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Discussion Starter #1 (Edited)
Some of you may have noticed that I have been answering a number of questions on this forum and posting a lot of info on the electrical systems of our cars.

The reason I have been doing it is because I have gotten myself into not only trying to make my cars electrical system work satisfactory but Brian's (BDC1013) 71 also.

This has been a 10 year journey with my car and a 1 year with Brian's.

The bottom line is that if you keep your car stock it is a good electrical system; it could be better but it will work well enough for most. Go to Mad Electrical's Website to see what can be done to improve the stock system.

http://www.madelectrical.com/

Now, if you want to add some modern electronics, power windows, better headlights or fuel injection the system is lacking.

Changing the alternator is the least of your problems. The factory wiring system is way off when these new loads are added to the system. Some of the after market stuff, American Autowire and Painless are two I know about, are not going to really solve your problem although they might make things a little better.They are trying to use the factory layout as much as possible and that limits what their products can do.

I am basing what I am saying on actually having gone through the pain of installing or preparing to install all these things and finding out the hard way about the issues (alternator output at idle, wire size too small, too much heat in a wire bundle, lack of fuses (FIRE), poor performance of stereo and FI, lights too dim under specific operating conditions, etc). Many of these things are documented in some of my posts. Please note that most of these posts actually have data attached. They are not just opinions.

I have found that most of the Chevelle owners I know "put up with it" as these thing are difficult to diagnose and hard to fix.

It is my desire that I pass on the things that I find and the fixes I come up with so that others don't go through the same pain.

To that end, I will add a series of items to this thread to document what we do in the process of solving these issues.

Please comment/criticize what you see posted in this thread, especially if you have some data based response. From some of the other posts I have responded to I have learned a lot about things I had overlooked.

Ron
 

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Discussion Starter #3
OK, part 1 is the point where all electrical power comes from, the point of regulation:

This is where the alternator's output is measured or sensed by the voltage regulator. It is the most important point in the system as it determines the system voltage (about 14.4V not 12.6 or even 13.8!).

In a stock Chevelle it is located at the horn relay on the radiator support. MAd electrical talks about this at length.

The problem is that when you add loads like dual fans, FI, high performance headlamps, stereos, etc, the wire size from the alternator to the point of regulation is too small, the alternators that were originally in the cars had too little output at idle much less their full current rating and the wire from the point of load to the main fuse box is too small.


In Brian's car we have moved the point of regulation to a panel next to the battery to reduce the length of the wire that carry the highest current in the vehicle in normal continuous operation (the starter is always the highest current in any car but only operates a short period of time); the alternator output cable. It is in the upper left hand corner of the picture below:



At the same time we have removed some of the loads that would have been on the after market American Autowire fuse box, basically the headlamps (16A), dual Derale fans (44A), the stereo (10A), power windows (25A) and door locks (Don't know the current yet but small average high peak, like a starter solenoid). Doing this lowers the current on the main fuse box a lot deceasing the voltage drop on the feed wire to something around 25A (wipers, dash lights, running lights, headlamp relay coil current, radio) no blower motor as Brian elected to remove the heater and ignition is very low as it only powers the "On" signal for the MSD box. Main power for the MSD comes from the battery. More about the MSD later is a separate posting.

All the high currents are run from the point of regulation separately.

This set up is shown in the picture below.


We had all this working after we installed the dual fans but I will measure all the voltages and currents under different conditions (hot, cold, lights on, windows operating etc) once we get it working.

I am not pleased with the way this looks or goes together. It is the first whack at getting it right. We may remove this panel, and redesign with a fuse block rather than all the floating fuses after the testing.

Ron
 

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Ron,

I agree with Dean. You have helped me greatly just in the last few weeks. I for one thank you!

Now with that said I have great interest in the project at hand in your last post. Exactly what I am undertaking on my own vehicle. I right now am in the process of cleaning out the main harness behind the dash. I have removed it from the car and am stripping out all the unused circuits. My car is an '82 so I had ECM wiring, etc etc. Nice thing is I now have two circuits, one at 10 amps and one at 20 that are ignition switched 12 volt power sources. I needed one for my relay/ignition plate I am making for my own car. I plan to have the MSD as well as relays for the nitrous, 2 step, clutch, and engine fuel pump all mounted to it. I needed a switched 12v source to activate these relays... well actually a fuse block to feed that circuit of each relay and now I have one instead of needing to add this source. That turned out to be a nice find!

Anyway, I am signed on and will be glad to add my project so that there is as much info as possible in this thread. I like the idea of keeping the factory fuse block clean and adding circuits in a proper fashion so as not to overload it. I hate fire! I also can't wait to see how you finalize your project. More info the better.
 

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You're the man, Ron. I always watch your posts and this one is tagged and flagged. MUCH appreciated - I will coming up on this very soon. :yes::thumbsup:

John - Same to you. I am certain it will generate a ton of interest. If not, i'll buy ya'll enough beers to make it worth it to pitch just to me. :D Very interested in doing it well and doing it right so im front row / center here.
 

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Might want to look into one of these compact fuse/relay boxes.
This one is very small, has Maxi and Mini fuses, 3 full size relays and 2 mini relays. Grabbed it out of a Lumina in the bone yard. Has a stud with a #8 wire that feeds a buss bar feeding the maxi fuses, and has a cover also. Plan to install it in my 72 when I install fuel injection. Jim.
 

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Sounds a lot like what I did a few years ago on my El Camino... only I really like the Ford Taurus or Explorer power distribution boxes:


Always puzzled me why more folks do not run a power distribution box in their "upgraded" electrical systems.

I converted over to a CS130 type alternator as well. I run an 8g power cable from alternator to power distribution box. Being a '68 my normal alternator location is DS, which I prefer anyways (allows A/C compressor to be on PS for shorter hose runs). My 8g is probably barely adequate since I run it asthetically rather than functionally. That means it runs back to the firewall and back up front so it is about 8x longer than it absolutely has to be.

Note that the power distribution box has lots of goodies in it that are useful for upgrading:

Maxi fuses of large capacity, some ATM fuses, and a bunch of relays. Needless to say I did read MAD Electrical's pages and my headlights and electric fans are relay supplied from the power distribution box. I think I am going to run a seperate power feed wire to the cabin when I install the EFI computer. Over engineered is not necessarily a bad thing.
 

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Discussion Starter #9
OK now for some fan stuff, I'll get back to the distribution issue later. We had to stop working on distribution as I had run into a fan and fuse issue.

The fuse issue is that the fan in my car, a 16 inch Spal, had been "blowing" fuses every once in a while. They did not blow to the point that they were open they were just a higher than normal resistance.

Fuses are rated by current and time. The relationship is I2t (current squared multiplied by time).

Normal ATO fuses have an I2t of about 1500. Was the Spal stressing the fuse beyound that point?

I decided to look at my car, Brian's car and a Flex a lite dual fan I had waiting to be put in my car to replace the Spal. Here are the results.

We took the dual Derale Fan we put into Brian's car and removed one of the two fans, big points for Derale as the fans are easily replaceable by just removing four bolts. Very nice!

We discovered that Derale uses Bosch fans, well designed stuff.

Here is the current envelop of the Bosch fan when it starts off the battery, car is not running.

125A peak current and when we check with the car running the start up current was 145A. This additional current is due to the higher system voltage when the alternator is running and represents the normal operation of the fan.
The key point is that the I2t of the fan start up is 2,862, way beyond the ATO rating of 1500. So in Brian's car the 30A ATO fuse on the 25A fan is being over stressed.

Next we compared the Bosch Derale against the Flex a lite, wouldn't buy the Flex a lite folks (even though I did already).

It was more noisy than any of the others and pushed less air but it did draw less current. I2t was fine for an ATO fuse.


Even the blade design is not as good as the Bosch or Spal.





Now we are to the single 16" Spal. It has performed really well for a number of years now, but I don't believe it is enough to cope with real hot days and A/C whch is why I was looking for a dual fan set up.

The I2t is beyond an ATO fuse also (just).

But none of these are beyond a 30A Maxi fuse, which has an I2t of 4070.

The lesson here is that the big fans our cars need should never be fused with ATO fuses! Maxi fuses should be used.

I will post more about the fan design contribution to noise and the airflow issue some time in the future. But first back to getting Brian's distribution right with the correct fuses!

Ron
 

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Why wouldn't you use a fusible link in this instance instead? I myself prefer them for protecting electric fans as they seem to hold up better. I have used fuses as well (albeit ATO which we now know is not the best choice thanks to your information). I tried a 25 and it blew on start up (of the fan), then tried a 30 which worked. BUT, over the period of a few weeks in would blow as well. I would put a brand new 30 in and it too would be OK for a few weeks and then blow. Did some reading on the MAD website and I switched to a fusible link and have not touched it since ('00 or so). Not challenging you... just want to get your take.
 

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Discussion Starter #11
Why wouldn't you use a fusible link in this instance instead? I myself prefer them for protecting electric fans as they seem to hold up better. I have used fuses as well (albeit ATO which we now know is not the best choice thanks to your information). I tried a 25 and it blew on start up (of the fan), then tried a 30 which worked. BUT, over the period of a few weeks in would blow as well. I would put a brand new 30 in and it too would be OK for a few weeks and then blow. Did some reading on the MAD website and I switched to a fusible link and have not touched it since ('00 or so). Not challenging you... just want to get your take.
Fusible links will protect a massive fault (as in very large currents meaning a couple of hundred amps steady state) but I'm not sure they would protect against a motor winding with a shorted turn or two.

It's the unknown of how a fusible link blows then that bothers me. I can understand the parameters of the fuse (as gross as they are) and engineer around that. I can't get info on the fusing characteristics of fusible links so I can't design anything with them.

If anyone knows of any where I can get info on modern fusible link wire I would love to hear it. I did find info from the late 1800's but I don't think it is applicable.

I would also love to know what fan or fans you were using.

Ron
 

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Ron more great tech :beers:

I would be interested in how the measured startup current compares to estimated startup current? Basically take an ohmmeter to the fan motors and measure resistance to calculate current. My Ford Taurus fans estimated out at 70A startup that way and run at 15A continuous. The factory fused them with a 40A Maxi fuse so that is what I have run as well. I also try to start them up with a monster large 1.2 ohm ceramic encased resister wired in series. Drops the startup current in half with little affect on running performance nor current draw.

My vote is for looking at the OEM design for the fans when they come from the wrecking yard and using their parameters.

My bet is when you get there you will find that the square tip flexalite fan makes a LOT more noise than the closed end on the Bosch and Derale. Wing and airfoil theory is that much of the turbulence and noise comes from the tip design. More advanced model airplane propellors all use a swept tip profile for this reason. That outside fence will also to a lot to stabilize the blades from vibration and flattening out in pitch.
 

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I would also love to know what fan or fans you were using.

Ron
Dual fans from a 1991 Z28 Camaro.

This is from a Thread I have saved as it had dual fan specs I used to base my wiring off of ...

"The right (secondary or passenger) and left (primary or driver) fan current draw was measured from my ’91 Z28.

DRIVERS SIDE FAN

36 amperes @ 12.6V [startup/inrush current] = 454 watts
13.2 amperes @ 12.6V [run current] = 166 watts

49 amperes @ 15.0V [startup/inrush current] = 735 watts
18 amperes @ 15.0V [run current] = 270 watts


PASSENGER SIDE FAN

40 amperes @ 12.8V [startup/inrush current] = 512 watts
13 amperes @ 12.8V [run current] = 166 watts

46 amperes @ 14.9V [startup/inrush current] = 685 watts
18 amperes @ 14.9V [run current] = 268 watts

As you can see, both fans draw essentially the same current (18 amperes run condition @ 15V). Only the inrush current is a little different. Because it happens for only a fraction of a second, it was difficult for me to obtain an accurate reading (my DMM does not have a “peak hold” function - maybe the next one)."

From this thread...

http://www.thirdgen.org/techboard/tech-general-engine/24311-how-many-amps-do.html

I have each of my fans on it's own relay, fusible link, etc. They share no wiring. Each originally had it's own 30 amp fuse.
 

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Discussion Starter #14
Ron more great tech :beers:

I would be interested in how the measured startup current compares to estimated startup current? Basically take an ohmmeter to the fan motors and measure resistance to calculate current. My Ford Taurus fans estimated out at 70A startup that way and run at 15A continuous. The factory fused them with a 40A Maxi fuse so that is what I have run as well. I also try to start them up with a monster large 1.2 ohm ceramic encased resister wired in series. Drops the startup current in half with little affect on running performance nor current draw.

My vote is for looking at the OEM design for the fans when they come from the wrecking yard and using their parameters.

My bet is when you get there you will find that the square tip flexalite fan makes a LOT more noise than the closed end on the Bosch and Derale. Wing and airfoil theory is that much of the turbulence and noise comes from the tip design. More advanced model airplane propellors all use a swept tip profile for this reason. That outside fence will also to a lot to stabilize the blades from vibration and flattening out in pitch.
1.2 ohms? Then the fan can't draw 15A; if E=IR then 15A*1.2 ohms = 18 Volts. The fans will have a lower voltage at the input terminals and they won't move as much air but the inrush would be limited at 14.4V/1.2 ohms or 12A (assuming the fan had a zero ohm winding).

Your correct about the noise, the Flex a lite is very noisy compared to the Derale/Bosch or the Spal fan and does not seem to move as much air but I did not measure velocity (easy to do) or CFM (very hard to do) on the Derale or the Flex a lite. I can get the numbers of CFM and current from the Spal website; they have good datasheets.

Ron
 

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Discussion Starter #15
Dual fans from a 1991 Z28 Camaro.

This is from a Thread I have saved as it had dual fan specs I used to base my wiring off of ...

"The right (secondary or passenger) and left (primary or driver) fan current draw was measured from my ’91 Z28.

DRIVERS SIDE FAN

36 amperes @ 12.6V [startup/inrush current] = 454 watts
13.2 amperes @ 12.6V [run current] = 166 watts

49 amperes @ 15.0V [startup/inrush current] = 735 watts
18 amperes @ 15.0V [run current] = 270 watts


PASSENGER SIDE FAN

40 amperes @ 12.8V [startup/inrush current] = 512 watts
13 amperes @ 12.8V [run current] = 166 watts

46 amperes @ 14.9V [startup/inrush current] = 685 watts
18 amperes @ 14.9V [run current] = 268 watts

As you can see, both fans draw essentially the same current (18 amperes run condition @ 15V). Only the inrush current is a little different. Because it happens for only a fraction of a second, it was difficult for me to obtain an accurate reading (my DMM does not have a “peak hold” function - maybe the next one)."

From this thread...

http://www.thirdgen.org/techboard/tech-general-engine/24311-how-many-amps-do.html

I have each of my fans on it's own relay, fusible link, etc. They share no wiring. Each originally had it's own 30 amp fuse.
Ah, GM used two fans that are smaller than the two Bosch Fans on the Derale unit. Sounds like possible overkill on our cars. What size is the radiator on your Camero? How many tubes?
Do you have an LS motor?

Ron
 

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27" x 18" 2 row. No LS here.. Gen 1 355 sbc. These cars do not have a grille to breathe through, they are bottom feeders fed by an air dam under the radiator support.
 

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Discussion Starter #17

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Nice finds/information Ron!

As of right now I have zero cooling issues so I am not in the market for fans. But if I do find myself there I have those links saved.

Only change slated right now for my car as far as the fans go is a rewire. When I initially wired them in '98 or so I used the cheapo primary wire from the chain parts stores. In recent years I use only Automotive grade wire so I plan to redo all of that with better wire. Otherwise routing, size and layout remains the same. Although I do want to add a temp switch as mine currently are only fully manual activation. I have found myself more times as of late finding the temp gauge at 200+ before I nervously turn them on and cool it down. Guess it is the age catching up to me....:noway:
 

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A note on the MAD Electrical system mentioned by Ron earlier in this post. I run the MAD electrical conversion and it works great. No issues. Relatively simple to install and the MAD guy (cannot recall his name) is a great guy to work with. My sytem runs right at the recommended 14.1 volts when charging, the battery is always right up to snuff and nothing goes dim when the fans hit. All you do is replace a couple of wires...similar to what Ron has talked about but Ron takes it further with his aftermarket fuses.

Last but not least I pulled out the separate regulator when I upgraded. I run the internally regulated CS 130 and it "works for me" as they say! The CS is a very simple install (physical install) involving clocking the brackets on the regulator and making a small sleeve like washer / spacer to get my belts lined up dead nuts. This was done on a BB running the long pump BTW.

Also in the BTW category I am suggesting that anyone doing this stay away from the one wire stuff. Those alternators just add more confusion to the conversion process and IMHO they are just not worth the benefit of removing a few wires from under the hood. Everytime I read about one wire alts. and problems with wiring the charging system I just smile. The MAD system is proven..it works and the information is available for diagnosis. Again just MHO, stay away from the one wire..it just does not look that great considering that it is (can be) a PIA to install and get working right.

The MAD guy is HARD HARD HARD to reach because he is a one man band AND because he will take the time to talk to you about what you are doing. Between actually working and talking to customers he can be tough to reach. Press on, persevere, if you have questions he is Da Man. He is an old time hotrodder from way back when and he knows his stuff. Also you can find a fair amount of information on his web site before you call him. The "new" Electrical system is described pretty well there in text and diagrams.
 
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