Star Ground setup.

[FricFrac]

Oddjob has a great thread about grounding your car in this thread

http://forums.hybridz.org/showthread.php?t=147928

 

Unfortuenately its kind of burried and difficult to find. I've been asked a few times about grounding so I though I would point out the work Oddjob had done and add a few points and some pictures to illustrate. I spent hours myself digging through info and I forgot to bookmark one of the threads I found on grounding that was pretty good. Hopefully this will thread will be a good reference point (no pun intended) for grounding. Poor grounds can cause some major electrical issues!

 

A couple of interesting things to note. Loop grounds may cause ground loops as well which cause countless problems that may be difficult to find. Also troubleshooting a loop system can be difficult. Its also interesting to note that steel is about 11-17% as conductive as copper! Most of the electrical problems in our vehicles are bad connections and poor grounds. A star ground is a great way to get rid off or prevent those problems.

 

Its not uncommon to use a star ground to increase preformance (Ok freeing up HP) by eliminating sensor reading issues in ECU controlled cars BUT its important to have a good electrical system in even a system as basic as a stock 240Z, etc. Our cars have thermal and oil preasure sensors that use the grounding on the block to complete the circuit. A poor ground will give an inaccurate reading. Grounding is also very important to the ignition system as well to give it as strong a spark as possible. Running a leg from a star ground to the distributor is a good idea as well. I run a lead from the head to the block and back to the star grounding point.

 

Another important thing to note is because of the dissimilar metals between our block and head makes a perfect battery/corrosion. Part of the grounding between the blocks and head is to short out that process and help reduce that battery/corrosion effect.

 

Here is a picture of my star ground and additional fuse panel. I've modded the car so I can reverse it back to its "original" condition (it wasn't original in '72). I built a mounting plate for the fuse panel and the MSD ignition system that uses the stock mounting nutserts. For the fuse panel I used the mounting holes for the relay to mount the plate then moved the relay to the edge of the mounting plate. I'd hate to drill holes in the body if I don't have to even if I wasn't going to keep it "stock". Anyhow the fuse panel is good for six circuits. I'm using two circuits right now with the MSD ignition and HID lights

 

 

 

 

You can see here how the battery cables are hooked up. The negative side goes to the transmission mount and a secondary goes from the negative battery terminal to the star ground. The positive side goes to the starter solenoid and the secondary positive goes to the fuse block.

 

 

 

Here is the HID kit I installed. The wiring harness that came with the kit uses chasis ground for the negative side close to the HID ballast. I run a star ground leg from to the chasis ground for an extremely low resistance ground. I've gone overkill with the wires running individual 10 guage grounds for each of the ballast.

 

[TrumpetRhapsody]

So to clarify, this has a ground coming straight from the battery, to a central piont on the body where everything else gets grounded, right? AKA no using the frame or block as a ground source?

[langfordchuck]

nice work Fric Frac! Likely to go teh direction of a star ground system myself, although i did buy a copper bus bar for marine applications that i might end up using instead: it gives me six ground attachments, and well, it is copper.

 

I like the look of the fuse box: what make is it?

[FricFrac]

nice work Fric Frac! Likely to go teh direction of a star ground system myself, although i did buy a copper bus bar for marine applications that i might end up using instead: it gives me six ground attachments, and well, it is copper.

 

I like the look of the fuse box: what make is it?

 

A copper buss bar is perfect. I just used a single point but if you've got room the buss bar works great. I think what I would do if I was using a bus bar is paint it except for the screw down terminals to keep the oxidiztion down and to keep it looking nice but that's more asthetics than anything.

 

The fuse box was a marine style one - I'll have to see if I can figure out which one it was and let you know.

[Oddjob]

nice work Fric Frac! Likely to go teh direction of a star ground system myself, although i did buy a copper bus bar for marine applications that i might end up using instead: it gives me six ground attachments, and well, it is copper.

 

Here's an example of a copper buss bar star ground on a Z.

[Oddjob]

Oddjob has a great thread about grounding your car in this thread

 

http://forums.hybridz.org/showthread.php?t=147928

 

Unfortuenately its kind of burried and difficult to find. I've been asked a few times about grounding so I though I would point out the work Oddjob had done and add a few points and some pictures to illustrate.

 

Thank you for the nice compliment. Here's a cheat sheet for finding the buried information on grounding: For the link above (in the quote), scroll down to Post #15, and then to Post #25 on page 2.

 

http://forums.hybridz.org/showthread.php?t=151560

 

For the link immediately above, scroll down to Post #15.

[Bartman]

Where can I get this 'Star Gound'. I would also like to use something similar for power distribution since I have so many things that want a direct connection to the battery such as HID relays, fan relays, stereo, etc. I used this product once, but there's no online ordering and he's very hard to get hold of. http://www.madelectrical.com/catalog/cn-1.shtml

[RB26powered74zcar]

Where can I get this 'Star Gound'. I would also like to use something similar for power distribution since I have so many things that want a direct connection to the battery such as HID relays, fan relays, stereo, etc. I used this product once, but there's no online ordering and he's very hard to get hold of. http://www.madelectr...alog/cn-1.shtml

 

I picked up two exactly like that from Jegs or Summit (can't remember which).

[Bartman]

I picked up two exactly like that from Jegs or Summit (can't remember which).

Hey Joel, if you can remember please let me know. I've looked, but I can't find them at either site.

[RB26powered74zcar]

Hey Joel, if you can remember please let me know. I've looked, but I can't find them at either site.

 

I had to be sure myself, so I went out to the shop and snapped a pic....

 

 

 

[Bartman]

I had to be sure myself, so I went out to the shop and snapped a pic....

 

So I found the 'terminal blocks' on Jegs site now, but I'm not able to find the other items. Are they some type of terminal strip? How are you planning in installed these items on your build? Are you going to use one terminal block and strip for power and the other for ground?

[e_racer1999]

So I found the 'terminal blocks' on Jegs site now, but I'm not able to find the other items. Are they some type of terminal strip? How are you planning in installed these items on your build? Are you going to use one terminal block and strip for power and the other for ground?

Ya, basic terminal strips. You can get them at RadioShack for $2-$3.

[FricFrac]

Where can I get this 'Star Gound'. I would also like to use something similar for power distribution since I have so many things that want a direct connection to the battery such as HID relays, fan relays, stereo, etc. I used this product once, but there's no online ordering and he's very hard to get hold of. http://www.madelectr...alog/cn-1.shtml

 

 

Ok I think you are a little confused so hopefully this will clear it up....

 

The "star ground" is simply having your ground wires radiate out from a central point. In my example I chose the stock firewall placement for my "star" and added additional ground wires to various parts of the car from that central point. You could do it from the terminal of the battery but it starts to get messy. Some people use a buss bar made of copper (remember steel is something like 11-17% as conductive as copper!) if they can't squeeze all their ground points under one bolt.

 

I would recomend on the positive side to run some sort of fuse block for additional circuits. The fuse block should be as close as possible to the battery to prevent any significant lengths of unfused wire running between the battery and your circuit. You can see my fuse block that is mounted on the firewall next to the star ground. There is a negative buss on the fuse block but I don't use it. Again I'd go with a fuse block rather than terminal strips for safety......

[Bartman]

Ok I think you are a little confused so hopefully this will clear it up....

 

The "star ground" is simply having your ground wires radiate out from a central point. In my example I chose the stock firewall placement for my "star" and added additional ground wires to various parts of the car from that central point. You could do it from the terminal of the battery but it starts to get messy. Some people use a buss bar made of copper (remember steel is something like 11-17% as conductive as copper!) if they can't squeeze all their ground points under one bolt.

 

I would recomend on the positive side to run some sort of fuse block for additional circuits. The fuse block should be as close as possible to the battery to prevent any significant lengths of unfused wire running between the battery and your circuit. You can see my fuse block that is mounted on the firewall next to the star ground. There is a negative buss on the fuse block but I don't use it. Again I'd go with a fuse block rather than terminal strips for safety......

Thanks for clearing up regarding your setup, but I think an insulated terminal block would be a better ground point than a bolt installed in a firewall. Regarding the positive side, I have several accessories that came with their own inline fuses and thought that a terminal block would be a good way to give it battery current without going through my fuse block which may not be suitable for the amount of draw these accessories require (such as driving lights, amp, HID lights, fuel pump, etc.). Obviously there are others that feel the same as I can find several sources for this type of product.

[FricFrac]

Thanks for clearing up regarding your setup, but I think an insulated terminal block would be a better ground point than a bolt installed in a firewall. Regarding the positive side, I have several accessories that came with their own inline fuses and thought that a terminal block would be a good way to give it battery current without going through my fuse block which may not be suitable for the amount of draw these accessories require (such as driving lights, amp, HID lights, fuel pump, etc.). Obviously there are others that feel the same as I can find several sources for this type of product.

 

 

Your chasis is grounded and using the firewall as ground is the correct way to do it. Isolating the ground is not a good idea. Look at the electrical problems the Corvette have with the fiberglass body. I can understand for asthetics having a bus bar to connect multiple terminals but that is still connected to the chasis.

 

If you have several accessories with their own inline fuse it becomes a bit of rats nest. The fuse needs to be as close to the positive terminal as possible. By adding a secondary fuse block (not your stock one) for additional circuits you minimize voltage drops and keep your wiring neat and tidy allowing for quick and easy access to each fuse as well.

[Tony D]

As the Corvette was mentioned, let me chime in at something I noticed long ago when comparing old Chevies and Old Datsuns: Datsun doesn't ground ANYTHING!

 

Look at a 70Z and a 69 Corvair for instance (or for that matter a 70 VW Beetle)... The first thing I noticed was lack of a big flat braided ground strap from the engine mount to the chassis. And another at the tailshaft of the transmission to the chassis.

 

A Corvair has at least four 3/8" flat braided copper ground lines from the four corners of the head, to the chassis surrounding the engine, as well as a larger 1" wide flat braided cooper ground line at the front of the transmission.

 

The VW's have a big flat braided ground line from the block to the negative on the battery (actually a star-point on my bus...) and another that goes around the rubber mount at the front of the transmission.

 

When you realize that the engine can in some instances literally become a 'floating ground point unto itself' because of lack of proper ground straps from the engine to the chassis, it's no wonder our Datsuns have the ground issues we do!

 

I star-grounded many things together when I did the MS conversion, and functionality of other components went up quite a bit as a result of this. In addition, several of those braided ground straps were added in similar points as on the old Chevys and functionality of gauges (ESPECIALLY THE GAS GAUGE) went up quite a bit!

 

While it may not be practical for everybody to star-ground everything, even on a run of the mill daily driver Z, the addition of several properly sized ground straps from the alternator to the block, block to the chassis, and transmission to the chassis (perhaps with a tie in to the firewall and right frame rail ground point of the S30) will make EVERYTHING in the car work a little better due to better transmission of grounds. For a car without sophisticated electronics 'more is better', but as the caveats above point out, sometimes you can get differentials on high end electronics which may drive you to no other solution than to master (star) ground everything to a common point.

 

When we did the LeMons car, we simply put everything to a common buss bar, and tied that to the firewall and the battery negative. Everything had power and ground wires. Basic Circuitry only, but due to everything being tied at one point any troubleshooting was point-to-point and drop through the system was nil. For what remained of the existing original wiring system, this worked well enough to preserve good function in a grueling racing environment of endurance racing. Having a place you know is "GOOD POWER" and "GOOD GROUND" makes tying in something trackside like a Hero Cam or Video System power inverter a snap.

Edited May 25, 2010 by Tony D

[FricFrac]

As the Corvette was mentioned, let me chime in at something I noticed long ago when comparing old Chevies and Old Datsuns: Datsun doesn't ground ANYTHING!

 

Look at a 70Z and a 69 Corvair for instance (or for that matter a 70 VW Beetle)... The first thing I noticed was lack of a big flat braided ground strap from the engine mount to the chassis. And another at the tailshaft of the transmission to the chassis.

 

A Corvair has at least four 3/8" flat braided copper ground lines from the four corners of the head, to the chassis surrounding the engine, as well as a larger 1" wide flat braided cooper ground line at the front of the transmission.

 

The VW's have a big flat braided ground line from the block to the negative on the battery (actually a star-point on my bus...) and another that goes around the rubber mount at the front of the transmission.

 

When you realize that the engine can in some instances literally become a 'floating ground point unto itself' because of lack of proper ground straps from the engine to the chassis, it's no wonder our Datsuns have the ground issues we do!

 

I star-grounded many things together when I did the MS conversion, and functionality of other components went up quite a bit as a result of this. In addition, several of those braided ground straps were added in similar points as on the old Chevys and functionality of gauges (ESPECIALLY THE GAS GAUGE) went up quite a bit!

 

While it may not be practical for everybody to star-ground everything, even on a run of the mill daily driver Z, the addition of several properly sized ground straps from the alternator to the block, block to the chassis, and transmission to the chassis (perhaps with a tie in to the firewall and right frame rail ground point of the S30) will make EVERYTHING in the car work a little better due to better transmission of grounds. For a car without sophisticated electronics 'more is better', but as the caveats above point out, sometimes you can get differentials on high end electronics which may drive you to no other solution than to master (star) ground everything to a common point.

 

When we did the LeMons car, we simply put everything to a common buss bar, and tied that to the firewall and the battery negative. Everything had power and ground wires. Basic Circuitry only, but due to everything being tied at one point any troubleshooting was point-to-point and drop through the system was nil. For what remained of the existing original wiring system, this worked well enough to preserve good function in a grueling racing environment of endurance racing. Having a place you know is "GOOD POWER" and "GOOD GROUND" makes tying in something trackside like a Hero Cam or Video System power inverter a snap.

 

 

Exactly - and most people say "good enough" when they use the metal body but its really important to remember that steel is 11 - 17% as conductive as copper - that's pretty poor! Start adding sensors, etc for MSII, etc and simple electrical problems become nightmares. I've seen cars with the ground just going to the transmission or block - not good! Don't forget disimilar metals tend to make non conductive oxide barriers, etc and the voltage drops keep adding up. On top of that add corrosion that you don't see in the stock 40 year old wiring harness and its a miracle anything works at all.....

[DuoWing]

A good thread and I know I'm bringing it back, but I've started doing this on my Z. I like the idea of everything having a good path to ground. Now my only real question is on ground loops. I'm not really sure how to tell if I'm creating a loop or not. Basically I started the same way fric frac did. Then I run a leg to another bolt along the firewall and generally do 3 connectors per bolt. So I keep moving along running stars from each point. I will test each thing that I'm unsure of for continuity before connecting it in. I assume that I can keep doing this as long as I don't end up connecting something from one star into another star or someway running it back to the main ground a way other than it came?

Edited October 3, 2013 by DuoWing

[madkaw]

Good thread to bring up, but not sure about the statement as far as the engine not being a good ground. All the MS stuff I read says to use a good engine ground and NOT the body/frame. As far as understanding ground loops - I am still unsure but reading more everyday. Matt Crammers book on high performance FI discusses ground loops and has some diagrams

[DuoWing]

Actually I managed to find the threads that FricFrac had linked to in the OP. The title of the thread is Rose's Ride. That's one problem I run into a lot on HybridZ is I'll find a thread with a link to another good thread, but the link goes nowhere, so I'm stuck trying to figure out what the thread was. Anyway from reading and searching it would seem my approach to a star ground is incorrect or at least closer to a loop ground. What I'm doing is going point to point, and branching from each point. So I'm adding a lot of grounding points which can apparently end up causing more noise/interference due to so many grounds. This is apparently why the star is so good because you're linking as much as possible to one singular ground point.