big 3/ wiring gauge question

[cbrrocketrdr 10+ year member]

Ok just gonna run down the (planned) setup of my car...someone feel free to point out an error or simply say no it wont be enough haha.

4g power wire to 800RMS sub amp split to 150rmsx2 speaker amp

4g for the big 3

2farad cap

ALT is rated 85-90amps

8g speaker wire and grounds for cap and both amps

will i truly be pulling what my amps are rated for or coming up way short?

ill prob put it in anyways but im sure an Optima yellow top will help, correct?

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[kross 10+ year member]

What does this mean:

4g power wire to 800RMS sub amp split to 150rmsx2 speaker amp

Does that mean you will have a run of 4-gauge wire run to the back, where it goes to a 2-way distro block, with 8-gauge outputs, one for the sub amp, and one for the speaker amp?

According to the Wiring Guide sticky, 4 gauge is just barely big enough for those 2 amps. You should really use larger wire for headroom, and to allow for future equipment upgrades. 1/0 into a distro block with two 4-gauge outputs would be great.

8-gauge power and ground wire for the 800wrms sub is too small. I'll bet the manual for the amp says to use 4 gauge. 8-gauge for the 150x2 is fine.

For Big3, I think that's usually done with 1/0, not 4 gauge. I could be wrong.

A cap is not necessary.

8 gauge speaker wire is too big. 14-16 gauge for speakers, and 12 for subs is perfect.

 

[05AztecRed 10+ year member]

For Big3, I think that's usually done with 1/0, not 4 gauge. I could be wrong.

Big 3 is done with whatever size wire is available, as long as it is larger than the stock wiring, usually driven by the size of the owner's wallet.

 

[2002XLT 5,000+ posts]

use the biggest wire you can afford. Ive got 1/0 for my big 3 and 2 guage for one amp.

 

[cbrrocketrdr 10+ year member]

to clear up...i have 4 gage running from battery to back split to both amps..meaning i have 4g power wire to each...not 8...but i will put 4g grounds as well

 

[phyphoestilic 5,000+ posts]

Ok just gonna run down the (planned) setup of my car...someone feel free to point out an error or simply say no it wont be enough haha.
4g power wire to 800RMS sub amp split to 150rmsx2 speaker amp

4g for the big 3

2farad cap

ALT is rated 85-90amps

8g speaker wire and grounds for cap and both amps

will i truly be pulling what my amps are rated for or coming up way short?

ill prob put it in anyways but im sure an Optima yellow top will help, correct?

Never use a smaller ground than the power wire. If u have to use 8AWG for the power and 4AWG for the ground.

 

[cbrrocketrdr 10+ year member]

what problem(s) do i run into? when i had this amp and sub combo in my last vehicle....(no speaker amp) i had the 4g power and 8g ground...nothing happened...or is it i just dont get the power im suppose to?

 

[wesl56 10+ year member]

Never use a smaller ground than the power wire. If u have to use 8AWG for the power and 4AWG for the ground.

why not? since the ground wire is usually shorter, it is fine to use a smaller gauge....you just need a bigger power wire because it has a longer distance to go

 

[05AztecRed 10+ year member]

why not? since the ground wire is usually shorter, it is fine to use a smaller gauge....you just need a bigger power wire because it has a longer distance to go

Incorrect. See below. ground size always matches power size, if all the grounds from all the amps are routed to a distrobution block, then have one common ground wire.

you just need a bigger power wire because it has a longer distance to go

Um... No... power wire size is determined by the amount of load it sees. You only upsize the wire size based on distance if it is an abnormally large length, to account for voltage drop.

 

[cbrrocketrdr 10+ year member]

thx ppl for clearing that up...so my current setup so long as i change the idea of using 4g grounds...i should be fine?

 

[jbl_marshall21 10+ year member]

i'd recommend uping it to 2 gauge power wire, but if 4 gauge is all u can afford then stay with it. Also if your power wires runs into a distro block and then 8 gauge to the amps then do the same with your grounds only backwards. 8 gauge to the distro and then one 4 gauge to the body of the vehicle.

 

[cbrrocketrdr 10+ year member]

i knnow this is old...but on that last comment....i read somewhere that you can't share the ground for an amp and a capacitor...i figured this applied for amps sharing one....can i share one ground with both of my amps? also my friend gave me an RF distro block looks to be 1/0 into 2 4g with 100amp tube fuses...should i run 1/0 from battery to back to this block through each 100amp fuse to 4g that goes to each amp or can i just run a small section of 1/0 and run 2 LONG runs of 4g the rest of the way to the back of the car to each amp? if it sounds confusing i can make a quick diagram of what I'm trying to explain