Battery Relocation - Ground Cables

[Pete68]

I have just finished my battery relacation but need help with running my 1/0 cable grounds. Here are my questions:

1) BATTERY to BODY: I have my battery in the trunk and this ground is done, I have a 1/0 cable running from battery to the trunk sheet metal.

2) BODY to ENGINE: I want to run a 1/0 cable from the body to the engine, where is the best location? Can I run from the starter and then just drill into the body sheet metal? Are you guys using self tapping screws or bolts? And where exactly are you guys running your grounds (from where to where)?

3) BODY to FRONT SUBFRAME: Does subframe need to be grounded? I was going to ground it only so I could ground the radiator support too so the headlights have a good ground. Where are you guys doin this ground?

4) FRONT SUBFRAME (or BODY) to RADIATOR SUPPORT: Ditto, Im wondering where to run this?

I know these grounds need to be there but Im not sure where to run em, Im looking for detailed specific suggestions on where to run each ground cable.

Pics would be great too. Thanks for the help! : )

[astroracer]

Get yourself a catalog from Painless Wiring. There is a ton of info in one of these. They outline the best practice and REASONS to have good grounds. You might find something on their site so do a search.
mark

[kyle @ ron francis wiring]

I suggest you get our free catalog at www.ronfrancis.com. We have a whole section on grounding situations in the 100 tech tips for wiring area of the catalog. We also sell some really neat products to assist you, if you want nice neat grounds and accessories.

[astroracer]

I suggest you get our free catalog at www.ronfrancis.com. We have a whole section on grounding situations in the 100 tech tips for wiring area of the catalog. We also sell some really neat products to assist you, if you want nice neat grounds and accessories.

Kyle,
Thanks! I MEANT Ron Francis in my above post... My bad.
Mark

[Chad-1stGen]

Hey Pete

Off the top of my head I have grounds as follows:
battery to trunk sheet metal
Subframe to body
Engine to body
Subframe to engine

I cant remember if I have designated grounds from rad support to anything.

[kyle @ ron francis wiring]

Kyle,
Thanks! I MEANT Ron Francis in my above post... My bad.
Mark

No problem! Glad it was us you were referencing and not Painless!

[Pete68]

Hey Pete

Off the top of my head I have grounds as follows:
battery to trunk sheet metal
Subframe to body
Engine to body
Subframe to engine

I cant remember if I have designated grounds from rad support to anything.

Can you explain how you wired each ground? Thats my question.

[Chad-1stGen]

Can you explain how you wired each ground? Thats my question.

Sorry. That is what I get for surfing PT.com on my phone while in a meeting.

Subframe to body is a ground strap attached using a self tapping bolt in the subframe and bolted to the sheet metal. This was done on the passenger side rail near the firewall.

Engine body is in a similar spot using cable from the block to the the sheet metal.

Engine to subframe is from two ground straps bolted to the front of the motor and attached to the subframe below the balancer via a self tapping bolt. (This spot is "OK' but not great).

For more specifics I'd need to look at the car as I don't remember off the top of my head and I don't have the car at home right now.

Also for me ground strap = flat braided unshielded. Cable = round insulated cable like a battery cable.

[Evldoer]

For a clean look, I attached a ground cable from the body, to the transmission on my car.Since the trans is connected to the engine, you wont need another cable to the engine. This makes things look alot cleaner.

You could also do the same thing for your sub frame under the car, that way you wont see any cables under the hood.

If you have your headlights and/or other electrical items grounded to the rad. support, this will need to be grounded to the sub frame. A short cable up front near where the support mounts to the frame would be perfect. If the sub frame is grounded properly to the body, you wont need to ground the rad. support to the engine.

[lfdsteve]

It would seem that Ron suggests a large wire from the battery( -) to the block, even if its a rear mount battery. Am I reading that right?
thanks
Steve

[Pete68]

Yes, I ran a 1/0 ground from the front subframe to the trans/engine and from the engine to the front body work.

[gray86hach]

I always run a ground of the same size as the power cable direct from the battery to the block. Also have one going from the body to the battery and then from the engine to the body and frame and at least 2 from the engine.

Gounds are more important than power is.

Tim

[lfdsteve]

Can you route these together or should one run up each side of the car from the trunk to the engine compartment? (that is the + and - leads)
thanks

[67rally]

Can you route these together or should one run up each side of the car from the trunk to the engine compartment? (that is the + and - leads)
thanks

They can run side by side.

I just relocated my battery to the trunk earlier this spring and used 1/0 for my starter wire and #2 for my main power wire. I didn't use a dedicated ground cable, I just grounded the battery to the bumper bolt at the rear frame rails, but I do have new frame rails, welded in subframe connectors and solid body mounts, so my ground is solid.

I have a 1/0 ground from the starter housing to the front subframe, 1/0 from the alt housing to the radiator support, and #8 from the radiator support to the front body work.

[ehummelman]

You don't need to run a long ground cable all the way from the trunk to the block. battery to rear frame works just fine since the frame is then connected to the block up front. I've never had an issue wired this way. Maybe I'm missing something, but the only variable that would be any different through a cable vs the frame at the same length would be the resistance of the 2 media. VD = (2 x Length x Resistance x Load) / 1000. Is it that different? I'm curious if anyone has definitive data on that. I'm guessing it's negligible.

[TheJDMan]

You don't need to run a long ground cable all the way from the trunk to the block. battery to rear frame works just fine since the frame is then connected to the block up front. I've never had an issue wired this way. Maybe I'm missing something, but the only variable that would be any different through a cable vs the frame at the same length would be the resistance of the 2 media. VD = (2 x Length x Resistance x Load) / 1000. Is it that different? I'm curious if anyone has definitive data on that. I'm guessing it's negligible.

I agree! My battery is in the trunk and the ground cable is all of 3ft long attached to the body. No starting problems what so ever.

[diesel25lrs]

I agree! My battery is in the trunk and the ground cable is all of 3ft long attached to the body. No starting problems what so ever.

I'm in the same boat here...I'm wanting to run a short piece directly from the trunk mount battery to the rear frame cross member. But...I'm running a 3link with no subframe connectors(as of yet) the only place it's connected to the front subframe is at the torque arm with a rubber bushing...does the battery ground need to be tied into the front subframe somewhere?

[parsonsj]

Anybody know if either method helps or hurts the dreaded " 'alternator whine' in your radio speakers" problem?

[ehummelman]

I don't think it matters which way, alternator whine can be a number of things, but any bad grounds in the system will be problematic. The grounding of the stereo head unit is especially important. You could read up some remedies on forums like DIY Mobile Audio.

[ErikLS2]

Anybody know if either method helps or hurts the dreaded " 'alternator whine' in your radio speakers" problem?

If the radio has a shielded coax cable antenna wire and the shield is grounded to the body somewhere or the radio chassis is in direct contact with the metal of the car body just disconnect the ground wire to the radio. I've seen this eliminate alternator wine in more than one instance.