Sooo, i figure i need spark, starter stuff, brake lights, a fuel pump, and a few gauges. how much does a stock wiring harness weigh -- how much could it weigh?

n

I have a complete wire harness out in the shed. I'll try to weigh it tomorrow. Its not heavy. I would guess about 3 or 4 lbs. I don't think it would be worth the effort to remove it. But then if you rewired the car for only the things you need, it could be more reliable as well?

I dont think you would get too much from cutting down the wire harness. When are you going to start cutting out unnecessary sheet metal? Do you have fiberglass hoods yet?

I have to talk to you about how you gutted your 75 model doors - I'm ready to go to phase 2 in turning the car into a more dedicated race car. I started to look at the doors and they are crazy heavy. I had my grinder all ready to go but figured I would talk to you first.

Andy and I weighed his and a 9146 harness... but I dont recall the number..LOL

We did pull 22lbs out of a 993. This included all the little "brains" that run the car. We left a couple of extra circuits for growth.

I think the late dooe braces when cut out are something like 15lbs. Cut and weighed one of those also.


B

yeah, there's a lot left to the car that can go... i need glass lids, no doubt. i'm just dreading paint work... $$ maybe white gelcoat wouldn't look that bad...?

the main harness isn't all that much, 4 or maybe 5 pounds total ...
Andy

thx guys. n

I have before and after numbers at the shop from cutting down Randal's harness. I think it's heavier than you guys are quoting. 12 lbs stock comes to mind.

what year is his car?

there's really not much to an early harness, if you exclude things like the FI computer etc. ...
Andy

There's a lot of wiring in the front trunk that doesn't need to be there in a race only car. Pulling all that wire and all of the corresponding electrical bits will save a fair amount of weight, including things like headlight motors, wiper motor, blower motor, headlights, etc. There would be one 20g wire for the fuel level gauge, and even that's optional.

The fusebox area can be reduced to almost nothing, and there's a LOT of wire there.

For a car with no lights, the center tunnel wires can all be reduced to 18g or less. I'd run four 18g wires (+12, switched +12, starter, brake lights), and the rest would all be 22g (alt light, oil pressure, oil temp, tach). There'd be one fuse (7-10A) for the gauges off the ignition switch and the alt light. I'd run one more fuse+relay for the fuel pump off switched +12.

I'd get rid of the relay board, and keep only the regulator, running the alt light wire directly off the back of the alternator.

Wild guess, if you pulled off EVERYTHING electrical that's not required for the car to run, you'd save about 25-30lbs. Use a PC680 battery, and that's another 20lbs.

I'd side with James on this one.
I'd say its 20+ lbs savings on our car. (started as a 1972)

we pulled every single wire out and remade an entire harness just for our essentials.

there are charts out there that tell you what guage you need for different draw at different lengths. We used the charts to accurately get the right guage. We replaced everything including all grounds and battery cables. We used Spruce supply to buy all of the wire. Its aircraft wire which is specially rated with thinner insulation (for flight)

we made up our new fuse board and only the guages and lights we actually needed.

for example. the brake lights are the only remaining lights in the entire car. They are powered by a single wire which runs from one light to the next. And the grounds for those brake lights runs to the chassis and not through a loom (6inches of ground max)

its a ton of work.
but I'd guess a net of at least 20lbs without taking into account the battery.

much of my wiring is pictured in my vintage thread.

brant

I plan on running a shift light and one tailight in my next car along with ignition and fuel pump (maybe a starter button)

No need for gauges. I cant do a damn thing about it when the oil light comes on.. it has ALWAYS been too late.. so no need for oil pressure/oil temp/or tach. By now I know what the oil temp is going to run depending on cooler size and line size.

It will be a 4cyl car. 69x96 RPM 1997cc screamer. Case/crank and rods are all out being done right now. Nickies are ordered. Shooting for 1600lbs.


B

I think 1600lbs are very achievable.
I would recommend a volt meter though

we added it as and after thought upon recommendation of AJ
its very helpful as a diagnostic and tells you things (like your regulator accidently came unplugged).

This happened to us once and we were able to solve the problem between runs and avoid a dead battery mid race.

Also, for a -6 (not your car brad) I really believe in the alternator light.
We used a shift light with huge bright output to be our warning light for the alternator. That is one thing you could shut down in time to save a motor.

I am fully convinced that 1700lbs is achievable with an all metal car
(no fiberglass lids)
I would very much like to build another -4 vintage car at that weight
and our metal -6 came in at 1850 wet, so I'm convinced that I could save 150 in the 2nd oil cooler, aluminum block, and oil tank..

heck we have 19qts of oil now, so I'm certain that a 1700lb metal car could be done. Meaning that a 1600lb glass car would not be much more work at that point.


brake wires:

brant

oh brad...
you should consider the secret alternator trick that AJ is using on all of his racers now.

brant

Anyone know how much is saved by eliminating the headlights, motors and doors and replacing with a fiberglass cover?

fiberglass...
whats that?

I recommend aluminum

brant

Personally, I have found that 300hp helps me forget about the 2lbs of material I have in the RS for keeping track of the oil vitals.

Try loosing some weight yourself (not aimed at anyone). It's easier.

Here you go. The scale registers in .5lb increments.

Since it still says zero, I've decided that this is a piece of diagnostic equipment I'm not going to loose in the name of weight savings.

Joe,

I could certainly afford to loose some weight myself..
but its kinda hard to get 300hp out of a 2.0 when the rules require an honest 1991cc and you decide not to cheat.

plus when the rules require only metal body panels, then a pound here and a pound there start to look appealing since your not allowed to buy CF.

auntie
brant

Nevertheless, I will never sacrifice the 1.5 pounds of oil trend-monitoring device on the dash.

It can tell you something is wrong long before an engine is consumed by the problem.

Its at least 15 lbs. Those things are boat anchors - the motors are real heavy and the assemblies are heavy as well. Then you have lights, covers, wiring, etc.

Metal isnt bad, you just need to get the course grade stuff on your sander spend a year sanding away the weight.

ha... thats true Grant.
I already did that where I could.
my "stock" roof for example is paper thin now, flexes with your pinkie, and weighs in somewhere under 10lbs now...

brant

Randal's car (which IIRC is a 75 chassis) had a 14 lbs wiring harness before I ripped into it and it weighed 3.5 lbs when I was done.

Ha, I think the same thing. But then, realistically, I can remove the unnecessary wires from a wiring harness and eat a large supreme pizza in an hour... loosing 12lbs probably take me a month if I was even remotely serious

No pizza, no speedo, no pizza, no speedo - hand me a slice while I throw this speedo on the used parts pile...

It is funny, but I do that - think "if I remove that and that and that from the car, that is like 20lbs. but then I could remove 40 from my frame, but the plasma cutter burns a bit. If you could only cut away 15lbs with some cheap tools...

I will try to remember to weigh what is left of my factory harness from the 72 ( I already removed a lot of wires, but added some in for other new items...) as I have to make a custom one for the tube car now... I think some of you guys will be surprised what a wiring harness weighs - more along the lines of McMarks values if you include the relay panel (which I do since I removed it).