Car Electrical options and upgrades




ALTERNATOR & CHARGING



I have been working on this upgrade for some time without realizing it. I started to run into problems when I installed some of the more popular options for the Z cars, like an electric cooling fan and water pump, to name a few.
The electrical system in the Z car was never designed to work with after market equipment, big stereo systems and upgraded lighting. The charging system was designed to provide about 65 Amps total to the complete system.
When you begin to install aftermarket electrical equipment you really need to evaluate the overall TOTAL CURRENT DRAW on the system with the extreme load. You can calculate how much current you will need by adding up all of the lights, fuel pump, any other electrical drain that will be commonly used like the brake lights and so on. Then you need to add in the requirements of your stereo, H1 lights thanks to John LOL.

So lets look at my car and determine how much current I will need. The fuel pump draws about 8 Amps; the Injectors about 3 Amps, the water pump, 7Amps, the cooling fan about 16 Amps. Then there is the ECU that will use say 1 Amp, the MSD 6A box that uses about 4 Amps at idle, the secondary cooling fans for the inter cooler 2 Amps. I think that is about it for total idle current drain on the system. Lets not discuss the stereo just yet, but I came up with about 43 Amps total that the alternator has to provide for my car at idle. That is allot of current folks, so I need a hefty alternator to deliver that kind of current at idle. Needless to say I have spent hours testing and trying different alternator combinations, pulley sizes and many dollars trying to find an acceptable alternator that was up to the task. Totaled I have spent about $1000.00 to get my solution. I will say I could have saved a bunch of money had I did a search on Ebay first just to see what is out there. The final solution ended up costing me about $240.00 and machine work making brackets and work on the alternator housing.
The reality of all my work time and money has gotten me to where I wanted, but had I done the research before I started buying upgrade alternators I could have save myself time, allot of money, and a big headache.
The charging system in the Zcar has a number of areas that require upgrade or reconfiguration. The biggest factor is the stock wire harness. Nissan, making the wire harness modular in construction, connected the three main harness assemblies together with spade lugs, and fuse links for the protection of various components of the system and to make assembly when the car was being manufactured fast and required simple assembly. The significant part of the system for the charging is the White wire to the alternator, through the black fuse link and then connected to the battery. The wire is a #10 and it can handle about 60 Amps, provided it is a short run like in the car. However, this wire is a big problem for a high output DRAW regardless of the alternator being utilized in the system. Here is a picture of the white MAINS wire that will need improvements.


You can see that this wire is not sufficient to handle a good current draw, say 120 Amps. How you ask? well if you are cranking up a good hot 400 Watt stereo, and it is at night like I drive, then now you have a high current drain on the system. We take my previous 43 Amps or so, and then add the current of the stereo, 70 Amps, and now this is the TOTAL CURRENT DRAIN on the system. That is what 113 Amps. Guess what quys, the 105 Amp upgrade is not good enough. Here is a picture of the stock alternator I upgraded with the new diodes and a regulator for the fun of it. That was 80.00 dollars for that, only AFTER I paid 218.00 for the upgraded unit in the first place. Seems there was a bad solder connection on the first diode block.


Good unit, spent allot of time polishing the case. To bad just not good enough. This unit not only does not have enough total current capabilities, but it will NEVER be able to supply anywhere near my requirement of 43 Amps. The dyno just doesn't have the correct sizing of the Stator, or the housing. Good stock part though, very reliable. NOTE the spacer I installed in-between the two halves of the pulley. That was my first attempt to fix my problems; again I went to all the trouble to make the part for nothing because I did not research the system requirements first. I wasted my time and effort.

The next problem tracing up the wire to the battery, we find the Black MAINS fuse link. This provides power to the ECU, Injectors, and other various sub systems in the car. Here is a picture of the ZX fuse link box.


This wire is made to open in the event of a high current situation, like the battery terminals backwards. Instant death to just about any system, I'm not going to go into the problems of reverse polarity, but it is not good at all.
So you crank up that 70 Amp potential stereo as you are running down the road, and now the fuse link is being stressed to the limits. The first thing that happens is the wire becomes like a solid strand wire, not good to much heat. Then if the wire doesn't open, then the spade lug connectors on the white wire begin to get hot, and don't forget the unsoldered crimps on the lugs themselves. There are two of these connectors in my 82zxt so I had to eventually remove them from the system and come up with a better way of connecting the harness. I did, AFTER I damaged my wiring, I decided it would be a good idea to take a look at the FSM of my car and evaluate the wiring connections on the schematic. When I did this, I realized that I was trying to draw that 100 Amp plus through the white wire, the black fuse link to the battery, and get this EVEN THOUGH I had my hopped up stereo, MSD box, Fan, Water pump HOOKED to the battery directly. Needless to say I had problems relatively quickly. The first failure was the crimp connector at the back of the alternator. I replaced that part, some improvement, then I found the white wire connectors were bad, then the black fuse link. Then I realized I am working 20 year old car, and started to look more closely to the wiring in general. Most of the stock crimp connectors for the grounds and b+ wires were bad. I replaced those as well. That change went bad in a short amount of time, so my solution was to SOLDER EVERY ground wire, and B+ wire in the engine compartment. That fix has worked VERY WELL. Here is a picture of one of the properly soldered connections.



The next thing was how to run a high current lead, and have it not affect the stock configuration wiring. I still want the protection of the stock fuse links for the rest of the car. I don't have any desire to watch my car burn down on the side of the road. Hey maybe I should get one of those little fire extinguishers and mount it on the passenger side of the car, yea that would look cool and everyone that rides in the car can look at my cool fire extinguisher. LOL Too Funny.
The solution? Run a heavy gauge wire from the alternator to the starter motor. That will bypass the system, and still provide charge current to the battery and all of the current drain on the system that is hooked to the battery. There is one drawback to this configuration, you may want to install a high current circuit breaker, I did not choose to do so, you can get one at a stereo shop, me I'm just to lazy and cheap. LOL Here is a picture of the line I did for my car.



The last thing I did was to get some good Maxima Diesel battery cables and run those to ground and to the starter, cool cables guys. I did make custom clamp brackets to the terminals, but that has worked excellent, and I have room to add additional B+ feeds. Here again is a picture of the battery terminals.



The second upgrade was the Hamilton Ferris alternator. This is a good quick replacement or upgrade to the Z car system. The unit mounts exactly like the stock unit, with little modifications to any bracketry. The unit will provide a good amount of current to a normal system, in fact I would highly recommend this upgeade as general practice if you want to run electrical options like an aftermarket electric cooling fan. Here are the pictures of this unit, NOTE the additional pully. This unit is available with a 2.7" pully and a 2.1" pully, to get a little more at idle. This unit will provide the car with 150 Amps of current. The idle current from my limited testing will give you about 25-30 Amps @ 900 RPM. Just a bit shy for my car.



I also went with an external regulator setup for this unit, and the regulator works very well for this unit, and I was thinking of installing this on the alternator I now utilize because I can adjust the regulator voltage for an output higher then 13.8 Volts when hot. Here is a picture of the regulator. The unit was about $140.00 but a good unit none the less.



This setup will work for most of the guys doing a general upgrade to get a little more current. The thing to keep in mind is that it will fall on its face with a high power stereo at idle, but it will provide good current at cruise rpm's.

And Now My Prize


This is the final solution to my problems. I got this unit off of Ebay, and it is new. The alternator is for the newer cars and it will provide at least 50 Amps of power HOT at idle with a voltage output of 13.8 volts. The unit was advertised to provide 95 Amps at idle. That is dependant on what car, idle speed and all that junk. I opted for the 1.4" pulley for this unit. I am depending on the regulator to maintain the voltage across the RPM range of my car. I did consider using the regulator pictured above, and it would be a good upgrade, I will see how it goes. Anyway, TonyD is thinking of using the alternator and regulator for his megasquirt project car. That BTY is Debbie's car to drive that has sat in the driveway for how many years Tony? Lets geter done LOL.
This unit is the new Chevy solution to the higher current requirements of newer cars today. Ford has a similar setup, but the case configurations of both units require some custom brackets in order to mount the units. I stuck with the Chevy part, as I don't appreciate Ford all that much anymore.
I did have to make modifications to the rear bracket and the top bracket to fit the unit below the water outlet on the front cover. I also made a tapered bracket for the watter outlet fitting. So there was some additional time changing the design to fit the car better. The radiator hose was to close to the top bracket and I am quite sure it would have resulted in a hose leak at the most inoppertune moment.




This unit has been my savior in this respect. I haven't fully tested the unit, but I can run my stereo, lights, and run the car and the lowest I have seen my voltage to is 13.5 volts at idle. Good enough for me. I think this will work out well. Making the brackets was not to fun, but in the end I got what I needed. and it looks alright.
The last thing to fix was the charge light. I build a little board to do the switching, as the Chevy alternator doesn't have the same configuration as the Nissan unit does. So I take one of the Stator outputs, rectify that and send it to a relay. When the Alternator is putting out voltage from the Stator, the light will go out. Here is a picture of the board I made.



So that's my story and I'm stickin to it LOL.