427 SO Timing/cooling fans

[RICK LAKE]

Hans-Olof Blom Hans if you go to the MSD site and check out Q&A you need 5 amps and 10.2 volt min. This doesn't include the coil. Do you know how big the compasitors need to be to put out on an HVC that makes 80-100,000 volts with 1 amp. About the size of a paint can. I have been running an MSD system for 10+ years on the cobra and another 15 years on my Trans-am. Number have posted above are very close to the real world numbers. Rick L. Ps I think you are saying that with the addition of 1,000 rpms the amps need to run the system increase 1 amp. It's more like 2-3 per 1,000 Also a 60 amp Atl can't power a ERA cobra with all the power on at idle with an MSD system. Alt putout is about 35-38 amps at idle. Msd, lights, blower motor, and 3 cooling fans, are over the max. I know from racing the car. Rick L.

[For Paw]

Thanks for all the advice. Just to set the record straight, the wiring has been done with the best of breed components-everything from 0 gauge non-oxidising bat cables used in high end audio applications run directly to the Alt, ground run right to the block/starter, to all the ground straps one could think of to mig welded ground bolts on the chassis. I have had great advice from the best in the industry and have followed their advice and double checked to make sure that i have not missed anything. The carbs have been tuned within an inch of their miserable lives, and I am as close to the sweet spot as possible without going to a Dyno (These are going to be replaced by a Weber Stack system over the winter once I get this idle issue solved) So I have chased this on and off for over a year now and everything keeps pointing to the Alt. I guess MSD like any other manufacturer can goof every once in a while.

I have decided to order a new Reactor 100A alt to replace the MSD 105A I had. The main difference in the two is that the Reactor deliver full capacity at 1450 rpm vs MDS at 3000 and delivers more at 1000 rpm (idle for my engine) than any 1 wire on the market. I plan on measuring all the outputs once I get my parts and install them.

Rick, Alt output is 14.7. In one of my tests I unhooked the alt wire before starting and I did not have the problem when the fans kicked in. It might be something as simple as this Alt is malfunctioning. I have a 6.5 crank and larger water pump. I don't want to start changing Pulley ratios as this could start a chain reaction of water pump and cooling problems. The engine has been built to my specs by Southern Auto and they seem to know their stuff and have done these for many years now. This is a problem I have caused-I should have used their 65A alt supplied but i did not like the 3 wire system appearance and wanted something more advanced-that is pretty much where all this began. I did not realize that the 3000 rpm kick in on the MSD would be a problem. I am still holding that Alt ready to go if the Reactor does not work. All I need to do is get a voltage regulator or convert that to a one-wire. We'll see soon enough.

Randy

[McD00]

Originally Posted by For Paw

Thanks for all the advice. Just to set the record straight, the wiring has been done with the best of breed components-everything from 0 gauge non-oxidising bat cables used in high end audio applications run directly to the Alt, ground run right to the block/starter, to all the ground straps one could think of to mig welded ground bolts on the chassis. I have had great advice from the best in the industry and have followed their advice and double checked to make sure that i have not missed anything. The carbs have been tuned within an inch of their miserable lives, and I am as close to the sweet spot as possible without going to a Dyno (These are going to be replaced by a Weber Stack system over the winter once I get this idle issue solved) So I have chased this on and off for over a year now and everything keeps pointing to the Alt. I guess MSD like any other manufacturer can goof every once in a while.

I have decided to order a new Reactor 100A alt to replace the MSD 105A I had. The main difference in the two is that the Reactor deliver full capacity at 1450 rpm vs MDS at 3000 and delivers more at 1000 rpm (idle for my engine) than any 1 wire on the market. I plan on measuring all the outputs once I get my parts and install them.

Rick, Alt output is 14.7. In one of my tests I unhooked the alt wire before starting and I did not have the problem when the fans kicked in. It might be something as simple as this Alt is malfunctioning. I have a 6.5 crank and larger water pump. I don't want to start changing Pulley ratios as this could start a chain reaction of water pump and cooling problems. The engine has been built to my specs by Southern Auto and they seem to know their stuff and have done these for many years now. This is a problem I have caused-I should have used their 65A alt supplied but i did not like the 3 wire system appearance and wanted something more advanced-that is pretty much where all this began. I did not realize that the 3000 rpm kick in on the MSD would be a problem. I am still holding that Alt ready to go if the Reactor does not work. All I need to do is get a voltage regulator or convert that to a one-wire. We'll see soon enough.

Randy

Are you running a amp gauge? Sometimes they limit your current flow. I run a
regular ford 65 amp alternator and it powers my fans,lights and msd at the same time no problems. Sometimes all these fancy pants alternators are not the way to go.
Shelby just used a regular alternator and if it's good enough for him it's good enough for me.

Long live the Cobra!!

[undy]

nudder thing.....

Most fan manufacturers rate their fan CFMs above battery voltage. Spal, as listed here, rate theirs @ 13.0 volts. I believe Flex-a-Lite rates theirs even higher. If you have an "undersized" alternator that goes into discharge at idle then your electric fan isn't providing it's rated CFM. If you're driving the typical "cooling challenged" Cobra, that's not a good thing. With everything on my alternator provides a constant 14 volts, at the battery OR the fan. If your car's wiring "infrastructure" is also inadequate, which a LOT are, then the problem's compounded. With your car running, at idle, run a voltage test at the cooling fan. A lot of people would be suprised. With my Lone Star's painless harness and provided 65 amp alternator I was getting 10.2 volts to my cooling fan till I rewired the whole circuit.

Dave

http://www.spalusa.com/fans/automate.../1516-1517.pdf

[RICK LAKE]

For Paw Randy Please read the info on MAD alt site and PA performance on there site. Yes some alt don't putout alot of amps at idle or 1,000 rpms. Some one wire systems need a min of 2,000 rpms before they start to charge the car after startup. IMO this is bad for both the electric system and the motor. Cold oil that is thick having to turn higher rpms than should be needed for a cold start. This is why you need a high cca battery. To be honest, 14.7 is high voltage for any system unless you are running a 16.0 volt system, then you are low. This sounds like a weak cell battery in your car. You need to have the battery tested for CCA and load. Most Alt deliver max output by 1,500 rpms. This is nothing new. The voltage regulator controls the output anyway. I run a 70 amp alt with all the same things you are running without any problems. For high ampage systems you should switch over to a voltage gauge. You need to find out what the ampage rate is first. Pulleys on the motor to water pump should be 1-1. pulley ratio should be about 3-1 on the alt to the other pulleys. Rick L.

[Hans-Olof Blom]

Rick,

You are recommending a minimum of 100 Amps for the alternator and that 140 Amps would be lot better. Then you write that you are using a 70 Amps alternator?

I am using an MSD Digital-6 unit with a current draw of 0,7 Amps/1000rpm. The numbers for the MSD units are from MSD's specification. I assume that they know what they manufacture and sell. A minimum of 5 Amps is probably what is needed to be able to drive the car.

I have a standard 65 Amps Ford alternator which is what ERA recommends. I have no problems with the electrical system. Yes, the Amp-meter goes negative when my 3 cooling fans kicks in at idle. But that is one reason why I have a battery in the car.

[patrickt]

Originally Posted by Hans-Olof Blom

I am using an MSD Digital-6 unit with a current draw of 0,7 Amps/1000rpm. The numbers for the MSD units are from MSD's specification. I assume that they know what they manufacture and sell. A minimum of 5 Amps is probably what is needed to be able to drive the car.

I have a standard 65 Amps Ford alternator which is what ERA recommends. I have no problems with the electrical system. Yes, the Amp-meter goes negative when my 3 cooling fans kicks in at idle. But that is one reason why I have a battery in the car.

Exactly the same for me, in all respects. If I'm sitting at a stop, with my two pusher fans and one puller fan spinning, and brake lights on, there will be a slight discharge. If I angle my heel over and kick the revs up a bit over a 1000 or so the ammeter needle swings back over.

[RICK LAKE]

Hans-Olof Blom Hans if you are smart and careful, you could run a 40 amp system on a cobra and a big battery. Would I want to?? NO way. ERA recommends a 60-70 amp Alt. This is just enough output for the ERA. When you add in opitional front fans, MSD ignition setup, and other things that drain the system you are short on charging at idle. This is with stock pulleys. I run 2 electric fuel pumps with relays, FI ECU, injectors, and the MSD 6AL with HVC coil. Racing the Alt can put out more amps than the car needs. The spikes of each system turning on and off is causing a blip in the car running. The MSD gets a miss. I am waiting for the return e-mail from MSD on the ampage needed for there system. ERA limits the charging ability with a 60 amp gauge. Can you use a 70 amp alt for the system, YES IMO. This is hard on a gauge designed for 60 amp limit. If you look at any car or truck from the last 20+ years NONE of them run amp gauges any more. They all run Volts.?? WHY? Because of the 80-200amp outputs in cars and trucks now. You would melt a amp gauge from the power going through it. Here is something else for you to think about, why does MSD have 2 12 gauge wires going to the msd box and you are to hook pos to the battery direct and ground to the main ground off the battery if possible? for .7 amps The box ecu may draw .7 amps the power end is a min of 5-7 amps plus. The coil is puting out 80-100,000 volts and around 2 -3 amps at the tower. The thing will knock your butt over the car from this power. You will be tasteing the power for the next 3 days. Yes I got zapped twice and it hurts I don't want to change the ERA amp meter to a volt meter but running the more power things in a cobra, this is the only safe way. There is nothing like letting the smoke out of a good wiring harness or gauge.Like siad before if you can idle a cobra for an hour, turn it off and it restarts you have no problems. If it will not start, better look for a jump or a hill to push start. That is if the battery has 10.-10.4 volts to fire the MSD box. I will be running a 100 or 120 amp with the next motor. I am adding air fans, cooler to the trans , cooler to the rearend. Both will need pumps to move the oil. More AMPS needed. Rick L.