dash cluster (officially called the EMIC, or Electro-Mechanical Instrument Cluster). Essentially, the ECM was reading sensors/senders on the engine for engine control and was then transmitting that information to the dashboard without additional sensors or wiring.
Technology at the time was quickly developing and rapidly being implemented across all vehicle manufacturers. As a result, the TJ uses 3 different bus/network protocols: CCD, PCI, and CAN bus. For the TJ, the breakdown is typically as follows:
1996-00: CCD - [Chrysler Collision Detection] - despite the name, it has nothing to do with vehicle safety. The "collision" in the name refers to signal collisions. It is a clever system that uses a twisted-pair to communicate across multiple bus modules (such as the ECM, gauges, TCM, ABS, etc). Each module "listens" for relevant messages and ignores messages that don't apply.
*Note about SCI*
SCI, or serial communication interface, was used on many early fuel injection systems, even prior to OBD-II. It is a
diagnostic interface, not a true bus or network protocol. You sometimes see CCD confused for SCI and vice versa since they were both used at the same time.
2001-06: PCI - [Programmable Communication Interface] - follows the SAE J1850 protocol and allows communications across networks via a single wire. Unlike CCD alone, the PCI bus was OBD-II compliant and utilized SAE protocols, which allowed further simplification of the networks (and diagnostic tools) across multiple-makes.
Note about CAN bus (aka "CAN BUS", "CANBUS") - [Controller Area Network] - CAN uses twisted pair wiring to communicate between modules on the bus.
No TJ came factory with CANBUS gauges, so if you intend to run a 2006+ Ram ECM, you will need to prepare to replace the gauges (or use a CAN to PCI converter) accordingly.
All 96-00 TJ's will need to swap their dash (if running an 02-05 PCI HEMI ECM) or run aftermarket gauges (for all 06+ Hemi ECMs). For 2001-2006 TJs, they should in theory work with early PCI Hemi ECMs (early Ram ECMs (02 to early 05) for the 5.7L Hemi were PCI). Note here that the '05 Ram model year was a transition year and some of the later 05 Hemi ECMs were the later CAN bus protocol. The later-2005 NGC up to the transition to GPEC (2010 for cars and 2012 for trucks) remained CAN bus. The GPEC should also be CAN bus but I believe is a different protocol and am not sure on if it will work without some modifications (I'm checking into it!)
Some links if you're really, really bored:
[URL]https://www.cnblogs.com/shangdawei/p/3570546.html[/URL]
[URL]https://www.autonerdz.com/yabbfiles/Attachments/dcx_network_ppt.pdf[/URL]
Fuel System & Emissions
97-04 TJs will need to swap their fuel pump out for a 05-06 unit due to pressure requirements.
*Note* you do not need to replace your tank or fuel pump module, just the electric-pump inside. However, if you intend to keep the TJ 100% emissions compliant, you will need to utilize an 05-06 fuel tank and NVLD (natural vacuum leak detection) system.
- More info to come...
