MOD Help

[nec_nec_2]

hey guys i just bought an 2003 g35 sedan rwd im looking to do some mods to make it sound more like the the coupe im looking at doing bolt ons only n/a . What would be the best exhust and does any compay make a dual exhust kit for the sedan and since you guys know alot better than i do to make more power out of the car. Short ram/cold air , maybe a after market intake manifold , cams. Iv been reading about grounding kits if some one could point me in the derction of a forume that explains why it would gain power or of some one minds explaing. Thank you for your help

[biggie]

I like the Z tube and JWT popcharger for intake on my coupe.

Not sure on sedan catbacks, but someone should drop in on that.

Could just get a plenum spacer instead of a new manifold.

[pfarmer]

Iv been reading about grounding kits if some one could point me in the derction of a forume that explains why it would gain power or of some one minds explaing. Thank you for your help

Stay away from grounding kits. Some may give you an improvement but that is only because you have a failure in your stock grounds. Simply fix your stock grounds by either cleaning up the connections or replace with like size and like positioning. Most claim to help with your various computerized modules but the fact is that is highly not likely when you consider what occurs with them.

If they keep the factory grounds in place you can now have circular currents due to the differences in ground potentials due to the construction of most kits. In many new cars many of the sensors are balanced. That is they do not use the car ground at all except for shielding. The signals are carried in the conductors within. In this case nothing would be gained signal wise even if a ground improvement was made. Balanced sensors are designed that way to cancel out noise. This is good since the shield can actually induce noise if unequal ground potentials existed along its length. Besides sensors for the engine you have the same situation between modules, many communicate via balanced lines, often with a shield around them, sometimes simply twisted conductors. If there is noise it will typically show up equally in both the positive and negative conductors. The module has a differential amplifier for inputs, simply meaning it will amplify the signals (the word amplify may mean 1 to 1 amplification) that are different. Since noise will typically be the same it is not amplified and therefore basically filtered out.

Your audio system is also another area where the same principals apply.

In an unbalanced system there is a greater chance of noise induction into signals since you do not have the benefit of the wiring helping out in cancelation. These systems typically have a center conductor with a grounded shield. In this case if you have a difference in ground potential along the length of the grounded shield the shield like the situation above can introduce noise that is not rejected by the the characteristics of the conductors.

Now assuming you really want to add a grounding kit and you want all parts of the system at equal potentials. The number one thing you would not do is stack grounds on the same point using a bolt or nut/stud. The reason is that even assuming the bolt or stud will provide equal potentials top and bottom equal to the contact point on the chassis, the ends of the conductors in the stack will each have there own resistance and as they age it typically goes higher. This will just about guarantee unequal potentials between conductors in the stack. Another factor is the length of the conductors as they have a resistance per foot. Another factor is impedance. Basically think of a changing resistance based on a changing signal. This is one reason why for signal purposes grounds are typically sized based on current requirements.

A good alternative to stacked grounds are grounding blocks. These take many forms, sometimes as simple as a round ring where all the connectors bolt into it, sometimes simply a block with set screws where bare ended connectors are connected.

Some kits try to follow the factory ground and using basically a single wire or a group of wires in a series configuration and follow the chassis natural grounding plane. This doesn't look as pretty but for grounding purposes the attempt here is basically to guarantee that the chassis ground is maintained. Usually if you see this you will see that the ground conductor(s) is directly connected to points on the chassis.

Sometimes simply jumping across a compromised ground point will get the job done. For example consider a water system in a city. A ground often follows the path of the water system and when it comes to your house a ground is often jumpered across the meter. This is done since the meter has gaskets and also the bolts in its assembling can age not providing a ground to both sides. In a car this can happen if parts are replaced in such a way that the factory ground is no longer present. In this case fix this but be careful since for some parts of a car it may well be the case that this is the normal condition.

I can pretty much guarantee that from the factory, mother knew best when it comes to grounding points.

Take in consideration cable sizes. How are you going to get more current flow from increasing the ground size without equally increasing the positive size? No need to have a 4/0 ground cable with an 8 gauge positive. For signal purposes it is highly not recommended.

Perry

p.s. Remember why Henry Ford wanted positive grounded systems, he understoond electron flow direction versus current flow direction.

[nec_nec_2]

thanks so far for the response and explashons for the ground kit and by z tube do u mean the stock intake pipe from the 350 cuz im looking for more of a cold air intake but is thats gona be better. I got another question has any one bought an after market manifold iv been looking at the kinetix ( http://www.kinetixracing.com/n....aspx) I was looking at the Iso Thermal plenum spacer but i personaly think the manifold will add more power and i finid it looks nice that the stock manifold but as i am new to the vq im gona stick to everyone advice here iv been modifying cars for the past 7 years (profesnaly and for fun)but this is gona be my baby and want to do evrything right and the best parts for it.

[SVTCOBRA]

Based on feedback that I've seen here, if you have an auto then you would enjoy the effects of the grounding kit. Have never heard any negative comments on them only positive. SEARCH the forum and see for yourself.

[pfarmer]

Based on feedback that I've seen here, if you have an auto then you would enjoy the effects of the grounding kit. Have never heard any negative comments on them only positive. SEARCH the forum and see for yourself.

Of course you will when someones spends bucks they expect benefits. Problem is that the car is grounded at the factory and if the factory grounds are in place and maintained you don't need to add others that can cause circular currents due to design. Also consider that you are only adding one half of the circuit (the supply) without regard to the return path which in reality is the one most likely to have been compromised over the years. Also consider that a good deal of the sensors as well as other equipment are balanced circuits. Even if the ground did no damaged via circular currents due to poor designs such as stack grounds (and there is documented evidence right on these forums, ie car failed to start when the added grounds were placed over factory grounds) there are no gains to be had on a balanced circuit as far as noise goes.

The ground in a car is the supply in a negative grounded car. You will get no more power to a module than what the positive return can handle. so it makes no sense at all to have a conductor many times the size of the return path, in fact for signal purposes it is a big no no right behind stacked grounds. A 2005 ECM has a 15 amp fuse. A number 8 conductor can carry 73 amps, a number 16 conductor can carry 22 amps for chassis wiring.

The only benefits that could be had is if a ground was reestablished due to a disrupted ground such as may occur during poor maintenance procedures or aging. In this case if you establish a secondary ground you pretty much have guaranteed circular currents and the noise they can introduce.

The best bet is to either completely eliminate the factory grounds and add new ones (have fun doing this with all the chassis grounded equipment) or renew the factory grounds. I challenge anyone to measure the current flow through their new oversized grounds. I challenge anyone with factory grounds in good condition to measure the resistance to various components. If you do you will find that you will have a lower resistance typically in the area of about 1-2 ohms over the entrie ground plane which is probably less than that within the new conductors. A number 8 conductor has over half this amount in a single foot.

Perry

[tollboothwilley]

Of course you will when someones spends bucks they expect benefits. Problem is that the car is grounded at the factory and if the factory grounds are in place and maintained you don't need to add others that can cause circular currents due to design. Also consider that you are only adding one half of the circuit (the supply) without regard to the return path which in reality is the one most likely to have been compromised over the years....

Perry...

I understand what you are saying here but the grounding kit made a HUGE difference. It is one of the best things that you can do for the 5AT. I can't recommend the grounding kit highly enough.

[pfarmer]

Perry...

I understand what you are saying here but the grounding kit made a HUGE difference. It is one of the best things that you can do for the 5AT. I can't recommend the grounding kit highly enough.

You may have had a defective ground or as I suspect in some cases and I don't mean yours misinterpret an improvement.

If you restored the car to normal operation by fixing a ground than my point is that you could have fixed the factory ground and not expose the car to possible other problems due to poor grounding techniques being used by the far majority of kits. You could augment the factory grounds by basically guarantee their function for example by doing following proper grounding techniques.

Now to the second point. If you introduce a problem in the ground that makes the car act more like you may want it to then that is what I mean to misinterpreting an improvement. As only an example the transmission shifts 'sharper'. Well maybe it is not designed to shift in this manner and an induced signal now makes it shift a little bit more on the harsh side. Not necessarily a good thing, but seems like a benefit to many.

I suspect that what one sees is one or the other or both. They have indeed fixed what was broken or they have induced an actual change from the norm which they interpret as beneficial.

What I find and I am going to use the term I was avoiding is that many of these claims by various manufactures are 'snake oil'. That is you are not actually changing the ground of a balance sensor for example since it has no ground that can be change. Not all sensor on the Nissan are balanced.

The same pertains to the sound system. Most of the audio parts of the sound system interconnects on at least the newer ones are balanced.

Basically on a balanced system the way it functions is that you have a positive and negative set of leads, the only ground may be a shield. The leads are often twisted, sometimes not. The idea is that if a noise is introduced in one the same noise is also introduced in the other. On the other end a differential amplifier which really doesn't amplify in the normal sense (1 volt in 1 volt out for example) amplifies the difference in signal. Since the noise is equal in both the negative and positive it is esssentially eliminated.

A grounding system would have little affect on this type of system since neither side is grounded and negative effects added by it will most likely simply disappear at the differential amplifier input.

If you want a ground system here are some things to look for. One is that for signal purposes the smallest diameter wire that can carry the load is beneficial. Do not stack grounds at all costs. Use a ring connector, a grounding block, some method of not allowing one conductor to introduce resistance into the group of other conductors. Keep conductors short as they have resistance per foot characteristics. Keep in mind that the goal is usually to keep all components at the same potential, different lengths of cables almost guarantees the chance for circular currents, the same problem with stacked connectors. All conductors within a system should be close to the same length.

If you have cable ends (which you don't necessarily have to have (grounding block for example) then you don't want normal crimped on ends, look for ones where a sufficient pressure method was used to cause a cold welded connection to be made. In utilities an explosive method is actually used for some very high current situations on high voltage lines. For our purpose the same concept applies the idea is to cold weld the connection. Note I didn't state solder which is often what is used by many as a cold welding technique, it is a pressure method of fusing the connector to the conductor.

If you go to the net and do a little research you will find some kits that do try to employ some of these features (for example a ring where the ground is attached and the rest of the conductors are attached to it). Some kits used the idea of a single conductor through the system. Basically a series of single grounding blocks are bolted into place on the chassis and a single conductor flows through them. The idea here I think is to jumper any bad factory ground connections that are body (chassis) based.

Still some kits simply replaced the factory grounds and may augment that with jumping across bolted sections such as outer fender to inner fender, firewall to fender, fender to radiator mount, radiator mount to headlights, and so on, simply jumping sections with very short conductors. I mention this since this is actually something I have seen and to a limited extent done with success after body repairs played games with something like headlight grounds. In an industrial grounding scheme this is often done between bolted together sections, especially control systems.

Perry