Electrical Components

I am in the process of trying to figure out where to put the main electrical system components.

My kit came with the ISIS system and I have the GMPP ECM kit with wiring harness.

Putting various bits of evidence together, it looks like perhaps the GM kit was designed with the intention of mounting the fuse box at the right (passenger) rear corner of the engine compartment.

The ISIS instructions say to mount the rear powercell on the left side of the firewall, "next to the GM fuse box".

The way the GM wiring harness is constructed, it is a bit awkward to fold the harness back on itself to mount the fusebox on the front left of the car.

The latest version of the SLC build manual shows a picture of the fusebox mounted on the right side of the car "on the wall of the engine bay". However, there is no wall of the engine bay in this area on my car - only the back side of the fuel tank - and it wouldn't be a good idea to screw into that!

The ECM harness is not marked for each injector; one string of the harness is marked "even" and the other is marked "odd". It appears this is a reference to even and odd cylinders; the ones on the right side of the LS7 engine are 2,4,6,8 and the left is 1,3,5,7 (both starting from the front). If the fusebox is designed to be mounted at the back of the car, then running the harness from back to front should get the right connector onto each injector. . . .maybe?

Keeping stuff away from the left side of the car seems like a good idea, so as to provide easier future access for getting a battery in and out of the car and for changing fuel filters or working on fuel pumps.

I'm feeling pretty uncomfortable trying to piece the evidence together about where this stuff should be mounted and concerned that I'm putting stuff where it might be a problem later. Can anyone shed any light on the following?

1) Should there be a firewall installed between the fuel tank and the engine compartment? If so, is this intended to be a builder-fabricated item?
2) Several builders have mounted the ECM on the right side of the car, between the frame and the body (see attached picture). With the ECM in this location, a natural position for the fusebox would be on the right side of the car on the frame rail next to the dry sump tank (see picture). Any problems with mounting in this area?
3) Should the GM harness in fact be run back to front, with the "evens" on the right?
4) Any problems with mounting the rear ISIS powercell on the left side of the panel behind the rollcage? (I guess you could call this an "upper firewall"?)

Any suggestions gratefully received. I think the way it is coming together will work, but it would be nice to have a guide to know if I'm about to box myself into a corner or screw something up. . .
 

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Put it whereever suits your build; mine is located on the left-hand side of the car.

Driver-front of the engine is #1, passenger rear is #8 .... your injectors should be marked with tags saying which is which. If they're not tagged (mexicans got lazy, lol?) I think if you run the harness from behind the engine the lengths will sort themself out.

Keep in mind servicability - some people are burying their electronics in a place that is almost impossible to get to in a completed car without doing major part removal .... I'm glad I kept mine in easy-to-access areas after I had a powercell die on me.

You'll also want to build some type of shield in the front to protect your master cell and powercell - mine are located in about the same area and I broke 2 connectors during my build from accidental strikes from my leg ... oops, lol.
 

PeteB

GT40s Supporter
I put my rear powercell on the back of the firewall on the right side. I plan on mounting the fuse box and ecu below it. I'm going to fabricate some brackets to put them below the firewall, in front of the gas tank. I'm probably just going to run a couple of pieces of aluminum bar from the top frame rail to the bottom frame rail.
 
I tried to mount the rear power cell on the right side (passenger side) and a Canton coolant tank on the left but there wasn't enough room between the front end dress idler pulley and the water pumps lines going to the bottom of the Canton tank. I finally mounted the Canton tank on the right, the ISIS rear power cell in the middle and the mega-fuses on the left. I will be mounting the ECU and GM fuse box on the right side.
 
my $0.02, future access as Alex pointed out is important. Another thing to take into consideration is all other components. I made the mistake of mounting things on the firewall without the engine front assembly on/fuel inlet hose in place and I ended up moving things a couple of times.

Obviously not a look everyone would want - but here is where I mounted my ISIS components.
 

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  • ISIS.jpg
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my $0.02, future access as Alex pointed out is important. Another thing to take into consideration is all other components. I made the mistake of mounting things on the firewall without the engine front assembly on/fuel inlet hose in place and I ended up moving things a couple of times.

Obviously not a look everyone would want - but here is where I mounted my ISIS components.

Well, you definitely got the accessibility part going on, haha!

What the heck are you running that you need so many powercells? :stunned:
 

PeteB

GT40s Supporter
Well, you definitely got the accessibility part going on, haha!

What the heck are you running that you need so many powercells? :stunned:

I could've used another powercell, but was too cheap to buy one. There's no circuits in the stock package for stuff like a stereo, backup camera, power ports, engine compartment fans, accusump, etc.
 
my $0.02, future access as Alex pointed out is important. Another thing to take into consideration is all other components. I made the mistake of mounting things on the firewall without the engine front assembly on/fuel inlet hose in place and I ended up moving things a couple of times.

Obviously not a look everyone would want - but here is where I mounted my ISIS components.

I think I may have seen that design somewhere before.....;)

back-to-the-future-flux-capacitor-replica-3.jpg
 
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