Hey folks. I've been trying to find the best ground point for my new amp in the trunk, but every bolt or screw thread is powder coated. Where did you all ground your amps? I tried using the brass bracket for the stock premium amp, but I got a lot of alternator whine. Thanks for the help.

 

i drilled a new hole in the center part of the chassis (the lower crossmember), an used a large diameter screw to screw it through. works just fine....no whine whatsoever. you can also run a ground cable back to a battery. it is probably the most correct way.

 

FYI running a cable back to battery from an amp is the worst thing you could ever do. Short whip to a close by chassis point is the ideal.

 

A ground wire should be no longer tahn 4 inches. And its best to drill a new hole, and sad the paint off the surface around the hole then put the screw in so it has good contact.

 

It's what works for YOUR particular installation. Short grounds can create noise (in some cases) and long grounds can create ground loops (which cause noise). In the G, which is a "unibody" type without a ladder frame, you should be able to ground just about anywhere you can get enough metal to hold your ground lug.

 

False. Short grounds 95% of the time do not cause noise. They are what standard for a high end install.

The best ground is how I said above. Do not just attach it to a bolt on the trunk and expect it to be a good ground. Most of the time it isn't.

 

Shortest possible..fresh hole, sanded/grinded down and preferrably a nut/bolt rather than just a screw.

Using seatbelt bolts and such typically have alot of locktite or some sort of threadlocking liquid on them yielding a poor ground.

 

4 inches?

c'mon, is that very realistic?

i try to keep my grounds under 24 inches.

vinh

 

Vihn he is right. The shorter the better. You dont want the ground wire to be long. 4 inches seems just about right.

 

Why is running a cable back to the battery the worst thing you can do? Just curious.

 

Originally Posted by Texasscout
It's what works for YOUR particular installation. Short grounds can create noise (in some cases) and long grounds can create ground loops (which cause noise). In the G, which is a "uni-body" type without a ladder frame, you should be able to ground just about anywhere you can get enough metal to hold your ground lug.

I must disagree with YOU on this. It's what works for YOUR particular installation. As an Amateur Radio Operator, I'm coming from a Radio Frequency point of view. ANY poor or long or short ground can create noise or ground loops. I know how to ground a car. I have 1/2" ground strap with soldered lugs on my doors, hood, hatch, frame, exhaust, battery, engine, and anything else that could cause a problem. I have ferrite split beads on all the Radio frequency noise sources, ignition wires, computer, alternator, fuel pump, etc.

In the end it's what works for your install. You are correct, the shorter the leads the better, but sometimes, you need to run a ground directly to the battery to make the noise go away and sometimes you can ground right at the unit.

 

Being a Radio Operator and understanding Electronics is completely different. I have installed a few high end stereo systems with over 2000 watts. Trust me when I say in car stereos 99% OF THE TIME its best to use the shortest ground cable possible. And always make sure the ground cable is equal or greater in size than the power cable. This prevents any engine noise or a bad ground.

The the user above, the longer the cable, the more chances of engine noise.

 

Why? If you are running a 0 guage power cable to the amp, and then a 0 guage ground wire back to the battery, aren't you creating LESS chance of interference from other components that are grounded to the chasis?

 

You are, but you will never get some people to believe it. The chassis of the car is a return path of almost all components of the car itself. The computer(s), air conditioning, wipers, widows, etc. all use the chassis to return to the battery. All this has pulse transients running everywhere. Most amps have very little (if any) RF (radio frequency) filtering in the power input. The have even less on the out put (the power supply uses a high frequency (about 50 MHz or the 6 meter ham band) to up the voltage.) When you run the ground through the chassis you take a CHANCE that you will pick up noise from the vehicle electronics (the noise that the electronics put out is at Radio Frequencies).

And, yes, I do understand electronics (I hold an EXTRA class FCC licence, the highest)

 

Thought I was going crazy. Check out the12volt.com. There is a whole thread on grounds.