Voltgage problem

[maro2nv]

I have a 68 camaro and i bought the ron davis radiator with the duel fan setup on it. I have a 140 amp alternator and i rewired the car with the painless wireing kit. When ever my fans turn on my volts drop from 14 to 11.5 when in gear. When its idleing in park you can hear a change in rpm, it drops. My alternator is from kragon auto parts, so i dont know the amps at idle. If anyone has any clue it would help.

[jigga99]

how many wire alternator is it? i think the 1 wire ones dont work until reved up, heres a link
http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

[maro2nv]

Sorry that i did not put that it is a one wire. I found out that it is 80amps at idle.

[Carver67]

Did your alternator come with a bench test data sheet. I know some companies are including them with their alternators. If no sheet was included just remember that just because it's rated at 80amps at idle you may not necessarily be getting that on the car. Also, how much draw is on the system (stereo, AC etc.)
Good luck,
-Mike

[PRRC]

A lot of street rods have this same problem. There are some companys that make a 1 wie that charges at idle.I will look and see if I can find you a name of the company.
Tim

[maro2nv]

No it did not come with the bench sheet. I called kragens and they called the maker and thats what they said. Im only running a crane hi-6 box and the electic fans on top of the normal electonics in the car. Tim thank you very much for looking for me.

Josh

[ProBell]

What are you running for pulleys? You can change the RPM of the alternate with the pulley combo. Most of the time they are under driven to gain HP to the tires. Randy

[maro2nv]

I have the regular march serpentine pulley kit.
-josh

[6'9"Witha69]

I am assuming that the "painless Kit" is the chassis rewiring kit, correct? If so, you need to look into relays. The link below illustrates how relays help in headlight situations but it is very useful for Fans and all other high draw electrical.

http://www.madelectrical.com/electricaltech/brighter-headlights.shtml

[maro2nv]

Sorry, yes it was the whole chassis kit. As for the releys i have two, one for each fan. Never thought about running them for the headlights. Thanks.
-Josh

[David Pozzi]

The horn relay is the main power distribution point on a 68 Camaro. Connect your fan power supply to this connector for maximum power. Your alternator power lead should connect to the horn relay.
If your fan power is coming off a battery terminal, that's not the point of maximum power.

The MAD electrical site has lots of good info on this subject.

[maro2nv]

No i dont have the horn reley. I have the alternator wire going to the starter. Thats what the painless wiring instuctions said to do.
is there another way i should of ran it?
-Josh

[David Pozzi]

No i dont have the horn reley. I have the alternator wire going to the starter. Thats what the painless wiring instuctions said to do.
is there another way i should of ran it?
-Josh

Well,
That's a different way than stock.
If your alt to starter wire is 10 gage, you might try an 8 gage wire. At idle with the Alt at full charge, you have max load on the alternator. Make sure your alternator is grounded and the battery ground cable attaches to the engine near the alternator.

Check that the belt is not slipping. The pulley will get hot after a running like that for a while if it is. I had a steel cad plated pulley get discolored because it was slipping.
David

[BRIAN]

Problem is what the alternator Co considers at idle. If your engine idles lower than 750RPM or so you can have a problem I also had a problem with March and their alternator pulley set up. I changed pulley to speed up alternator at idle and it clearedup everything and even helped the idle itself. If it is FI motor they rely on having the correct amps at idle.


I agree with the above of running the correct size wire but a simple meter hooked up with the car in drive at idle will give you the info you need. Rev it slowly and see if the gauge jumps and then see where it should level off near idle. Mine dropped a considerable amount below 800RPM.


You should also do your tests with every accys on and your stereo at a loud level as they draw more at different levels.

Good luck

[maro2nv]

Brian, My car idles in gear about 900 to 950rpms. I have to rev it up to about 1300 to get the volts back up and thats with just my head lights and fans on. If march has a smaller pulley that would solve most of my problem. If not i was looking to go back to the normal 3 wire alternator, to see if it would do better at lower rpms.
-Josh

[gmachinz]

I see a couple of problems with your system based on your data. First, you are running both fans (I assume 11" fans, right?) off relays which if you are running them in parallel, that's about 40-45 amps total amp draw when they come on-I am a Spal dealer so I know the specs on their fans. While the battery can absorb the majority of the load initially, the system is being taxed if the fans are left on for any extended amount of time. Your voltage gauge is indicating way too much voltage loss through the wiring. My advice is to get rid of the 1-wire design altogether and go back to the 3-wire design and run your fans off a controller and utilize a junction block that routes power from your alternator via the charging post and run all of your accessory wiring from that point along with the remote voltage sensing wire tied in as well. Assuming you have correctly modified your wiring to an internally regulated alternator, this will solve your problem assuming everything else is wired as it should be. Measuring the voltage out of the alternator is easy enough but DO NOT use a multi-meter to gaug eamperage output as most are only fused to protect up to 10 amps-use a quality amp probe which are normally rated to read up to 600 amps for a proper output reading. I use an Actron clamp type amp probe-it reads AC and DC voltage /amperage readings as well as Ohms, continuity, etc. If you need help figuring it out, drop me a line and I'd be more than happy to help.

[MonzaRacer]

I disagree with hooking any accesory up to a junction point especially an set of electric fans.
If you run electric fans, one never just wire them to run all the time and second use a heavy duty relay.
You can wire from the battery to the powerside of the pull in relay in with your heavy power in to the relay then run power to the fans and hook the grounding side of the pull in circuit to your choice of fan switch.
Some people will use 12 volt key on to turn the realy on but I prefer to let the fan run after the key is off.
I always pull my fan power straight from the battery or the largest power wire that comes from the battery.
Also for one wire alternators, I dont like them. I have had to repalce so many of them and run new wires.
Heck on a GM application you only need 2 wires. One of the wires from the plug just loops back to the battery terminal and the other wire from the plug is hooked to 12volts key on run.
I have seen several brands of power wire alternators and never had any great luck with them over the long haul and usually on streret driven cars they give more problems than they are worth and they are overpriced.
Lee

[maro2nv]

When i bought my radiator rondavis had the duel relay w/ a thermostat for the fan setup (13 inch fans) i have. I bought that kit. Seems like all you guys are saying that i need to get a three wire alternator. So i think I will try that first and see how things go. I am also going to do the relays to the headlights. That was a good idea.

[MonzaRacer]

Just remember to hook the main power wires to the relays with a heavy guage wire and a heavy fuse then the fans will never give a problem.
I would use 10 guage wire with a 30 amp maxifuse to the fans and ground to either directly to the battery or ,say if the battery has a ground to the rad support then the support is good too.
Never be afraid to use heavier wre or to add an extra ground in electrical.
OH and on electronic items a fuse of equal size in both power and ground will protect them incase of wires being crossed or say if someone tries to jump the car and hook the cables up wrong(had this happen) and it trashed the ignition box.
I had fella hook up a high dollar CB once and they did it backwards and burnt a trace inside. Luckily it was fixable.
Good luck.
Lee

[paul67]

I had this problem and found I had not got enough earths. See my post

[Bow Tie 67]

Just incase that throws anyone, earth = ground :)

What is interesting is the LS1 uses a one wire alternator. Although the factory system utilizes a main fuse / relay panel in the engine compartment, which helps reduce some of the long wire runs and therefore reduce voltage drop.

I have almost finished, fingers crossed, adapting a 4th gen body harness to fit in my 69 for this very reason. I'll post pics soon in the project update section.

[gmachinz]

No matter what your gauge reads, what is your actual volt reading taken directly off your alternator charge post with your fans on? The LS series motors as well as the Vortec families use a 1-wire from the alternator-it goes to the gauge. I believe the remote voltage sensing lead is further upstream from it in the wiring loom. I would advise going wih a good fan controller and using a HD relay as a backup instead. There's a wide variety of ways to incorporate a controller with (2) fans but I mainly have issues with the start up spike of fans when using relays....diodes and bridge rectifiers don't like high spikes. Over time, it's just a strain on the charging system that can easily be avoided.

[MonzaRacer]

Ok you use a resistor suppresed relay and you never have any problems with any type of spike.
If you use a diode suppresed relay you have to make sure you have the power on the proper side.
As for "spiking" an alternator I have ran SI and CSI alternators for years with electric fans.
The big thing to remember is to hook the heavy power wire straight to the battery with a fuse inline.
As for the "one wire" alternator. The term one wire means no wires to the regulator ,just the battery wire. These are using internally shorted regulators to "turn on" . A resistor allows it to not drain the battery.
CSI internal fan alternators are more sophisticated and can actually turn on and off with the rotation of the armature with out having a key on wire, you simply need a wire that goes to the charge light(still giving the regualtor something to activate by) see the regulator sends a 12 charge through the wire and the wire to the charge light gets 12 v key on,,,, the regulator/alternator fails to charge the light grounds.
If you draw heavy current from the battery or get a large brass power block from a stereo shop and hook a short 4 guage wire to the battery from it and draw power for accessories from that and the spikes and motor nise is usually absorbed by the battery(see batteries are large capacitors).
All you need to read system power on a volt meter is hook into battery power near battery (I prefer same connection as the feed wire from alternator.
Oh and most current fan motor designs do not create spikes upon starting, ripples as the drain is met by alternator, but not spikes.
Spikes are created when the electrical field colapses, but since you are opening the positive the spike is damped by the fan windings to ground.
As for controlers I just like to use the simple adjustable fan switch with a bourbon tube sensor slid into the core near the return hose from the engine. It grounds the relay the realy turns on the fan. NEVER run just the controler, after having a friend have his car burn up from doing that I take great precautions anymore.
BUT you need not worry on fans as I would stage them by having one fan come on at approx. 200 to 210 degrees and turn of in the 190/195 range. Use a 195 thermostat and dont worry as a typical engine runs more efficiently at those temps.
The second fan I would wire in two ways, One turn on would be wih the A/C (possibly even both fans at that time to make the condensor work more efficiently) and at a 210 to 230 temp.
The big tell is if your A/C system(if you run one) has a small high efficiency condensor then running both fans would make it more effiicient.
Cooling sytem setup isnt rocket science and I see so many smart people making simple blunders because they dont understand how electric fans and the cooling system should operate.
And I am not talking $600 radiators and $300 fan setups.
I spent $100 bucks on a 3 row copper/brass recore and a $20 junkyard single fan, a $15 controller and had a nearly 11 to 1 big block chevy running no higher than 200 degrees even when racing or driving in high heat.
I had a 350 chevy in an 86 Ranger with a 4 blade solid fan and the stock 2.0 4 cylinder no air radiator and that truck NEVER got over 200.
Cooling systems are not hard to setup and do not take lot of high dollar parts everytime.
I would only spend big money on parts that are needed.
But then thats me.
Lee