Okay so Im having a little trouble with grounding my amp to my car.. i cant get it to power on. where do most people ground there amp in there rx8 trunk?

 

there are two bolts next to where the struts come up into the trunk after you remove the carpeting scrape off the paint so you are getting good contact to bare metal

 

there is a factory ground bolt on the driver side of the trunk that can be used,

i used a existing hole on the passenger side i just sanded down the paint and bolted onto the panel, both worked for me with no issue

 

Although obviously some extra work for a trunk mounted amp, the best audio ground is the negative battery terminal. The same goes for vehicles as home audio, you want 'true Earth' ground and not 'chassis' ground to preclude RF interference. A specialty grounding kit includes a direct battery ground, so ....

But again this is a good deal of extra work, especially if you're not an audiophile (and vehicles aren't prime listening environments anyway) so as already cited the next best is the factory grounding stud trunk-driver's side. Do make sure it is clean of paint or any other coating. You must have bare metal.

 

over thinking a simple ground location. could just upsize the battery to chassis ground. I am running ~700watt rms @4 ohms to that ground location with no issue. You may get a little more power out of it but not really worth the effort. (amp is a 1400 watt amp @2 ohms)

 

+1

that is what i used. it is on the rear side of the wheel well (facing to the rear of the car). when you pull the carpet back, you can see it pretty easily.