Car relay box question

[240Matt]

Hi everyone,
so I'm making relay box for a completely stripped car. it's a track car so nothing fancy is needed. The relay box is going to draw roughly 150 amps when all 8 relays are closed. I've got 2 questions.
1) should I run one large gauge power wire into the relay box and then split it off into the proper gauge wires for each circuit (how would I split 1 large gauge wire into 8 smaller gauge wires)
2) the parking lights are also the turn signals so they're dual filament, autozone says it uses 26.88 watts. Is this with one or both filaments lit?

(http://www.autozone.com/electrical-.../sylvania-brake-light-mini-bulb/575126_0_1556)

 

[Bluejets]

You left out an important aspect.
How long is each run.
In any low voltage circuit (I'm assuming 12V dc) high current creates rather large voltage drops depending on cable sizes.

As far as stop/tail bulbs they are usually 21w (stop) and 5w (tail)

Just out of curiousity what are you driving at 150Amp?
That's going to require one decent battery and alternator to keep up with the demand.

 

[240Matt]

yeah I calculated it wrong haha. 8 foot long runs, im going to be running the headlights, horn, tail lights, brake lights reverse lights, and turn signals. Looks to be around 400 watts. 400watts/13.5volts = 30 amps.