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.