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said to help the computers that run the car work better since the stock grounding wires are somewhat small, but personally i feel that they are more the suficient
 

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They're purely for looks, altho some people will argue it will help the car idle better and the electronics to work more efficiently since the gauge of the wires on aftermarket kits is larger.
 

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The cheap kits (like OBX) don't do much. The kits from Apex-i and Sun Auto do actually increase HP. I saw 4 whp across the midrange on my '01 Tib with the Sun Auto Hyper-ground kit. My car was dynoed, I installed the kit and re-dynoed it without unstrapping the car from the dyno. Sport Compact Car and Turbo magazine did several dyno tests with several cars and all saw increases in power. The amount of increase depends on wire placement and how bad your stock ground system was.
 

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I am reposting this because feel the need to inform:

I hate to seen cynical, but grounding kits have to be one of the best scams going. What in the world are we supposed to be grounding? These kits are not grounding your car, there is no connection to ground. Connecting to ground requires a connection to the earth. What many people like to call a ground line is really a return line. All electrical circuits need a supply line and a return line for current to flow. What electrical circuit are you completeing by installing these "grounding kits"?

Here is a vendor's explanation of the need for a grounding kit that was posted at 350Z Motoring.com. I deleted the vendor's name in the interest of good manners. Following his expalnation is my reply. I look forward to furher discussion on this topic.


Quote:
Originally Posted by xxxxxxx
350Z Engine Grounding/Earthing Kit:

Automotive electrical and computer systems are designed to tolerate up to 100% noise on its input lines. Meaning, if the ECU is expecting a 12-volt input signal, the signal may vary in the range of 0 to 12 volts. Fluctuations in signal are due to noise in the system. Noise is generated by spark plugs firing, discharges through the tires to the road, alternator turning on/off, etc. In other words, there is a lot of inherent noise an automotive electrical system.

One of the best-proven ways to compensate for noise is with proper grounding.

When measuring a DC (direct current) signal, almost any kind of wire will due. However, when measuring a high frequency input (i.e. the mass air flow sensor or the air/fuel mixture sensor) it is necessary to run a ground wire in parallel with your signal. The engine grounding/earthing kit provides grounding along side each signal wire.

The 350Z Engine Grounding/Earthing Kit allows for cleaner data transfer to the ECU. The result is more accurate measurements by the ECU and therefore more accurate performance, smoother idle and acceleration.



My Reply:

Sorry, but I have to call you on this.

1) No electrical system will operate on 0 volts. There must be an electrical potential for current to flow and every electrical device has a minimum voltage it wants to see. Prove this to yourself. Go to Analog Devices web site (www.analog.com), choose any device, look at the data sheet and you will find min. and max. voltage operating ranges.

2) Noise will cause distortion in a signal. Noise is defined as any unwanted signal. Grounding WILL NOT remove noise from a signal, Shielding will prevent noise from interfering with a signal and filtering will remove noise from a signal. Auto manufacturers go to great lengths to shield their electrical systems from receiving and generating unwanted signals. The FCC mandates this. If ignition wiring voltage (tens of thousands of volts) gets to your ECU then your ECU will immediately fail due to over voltage. The max power supply voltage most miniature circuits want to see is 15 volts and signal voltage is lower.

3) There is no current flowing through the tires!!! The tires are rubber and act as an insulator. This is why static charge builds up on a car and you will occasionally get a shock when you touch the car. If the tires were conductive this current would go to ground. By the way, if the static charge is strong enough for you to feel, then it is at about 20,000 volts.

4) Grounding WILL NOT remove noise from a system. Improper grounding can induce noise by setting up a ground loop.

5) Measuring DC vs. alternating current. I am a little confused by this statement. Measuring AC or DC voltage or current only requires a multi-meter. I have one and have done all of these measurements. If this statement actually deals with running AC vs. DC circuits, both circuits require a 'ground wire'. It is actually a return wire (A ground wire is the third wire you would typically see in your home wiring. This wire actually goes to ground and is a safety precaution). A circuit has to be complete for current to flow.

6) The signal sent by the MAF and A/F meter is a DC signal of varying voltage. The voltage may vary rapidly, but this in no way, shape or manner makes the signal anything other than DC. The frequency of the signal is zero.

7) I cannot imagine how a grounding kit will allow cleaner data to be made available to the ECU. Grounding WILL NOT remove noise from a signal.

8) If there is a difference of voltage potential between various parts off the car it can be measured with a voltmeter. I did this with the car running.

I made measurements based on the instructions for placement of the grounding wires. There was NO difference in the voltage potential between the different sides of the plenum. No difference between either side of the plenum and the front of the engine. No difference between either side of the plenum, front of the engine, and the vehicle chassis. Where I DID measure a voltage potential was between the negative terminal of the battery and all those other pieces. The bad news was that all those other pieces were at a lower potential than the negative terminal of the battery by 0.015 volts. The reason that the negative battery terminal has a voltage potential greater than zero is because the negative terminal of the alternator now serves as the low voltage reference. If you run a wire from the battery to those other parts, current will flow from the negative terminal of the battery to those parts. I don't really think that is such a good idea.


So, what is a grounding kit doing ...maybe just demonstarting that the palcebo effect is real.
 

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While the above post is pretty right on. I must clarify the term "Ground" traditional refers to earth ground as in how the electrical grid for home works. However in the car you have a chassis ground, the entire chassis of the vehicle is your "ground" and it is proper to call it ground because it acts just like earth ground does for the grid. Ground in this sense is not talking about dirt ;)

Just trying to clarify things a bit.

For more info:
http://en.wikipedia.org/wiki/Ground_(electrical)
 

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I am reposting this because feel the need to inform:

I hate to seen cynical, but grounding kits have to be one of the best scams going. What in the world are we supposed to be grounding? These kits are not grounding your car, there is no connection to ground. Connecting to ground requires a connection to the earth. What many people like to call a ground line is really a return line. All electrical circuits need a supply line and a return line for current to flow. What electrical circuit are you completeing by installing these "grounding kits"?

So, what is a grounding kit doing ...maybe just demonstarting that the palcebo effect is real.

You can tell me your theories until you're blue in the face. Doesn't change the fact that many people, including myself have seen the results with our own eyes. My two dyno pulls were less than 30 minutes apart. Have you actually tested a high quality ground kit?

You do know how an engine works, right? You do realize that your sparkplugs are grounded to your heads, right? The electricity from the plugs needs to get back to the battery to complete the circuit. The amount of resistance in this return path effects the amount of energy (in Joules) in the spark. The lower the resistance, the greater the spark energy. How do you decrease the resistence? By increasing the number or size of the paths from the engine to the battery's ground post. Multi-stranded, low oxygen copper wires are the best way to do this. Most grond kits are designed to increase the number of grounding points from the engine to the chassis and usually come with an additional wire to improve the ground from the chassis to the battery.

Tell you what... how about a little wager? I'll buy a ground kit and do a before and after dyno on my Z. I'll even video tape the whole thing, including the installation. If I pick up 5 whp or more, you re-imburse me for the cost of the kit (about $100). If I don't pick up at least 5 whp, I'll send you $100. You game?
 

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toward dm4 yes it is just a return line, that is also known as a ground on a car always has been so argue that with those old guys that are dead, there is much first hand experiance with grounding kits (for ur sake return line kits) and it does produce gains, personally u can buy some say 8 guage wire and some ends and make ur own grounding kit as long as u know the correct placement for the lines

these kits are made to allow the cars onboard computers to run truer and better, argue what u want say what u feel but this is what they do and are proven so ur argument is wrong at parts and has no backing

oh and since when is a dyno affected by a placebo?
 

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Guys, there is no magic here. This is basic stuff.

First, Cobra is correct. The circuit for the spark plugs uses the engine cylinder heads as part of the return path. The “ground” wire from the cylinder heads to the chassis is part of this circuit. If the return path is intact, then adding additional ground wires serves no purpose. This is easy to check. Using an ohmmeter, place one probe on the cylinder head and the other probe on the negative terminal of the battery. You should get a reading of less than 1 ohm (more likely 10ths of an ohm). If you get higher readings then there is indeed a problem.

Charged, it is impossible for the addition of these grounding wires to have any effect on any of the car’s computer or control systems, or radio, or navigation, or A/C, etc. None of these systems use the engine heads or block in any part of the power supply path or signal path. The only circuit that uses the engine block and heads is the spark plug circuit.

If I am missing something or I am misinformed please explain. Thanks
 

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First, Cobra is correct. The circuit for the spark plugs uses the engine cylinder heads as part of the return path. The “ground” wire from the cylinder heads to the chassis is part of this circuit. If the return path is intact, then adding additional ground wires serves no purpose. This is easy to check. Using an ohmmeter, place one probe on the cylinder head and the other probe on the negative terminal of the battery. You should get a reading of less than 1 ohm (more likely 10ths of an ohm). If you get higher readings then there is indeed a problem.
Doesn't matter how low the stock resistance is, adding additional ground wires will lower it. In addition to the sparkplugs, the alternator is also grounded through the engine. The more resistance the ground path presents, the harder the alternator has to work and the more drag it places on the engine. As we all know, accessory drag can consume a few horsepower.
 

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doesn't everyone realize that you can take the same car and do 10 pulls on the dyno and get a different reading each time? just because you run one pull on a dyno and get one number...then slap on a "grounding kit" and do another pull on the dyno and get a different number....well, that doesn't exactly mean it was the "grounding kit" that changed the number. :)
 

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doesn't everyone realize that you can take the same car and do 10 pulls on the dyno and get a different reading each time? just because you run one pull on a dyno and get one number...then slap on a "grounding kit" and do another pull on the dyno and get a different number....well, that doesn't exactly mean it was the "grounding kit" that changed the number. :)
I will acually agree with Dj on this one.
 

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Doesn't matter how low the stock resistance is, adding additional ground wires will lower it. In addition to the sparkplugs, the alternator is also grounded through the engine. The more resistance the ground path presents, the harder the alternator has to work and the more drag it places on the engine. As we all know, accessory drag can consume a few horsepower.
As I understand it, the power for the spark plugs runs from the battery, through a timing system (engine management controlled), to the spark plugs, and then back to the battery, with further grounds to the chassis, in case anything goes wrong. If this is the case, the only place you would see any real gain would be on the return line to the battery, not to the chassis, as the return line completes the circuit, thus lowering the resistance here increases the energy that can be released from the spark plug. So in this case, you want the lowest resistance possible only on the return line, as the others don't matter.

If I'm wrong, and the chassis completes the circuit back the the negative side of the battery, changing the ground wires may have some effect, as they'll make it easier for the charge to get to the chassis and back to the battery, but most of the resistance will be in the chassis, not the wires, so any gains will be minor.

If its a combination of both, the battery return is the best wire to replace, but again ground wires will have some (albeit very minor) effect.

As was suggested earlier, ground kits are easy to make. Go buy the lowest gauge, highest quality wire you can, that should have the lowest resistance. Buy some connectors and crimpers and make custom wiring that runs the shortest possible distance. Also be very cautious, at some point you're going to close a circuit, that may or may not have a significant amount of amperage (what kills you) running through it.

On the dyno issue, as David said, 5 hp is within the margin of error.

My personal (with some physics, but not alot of car knowledge) opinion, grounding kits are a piece of bling, while some kits (especially on poorly setup electrical systems) may yield a couple horses, they're mostly for a nice looking engine.
 

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As I understand it, the power for the spark plugs runs from the battery, through a timing system (engine management controlled), to the spark plugs, and then back to the battery, with further grounds to the chassis, in case anything goes wrong.
How do you think the electricity gets back to the battery? It goes from the plug, through the head, through the block, down the ground strap, through the chassis, up the battery to chassis ground wire. That's quite a bit of distance. Increasing the number of ground wire from the engine as well as changing the locations can help.

On the dyno issue, as David said, 5 hp is within the margin of error.
On a car making 250whp, 5whp is NOT within the margin of error if your dyno operator knows what they're doing. 5whp is 2%. The margin of error on a Dynojet that is operating correctly is less than 1% or 2.5 whp on a 250 whp car. On my Tiburon, the margin of error would be 1.9 whp. I saw gains of 4 whp through the midrange and a peak increase of 3 whp. The after dyno never dropped below the before dyno. I ran 3 pulls before and 3 pulls after. The comparison was made between the best before dyno and the worst after dyno. If you averaged the runs, the gains were actually around 5 whp, not 4 whp. The runs were less than 30 minutes apart and the car was never unstrapped because how the car is strapped can effect readings.

Guys, I've been doing this for 18 years. I don't sell grounding kits. I gain nothing by lying to you.
 

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How do you think the electricity gets back to the battery? It goes from the plug, through the head, through the block, down the ground strap, through the chassis, up the battery to chassis ground wire. That's quite a bit of distance. Increasing the number of ground wire from the engine as well as changing the locations can help.
On a car making 250whp, 5whp is NOT within the margin of error if your dyno operator knows what they're doing. 5whp is 2%. The margin of error on a Dynojet that is operating correctly is less than 1% or 2.5 whp on a 250 whp car. On my Tiburon, the margin of error would be 1.9 whp. I saw gains of 4 whp through the midrange and a peak increase of 3 whp. The after dyno never dropped below the before dyno. I ran 3 pulls before and 3 pulls after. The comparison was made between the best before dyno and the worst after dyno. If you averaged the runs, the gains were actually around 5 whp, not 4 whp. The runs were less than 30 minutes apart and the car was never unstrapped because how the car is strapped can effect readings.

Guys, I've been doing this for 18 years. I don't sell grounding kits. I gain nothing by lying to you.
Ok, so I'm back for some actual physics know. This discussion is about resistance. The entire ingnition system can be explained relatively easily. Charge will build up on the tip of the spark plug until the charge creates a breakdown in the surrounding air, making it conductive, and resulting in a spark jumping across between the electrodes. This is a pretty significant amount of energy, with HowStuffworks.com putting it at anywhere between 40,000 and 100,000 volts of electricity. Now, the entire purpose of resistors is to create a voltage drop in a circuit, or taking a voltage at one level and making it a lower voltage. Now, the other aspect of resistance is the current being pulled through the circuit. Since a transformer is used to go from 12 v to 40,000v, we need to account for the change. This results in a current that is .0003 * the current coming from a 12 volt battery, a quick web search shows that Cold Cranking a car typically takes as much as 600 amps (although its doing more than just spark), so the voltage in the ignition system is roughly .24 amps. Now, lets assume that the chassis of the car was good for 1000 ohms (probably way high, as brass and steel are pretty good conductors), we see a drop of 240 volts across the chassis. This is .6% of the total voltage drawn through the system. Some of these numbers are off, as the calculation for current only included the 40,000 volt drop, but it is approximate, and made for a considerably easier problem (as I don't have a volt meter to measure a cars resistance w/ etc.) While they may have some effect, I truly doubt it would be noticable.

In response to the assumption that a dyno is accurate to 1%, I highly doubt that. I've had physics labs where we estimated the error in volt meters to be as high as 1%. A voltmeter is a simple device that relies of few variables. A dynamometer is far more complex. Furthermore, you can never really test your car twice the exact same way. Experimental controls would mean having two cars with identical engines (try gettin that at the showroom), in climate controlled booths, with only one thing different, and running the test. When doing dyno pulls, the first run may have heated the engine or the tires enough to see 5 hp gains the next time around, warm engine making it run better, warm tires making it stick better.

I hope that this information is helpful and accurate. If there are any mistakes, please send me a pm and I'll fix the mistake or address it in the thread.
 

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In response to the assumption that a dyno is accurate to 1%, I highly doubt that. I've had physics labs where we estimated the error in volt meters to be as high as 1%. A voltmeter is a simple device that relies of few variables. A dynamometer is far more complex. Furthermore, you can never really test your car twice the exact same way. Experimental controls would mean having two cars with identical engines (try gettin that at the showroom), in climate controlled booths, with only one thing different, and running the test. When doing dyno pulls, the first run may have heated the engine or the tires enough to see 5 hp gains the next time around, warm engine making it run better, warm tires making it stick better.
Dynojets are supposed to be calibrated on a regular basis. Most shops do adhere to the recommended schedule. If there are errors, they are recalibrated to within 1% of actual. As far as not testing the same two times, this is why you do at least 3 before and 3 after pulls. As I stated, I took the best before and worst after. I eliminated most of the variables by testing 30 minutes apart (no climatic changes) and by not unstrapping the car. Also, by making 3 pulls, the engine temp was normalized.

I really don't care if you believe me or not. I use grounding kits because I've seen that they work on several different cars. You don't want to use one, that's fine with me. Like I said, I don't sell 'em.
 

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But Dynos can do nothing for the air environment. If you made the room cooler by 10 degrees you would see an improvement in dyno numbers with nothing else changing on the car. This would have NOTHING to do with the dyno being calibrated.

5 whp on a single run is not enough of a change unless you can see it across the board avg. of several runs.
 
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