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My battery relocation project

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v8s_are_slow

20+ Year Contributor
2,823
266
Sep 30, 2002
Panama City, Florida
I recently ordered the new JMF, billet intake manifold and S90 74mm throttle body. And all I can say is that this thing is huge. So large in fact that I'm having to do a battery relocation, which honestly I did not want or had any intentions of doing. I LIKE it in the stock location and small batteries plain suck, but in my quest to do what's needed for more power, I'm doing it. Obviously. Sigh....

Anyway, I'm not making some write-up article where people can't reply because I'm still wondering about a few things here and there. I will say that some people suggested that I cut out the floor pan in the rear of the car, get a piece of metal to weld in there and make it a cleaner look. My thoughts on that were a big no for a few reasons. #1, I'm trying to get my car ready to race asap and just don't have that sort of time, nor the extra funds to do it. #2, By doing that, I feel it's allowing more air to be trapped up under the rear of the car and caught by the rear bumper, thus helping to slow it down. I'm no fan of holes or having a hacked up rear bumper. And #3, okay, I forget that reason. But anyway, I'm posting everything I purchased (all from Amazon because I returned a part and they gave me store credit and made life easier for "me" to just get it from them).

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First item was to drill through the rear bumper for the battery kill switch. I'm not a fan of "not" doing things correctly so yes, I'm using a kill switch, even though not everyone does. I used a 3/4" wood drill bit thing or whatever it's called and picked out a nice location to drill. Going straight through also allowed me to poke a small hole on the inside so I'd know where to cut and be centered with the hole in the bumper so that I could install the switch. Be careful not to get any wires of course. My rear interior is all stripped out by the way to save weight and I don't have anyone sitting in the back seats anyway.
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At this point I used a 3" hole saw to cut the hole. Probably could've used a bigger one so I could squeeze my hand through the hole but I didn't wanna go crazy. I of course drilled through the spot welds of the bracket in the picture above to get the gas door cable out of my way, and drill a small hole above where I drilled the 3" hole so that I could relocate the clip for the wiring.
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Next for me was to remove this ugly piece of crap in the back and clean up the rear some. This step could be skipped by some or if you wanted it in a new location but I just couldn't skip it. No, that's not rust, it's dirt from the previous owner that I never saw or noticed until I took out the spare for this job.
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I drilled out all of the spot welds and out it came.
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Looks like my car was at a shooting range.
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After using a grinder with a flapper disc, I was able to clean out much of the dirt, sharp edges, and remove the old paint. Then of course taped everything off. I didn't wanna deal with welding the holes shut (which I could've done) because of time restraints of getting the welder which doesn't belong to me and figured most of these holes wouldn't be seen anyway because of the battery box so I used silicone to fill them in. I smoothed out the silicone the best I could and drilled 2 holes for the battery box and then painted away.
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This is "most" of everything I had ordered. At this point, I was missing the 250 amp, inline fuse and grommets aren't pictured. I ordered 2 wiring kits because I'm running a power wire to a distribution block under the hood, and then another directly to the alternator. Ignore the ARP's. Those were for my hubs because of the Weld wheels I have on my car and needed longer studs (that wasn't a fun job at all).
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Some people tell me the Moroso box use to come in blue but now come in black. Had it been blue I would've ordered something else. Some people go with a Taylor box, and some people no box at all. Yes, I'm running an Optima battery which "might" not require a box but my decision for getting a box anyway is that if I ever decide to purchase a new battery, I'll have a box already that will get the job done and no worries on my end.
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This is where I'm at currently with it. I need more grommets and the local stores are currently sold out of the sizes I need so that's stopping me from running the power wires to the front where I need them.
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I went with a civic battery and made a bracket to put it right on the subframe. im still contemplating a relocation so I could have a little more room there though. looks damn good so far.
 
I couldn't drop the battery to the subframe due to my fuel lines. Small battery could've done it possibly but I hated mine when I had it for cold morning starts.
 
I use a odyssey 925 battery on the subframe. You’re right the billet im is huge, tight fit. One other thing on my 1g, I had to fab a bracket for the throttle cable to fix properly. Do know if that’s the case for 2g.
 

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Looks great man I'm looking to get a battery but cant decide which one since its already set up for the trunk location, I'm concerned about the accessories as ill be running a small amp, gonna get a Saturn altentator to help.
 
Nice write-up Scott, thanks for sharing with the community! Cleans up the engine bay and distributes weight to the rear, it's a great mod for these cars.

Got a photo of the shut off switch completed?

I'll take more pictures here soon. This isn't 100% completed yet. And still wondering a couple of things before I complete it and will verify on here.

For one, I'm seeing people's diagrams for the wiring and they're using the positive cable to the switch. Just not understanding why people aren't using a negative cable to the kill switch instead. I'm tired and forget the other questions so I'll have to ask later. Hoping I can get the rest of the grommets tomorrow so I can hopefully finish this all up, and add additional pictures.
 
So I've been looking and looking all over town for grommets and finally found some at my local Harbor Freight. This kit was only like $5. Can be found online as well. Now the biggest ones (which is what I needed) only have a quantity of five in the container. I cut a 1 inch hole with a hole saw wherever needed and used the biggest ones I needed. Now my short review on these are that they're WAY better than the Home Depot grommets that I was paying over $1 and some change for. And that's for an individual grommet. These are much thicker and sturdier than the previous ones I was using.
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This is where I cut the holes in the back of the car and where I mounted the switch. Three 1" holes below it for the wires to go through and the grommets inserted. I actually had to take a small flat screwdriver to get the grommets in. From the battery I'm using a 250 amp fuse. I'm assuming that's a good one to use from what some people have told me. Of course I've never done this before so only taking word of advice from others.
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And this is how I have my wiring routed in the back. I have 2 positive wires going to the front. One on a 100 amp fuse directly to the alternator, and the other to a power distribution block (I don't have it all the way to the front of the car yet though).
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The Moroso box comes with the rubber uh, stuff, that goes around the inside of the lid to make it sealed when you fasten the lid. Have to cut it to length to get the exact length. I put in in there but it fell out when I flipped the lid over. I had some spray for headliner laying around so I sprayed a very small amount in it and put the rubber in it to secure it. Wiping off any excess because the stuff is VERY sticky. 3M spray probably would've done the same thing.
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I was gonna fasten the lid on it tonight but I'm stuck trying to figure that part out. The directions suck in this one general area. I'm not sure if I'm supposed to put the rubber bushing down in the metal clip, above it, or what. Some feedback on this part would be GREAT.
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This is all I've got for the time being. I'll post up more later.
 

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Okay sorry this is taking so long but I really don't get much time for all this. And I'm getting old and very sore after doing all of this crap. Anyway, figured out how to get the lid on for the Moroso box so that's now complete. The wiring in the back is now complete but just had to get the ground cable completed and installed. I see some people using small bolts near the rear of the car but that just doesn't seem very fitting in my eyes to have such large cables and then use a small, wussy looking cable lug to bolt to the body. So I drilled out the lug a big larger and used the rear seat belt buckle harness bolt. However I wanted to make sure I had a nice clean surface so I just used a drill with a wire wheel attachment, or whatever this thing is called. Have to clean things up a bit later because it looks a bit dirty in this area of the car. Let me just mention to make sure you connect the ground wire LAST when completing this job unless you want to be supplying power to the alternator wire even if the kill switch is turned off.
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I don't have the rear interior in my car but you could run the wiring up under the seating if need be. I'm running mine right up under the console. Screw running it up under the carpet and risk the wires getting stepped on, crimped, cut somehow, etc. and arcing out on the body. Sorry, that's just not for me. I'm going to have to trim the back of the console though to make room for the two positive cables to fit underneath without interfering with the fitment of the console, but that's no big deal. I'm also going to fasten the wires to the center panel next to the fuel pump but I'll get that done later. Again, not a big deal.
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Word of caution here is to just be careful not to get the wiring too close to anything that can cut the wires. I ripped out the air bags and the module under the console so I have a bit more room than most. Also had to test to make sure my e-brake wasn't getting too close to the cables when raising and lowering the handle.
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Okay I'm just going to say that I saw someone else who drilled holes up under the dash for the power wires to go through. And I'll just mention that to do it from the inside would not only be a HUGE pain, but also very risky because your brake lines are right on the other side of the firewall. Whether doing it from the inside towards the engine bay OR from the engine bay going inside, you need to LOOK AT WHAT YOU'RE DOING before you cut. Wanna ruin your day? This is a quick and easy way to do just that. I chose to cut from the engine bay towards the inside of the car because I already had the intake manifold removed and trying to fit the drill in there from the inside would've been a huge pain. I had already thought of using this area before I saw the other person's write-up, but I'm certainly going to point something out to y'all (aside from saying there's brake lines just on the other side of the firewall if cutting towards the engine).
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There's really not a lot of room for cutting through the firewall. And trust me, I looked because I not only wanted to have a clean installation, but make it easy if as possible because I do NOT like running anything through the firewall. Just not a fun job for me. But if you look at this picture, you'll see something that's round looking. At first I figured maybe this was just where the factory had pressed the metal and it just looked this way. But that little circle is actually the back side of the stud that your shift cables bolt to on the inside of the car. You cut that sucker and your shift cables are gonna move around. And boy was I happy before I made that cut.
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After my cuts, I put the grommets in and then the wiring. What a relief it was to have this part done. Another tip here. Earlier I was stating that the grommets from Harbor Freight were much sturdier and better to use. But the metal in this area was a bit thicker and not as fun to get the grommets into because they didn't flex very well. The Home Depot grommets were a bit easier to move around. In the picture above this one, you'll see one grommet looks more circular, and the other a bit oval. The round one was the Home Depot grommet that installed a bit easier. The oval one was the sturdy grommet from Harbor Freight. That one was a PAIN to install and I'd probably suggest the Home Depot grommets from this particular area to make life easier because of the flexibility of them. But anyway, wires through the firewall. Yay!!!

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One wire connected to the alternator.
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I might be a bit late to say this now but be careful with cutting the wire, and might wanna purchase wire that's about 5 feet longer than what I purchased. I have an alternator relocation, and I ran the wire straight through and under the console. This is what I had left after connecting the wire to the alternator. Not much left but I also used this particular wire to go from the battery, to the kill switch. The other wire had a bit more left over but still. I'll try and get a picture of that one later.
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Time to make a bracket for my power distribution box. This will be going in the place of the stock battery bracket.
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Cut it with a hacksaw, rounded off the corners with a grinder to make sure I wouldn't be cutting my arm on it if I was working on the car, and filed down the edges. Then painted away with some bedliner spray paint from Walmart.
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Installed. I have some of the wiring connected but didn't get a picture. I guess the next post I make "should" show everything being completed with this part of the project. Notice I won't be getting cut by any sharp corners from this thing.
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Just realized I never posted a picture of the kill switch actually installed from the outside. So here it is.
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You know you could have run those wires in the designated wire areas along the sides of the car right? I fit all my 1/0 gauge wiring for my battery in them and don't have to worry about running them by the shifter and console area.
 
I don't like running them down the side though. Also, I would have run out of wire so I'm glad I did it the way I did to be honest.
 
I'll take more pictures here soon. This isn't 100% completed yet. And still wondering a couple of things before I complete it and will verify on here.

For one, I'm seeing people's diagrams for the wiring and they're using the positive cable to the switch. Just not understanding why people aren't using a negative cable to the kill switch instead. I'm tired and forget the other questions so I'll have to ask later. Hoping I can get the rest of the grommets tomorrow so I can hopefully finish this all up, and add additional pictures.
I don't like running them down the side though. Also, I would have run out of wire so I'm glad I did it the way I did to be honest.

so you ran 1/0 from both the alt and the battery to the distribution block in the back?
 
Distribution block is in the front under the hood. The wire going to the distribution block is then feeding the starter, fuse box, and fuel pump. The other cable goes directly to the alternator.
 
ok I see it now LOL for some reason when I looked at the distribution block yesterday it looked like it was in the back. sorry if this is a stupid question but out of curiosity. what was the reason you ran the alt wire separate from the distribution block?
 
ok I see it now LOL for some reason when I looked at the distribution block yesterday it looked like it was in the back. sorry if this is a stupid question but out of curiosity. what was the reason you ran the alt wire separate from the distribution block?

To wire up the kill switch properly you have to run the alternator charging wire back to the battery side of the kill switch. If you ran it to the distribution block, the car would run with the kill switch off as the alternator is still powering the car.
 
What Boomdeeze said. I was thinking that the kill switch would cut power to both. Power is constantly being fed to the alternator even with the kill switch off. Reason I'm saying to connect the ground wire last. If you put the wire on the side of the switch that kills power to the fuse box, you can turn the switch off, but the alternator will still supply power back to the switch and then back up to the fuse box and everywhere else, completely defeating the purpose of the switch. Keep in mind that the switch was not designed to cut power to the alternator, just the fuse box, etc.
 
So just an update but I finally finished up my relocation. Learned a few things here and there. Lemme go ahead and get started.

Notched the console in the back so I could run the wires up under it and still be able to get the console all the way down.
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If you're not lazy and you wanna do a relocation "correctly", you need to remove the stock power wires going to the alternator. Everyone I talk to tends to not put a kill switch in the back, they leave the wires connected, or whatever. But the object of doing all of this kill switch stuff in it is so that in the unfortunate event that you get in a wreck, they power can be turned off from the back of the car. If you have the stock alternator wires going from the fuse box to the alternator, the alternator will still supply voltage to the fuse box. So you need to either remove the wires completely (larger task than I cared to handle at this time), or cut the wires, and remove them from where it bolts to the fuse box. I also cut the other end off at the alternator to prevent power from going through the wires to anything inside the fuse box.

If you take the fuse box and flip it over and take the bottom off like so, the wires you need to remove and cut are the 2 to the right.
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You do NOT want to remove the other wires to the left, otherwise the fuse box won't get the power it needs. Yes, yes, I'm a dummy and found out the hard way and it wasn't fun trying to diagnose all of my many many electrical issues. Windows wouldn't go up or down, no power to radio, no dome lights, no a/c fans, when I turned my headlights on, they wouldn't turn back off until I turned off the kill switch. All sorts of fun I was racking my brain over. Everything is resolved now. Car isn't running at this time though. Thinking my injectors are clogged and sending them off tomorrow to be cleaned (thanks to E85 and me not doing the proper storage procedure for them). But this basically ends the write-up unless you guys have any other questions or comments. Only thing I will say is that I've added a couple of additional wires for my new fuel pump, clamped down the battery cables in the rear seat area, and just have to vacuum out the loose wires from when I stripped the insulation. But that's about it. Hope this is helpful to you guys.
 
Nice write-up! This answered a ton of the questions I had in regard to main power wires on the fuse box and alternator wiring. Thanks!
 
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