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Posted (edited)

I have a 69 02 down to the frame and being restored. Putting in a modified M10 engine with 318i head, and 1978 block and 38 DGES carb. Goal approx 150hp. Trying to address electrical issues/upgrades while I have a clean slate. I plan on getting a new wiring harness from Rhode Island Wiring Service

 

I would like to convert to modern fuses

 

Additions:

1. electric fan

2. A/C

3. stereo

4. fog lights

 

Upgrades:

1. 80 amp alternator

2. hi torque starter

 

I'm not doing this myself, plan on having most of it done, but not sure what else I should be considering or asking about. If you could start from scratch with your car, what would you consider for the electrical system?

 

Thanks,

Dennis

 

Edited by Pdxguy
added carb info
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Posted (edited)

On your year 02 I would add relays for both hi and low beam headlights and a circut for a electric fuel pump to be added if needed due to the non stablised fuel boiling in the float bowl starting problem. Add blade type fuses, for a 2002 you'll probably have few enough fuses to use the larger ATC size rather than the mini's, the larger size in easier to use in the dark on the side of the road, most of the mini you need a pair of needle nose pliers to pull.

Edited by Son of Marty
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Posted (edited)

Not a bad idea to route a few extra (for later) wires front to back with adequate length (neatly stowed of course)

I ran a pair of 10 gage, a 12 and a 14 gage I think. 

Also nows a good time to relocate your battery if you are into that sort of thing.

You are going to need some serious pistons and camshaft to get even close to 150HP

Edited by tech71
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And since you're starting with a pretty clean electrical system slate, branch your circuits more than the original (6 fuse) setup so that fewer items are on a single fused circuit. 

 

If you're having the harness made from scratch, it would be useful both for you and for a future owner to follow BMW's wiring nomenclature:  solid color wires are for non-switched circuits (i.e. those that are hot all the time, such as the lights, emergency flasher etc) and striped wires for switched circuits--those that are live only when the ignition is on.  And solid brown only for grounds.  

 

Finally, if you're going whole hog, there are better places for a fuse box than under the hood...

 

mike

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"Finally, if you're going whole hog, there are better places for a fuse box than under the hood..."

Please elaborate. Likely a simple explanation, but was just starting a search on putting the fuse box in the trunk. Must be a good reason it isn't done.

 

Thanks

Dennis

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In most cars the battery and motor are in front making wire runs shorter so the fuse box is located there or under the dash, if you relocate the battery to the trunk or under the rear seat some things will move closer but there's not much you can do about the engine.

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On 5/1/2021 at 2:49 PM, tech71 said:

Not a bad idea to route a few extra (for later) wires front to back with adequate length (neatly stowed of course)

I ran a pair of 10 gage, a 12 and a 14 gage I think. 

Also nows a good time to relocate your battery if you are into that sort of thing.

You are going to need some serious pistons and camshaft to get even close to 150HP

I plan on moving the battery to the trunk. What are you thinking of for the 2 ten gage, 12 gage and 14 gage wires to the rear?

 

Thanks,

Dennis

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On 5/1/2021 at 8:08 PM, Mike Self said:

And since you're starting with a pretty clean electrical system slate, branch your circuits more than the original (6 fuse) setup so that fewer items are on a single fused circuit. 

Planning on using the later 12 fuse set ups as a template. Any areas that needed tweaking on the 12 fuse boxes in terms of schematics?

On 5/1/2021 at 8:08 PM, Mike Self said:

If you're having the harness made from scratch, it would be useful both for you and for a future owner to follow BMW's wiring nomenclature:  solid color wires are for non-switched circuits (i.e. those that are hot all the time, such as the lights, emergency flasher etc) and striped wires for switched circuits--those that are live only when the ignition is on.  And solid brown only for grounds.  

Will do, I like organization

On 5/1/2021 at 8:08 PM, Mike Self said:

Finally, if you're going whole hog, there are better places for a fuse box than under the hood...

Thinking of using a mix of some in cabin, some in engine bay. Haven't got that far yet

 

Thanks all,

Dennis

 

On 5/1/2021 at 8:08 PM, Mike Self said:

 

 

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So I'll chime in with what I've done.

 

First, don't put the battery in the trunk.  What exactly are you trying to solve for?  Space?  The easy solution is a Lithium battery, weighs 7 lbs, super small, and you won't have to worry about voltage drop with too small wires.

 

Second, think about the fuse box you want and where you want to put it.  Mine is going under the dash somewhere, but in hindsight, I should have put it by the glove box (or in it)

 

I went this route:  https://www.tacomaworld.com/threads/diy-build-and-install-a-bussmann-rtmr-fuse-relay-block.399454/

 

Third, I highly recommend using relays to stop running high current through the ignition and light switches.  Not sure about your 69, but my 76 had two ignition circuits (green wire + purple wire) coming off the ignition switch, I made those trigger a relay, then had all the circuits run through the relay.

So inside, I have 4 relays:  2 for ignition circuits, one for fuel pump, one for horn.

For the lights, I have a two relays hidden behind the headlight to run them plus a 3rd relay for an electric cooling fan.  These are close to the battery, so the headlights get full power.

 

For wiring, I have 4 AWG to the starter + engine ground + body ground

8 AWG to the alternator + running inside to a separate 4 fuse distribution block that feeds the main fuse block (12 AWG)

I bought 11 color packs of 12/14/18 AWG TXL wire from WireBarn:  Wire Barn Color Pack 12AWG

 

You'll need to make yourself a wiring diagram, figure out where to use each color and size.

 

I pulled the original engine bay harness into the interior, ran all new wires into the engine bay, then spliced things in to the fuse box I made.

 

Pics:

20190815_201210.jpg

20190902_120116.jpg

 

20190902_120153.jpg

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2 hours ago, Pdxguy said:

I plan on moving the battery to the trunk. What are you thinking of for the 2 ten gage, 12 gage and 14 gage wires to the rear?

 

Thanks,

Dennis

My battery has been relocated to the trunk.

1 ten gage for possible future EFI upgrade ( dedicated power to ECU from forward mounted relay)

 The other ten gage  or 12 gage could be power for electric fuel pump delivered from forward mounted relay 

The 14? I dunno, its there should I ever need it.

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2 hours ago, tech71 said:

My battery has been relocated to the trunk.

1 ten gage for possible future EFI upgrade ( dedicated power to ECU from forward mounted relay)

 The other ten gage  or 12 gage could be power for electric fuel pump delivered from forward mounted relay 

The 14? I dunno, its there should I ever need it.

Bit of a luddite here. I figured you meant red (hot) lines to the trunk. If you mean a line coming from the fuse box area, is it wired into anything in the fuse box, or unconnected wire in place waiting for future use. 

Thanks for patience

Dennis

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Posted (edited)

I can't believe that 9 posts didn't prompt a post recommending LED signals, brakes and running lights.  Poor illumination has caused many rear enders.

 

The very best taillight solution is 

classicautoleds.com 

 

Pricey but AWESOME.

 

Front corners, look at Sirius leds.  Double the output of all competitors.  KG Series.

Edited by PaulTWinterton
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My friend and I have undertaken the task of using a 22 Circuit Universal GM harness from Speedway to redo the wiring in my project. 

We've taken the parts of the OEM harness that are largely self contained - the wiper/washer harness for instance out of the original loom and wired it into the fused power from the Universal kit.

 

The challenge associated with the rest is making the germans and americans work together - the intent being the OEM switches working as intended etc. The headlights have been wired similarly to what has been mentioned above - although it was a PITA to get the highs to work with the main switch off. The box has fuses for almost every system you can think of and some you may not need can be repurposed - we used cruise control for the headlights to have a fused line.

 

The fuse box is located under the dash next to the hood release, mounted on stainless screws sent in from behind the drivers fender and held in place with some acorn nuts. A small bracket I've yet to fabricate will hold the relays needed: high/low beams, AC Fan, AC Compressor, etc.

 

We're learning as we go, taking it step by step—all this to say it's certainly extremely possible to have a more modern system in an 02 with dedicated fuses for each system.

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1 hour ago, Pdxguy said:

unconnected wire in place waiting for future use. 

This one, they are not currently connected to anything just routed along driver side of interior along with the battery cable. Very easy to include them when I routed the batt cable.

Even if I never utilize them they are there and ready for whatever.

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