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revrico
revrico GRM+ Memberand New Reader
3/8/16 10:30 p.m.

So I'm still pretty new here, and wasn't sure what part of the forum this particular thread should go in, I'm a little to used to the million sub forums on miata.net and they rather dislike me for doing what I want with my NA instead of MORE STOCK.

But anyway, I'm fabbing up a light bar for my part time offroad NA miata. While I think I have most of the metal work down, 3/16 plate steel bar attached on either side, then a solid piece joining them. Lights go through the plate where they overlap, then welded. Or maybe 1" square tube to join the sides. Or both?

That's the idea anyway. I haven't figured out the search function here, it brings back all kinds of random stuff, but I was wondering if any of the rally or offroad builders had made a similar bar?

And where the E36 M3 can I draw power from on an NA? Going to go with Hella 500s, but no idea where I'm powering them from. Power window circuit? a/c circuit? the rear defroster? (just electric things I know are there and I don't use)

Thanks for the help, and I guess if this could be somewhere better, feel free to move it.

<img src="" />

Cardboard mockup I made the other night, although I'd like them close to center, I dont think the joints would be strong enough without the light stud going through it even welding them.

EDIT: didn't realize, the mounting point I have picked out is the baby teeth mounts. Sorry, 3 different forum threads in 3 windows isn't the best way to stay on top of everything

mad_machine
mad_machine GRM+ Memberand MegaDork
3/8/16 10:43 p.m.

I would go for a direct route.. take a lead from the battery (or starter lead as I am not sure where the battery is on a Miata) with a relay to control the power from a switch inside the car. The point is neat and efficient.

revrico
revrico GRM+ Memberand New Reader
3/8/16 10:50 p.m.
mad_machine wrote: I would go for a direct route.. take a lead from the battery (or starter lead as I am not sure where the battery is on a Miata) with a relay to control the power from a switch inside the car. The point is neat and efficient.

The starter never even crossed my mind as an option, that would work really well for the location. The battery being in the trunk, getting a wire the whole could be doable, but a PITA

mad_machine
mad_machine GRM+ Memberand MegaDork
3/8/16 11:03 p.m.

I am just really unfamiliar with the Miata. But like I said, you want simple, easy, and efficient. You do not want it to break, but if it does, you need it to be easily traced and fixed.. and you definitely do not want to burn down the car when it does.

Keep the leads short from power source to relay, and then from relay to lights. The power from switch to relay can be longer as all it does is turn the relay "on". You are also going to want a good fuse, heavy duty wire, and a strong relay rated for the amperage it is going to see.. and while cars may only have 12 volts, their batteries can throw a lot of amps in a short amount of time.

revrico
revrico GRM+ Memberand New Reader
3/8/16 11:17 p.m.

In reply to mad_machine:

Think the power line and fuseblock from a sound system would be sufficient? I happen to have one laying around since my boxes don't fit in the miata. Then I could just grab another headlight relay at napa.

Stefan (Not Bruce)
Stefan (Not Bruce) GRM+ Memberand MegaDork
3/8/16 11:42 p.m.

Yep, that should work just fine.

aircooled
aircooled MegaDork
3/8/16 11:49 p.m.

Looks like the 500's are a bit under 5 amps each (?). If you wire straight to an unused part of the box, just swap the fuse for a 10 amp. If you want to use the stock wiring, make sure the stock fuse is at least 10 amps. I suspect the rear defroster would draw a good amount if it's not on a relay (wiring is in the wrong end of course).

The power wire to the relay is what you are worried about (wire gauge and breaker amperage). The switch wire to the relay has very little draw (which is the point of relays).

Wiring the power wire to the starter wire is probably not ideal. I am sure the fuse or breaker on the starter circuit is quite large which means if you ever get a short in the lights power circuit it will likely smoke the wires before tripping the fuse/breaker (it's purpose).

revrico
revrico GRM+ Memberand New Reader
3/9/16 12:43 a.m.
aircooled wrote: Looks like the 500's are a bit under 5 amps each (?). If you wire straight to an unused part of the box, just swap the fuse for a 10 amp. Wiring the power wire to the starter wire is probably not ideal. I am sure the fuse or breaker on the starter circuit is quite large which means if you ever get a short in the lights power circuit it will likely smoke the wires before tripping the fuse/breaker (it's purpose).

I'll be using a 2 gauge amp power cable with a 20 amp inline fuse, although I may take that to 15amps. I was thinking of going to the AC circuit in the main fuse panel, as there's already a switch in the cabin, and my compressor is shot, but that could be a whole other set of problems. I'm good with general electric, but car electrical systems, and haynes diagrams in particular, just confuse and scare me a little. I'm not worried about getting shocked, but letting the smoke out of something expensive

As for something breaking, I'm more worried about something dismounting a light at speed, and sending it right up the hood.

foxtrapper
foxtrapper UltimaDork
3/9/16 7:42 a.m.

Your a/c switch notion should work just fine. Be aware that the switch controls a relay that provides the power to the A/C compressor.

A relay for battery power to the lights is generally a good idea, it helps ensure maximum illumination of the lights. The oem relay for the A/C compressor is probably quite sufficient to the task.

WonkoTheSane
WonkoTheSane GRM+ Memberand HalfDork
3/9/16 8:43 a.m.

Your car may already have foglight wiring somewhere in that harness. Those probably aren't to be pulling that much more than what the factory had, maybe try to find that wire size? Then just add a relay to trigger it.

Where were you going to mount the bar to? I'd make it so it mounted to the baby teeth location myself and bent it so it doesn't destroy the front bumper when it inevitably gets bent backwards a bit :)

alfadriver
alfadriver MegaDork
3/9/16 8:53 a.m.
WonkoTheSane wrote: Where were you going to mount the bar to? I'd make it so it mounted to the baby teeth location myself and bent it so it doesn't destroy the front bumper when it inevitably gets bent backwards a bit :)

that's what I was wondering. There's not a lot immediately behind the bumper skin there, so a bar of lights would not be supported all that well.

The idea of putting it lower to a know structure is good, but what about higher? In between the lights? Like old rally cars:

Hungary Bill
Hungary Bill GRM+ Memberand UltraDork
3/9/16 12:32 p.m.
revrico wrote: So I'm still pretty new here, and wasn't sure what part of the forum this particular thread should go in, I'm a little to used to the million sub forums on miata.net and they rather dislike me for doing what I want with my NA instead of MORE STOCK. But anyway, Thanks for the help, and I guess if this could be somewhere better, feel free to move it.

Use the search button newb! This doesn't go in "off topic" !!!!!!!!!!!!!!!!!!!!!

Hi, and welcome to GRM I think you're going to fit in just fine here.

Your AC compressor is a great idea. First, it already has a relay and two it's already 90% wired up for you (with switch and everything!). Third, I'm seeing that AC compressors draw anywhere between 5 and 10amps so the lights should be reasonably within the limits of the associated wiring system.

I might simply cut the wire to the compressor (or if there's a connector nearby, even better) and run that as your positive lead to your lights. Hit the AC switch, relay clicks, and let there be light Maybe if you were really worried about it, change the amp rating of your AC fuse to about 15 amps or so?

Good times

WonkoTheSane
WonkoTheSane GRM+ Memberand HalfDork
3/9/16 12:59 p.m.
alfadriver wrote: that's what I was wondering. There's not a lot immediately behind the bumper skin there, so a bar of lights would not be supported all that well. The idea of putting it lower to a know structure is good, but what about higher? In between the lights? Like old rally cars:

My problem with this always is that it never looks good unless you got through the effort of making a cool light pod (or buy one), and you destroy your hood. Plus, the Miata hoods are aluminum, so I wouldn't think they'd hold up well to mounting a light directly.

I guess it depends on projected (hah!) use. What are you primarily going to use it for, RevRico? To look cool, to rallycross or to end up offroading & stage rallying? :)

Edit: Also, welcome to the forum. I would guess that no one would be surprised to see this under the "grassroots motorsports" section.. Off topic is for... Well, okay, the lines are pretty blurry...

revrico
revrico GRM+ Memberand New Reader
3/9/16 1:13 p.m.

In reply to WonkoTheSane:

When it isn't being used for auto cross and dd duty, it will be lifted up to go trail riding and puddle jumping, or just to cruise around and confuse people.still based on the assumption the flying miata lift kit is easy on easy off, I'd love to hear from Keith Tanner on that one.

Even though there's perfect terrain and lots of poor farmers in my area, there's only one stage rally I know of, on the other side of the state. The waste management Susquehanna stop on the wrc.

I've just enjoyed the Hell out of this on dirt, and have a sneaking suspicion that like an 80s rabbit, I could take this car places some jeeps can't go.

Im now in a weird spot waiting on front tow hook bolts, because all the sizes id found online, as well as the rear bolts don't fit up front. Half tempted to weld the Bitch on. 6$/bolt at the stealership is frustrating to say the least.

Looks like a.c.circuit is the way to wire though, that'll make things easy. And having the second fan kick on when those lights come on is just a bonus.

For mounting and wiring, think bar stock will be alright? I kind of want the cross piece to be square tube to run the wires through, but at least with my mock up lights, that wouldn't help much.

alfadriver
alfadriver MegaDork
3/9/16 1:26 p.m.
revrico wrote: For mounting and wiring, think bar stock will be alright? I kind of want the cross piece to be square tube to run the wires through, but at least with my mock up lights, that wouldn't help much.

A square tube would be fine, assuming you attached that to something solid on the car. The bumper cover and foam behind that isn't exactly solid. Which is why we are asking.

revrico
revrico GRM+ Memberand New Reader
3/9/16 1:43 p.m.
alfadriver wrote:
revrico wrote: For mounting and wiring, think bar stock will be alright? I kind of want the cross piece to be square tube to run the wires through, but at least with my mock up lights, that wouldn't help much.
A square tube would be fine, assuming you attached that to something solid on the car. The bumper cover and foam behind that isn't exactly solid. Which is why we are asking.

I thought I said up top, I'm mounting where the front babyteeth were. there's some cardboard mockups over in my build thread. For secure mounts, I think the babyteeth holes are the best spot. Especially is I red locktite the bolts in.

I did some math shudders. I've spent about 88 cents per mile since I got the car last may in repairs. I know there is no way in hell I'm recouping purchase price, ever, let alone any sort of repairs, so I'm just going custom. I feel that's important to say, because knowing the car will be driven until it falls apart makes fab work a little easier, not worrying about how pretty things come out.

And when the carpet rots away, I want to pull the body and cover inside and out with bed liner, but that's a whole other thread.

alfadriver
alfadriver MegaDork
3/9/16 1:53 p.m.
revrico wrote: I thought I said up top, I'm mounting where the front babyteeth were. there's some cardboard mockups over in my build thread. For secure mounts, I think the babyteeth holes are the best spot. Especially is I red locktite the bolts in.

I'm missing that part.

Those are below the bumper and behind the bumper surface, right? (I've never addressed those on my Miata, so am not sure what they are)

If they are, you should look into some securing above it- assuming you want the lights were you have the cardboard mock ups. If not- that's along amount hanging in front- so bouncing will make the light mount bounce, too.

wae
wae Dork
3/9/16 2:13 p.m.

I made a bar for my Neon and used leftover bits from an outdoor canopy that blew over in a windstorm. I had 7/8"(ish?) square tubing and 1" square tubing to work with along with a few bits of bar stock. It's bolted to the core support in a couple places and while I don't think I could use it to lift the front end, it's very solid. The light I use is a bright-as-the-sun LED lightbar and I bolted the mounts to the bracket and then bought big knobs to use for the light-to-bracket mounting so I can remove it without tools.

For power, I got a couple weatherproof connectors for easy disconnect and bolted one to the where-everything-else-is-grounded spot on the core support. For +12V, I tapped in to the PDC which was right near the lightbar anyway and stole something that I wasn't using anymore and put in a weatherproof in-line blade fuse holder (with a fuse!). To switch it on and off, I've got a lighted switch mounted to the dash that powers a relay.

Here are some pictures of the bar:

revrico
revrico GRM+ Memberand New Reader
3/9/16 2:15 p.m.
<img src="bt" /> Inside the bumper cover, bored into what I believe to be the front subframe. The picture is the passenger side. <img src="#//postimg.org/image/r8ndmdas7/]" /> This was my first choice of mounting spot, inside the "grill" area but off the the side. The bolts that were in the hole don't fit back in with bar stock on them, I have no idea their original purpose, but I can't find anything at all that threads into the hole. Its metal, whatever the hole goes into (bumper support?) but I decided that multiple bolts through the towhook would be better. If I was better with photoshop or autocad, I could draw it up, but from the BTmounts, the bar points down and towards center. I only want to come out in front of the bumper maybe 2 inches, and I'm thinking, if I can find something that will thread into where the front license plate bracket would go, I'll run legs to the front bar for extra support.
WonkoTheSane
WonkoTheSane GRM+ Memberand HalfDork
3/9/16 2:44 p.m.
revrico wrote: I thought I said up top, I'm mounting where the front babyteeth were. there's some cardboard mockups over in my build thread. For secure mounts, I think the babyteeth holes are the best spot. Especially is I red locktite the bolts in.

Whoops, must have missed it, sorry.. If you need, I have my miata up on the lift, I can figure out the threadpitch for you so you can use some auto parts/lowesdepot bolts.

revrico
revrico GRM+ Memberand New Reader
3/9/16 2:48 p.m.
WonkoTheSane wrote:
revrico wrote: I thought I said up top, I'm mounting where the front babyteeth were. there's some cardboard mockups over in my build thread. For secure mounts, I think the babyteeth holes are the best spot. Especially is I red locktite the bolts in.
Whoops, must have missed it, sorry.. If you need, I have my miata up on the lift, I can figure out the threadpitch for you so you can use some auto parts/lowesdepot bolts.

That would be awesome. I've been crawling around under jack stands, but I don't have a pitch gage. Everything I've seen online says 10x1.25 mm but they don't fit

Kylini
Kylini HalfDork
3/9/16 3:20 p.m.

Mmmmm... rally lights on a Miata.

I power mine from the battery bolt at the bottom of the fuse box in the engine bay. Yes, this powers the whole car. Yes, I have an inline fuse. Works fine for both my LED light bar and for my overwatt Hella headlights (both of which are run off of switched relays).

There's a rubber grommet in the firewall near the brake master cylinder which'll let you pass wire for a switch right to your dashboard. I used an unused spot to place a rocker switch on the far left (it's where the fog light switch would go on optioned cars).

WonkoTheSane
WonkoTheSane GRM+ Memberand HalfDork
3/9/16 4:28 p.m.

Everything you read online is right.. I still have the baby teeth in mine, so I pulled out one of the bolts to check and it is indeed M10x1.25.

revrico
revrico GRM+ Memberand New Reader
3/9/16 4:59 p.m.
WonkoTheSane wrote: Everything you read online is right.. I still have the baby teeth in mine, so I pulled out one of the bolts to check and it is indeed M10x1.25.

I was really hoping you were going to tell me something different. I can't even get the 10x1.25 to fit in the hole, let alone thread in. This project just got really interesting, almost time to just call in the welder. I'll see what the dealer gives me tomorrow, and I'll test fit in the parking lot.

WonkoTheSane
WonkoTheSane GRM+ Memberand HalfDork
3/9/16 5:13 p.m.

Hmm. I'm guessing all 6 are the same, too. This was on a 91, perhaps it changed later in the run? Looks like yours is a 95ish..

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