Megasquirt Relay panel install

[merlinfe]

Thought this might be of use to those of you going the way of EFI. I bought a Megasquirt Relay board as a simple way of getting power to the injectors and EDIS I plan on using in my EFI conversion.

When I got the unit, it quickly dawned on me that just leaving it in the open was foolhardy at best. I searched for a cover of some sort online and found a few but ultimately I wanted something simple and easily modified in case there were changes that needed to be made.

I found a Project Box at Radio Shack that fit my needs nicely. After a little porting and a few grommets it should protect the Relay board, and provide a way of keeping the mess of wires somewhat together in the engine bay.

Pictures speak louder than words so here you go:

[betterair]

.....I found a Project Box at Radio Shack that fit my needs nicely. After a little porting and a few grommets it should protect the Relay board, and provide a way of keeping the mess of wires somewhat together in the engine bay. ""

NICE find.
My relays and ECU (KMS brand)are mounted behind the driver seat.
What do the Megasquirt gurus say about mounting them in the engine compartment?
Lots of heat back there.

[merlinfe]

From the B&G site
:

Q: So, this means that the top of the board is exposed?
A: Yes, but this is acceptable in a engine bay environment. The unit is mounted under hood, so the likelihood of accidental shorts, contacts to foreign objects, etc. is the same as with any other engine component (starter, alternator, fuse block, etc). The PCB has a solder mask layer which will provide some protection, and the user can coat the finished board with conformal coating or polyurethane before mounting in the case. In addition, all circuits are fused, so an accidental contact will cause a fuse or polyswitch device to open. One thing to remember is to drill a small (1/8") hole in the bottom-side of the case to allow the escape of moisture from the backside of the PCB/case interior.

Looks like it was designed to be in an engine compartment. I agree the 911s situation is a little different, but I would say the biggest danger will be at a stop light or stop and go traffic. I have yet to hear of any problems from those who have installed the Relay board back there.

-Steve

[72911]

Where will you bring your wires out for the JP1 terminal block and power & ground plus injector wires?

[merlinfe]

I'll be running them through grommets in the areas marked in silver. Lots of room under the lid to run wiring. I'd like to keep the power wires, injectors, and EDIS separate so I may run more outlets.





-Steve

[targa44]

I haven't done measurements yet, but I plan to put my relay board in the (removed) CDI area of the left side aluminum panel and then use the black cover plate to protect. Are people thinking too much heat back there?

Also, is anyone planning on using a bulkhead connector as a method of extending wiring to the ECU in the cabin?

[JohnJL]

I used the relayboard once but removed it later and left if it out of subsequent efi builds. Those screws loosen themselves, its a pain to get wires into the blocks once the box is installed, and its another point of failure.

[Otter74]

This is how my car is done.

Originally Posted by targa44

I haven't done measurements yet, but I plan to put my relay board in the (removed) CDI area of the left side aluminum panel and then use the black cover plate to protect. Are people thinking too much heat back there?

Also, is anyone planning on using a bulkhead connector as a method of extending wiring to the ECU in the cabin?

[targa44]

Maybe we can continue a little on the relay board topic?

What pin/colored wire are you tapping into at the ignition switch for the "switched 12V" input on the relay board? I've tried reading the electrical schematic and don't have a clue... need a wire that has continuity for both on/run & crank positions to send to the board. I'll guess the larger 12 gauge? yellow wire (pin 50) - but, it's a guess.

Ques. for Merlin and others... anyone using the MS bulkhead connector for quick disconnect abilities?

thanks,

['76 911S 3.0]

Originally Posted by targa44

Maybe we can continue a little on the relay board topic?

What pin/colored wire are you tapping into at the ignition switch for the "switched 12V" input on the relay board? I've tried reading the electrical schematic and don't have a clue... need a wire that has continuity for both on/run & crank positions to send to the board. I'll guess the larger 12 gauge? yellow wire (pin 50) - but, it's a guess.

Ques. for Merlin and others... anyone using the MS bulkhead connector for quick disconnect abilities?

thanks,

I used the Reverse Light +12v feed from the 14-pin connector in the engine compartment. Has power when ignition in the on/run/cranking. The large yellow wire is the starter 50 circuit, only has +12v during cranking.

[targa44]

Merlinfe.... where are you planning to mount your board w/cover? Is there an orientation requirement? - i.e. laying flat. Can it be vertical?

Also, will covering it lock in more heat? I don't know which gets warmer, the relay board or the MS unit.

Finally, are you using the 4' relay cable to stretch from the board to the MS unit?

thanks,

and thank you 911S 3.0 - sent PM

[merlinfe]

I'll be mounting mine on a custom relay/fuse panel I made from scrap aluminum.

I'll be using a 10' cable run through the tunnel and into the engine bay, keeping the MS ECU in the car in the stock ECU location.

Not sure on the heat issue. Once I get everything installed and running I'll take temp readings with an IR thermometer.

[targa44]

That's a very clean look. Well done.

Is your 10' cable from DIY MegaSquirt? I just got a reply back from them as they only offer a 4' "relay cable".... the 10' MS wire bundle (with one end connector) is not exactly the same. Therefore, special attention to detail on matching the pins.

Is that what you're doing or are you just making your own cable?

thanks,