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Wish someone would make a plastic 6.1 intake. They are heavy, although I put the time in to lighten mine quite a bit. 6.4 intakes have been swapped onto 6.1's and 5.7's both. Modern Muscle even offers CNC of the TB opening.



Will the 6.4 intake fit a 5.7


With Eagle,6.1 or Apache heads, yes.



Ok



There is one fitment issue for the 6.4 VR manifold on an early 5.7 or 6.1 block. The intake manifold hits at the water passage area at the front of the block, and may also have problems with the water tubes that run across the top of the block.
I pirated some info from another forum with some info on the fix. Basically grind off the webbing where the interference is, then heat and bend the plastic a bit, putting a small dent in the offending runner for clearance. I plan to grind the block casting some to keep the dent to a minimum. Another option would be some grinding and a spacer for the manifold. Here is some info on controlling the runners also. http://www.lxforums.com/board/showthread.php/266543-2011-Variable-Runner-Intake-Manifold

The Part Numbers
Intake manifold P/N (includes all gasket, O-rings, mounting bolts): 68090674AA
SRV (short runner valve) actuator P/N: 5038529AA
Actuator bolts (3 required) P/N: 6509377AA
Pigtail connector: 1-68064996AA

Update 2011-05-19:
After testing the OEM actuator using a signal generator to simulate rpm and a digital oscilloscope to monitor pin 3 / 4 outputs, it became clear that readily available rpm switches used to control nitrous or transmission shift events would be ideal to control actuation at any rpm set-point.

When the actuator is first powered up, similar to the throttle body the actuator goes through one open / close cycle to confirm proper operation. NOTE: trying to make the actuator operate without a load (the manifold's actuator rods / valves) will result in irratic operation, or no movement at all.

Connectorship
I advise buying the proper pigtail / connector (1 of 68064996AA) from any number of OEM outlets. If you elect to forgo the connector, pin 1 is on the left as you are looking at the pins inside the (male) connector housing on the actuator with the driveshaft pointing downward. See the pigtail connector diagram below from Chrysler (the numbers 1 and 4 are cast into the pigtail connector housing). Below is the pin-out and connection protocol:

Pin 1: B+, switched (attach to a switched 12V source)
Pin 2: B- (attach to chassis ground)
Pin 3: signal, logic level (negative going)
Pin 4: signal, logic level, no connection (can be used to activate an annunciator)

Actuator Operation
Pins 3 and 4 of the actuator use logic-level (0 or 5V reference) protocol to initiate (pin 3 – shorted to ground) and confirm (pin 4 – logic low during short runner mode). Both pins I/O are low impendence. Pin 4 requires no connection, but must not short to ground GND or power B+.
Note: pin 4 sits a ~6.5VDC and goes low allowing the PCM to confirm proper operation of the actuator when the valves open. A typical 5mm LED (including blue) can be forward-biased (activated) by connecting the negative lead to pin 4 and the positive to pin 3. This would provide a visual aid to display the actuator has PWR, and when exceeding the rpm set-point (and valves open) the LED will turn off.

For an LED to activate above the set-point will require a small logic circuit to supply regulated current (in this case from B+) when the pin4 go low (at some point I’ll try and find an off-the-shelf a logic / driver module that makes it simpler for folks to install).

FYI; maximum current consumption during transition is ~2.6A. Steady-state (open or closed) is ~2-300mA.

The Set-point
Although the SRV system on the 392 HEMI’s transitions from long runner to short runner mode between 4800 and 4900rpm, this may vary a bit when the SRV system is mounted on other engine profiles. The best method of determining where to set rpm threshold will be to dyno in long runner mode to redline, then short runner mode. After a few pulls, compare the files looking for where they cross.

Something worth observing and discussing will be whether to make the rpm set-point value above to below the actual crossover point. It will be clear with different engine configurations the area under the curves will either drop off more rapidly, or gain more rapidly in one mode or the other. For example, if your engine’s global TQ gains are reducing quickly in long runner mode approaching the cross over, while in short runner mode it appears more area is under the curve just past to the crossover point, it would be prudent to lower the set-point to allow short runner mode to produce those gains at an earlier rpm.

Another thought is whether to use the individual TQ or HP areas under the curve to determine the set-point. IMO where this will come into play is on the strip where shift points occur and the resulting next-gear rpm commences.

UPDATE, 2015-01-26;
It's become evident across a number of different platforms that 4800rpm +50 is the set point. I originally thought larger displacement engines would need to have a lower set point given extra air flow. Ut seeing how more and more engines of differing displacements are also settling in around, if not right on, 4800rpm, something else is the main driver.

It's rather simple; for any given rpm, the rate at which the intake valves stop and start airflow within the runners is the same for any engine no matter what the engine displacement. It is this act that leads to runner length resonance being directly related to rpm - and not displacement.

In simple terms(?); the act of pumping more air (tuned resonance) into the combustion chambers during the intake stroke than would normally enter depends on what rpm is present to produce the reverse wavelengths, otherwise known as Helmholtz effect. This is precisely the same function long tube headers provide to extract more spent exhaust gasses out of the combustion chamber.

Update 2012-10-24:
After testing a number of rpm switches on the vehicle, it became evident EMI / RFI noise was gong to be an issue. Proper filtering of the incoming rpm signal, along with a normally open (NO) trigger, and receive rpm signal from either an injector or coil pack B- was essential. The most reliable rpm output turned out to be a primary winding feed to B- for the coils. To determine this I used my digital oscilloscope connected with with the scope riding on the front windshield and an RS232 cable running into the vehicle to allow logging to a laptop. This was a PITA as I needed to run 110AC out to the scope from a 12V invertor, but the results were definitely worth it. An appropriate window switch must have a normally open (NO) output that shorts to ground (GND) when the desired rpm threshold set point is crossed.

The MSD Ignition 8969, digital RPM window switch (http://www.summitracing.com/parts/msd-8969) took the lead and never gave it up throughout testing. Here's the connection map;
- Connect white lead to a negative coil lead at injector (all injectors across all platforms will have one color-coded lead in common - this is GND)
- Use yellow lead to trigger SRV actuator's pin3
- Configure the MSD controller for single cylinder operation (there are eight coils, so you want the unit to recognize single cylinder operation)
- Initially configure opening setpoint to 4800rpm (factory 392) until you can dyno in either mode to find crossover

Pigtail (OEM) Connector PN / pinout (note you are looking into the connector body in this pic, pin 1 and 4 are molded into housing):



UPDATE: 2013-01-13;

Last edited by gregsdart; 01/29/15 10:07 AM.