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Discussion in 'Mustang Sound & Shine All' started by Krusher, Dec 11, 2003.
hey... where's a good place to run the ground wire in the trunk for amps?
Take out the rear seats and run the ground to one of the bolts that holds the middle seat belts in.
I hear that the lenght of your ground should not be really long,, like over 3 feet.. is this true..
yes, 2 ft is typically max... 1 ft is ideal... I got 2 ft... should be fine... but I am having engine noise so I'm gonna have to try and rig some sort of noise suppressor...
A ground connection should be "electrically" short. This may not necessarily mean the cable itself is physically short! Let's not confuse the two. The system in my 'stang has three thousand watts of continuous power. I use 1/0 cables for both the main power and ground connections because of its' low resistance per foot. There is not a suitable place on the sheet metal of any car that you can pass this much current, so the grounds are tied directly to the frame rails on the drivers' side of the vehicle, same side as the battery. The subframe connectors on my car do double duty -- strengthen the chassis AND shorten the return path. The ground cable from the frame to the amps is about 6 foot long, but since it has SO little resistance it is electrically VERY short.
If you're installing an ordinary power amp in the trunk of your 'stang, then do your best to find a nice flat piece of metal that doesn't have 6 spot welds between it and the body. Scrape off the paint and VERY securely fasten your ground connection to this area with a silver or gold screw -- do not use black or black oxide screws. [It goes without saying to check under your car before drilling holes in it!] After tightening your connection, attempt to wiggle it -- it should be wiggle free.
There is no reason to use silver or gold plated screws. You should preferably use a bolt or screw with a nut on the other side of the chassis panel to get a good connection. The reason for the bolt is to keep the wire terminal tightly against the chassis; the bolt should not have to carry any current. You can buy special grounding terminals at car audio stores, which work very nicely for making a ground connection.
Also with a high power amp, you should upgrade the ground wire between the engine block and chassis. When the engine is running all of the electrical power comes from the alternator, which is grounded through its housing to the engine block. Since the engine is mounted with rubber mounts, the only good ground connection to the chassis of the car is through the factory wire between the two. But this is usually not big enough for a high power stereo system and can cause problems and add unnecessary electrical resistance.
I did not use the word plated, was just trying to caution against using black or black oxide screws that have high surface resistance. 302stang's advice on upgrading the return path from the alternator is solid. I prefer all ground upgrades use the frame as a connection point, and not the chassis.
Nice Info Guys
The resistance of the bolt doesn't matter because like I said before, the screw shouldn't carry any current. The screw or bolt is only to hold the terminal against the cleaned metal surface of the chassis. All the current should flow between the terminal and the chassis and the bolt shouldn't have to carry any.
You said to ground to the frame and not the chassis; what does that mean? A chassis and a frame are the same thing. Since a Mustang is a uni-body there is no separate frame, the whole body of the car is the chassis/frame. As long as you ground to any large chassis panel, the resistance should be negligible.