Mil-Spec Bulkhead Connector

[Turbo67camaro]

I decided to spend some extra dough and go the mil spec circular connector route. While more expensive, the price differential is not too extreme. Prices vary a LOT from one seller to another, so SHOP AROUND! Here is what I just ordered from http://connecticc.com. They have excellent prices, but their website is a bit slow. I think their inventory server with quantities on hand was just offline, as everything was showing out of stock, whereas a couple of days ago everything was in stock with fairly large quantities on hand. Another good seller with competitive prices is http://prowireusa.com.



# of connection count by size summary
==============================
Firewall (connectors 24-61, 24-31, 24-19):
a) 61 size #20, 31 size #16, 19 size #12

4L80E Transmission tunnel (connectors 22-41):
b) 27 size #20, 14 size #16

Trunk (connectors 16-14):
c) 8 size #20, 6 size #12



Connector size to wire gauge to max amps cross reference:
1) Size 12 = AWG 14-12 = max 23.0 amps
2) Size 16 = AWG 20-16 = max 13.0 amps
3) Size 20 = AWG 24-20 = max 7.5 amps

Total # Connectors summary:
a) 96 #20
b) 45 #16
c) 25 #12
----------
166 total connections

Overkill? Perhaps, but I only want to add these connectors once.
Able to handle future added electronics? Very likely.

I bought a used DMC AF8 M22520/1-01 crimper with a TH1A M22520/1-02 turret attached for $129.99 off ebay.

I went with flange receptacles to avoid having to cut D shaped holes recommended for the jam nut receptables (i.e. rotation prevention). Narrow flanges instead of wide flanges to conserve space.

I'm considering using 90 degree strain relief adapters. They run about $10 to $15 per connector side on http://mouser.com. Again, the prices on the strain relief adapters varies dramatically, so shop around.

My electrical system is ISIS Power based, which results in a LOT less power wires being routed through panels, so the appropriate connector sizing and counts will likely vary a lot for a car that is traditional wiring. A traditionally wired car will likely need more larger gauge connections.

[TonyV]

Hey Mike thanks for the info....i'm doing my initial research into using the mil specs connectors. any pics on locations and how your routing your wires would be great. I'm using the ISIS system also i'd like to see and compare.

[Turbo67camaro]

67 Camaro install pics (no pins or wires installed yet in these connectors). Install is pretty easy, just make sure you don't drill the 4 bolt holes on an angle (keep them straight and level):

Firewall connectors viewed from engine compartment: Car is currently manual brakes w/o booster. If I ever switch to power brakes, I'll probably use a hydroboost based system which I think will clear these circular connector mounting locations. The wires exiting from connector in the lower right of the picture are getting close to the wheel well, but I'm pretty sure there's enough room left for a strain relief backshell.


Firewall connectors viewed from passenger compartment: View is looking through hole in dash for driver's main gauges. In case I ever switch the car back to manual shift, I'm nearly sure I've got these mounted out of the way of a clutch pedal and linkage. This location should nicely support adding straight strain relief backshells for the 2 smaller gauge wire harnesses, with those harnesses routed over the steering column behind the gauges, over to the center console area, where I'm centralizing most wire connections. The large gauge wire harness will probably get a 90 degree angle strain relief backshell, with the wire harness routed along the firewall. I'm inclined to keep the higher amp. wires away from the lower amp. wires as much as possible.


Trunk mounted connector is close to centered in the trunk slightly up the angled sheet metal. Should provide a nice short wire run to the fuel pump, but a longer run for most other electronics mounted in the rear/underneath portion of the car. An ISIS Power Cell is mounted about 18 inches from this connector behind the rear seat frame making most wire runs to this connector short.


The trans. tunnel mount is a work in progress. Car was originally manual trans., and is now automatic 4L80E. I'm leaning towards buying or building a raised box to mount over the old manual trans. shifter hole, and mounting the circular connector to the raised box. Purpose for using a raised box is to give more clearance for the outside wiring harness and connector to clear the transmission underneath the car. I'm building a console frame out of aluminum DIN rail, piano hinges, and angle brackets. A tablet computer will be mounted between the hinges shown on another piece of not yet mounted hinge. The hinge mounted tablet will be able to swing open to expose the electronics underneath. The ISIS Master Cell will be mounted vertically underneath the tablet with the cell display facing the driver. An ISIS Power Cell will be mounted vertically underneath the tablet with the cell display facing the passenger. I'm probably going to make those ISIS cell displays VISIBLE in the finished console, in case the cells are visually reporting an error.


Most of my wiring runs are up the center of the vehicle, which will keep the wire lengths nice and short. I will likely end up with a console running the full length of the trans. tunnel (front and rear seat areas) to cover all the wires, which means my rear seat customization requirements get more involved to pass a lot of wires into the trunk. Large amp wires will be on one side of the trans tunnel with small amp wires on the other side.

I don't know how well my wire routing will work when it comes to EMF, RFI, etc..

[TonyV]

great pics Mike, thanks for sharing....one question why so many connectors? I'm just asking because i'm doing the same thing 1 connector for supplying 12v up front (estimate about 14 wires at 14g) and one for the holley ecu which is abou the same...wondering if i missed something.

Keep plugging away love the progress and can't wait to see how your console comes out.

Tony

[Turbo67camaro]

I went with such a large number of connectors simply because I can't predict how many electrical devices I will want to add to the car in the future, and I don't want to rack my brain now to figure that out. So, I find it easier to accommodate a large amount of expansion potential, rather than get stuck in analysis paralysis during the build now. I'm a software engineer by trade and I tend to adopt the same philosophy there. My car's theme is more street car than race car, and with all the awesome electronics today and coming down the pike, I anticipate I'll be continually adding more electronics year after year.

[Aficionado]

I went with such a large number of connectors simply because I can't predict how many electrical devices I will want to add to the car in the future, and I don't want to rack my brain now to figure that out. So, I find it easier to accommodate a large amount of expansion potential, rather than get stuck in analysis paralysis during the build now. I'm a software engineer by trade and I tend to adopt the same philosophy there. My car's theme is more street car than race car, and with all the awesome electronics today and coming down the pike, I anticipate I'll be continually adding more electronics year after year.

Mike-

Any updated pictures on the MIL plugs? I'm in the throes of figuring out how to route the EFI wiring through the firewall of my '72 Stingray, and trying to decide if I want to use the Mil-spec connectors or a slightly simpler circular connector. To be candid, I'm having a really hard time figuring out how many parts are in the MIL connectors (plug, receptacle, backshell?), much less which specific ones I need (since most of the suppliers are to-the-trade, their websites seems oriented to people who already know what they need, or at least the speak the language). If yours are installed, a photo would help me understand better what all is involved.

Thank you....
J. Clough

[CamaroMike]

http://www.chasebays.com/product/gm-...-drive-by-wire

He makes them with the mil spec connectors, hope this helps

[pist0lpete]

I would strongly recommend deutsch connectors. The crimp tool isn't cheap but they are great connectors to work with. Laddinc.com is a great site with great tech support if you call them. No personal tie to the place just had good experiences.

[Rolling_Thunder]

Sorry I just found this page... I've been using the Mil-spec circular connectors for years... great system. only down side is the cost.