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Grounding amp in trunk. Need help w/ seat bolts.

2820 Views 24 Replies 8 Participants Last post by  ice992
Hello friends,

I am installing an amp in my trunk, and I am trying to keep the ground wire as short as possible. My buddy yesterday suggested I use the luggage tie-down hook bolts for that, but I don't want to run a wire twice as long just because it's not easy to take the seat bolts out.

Ford used some stupid-ass TORX head bolts for the rear seats. I wanna know if anyone's ever put the ground there and also... what size TORX bit/socket do I need for that?

Thanks much!
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It would be best AND easiest to just drill a hole in the chassis and scrape like a mo' fo' to get all the paint away and then get a big @$$ bolt and then ground there.:thumbsup: That is going to give you the best ground and you can do it literally anywhere you want.
OK! Where do I drill? Got a pic? I found another thread with pics but they were offline.

Oh, and what type of screw/bolt do I use?
he said you can do it anywhere
but it's best to scrape away somewhere in the trunk bed and then put a terminal on the end of your ground wire and screw it down to where you scraped the paint
don't drill a hole
Get a really long drill bit and do it over the gas tank ..... jk

if your gonna do a bolt and nut it would probably be best if you look under the car for a spot you can get the nut on later.

The kind of bolt really doesnt matter. Personaly when im grounding anything i like to use a med sized stainless steel bolt, grounding accelerates oxidation, using stainless steel can help slow it down. Of corse i always use NoOxid on all my grounds too but most people dont even know what that is.
If you don't drill a hole, how do you plan on fastening it to the chassis???
there is that piece of plastic over the very back of the trunk, if you remove you you will see some hole in the metal. a half inch bolt fits in there and just use that as the ground. make sure you sand it a bit first though
I bought a thick sheet metal screw and I plan on making a hole as close to the rear seats as possible. Where's the gas tank? I'll have to go look.

I already soldered the ground wire to the gold plated ring terminal. All I gotta do is drill a hole in the metal and screw the terminal down.

I live in California. Rust is not a huge problem. Do I still have to go find a stainless steel screw? The one I have is a "body screw". It's huge, but not SS.
You are fine without a stainless steel one. I live in minnesota lots of snow/salt and mine is completely fine.
as i told redcougarguy when he had problems installing his amp:

"Anyplace in the trunk area is a good place to ground... DO NOT use exsisting holes... If you are running small wire... IE less than 4 GA, and you elect to mount your amp to the back of the seat... where the carpet meets the back of the seat in the center, is a decent place to put a single screw ground. Get a wire wheel and scrape the paint off, the metal is thin enough you shouldnt have to predrill... make sure you use lock washers, and it get tighted securely without stripping the hole... once tightened, pull on it and wiggle it, make sure its not going to move... then get yourself some white lithium spray and spray the exposed metal and the ground itself... this will help keep the ground and the surrounding metal from corroding.

If you elect to mount the amp other places... use the same proceedure but anywhere else in the trunk area... but before you go punching holes in things, check the other side, make sure you arent going to pierce a fuel tank, a brake line etc... (common sense however its better to remind then assume)"
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"make sure you don't drill through a gas tank or brake line"... Your advice came in a bit too late. I managed to... nah... just kidding. :p

Here's what I did.

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Looks good, one thing though, the 12.5V isnt as important reading as the Ohm test to the battery.
How would you measure the "Ohms to the battery"?
Originally posted by: Intruder
"make sure you don't drill through a gas tank or brake line"... Your advice came in a bit too late. I managed to... nah... just kidding. :p
Silly east bayers :tongue:
lol, where are you (East Palo Alto?)? Are there any meets going on?
Originally posted by: Intruder
lol, where are you (East Palo Alto?)? Are there any meets going on?
PM'd :biggrin:
Take that meter and some scrap wire... go from you ground point to the negative battery cable.... it should read 0.3 or less. its the Omega looking symbol on your meter ;)

oh and by the way the ground it self can induce rust, granted what i was working on was totaly different things BUT the ground points i did would rust INSIDE temperature controled buildings if we didnt treat them. anyway dont listen to me no one does :)
OK, now I understand what you were talking about. I thought you wanted me to measure the resistance between the positive and negative wires in the trunk and I was like "WTF is this guy talking about". lol

You think I would have an HP multimeter and not know what omega is? :)I'm a EET major, and I know quite well which symbol is what. ;) Big omega, small omega... lol

Err.. I don't know if it's worth the effort to measure the resistance. It bumps quite well. It doesn't seem to be lacking power.
The idea is to get the difference in resistance as close as possible. So the battery terminal would be your starting point..then you could use that as a reference to find better ground points throughout the car.
or, you could go to autozone and buy a 55torx. then after 5 minutes you'd be set. and not extra holes. mines a great ground.
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