I'm installing an EZ-EFI 2.0 on my 1970 Dodge Dart. Trying to figure out if I need to upgrade my alternator. Can anyone tell me the amperage draw of the EZ-EFI 2.0?

I'll guess the ECU itself is in the 5-10 amp range. In addition you will need an electric fuel pump that draws 10-25 amps. Total added draw 20-35 amps.

EFI systems do not like voltage variations. The factory system from 70 already discharged at idle with no added loads. With added load it would be bad. As absolute minimum you need a later factory squareback (78 amps) or something similar or better from Powermaster or Tuff Stuff. It will bolt right in. In addition, you need to bypass the ammeter and bulkhead connector with charge current to handle the higher load.

I ran an XFI system with a higher rated square back and it was marginal at best with big fuel pump. I upgraded to a 105 amp alternator and much better.

Bottom line you need to upgrade from the 70's system for EFI.

What engine? A delco 12si which can be had cheaply at 94A is an easy swap on a small block at least. They charge well at idle.

The picture is from my friend's car. But mine also has a 12si and I have a Megasquirt 3 Pro, 340lph Aeromotive fuel pump, and contour fans and the 78a version is still keeping up well.

For what it's worth. I have an inductive ammeter setup on my MS3 and with the same fuel pump, ECU and fans, I can only pull about 35a once the fans are running. With headlights and the blower on high I hit about 60a. Not a problem for my charging system, though.

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For what it's worth. I have an inductive ammeter setup on my MS3 and with the same fuel pump, ECU and fans, I can only pull about 35a once the fans are running. With headlights and the blower on high I hit about 60a. Not a problem for my charging system, though. [/quote]

Thanks! That's really helpful.

Yeah, This is probably why it can keep up. There isn't an original style mopar alternator that charges anywhere near 40A at idle, I think the SI will do about 50A at idle with my curb speed and pulley ratio.


The 94A is probably a better choice but this one has been on the car for almost 6 years already

Following this one

The 160a Hemi alternator is a tad bit overkill for this car. Maybe I need a winch or something run.

I run a 70amp and I bet thats why my fuel pressure dips at idle

FWIW, the latest issue of Mopar Action has a good article on charging systems, including the bypass, voltmeter, etc. Also points out the need for heavier-gauge wiring to handle increased amperage.

It's not in the Dec 2017 issue?

I'm running a powermaster squareback. I've never had a mopar charge like this. The car was always burning up voltage regulators before. I always blamed the cheap vr. I'm not running a ton of stuff but I have upgraded headlights, ez efi, the in tank pump, stereo, and dash full of auto meter gauges. Before the blinkers would slow down, headlights would dim. All that stuff, now it's nice and stable. I wasn't sure if it was going to be money well spent with it being hard to find good vr, but it seems to be working good.

James what amp alternator are you running?

The Feb 2018 is the current issue.

Box says90 amp / 50amp at idle.

Thanks John and James

I know it is not for everyone but I put a GM CS140 alternator on my car and bypassed the ammeter and that is one of the best mods I have ever done to my car.

I put the cs144 on my jeep. I had another one and made an attempt to put it on the duster, it wasn't looking to good. That was when I decided to just go with the powermaster.

"Current" issue ...I get it LOL

I have the ez EFI on my 72 road runner, I run a late 90's Chrysler alternator, i have no issues.