I'm new to the audio world so bear with me guys.........

I have a ground wire coming out of the rear of the new HU w/ a metal clip at the end. I also have a ground wire coming out of the Metra wire harness adapter. Is it better for me to simply ground the clip to the chassis coming directly from the HU and tape off the harness ground OR cut the clip off and solder the adaptor ground to the HU ground?

 

cut and solder

 

Any particular reason why, wouldn't a ground directly to the chassis be more direct?

 

just clip that ring terminal off and crimp/solder it to the metra kit, that ground is there because occasionally some cars ground through the antenna and thats not very sufficient. the metra harness ground should be good, its a little bit longer path to ground, but i can assure you its a good ground from the factory. if you do ground the lug, you need to make sure its a very good ground and you loose a little on the "plug and play" factor if you want to remove it.

 

With any aftermarket HU I recommend grounding to the stock ground, [ground in Metra harness] however, it is best not to use the stock 12V+ constant, [yellow lead in Metra harness] instead run a fuse 12ga lead directlyfrom the cars batt. and connect the HUs 12V+ constant, [yellow] to it, [cap off or remove the yellow from the Metra harness.

It is also a good ideato run a 12ga ground from the chassis of the HU to the cars chassis, if you already have the HU connected to the chassis you do not need the 12ga ground.94

 

Why is this?

 

Got it , thx for the insight guys

 

The idea is sufficient power delivery, actually back a few years alpine had a hu in which they had a max rating of 60w x4 on it- not that, that matters, but thats all i can remember about it, but alpine recommended an amp kit for the hu because of its power output. Also i think pioneer may have done that once as well, one time they had a hu with a 70w sub channel on board.

 

That would make sense, but I would be just assuming that this Pioneer doesn't require nearly the kind of current needed to have 12 ga power wire.

 

As mentioned, it is to get required current to the HU, aftermarket HU are considered "high power" most, if not all, have true 4ch amps built-in and the require more current then can be supplied by the stock 12V+ constant, it was designed to supply memory power only as the stock HUs main power was the 12V+ acc, aftermarket HUs main power is the 12V+ constant, [like on an amp].

You could get away with a smaller gauge then the 12ga, [40A capacity] a 14ga will get you a 25A capacity, a 16ga will get you a 15A capacity, don't forget distance, [lenght of power lead] will also have an effect. 94

 

I don't know what radio it is, but assume its a 50w peak X4. That would be 25WX4 RMS. 100W/12V=8.3A. It should really be more like 13.8V, which would be 7.2A.