Amp Channel/Watt question

[stuntjunkie199]

I have a 760w max Pioneer amp. It's a 2 channel, bridgeable amp. Bridged at 4 ohms, it's rated at 380rms. I currently have it bridged running to a 1x12. My problem is that when I crank up the volume or a bass heavy song comes on my lights dim, even my dash lights. So obviously I'm pulling too much juice.

My question is since my amp is 2-channel, instead of bridging it, can I run my sub off of one channel which would be 125w rms? Wouldn't this draw less power? Also would this harm the amp since I am using one channel and not the other?

Also, I just ran 8 gauge power and ground wires made sure the amp had a solid ground.


Thanks

[conozo]

I'm assuming that your lights are dimming when the bass hits and not just during the entire time you have it cranked up.

I wouldn't recommend running the amp with one channel unless it supports it, you have to look at the user manual to see what channels and modes it supports.

-1st make sure the ground connection is good and on bare metal.
-2nd you can get a 1 Farad capacitor to help give the amp the power when it needs it and it will also be better for your alternator.

[stuntjunkie199]

Yes you are correct, only when the bass hits. Which ground do you mean, the amp ground or battery/chassis ground?

[conozo]

I meant the amp ground, but you might as well check the battery connections for corrosion while you are at it.

[stuntjunkie199]

Ok I will do that. Also, if you happen to know, where is the engine ground located on these cars? I was just gonna go over all the ground connections before moving on.

[Strangeduck]

One thing about these cars is the charge wire from the alt is like 8ga or 10ga. It's pathetic. I would look up what the "big three" is.

You don't need 1/0 wire, but running an addition 4ga wire from your alt to your battery and run a new 4ga fro the alt bracket to the strut tower and ground to the strut tower in back to the amp with 4ga.

You can also upgrade you battery to chassis ground with 4ga too. Make sure of course your grounds are bare metal and you good terminals on your wire. If you can't solder or crimp you can by new wire with ends already on them or check out C&e auto supply.

CE Auto Electric Supply - Big 3 Upgrade Kits / Big Three Upgrade Kits / Big 3 Wire Kits

They make custom kits have good prices and will hook you up.


edit:

The strut tower isn't the best place to ground to, but on these unibodies there arent a lot of choices.

[stuntjunkie199]

Alright sounds good. Where can I buy like 10 ft of 4 gauge? I can cut and lug the cable myself

[Strangeduck]

Alright sounds good. Where can I buy like 10 ft of 4 gauge? I can cut and lug the cable myself

I like skyhighcaraudio on ebay. They have good prices and fast shipping and the owners are pretty good guys. Knu concepts has good wire too. Just be ssure to buy OFC (oxegen free copper) and not CCA (copper clad aluminum).

Sky high has everything you need, speaker wire, terminals, heatshrink, power cable, fuse holders, fuses.... Of course KNU has all of that too, but i think their prices are a bit higher. And, i would avoid monster cable brand, there is much better available for the money.

[Strangeduck]

Oh, one other thing, setting your gains properly is also important. Optimally you should use an o-scope or DD-1 to set them. If they are too high you could be clipping and that will make your amp draw a lot more power than it would normally.

[stuntjunkie199]

Ok on my gain knob it's labeled 6.5v to 0.2v. All the way clockwise is 0.2v, 6.5v is counter clockwise. I'm assuming 6.5v is cranked gain? It's just strange that you turn the knob to the left to increase gain.

[Hauntd ca3]

a 380w rms amp will draw max of about 35amps .
and if all things are well and good with your electrics, a 35 amp draw shouldnt make the voltage drop enough to dim lights,, even with the motor running.
if it is, i'd look at the battery size and condition first, then battery terminals, then earths etc before even thinking about bigger cabling or capacitors.
the caps in the amp should be sized well enough that they could handle any sudden demands for a few seconds at least.
even with all the accessories going, the altenator should be able to keep battery voltage high enough to stop any lighting problems

[stuntjunkie199]

What do you mean by "earths"?

Thanks

[Hauntd ca3]

What do you mean by "earths"?

Thanks

grounds are what some people call them.
a nice big engine to body one or two and a nice big battery to body one.
since earth cables tend to be short, you dont need huge ones.
a couple 4 gauge ones will be heaps

[stuntjunkie199]

Ok sounds good I will do that. Do you have any idea where the original engine grounds are? I can only find the battery to engine and valve cover to chassis. I would think there was more. However since my battery ground runs to the engine block can I go ahead and add a body ground from the battery too? Thanks

[Hauntd ca3]

the factory ground connections are usually pretty weedy, and after 20 odd years they batt to body one can get quite corroded .
the one from the battery will be bolted to the chassis rail just below the battery and then continue to the motor/trans.
thats the one that you really need to check over.
the wee body to tappet dosnt do to much really

[stuntjunkie199]

Ok I gave it a good look over and since it was like 10 gauge I just replaced it with 4 gauge. It seems to start better and also minimized the dimming. However the new cable didn't have the spot to ground on the chassis rail so Ill run another ground from the actual terminal.

I have a second question now though. In looking at the power wiring, the battery runs to the distribution block correct? So that must mean the alternator feeds the block from the other side. Would there be any benefit or harm in leaving the existing wire from the alternator to block and then running a direct 4 gauge to the battery in addition too? Have one feeding the block and one feeding the battery directly?

[Vanilla Sky]

Don't bother with a capacitor. They are a band-aid fix for a potentially serious issue. With enough battery capacity, a large enough alternator, and the proper cabling and terminations, you won't have dimming lights.

[Strangeduck]

I don't know what changes were made in 89, but you should ADD a run from the alternator positive terminal to the battery positive. Like i said earlier, look into what the big 3 is.
The alternator positive should just go straight to the battery not the distribution block. At least that's the way it is on mine. I have an 87. If you want you can fuse your positive
run from the alt to battery, but if you route it carefully you shouldn't have to.

[Vanilla Sky]

All of the 3geez I've worked on or taken apart have 2 12V positive lugs on the engine bay fuse block, one for the alternator with a fuse, and one for the battery. The 2 positive leads from the battery should go to the fuse box and to the starter solenoid.

[Hauntd ca3]

I don't know what changes were made in 89, but you should ADD a run from the alternator positive terminal to the battery positive. Like i said earlier, look into what the big 3 is.
The alternator positive should just go straight to the battery not the distribution block. At least that's the way it is on mine. I have an 87. If you want you can fuse your positive
run from the alt to battery, but if you route it carefully you shouldn't have to.

this is dangerous
like this, there is no fused protection and any short in this cable will result in a fire
if you are going to upgrade the cable from the altenator, either run it to the fuse box so it is protected or use a large car stereo type fuse and holder

[Strangeduck]

this is dangerous
like this, there is no fused protection and any short in this cable will result in a fire
if you are going to upgrade the cable from the altenator, either run it to the fuse box so it is protected or use a large car stereo type fuse and holder

I agree, but mine has an unfused run from the alt right to the battery no fuse. Can't tell if that is factory or not, but it looks like oem to me. I'm not condoning not fusing, but i won't be fusing my 1/0 run from my alt to battery run when i install my new alt. Not everyone likes doing this but it's what i'm doing. With some careful routing it's safe, just not something inexperienced people should attempt.

[stuntjunkie199]

So basically I would have no benefit of running a large wire directly from the alternator from the battery over just upgrading the current wire setup alternator to distribution block to battery right?

[Hauntd ca3]

thats pretty much it, unless you are sticking on a bloody great 100amp altenator, factory wiring is fine.
these old girls only have a 60 odd amp altenator.
you may reduce the voltage drop very slightly , but thats it really

[Vanilla Sky]

I think I might measure my voltage drop on my OEM wiring. My car has dimming lights, but I point my finger at a bum battery. When the battery gets replaced in my car, I'm going to have one of my alternators wound for more current. That should solve my voltage drop issues.

Keep in mind that if there's poor engine grounding, the alternator won't put out as much current. Electricity has to have a good return as well as a good feed. Our engines have one main ground and a few secondary reference grounds.

Again, I'll probe some stuff out and see what kind of voltage drop my car is experiencing over the primary wiring.

[stuntjunkie199]

Where is this main ground located?