So, after 6 years, im finally getting around to putting a radio in my car.

I know most of you read this and thought I was insane but, to put it out there, theres no sub in the car. What ive got it a pair of kenwood components in the doors, and a small 50x2 amplifier to push them. I dont think my headunit would be strong enough to properly get the job done by itself.

I have a single 8 gauge wire running back to my fuel pump from when I did the rewire. I knew it was overkill at the time, but I had alot of it laying around. So now im wondering if that wire sould handle the increased capacity of the small amp.

Also, I re-wired the pump about 3 years ago, how about the condition the wire is in? Should I re-run a new wire, or should the original be ok? The car has sat in a garage most of its life, and has seen maybe 1000 miles since ive owned it.

Any thoughts would be appreciated.

 

I would run a new wire and fues it at the bat. you dont want the chance of a voltage drop on your fuel pump.

 

Its 8 gauge, to the fuel pump, lol.

Its already fused btw.

Thanks for the opinion too.

I guess im just trying to save myself more work, but I have to pull all that **** (carpet and panels) up anyway to run the speaker wires

 

the FC has a very weak electrical system. your risking taking power away from the fuel pump. we all know what happens then...

 

I'd probably run another wire...especially if that amp is underrated at all. Maybe even replace the 8 gauge wire with something heavier to the back, then put in a distro block that splits to (2) 8 gauge wires...and run 1 8 gauge for the pump and one for the amp.

 

Im running a -RE alternator (AKA luxury car), I dont have a problem with the electrical system, also running an upgraded fuel pump and a fuel pressure gauge.

The amp is probably over-rated. Only 50x2, cheapest of the cheap, I paid $30 for it.

 

that sounds like a very weak amp....not an offense, but just saying that an amp like that can take 12 gauge wire easily. I don't think it would have any effect on the fuel pump although personally, I wouldn't wire it with such a crucial part of your car. Wire it separately, don't compensate reliability with simplicity.

 

Thats why I thought such a large wire would handle both no problem. (small amp)

 

The fuel pump is stock wired with a 16 gauge wire I believe so although you upgraded your fuel pump, 8 ga is quite overkill.

 

lol right.

So the load of the small amp shouldnt be a problem right?

 

Well a lot of other factors can come into play, like resistance, noise, and voltage drop. All in all, the load of the amp shouldn't be a problem.

 

A 2x50Wrms amp will only draw ~8A, but use the onboard fuse as a wire sizing guide (probably 15A). Even with the fuel pump, your 8GA wire is still overkill.

 

Im sorry this confused me a bit. Could you explain it another way?

I think they inline fuse is 40A or so?

 

Most amps have a fuse mounted on them, and the size of fuse provided by the factory is a good guide for sizing the cable because you know it'll never exceed that.

 

I don't agree at all about splicing onto the same wire as the fuel pump.

You can try it. I would then take an analog volt meter (the one with the needle) and connect it to the fuel pump while the amp is operating at its highest level. Then see if the needle bounces while the bass hits. If it does. Run a new wire. If not. Your ok.

 

Voltage drop will not be an issue with such a small amp. The major issue will probably be noise on the line created by the fuel pump.

 

Ah, ill have to check out the amp and report back.


I kinda thought about that too. I wonder if theres some sort of filter or noise isolator I could use though.

Are you saying there would be noise in the power line, or the signal line? I can run the signal line on the other side of the car no problem.

 

i wouldnt do it cause what if something happens and your main 8g wire fuse at the battery blows the there goes the fuel pump if its on the same circut...not a good idea and its not worth any chance of something not working out...just run a new wire its not hard

 

Its a 25 amp fuse on the amplifier.

Also, my question wasnt about if I should run two wires, but if the one I have is large enough for both.

 

When you start to spend money on filters and stuff, you might as well run a new + and ground wire to your amp.

 

I got it all wired up, theres no noise issue at all thankfully. Fuel pressure looks to be unchanged.