[IndyL03]

Added one up front. Used an existing hole and opened up to 5/16”. Used a self threading screw 3/8”& a star washer. Wondering if there’s a spot to do this to the rear of frame?

 

[Fred Kiehl]

Rear of the frame to what?

 

[IndyL03]

To body possibly. I’m going to run 2 small amps (4channel ~300-400rms & a monoblock ~300rms) sometime in future

 

[IndyL03]

Trying to minimize drilling holes in body if avoidable

 

[Fred Kiehl]

The factory put grounds on the driver's side A pillar. That would be a good place to start. Any welded to the body panel would be a good body ground. There is a body to engine ground at the firewall, behind the driver's side head of the engine.

 

[Sinister]

How many grounds do you think you need?

 

[Z09B4U]

How many grounds do you think you need?

The OP is not wanting to run a extra 60-100 Amps through the car body.

Trying to minimize drilling holes in body if avoidable

You want to use the frame for ground. With this in mind my suggestion would be only one hole.
Pick a spot on the rear frame for a ground cable. Then pick a spot to drill through the trunk sheet metal.
Make a sandwich. Bolt, ground lug from frame cable, car sheet metal, lug from ground cable to amp, and a locking nut.

I can not help with a best location.

The enemy of this method is the ground lugs rusting and not conducting. The best is to use copper anti-seize or di-electric grease (silicone) to prevent salt and air getting between metal layers, and painting over the bolt, lug, and frame or body metal to stop the rust.

 

[Blue Bowtie]

Another good step would be beryllium-copper or phoshor bronze bolts and nuts. Those are made for electrical connections for bussing and taps in substations and switchgear, which are also subject to weather and a lot more current than an audio amp will ever absorb. I keep some on hand (leftovers from a past life) and are available at well-stocked suppliers.

 

[IndyL03]

I replaced the strap from drivers head to body with one a size bigger. I need to look and see where I could run a big strap to the body in back, pass through the trunk qtr panel rubber plug, or make a ground lug like suggested earlier. I'm just trying to not do too much with no gain and not put myself at risk for rust since I'm up north. Planning on doing a ziebart treatment before winter and cover in wax and oil on that

 

[Z09B4U]

and not put myself at risk for rust since I'm up north.

Since you said it first, I would suggest cables with double wall heat shrink to protect the wire/lug seam.

I could tell you that a "ground strap" is a bad idea where road salt and water are common but have a look at this video at 30:00. This one lasted less than four years.

Another good step would be beryllium-copper or phoshor bronze bolts and nuts.

Any bolt and nut is better than:

Used a self threading screw 3/8”& a star washer.

The screw is more prone to loosen than a nut and bolt. If you clean the nut side of the frame you increase the electrical contact surface.

 

[IndyL03]

this is the fastener I used. In the back I may use that premade wire the guy used in that video and put that adhesive line heat shrink tubing on it. I dont drive this much hardly if salt is out. usually have the Saturn running. past few winters have just been cold with 2 major snows

 

[madamorr]

Added one up front. Used an existing hole and opened up to 5/16”. Used a self threading screw 3/8”& a star washer. Wondering if there’s a spot to do this to the rear of frame?

Where did you source those ground straps?
Thanks,
Michael

 

[IndyL03]

They’re Standard Motor off Amazon

Amazon.com: Standard Motor Products B12G Engine Ground : Automotive

Buy Standard Motor Products B12G Engine Ground: Engine Mounts - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

[Fred Kiehl]

I got something like that at my local speed shop.

 

[Sinister]

We have those straps on the shelf at the shop.