I need custom ideas.

[Richard454]

I was in the 12v industry for 20 years but that was 15 years ago-and before that, put myself through college (Georgia Tech) installing car stereos-got my Amateur Radio License at 12-and when I was 7 plugged my Hot Wheels Sizzler car into a 120 outlet instead of the Juice Machine!!!

Just trying to help you out- looks like a NICE build- a few bucks more to do it right?? Why not!


FWIW- electricity moves as slow as molasses compared to the speed of light- and connecting to the battery does make a difference...

I'll throw this out - The car where I got my engine from- a BMW 750IL- $98,000 NEW- a lot of electronics - stock 140A alternator and had an optional 2ND alternator...

BMW runs a 4GU directly to the battery from the alternator


Battery in the trunk


Three wires- Starter-Alternator- ECUs



Running to the front of the car- BTW the junkyard is a GREAT place to get this wire- cheap and it is REALLY good stuff!!!

I think the solution for your firewall wires it to route them inside the car.
For aesthetics it's better not to have any of those wires visible if possible.
Feed them through the firewall on the drivers side and then cross over to the passenger side.

That's exactly how I did mine-

Battery is in the back- ran 1/0 to the starter AND alternator- and 4GU for vintage air/ECU/Power windows





Hiding the wire-"Custom ideas"



No wire (OK- I have covered the plug wires I relocated..)



here's another way to hide- had some extra SS line from my Dry sump set-up





Howabout this- used a Voltage regular cover to hide the relays for the electric fans



Hiding fuel injection wires-

Custom fuel rails- the second set of rails is for the vacuum



Get a wire book from Home Depot/Lowes- really helps keep the wiring straight... ESPECIALLY when relocating coils



Cover it w/ split loom fabric-



Copper pipe- cut on a table saw-




Then a black wrinkle finish-

[Motown 454]

Richard 454, I have one thing to say about your wiring! I need you at my garage... lol Nice job.

[badazz81z28]

Not sure how the topic took an exit from the original question, This is not a winker measuring contest. I too have been doing wiring stuff for years and too worked on stereos, I even have professional education in aircraft electrical which goes back a couple decades too. I can tell you in all my experience and education, never was a time that says "Always connect electrical loads directly to the battery". Like mentioned, some electrical systems don't have batteries and look at how some engineers designed vehicle electrical systems. Take the Sec Gen Camaro for example. The battery lead goes directly to the starter. From there a 10ga wire goes up to the center of the engine where the alternator source and main fuse box power are spliced and spliced 3 ways if you had AC. The 4th Gen Camaro alternator lead and the fuse box power are spliced together at the battery. No matter which way you look at it, the circuit is the circuit. Electrical fundamentals tells you that.

Is the power off the alternator precisely constant? Of course not, the engine RPM is affecting that. Just like the engine is not really idling at a particular RPM...Its fluctuating up and down. It doesn't impact anything in a negative way, just like voltage varying between 12-15V.

Do you have any actual data to support what you claim? I don't, but I can say real world I haven't seen an issue.

I will say having a battery in the trunk and running all the wires back to it sure is a waste of wire, weight and money. Not to mention a PIA to hide it all.

[gator68428]

Hey man, I recall you asking for ideas and then moaning about how no one replies.

I gave you an idea to run it through the interior. Do it don't do it fine.

We did get a little off. We provided you two examples of top tier vehicles (a G8 and a BMW) of an example of where it seems the engineers felt it necessary to run extra wires to the trunk.

I went out of my way to give you input and investigate an open hypothesis. Take the data (on actual wiring of a factory LS3 (very similar to your LS7) with trunk mounted battery) or don't. You asked for it. This a forum for people to learn things. I'm still learning too. I think it's an interesting topic and have no issue taking all inputs.

A response to your second gen example is that a second gen is NOT fuel injected. EFI systems are sensitive to noise. So it may be that it doesn't matter as much with a carb, and mechanical disributors etc. (no sensitive electronic ECU controlled timing events there)

[Richard454]

Richard 454, I have one thing to say about your wiring! I need you at my garage... lol Nice job.

THANKS Wayne!!!

Hey man, I recall you asking for ideas and then moaning about how no one replies.

I gave you an idea to run it through the interior. Do it don't do it fine.

Not sure how the topic took an exit from the original question, This is not a winker measuring contest. I too have been doing wiring stuff for years and too worked on stereos, I even have professional education in aircraft electrical which goes back a couple decades too. I can tell you in all my experience and education, never was a time that says "Always connect electrical loads directly to the battery". Like mentioned, some electrical systems don't have batteries and look at how some engineers designed vehicle electrical systems. Take the Sec Gen Camaro for example. The battery lead goes directly to the starter. From there a 10ga wire goes up to the center of the engine where the alternator source and main fuse box power are spliced and spliced 3 ways if you had AC. The 4th Gen Camaro alternator lead and the fuse box power are spliced together at the battery. No matter which way you look at it, the circuit is the circuit. Electrical fundamentals tells you that.

Is the power off the alternator precisely constant? Of course not, the engine RPM is affecting that. Just like the engine is not really idling at a particular RPM...Its fluctuating up and down. It doesn't impact anything in a negative way, just like voltage varying between 12-15V.

Do you have any actual data to support what you claim? I don't, but I can say real world I haven't seen an issue.

I will say having a battery in the trunk and running all the wires back to it sure is a waste of wire, weight and money. Not to mention a PIA to hide it all.

Umm- GM/s beancounters saved as much as they could- Using smaller gauge wire and sort of cheat by raising the alternator's voltage output- Oh- don't believe me- here's an article by Mad Electric-

http://www.madelectrical.com/electri...evymain1.shtml

You can talk Ohms law all you want- when you are talking a simple series circuit- but a car is NOT a simple - electricity not only takes the path of least resistance but ALL paths as well.

Here's the problem- Alternators create AC power-then it's filtered by diodes BUT not all of it is filtered-so the battery filters it. "Google" AC ripple if you don't believe me... Electronics do NOT like AC- and as the load on the alternator increases-and heat- the more AC voltage is messing with your electronics.

Looks like you've spent a LOT of time and money on your ride...another $100 to run the alternator wire to the starter lug and a smaller wire to the electronics - doesn't seam like that big of a deal...

Richard

[badazz81z28]

I'm confused on what your even talking about. ^^^^ did you even read my first post or look at the pictures?

My alternator is already wired directly to the main battery cable..I was looking for ideas to tap for the external fuse box. In fact your link for "upgraded alternator" is how mine is wired ....

[Richard454]

I'm confused on what your even talking about. ^^^^ did you even read my first post or look at the pictures?

My alternator is already wired directly to the main battery cable..I was looking for ideas to tap for the external fuse box. In fact your link for "upgraded alternator" is how mine is wired ....

Yes- the upgraded diagram is for a 90A alternator..and the article is 15 years old- notice NO ECU in the diagram... And looks like you've got a 140A?


Rule of thumbs- wire under the hood sees a higher temperature- wire current rating is done at 70ºF -heat adds resistance so figure going up one wire size to compensate for the heat.



See below for what I recommend...

IF you have added other things to the car- electric fans- aftermarket AC- those should NOT be connected anywhere near the OEM panel- use the starter or upgrade the wire from the battery to the ECU.

[rickpaw]

All good comments here. My philosophy - when in doubt, follow the OEM.

OP, if you don't like other's people's idea, then don't do it. You did ask for comments/ideas.

Either way (how the OP's suggested vs. running extra wires to the battery) works. I ran my constant power for the ECU fuse panel to the battery terminal as suggested by the harness manufacturer's instructions (battery is in the trunk). So far no issues.

Try to follow original GM wiring schematic (60/70s) is fine, as long as you're doing a stock restoration. The moment you add EFI/AC/stereo/fans; then everything changes.

Also, the alternator does not provide power to the vehicle. The battery does. Once you have the car running, take the battery off the system, and see how long the car stays running.