FJ40 Alternator question (sniper, vintage AC, DUI/HEI, Bluetooth audio) (1 Viewer)

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Ive read a lot of threads to determine the best alternator setup for my build. Will appreciate your input. I’ve got a 77 2F with Sniper EFI, DUI distributor single wire, also adding vintage AC system. ALso have Bluetooth audio system. I’ve been told the factory alternator is not going to be enough amps. However, I don’t want to overdo it And burn up something in the harness or gauges. Can someone with a similar setup let me know what works? Should I go with a later FJ60 alternator with internal regulator? Not sure . Thanks in advance.
 
Pics for your attention to my question. Just love looking at it.

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I'm running the stock 40A (?) alternator with no issue after adding the Sniper, fuel pump, and a Hyperspark CDI. I did flip over to LEDs for all the lights, including headlights, which does help on the draw...but really only at night as far as max-draw goes. I didn't measure it, but the Sniper isn't going to pull a ton of amps for what it's doing, and our low-RPM tractor motors don't pull much on the spark side either.

I don't see why you'd need more amps offhand, especially if you flip to LED headlights...and adding more amps would hit limits on the factory harness at some point if you keep the stock ammeter.

And that is a nice clean chassis!
 
For sure - I was mostly doing the napkin math on usage.
  • The vintage AC shouldn't draw anything more than the heater fan, and you wouldn't run them at the same time (or it shares the fan, not sure...). Either way, likely net 0.
  • The DUI shouldn't draw any more than the coil it replaced, if not more less from being more efficient...so also likely a net 0.
  • Bluetooth audio should be pretty light, no more than the factory-era OEM radio due to improvements, likely a net 0.
  • The Sniper and fuel pump would be net new and constant - looks like a Walbro 392 pulls about 7-8A at 60PSI. Sniper draw would also be fairly based on RPM+injector count (similar to ignition) - would guess under 10A at full tilt (less at cruise) for our rigs, but they don't publish much.
So really it's about adding the Sniper/fuel pump load more than anything else, to me - and I don't think many upgrade output just for that. Curious to see if others have run into anything, though.
 
For sure - I was mostly doing the napkin math on usage.
  • The vintage AC shouldn't draw anything more than the heater fan, and you wouldn't run them at the same time (or it shares the fan, not sure...). Either way, likely net 0.
  • The DUI shouldn't draw any more than the coil it replaced, if not more less from being more efficient...so also likely a net 0.
  • Bluetooth audio should be pretty light, no more than the factory-era OEM radio due to improvements, likely a net 0.
  • The Sniper and fuel pump would be net new and constant - looks like a Walbro 392 pulls about 7-8A at 60PSI. Sniper draw would also be fairly based on RPM+injector count (similar to ignition) - would guess under 10A at full tilt (less at cruise) for our rigs, but they don't publish much.
So really it's about adding the Sniper/fuel pump load more than anything else, to me - and I don't think many upgrade output just for that. Curious to see if others have run into anything, though.
Thanks for the input!
 
With the DUI you already eliminated a few wires. With an internally regulated alternator you would eliminate a few more.
 
I have NOS 💯 % NEW Genuine OEM NipponDenso Alternators, NoT Remanufactured in any way …

- 45A Amps

- 50A Amps

- 60A Amps Cold Climate spec . Units


ALL my NOS units come with all the mounting hardware , new rubber. Boots and a new replacement connector plug

All OEM yazaki japan parts …

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It's all good as long as you don't drive in the rain.

Headlight (all lights turned on, none are LED), windshield wipers and fan (stock, no rear heater fan), along with a DUI ignition all hit about 30 amps together.

I did a quick less conventional rewire on my alternator with a lead going directly to the battery with all power output still using the white / blue wire. The fusible link was replaced with a 30 amp resetting breaker. And, I have blown it with everything turned on.
 

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