Location for relays for fan fuel pump etc...

[David Lee]

Originally Posted by Mark Yacavone

Yes, all nice and neat looking, but DC power diminishes with wire length.
Also, as stated , the w/p and fan both use a bunch of amps.
Best to keep the the wire large and the run short on those items, in my opinion.

Mark, I value your opinion. I was also thinking of making a small board and mounting it to the upper flat section of the driver's firewall

[Eman]

Here's a link to some good info and a wire sizing chart http://www.yellowbullet.com/forum/showthread.php?t=431340&highlight=wiring+skills Do yourself a big favor and buy a lot of different color wire and also make a wiring diagram. At home it's no big deal to trace circuits, at the track it's frustrating.

[Hacksaw]

Putting all those relays together in the glove box or on a piece of aluminium in the driver's compartment sure looks nice and tidy. Guess what happens if your fuel pump self destructs and dead shorts. I'll tell you, your heavy feed wire to the pump will fry all the way back to your fancy relay panel melting every other wire it's close to. How would I know that?

[FireSale]

All my circuits are fused no matter what amperage they run. I have a breaker in the main power distribution block, too. It shut my car off when I floored it once. Something big shorted out. Nothing burned. Same for the fuel pump. Shorts pop fuses.

[HandOverFist]

Same here...everything fused and fused correctly. Funny, why would anyone take advice from someone who admitted to burning his junk down?

[Eman]

Originally Posted by Hacksaw

Putting all those relays together in the glove box or on a piece of aluminium in the driver's compartment sure looks nice and tidy. Guess what happens if your fuel pump self destructs and dead shorts. I'll tell you, your heavy feed wire to the pump will fry all the way back to your fancy relay panel melting every other wire it's close to. How would I know that?

That's why everything gets fuses or a circuit breaker for protection. I've seen the burned wire to the fuel pump on cars before, no fuses and some had no relay. I don't class race and my battery is in the back. My fuel pump and it's relay are in the back also and both circuits to the relay are protected. Also my fuel pump ground goes directly to the battery, not a sheet metal screw into the floor pan.Nothing increases current draw like a bad ground.

[Hacksaw]

Originally Posted by HandOverFist

Same here...everything fused and fused correctly. Funny, why would anyone take advice from someone who admitted to burning his junk down?

My stuff was all fused through an ARC panel. Maybe the pump did not dead short, but the feed wire melted back to the relay and the pump was toast. Never burned it down. Funny, how my junk managed to set the NHRA SS record 3 times.

[FireSale]

I had an ARC relay set before I rebuilt my panel. One of the relays went bad right away and all of the wires seemed too small a gauge for the amps required by race electronics. A relay is just a low voltage switch in a high current draw line. The wire in from power and out to the device still needs to match the needs of the load. I can see a bad fuel pump burning out 18-22 gauge wire on an ARC relay. My Pico relays came with 14G pigtails.

[Eman]

Originally Posted by Hacksaw

My stuff was all fused through an ARC panel. Maybe the pump did not dead short, but the feed wire melted back to the relay and the pump was toast. Never burned it down. Funny, how my junk managed to set the NHRA SS record 3 times.

The ARC panel fuses the trigger for the relay. The main feed to the relay that powers the pump should have a circuit breaker or fuse properly sized for the wire and the load it's feeding. If the fuse is rated higher than the wire the wire burns. That's the reason I posted the wire gauge chart, size and length of the wire is important.
I have a friend with an ARC panel and it was the same deal but he didn't have a relay and still burned the wire, basically his wire became the fusible link.

[HandOverFist]

Originally Posted by Eman

The ARC panel fuses the trigger for the relay. The main feed to the relay that powers the pump should have a circuit breaker or fuse properly sized for the wire and the load it's feeding. If the fuse is rated higher than the wire the wire burns. That's the reason I posted the wire gauge chart, size and length of the wire is important.
I have a friend with an ARC panel and it was the same deal but he didn't have a relay and still burned the wire, basically his wire became the fusible link.

But...he obviously knows what to do. After all, he set a SS record three times.