I've had a lot of downtime since COVID-19 hit and noticed that my plan calls for a huge electrical load on the system. I've found approximations of amperage draws for the following:

-MR2 electric power steering pump: 30-40 amps typical load, up to 70-90 amps max load.
-Tilton transmission cooler pump: 2-3 amps typical load, 6.6 amps max load.
-In-tank Walbro 255 puller pump: approximately 5.2 amps @ 10 psi fuel pressure.
-Bosch 044s (or similar) pusher pumps x2: 9.73 amps each @ 40 psi fuel pressure, 13 amps each @ 130 psi.
-12" Spal fan (or similar), approximately 1200 cfm: 14.5 amps.
-Ignition amplifier box: 6-20 amps, plus 6 amps per coil.

All in all, this adds up to a lot of electrical load on the system, not even counting the general accessories (lights, ECU, sensors, injectors, etc). How do DSMers and Evo owners typically deal with this? Is it as simple as a big alternator and upgraded wires? What alternator output would work best, and what other tricks do people have?

 

on top of upgrading the alternator, you will also want to do whats known as "the big 3". Which is the ground wire from the frame to the engine, the ground wire from the battery to the frame, and the power wire from the alternator to the battery. If you haven't already, I would look into some of the aftermarket power distribution panels out there, so you end up with something cleaner then a bunch of stuff tied into the positive battery terminal.

 

The battery, fuel pumps and electric power steering will all be in the trunk, so the engine bay wiring won't be cluttered at all. There shouldn't be any grounding issues as long as the trunk setup is well done. For most people who run their surge tank and electric power steering pumps up front, I agree 100% that grounding upgrades and clean distribution are essential.

 

regardless of where you are putting stuff, you still need to upgrade the engine to chassis ground because the alternator grounds to the engine and all the amps need to get from the chassis to the alternator. Wire resistance increases with length so make sure to keep that in mind when you are sizing your alternator/starter to battery cable.

 

Advance Japan offers a 130AMP upgrade alternator and Lamspeed Australia also offer a 130AMP or 150AMP alternator

 

I have an OEM core if you need one for a build. It was going in and out so I replaced it late last year with a new OEM. PM if interested.

 

I also have an OEM core lying around.

Where do you send these for rebuilds?

 

I use the Evo 123/DSM alternator, I'll probably just get one of the eBay specials that reviews well. I'm going to try to use the Equinox/Vue electric steering column instead, which should draw less current and does away with hydraulic fluid. I might go down to one pusher pump too, so it should be okay in the 135 amp range.